Textile testing & quality control

Textile Testing & Quality Control Md.Azmir Latif, M.Engr.(Textile)
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Textile Testing:
The testing of textile products is an expensive business. A laboratory has to be set up and furnished with a range
of test equipment. Trained operatives have to be employed whose salaries have to be paid throughout the year,
not just when results are required. Moreover all these costs are nonproductive and therefore add to the final cost
of the product. Therefore it is important that testing is not undertaken without adding some benefit to the final
product. There are a number of points in the production cycle where testing may be carried out to improve the
product or to prevent sub-standard merchandise progressing further in the cycle.
Reasons for Textile Testing
1. Checking Raw Materials
2. Monitoring Production
3. Assessing the Final Product
4. Investigation of Faulty Material
5. Product Development and Research
Checking Raw Materials
The production cycle as far as testing is concerned starts with the delivery of raw material. If the material is
incorrect or sub-standard then it is impossible to produce the required quality of final product. The textile
industry consists of a number of separate processes such as natural fibre production, man-made fibre extrusion,
wool scouring, yarn spinning, weaving, dyeing and finishing, knitting, garment manufacture and production of
household and technical products. These processes are very often carried out in separate establishments,
therefore what is considered to be a raw material depends on the stage in processing at which the testing takes
place. It can be either the raw fibre for a spinner, the yarn for a weaver or the finished fabric for a garment
maker. The incoming material is checked for the required properties so that unsuitable material can be rejected
or appropriate adjustments made to the production conditions. The standards that the raw material has to meet
must be set at a realistic level. If the standards are set too high then material will be rejected that is good enough
for the end use, and if they are set too low then large amounts of inferior material will go forward into
production.
Monitoring Production
Production monitoring, which involves testing samples taken from the production line, is known as quality
control. Its aim is to maintain, within known tolerances, certain specified properties of the product at the level at
which they have been set. A quality product for these purposes is defined as one whose properties meets or
exceeds the set specifications. Besides the need to carry out the tests correctly, successful monitoring of
production also requires the careful design of appropriate sampling procedures and the use of statistical analysis
to make sense of the results.
Assessing the Final Product
In this process the bulk production is examined before delivery to the customer to see if it meets the
specifications. By its nature this takes place after the material has been produced. It is therefore too late to alter
the production conditions. In some cases selected samples are tested and in other cases all the material is
checked and steps taken to rectify faults. For instance some qualities of fabric are inspected for faulty places

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which are then mended by skilled operatives; this is a normal part of the process and the material would be
dispatched as first quality.
Investigation of Faulty Material
If faulty material is discovered either at final inspection or through a customer complaint it is important that the
cause is isolated. This enables steps to be taken to eliminate faulty production in future and so provide a better
quality product. Investigations of faults can also involve the determination of which party is responsible for
faulty material in the case of a dispute between a supplier and a user, especially where processes such as
finishing have been undertaken by outside companies. Work of this nature is often contracted out to
independent laboratories who are then able to give an unbiased opinion.
Product Development and Research
In the textile industry technology is changing all the time, bringing modified materials or different methods of
production. Before any modified product reaches the market place it is necessary to test the material to check
that the properties have been improved or have not been degraded by faster production methods. In this way an
improved product or a lower-cost product with the same properties can be provided for the customer. A large
organisation will often have a separate department to carry out research and development; otherwise it is part of
the normal duties of the testing department.
Textile Testing & Quality Control (TTQC) is very important work or process in each department of export
oriented industry. Buyers want quality but not quantity. In every department of textile industry quality
maintained of each material, Because one material‘s quality depend on another‘s quality. For example, if
qualified fiber is inputted then output will be good yarn.
Testing : Testing is the process or procedure to determines the quality of a product.
Quality : The term quality refers the excellence of a product. When we say the quality of a product is good .
We mean that the product is good for the purpose for which it has been made.
Control : To check or verify and hence to regulate.
Quality Control: Quality control is the synthetic and regular control of the variable which affect the quality
of a product.
The operational techniques and activities that sustain the quality of a product or service in order to satisfy given
requirements . It consists of quality planning , data collection, data analysis and implementation and is
applicable to all phases of product life cycle ; design, manufacturing, delivery and installation, operation and
maintenance.
Objects of Quality Control:
 To produce required quality product.
 To fulfill the customer's demand.
 To reduce the production cost.
 To reduce wastage.
 To earn maximum profit at minimum cost.

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Objective of Testing
Reasons for Textile Testing:
Checking the quality and suitability of raw material and selection of material.
Monitoring of production i.e. process control.
Assessment of final product, whether the quality is acceptable or not, (how will be the yarn performance in
weaving? etc).
Investigation of faulty materials (analysis of customer complaint, identification of fault in machine etc.).
Product development and research.
Specification testing: Specifications are formed and the materials are tested to prove whether they fall within the
limits allowed in the specification (e.g. specified by a customer).
Test Requirement for Export quality Textile Product

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Standard Operating Procedure(SOP)
6
Supplier submits
samples & TRF
LAB Project Team
receives and
acknowledges receipt
of sample & TRF
Sample preparation
Testing starts
Test Data available
Supervisors
verify results
Prepare Test Report
& invoice
Report issued and
sent to suppliers
10.01.2015 Corporate Presentation

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Major Chemical Test of Textile Product
Formaldehyde
 Volatile compound
 A gas at room temperature with a pungent smell
 Readily soluble in water to form formalin or formol
 Washing might reduce formaldehyde of fabrics
 Release from textile at body temperature
 Formaldehyde exposure can be in the form of gas –phase inhalation or liquid - phase skin absorption
Exposure to high concentration formaldehyde can be fatal; it can cause skin allergy and mucous membrane irritations.
 Long term exposure may cause respiratory difficulty, eczema and sensitization
It is classed as a human carcinogen and has been linked to nasal lung cancer, and with possible links to brain cancer and
leukemia.
Nickel Release
 Asthma and chronic bronchitis
 Allergic reactions such as skin rashes
 Heart disorders

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Hexavalent Chromium (Cr VI)
Chemical element chromium (Cr) exists in three main forms:
1. Chromium metal
2. Trivalent chromium (Cr III)
- health effect: safe
- Cr III sulfate: tanning processes
3. Hexavalent chromium (Cr VI)
- inhalation exposure: lung cancer
- direct skin contact: cause skin irritation
WHO & EPA: Cr VI is human carcinogen WHO EP
Requirement is 3 mg/kg
Phthalates
Phthalates , or phthalate esters, are esters of phthalic acid and are mainly used as plasticizers (substances
added to plastics to increase their flexibility, transparency, durability, and longevity). Phthalates are
manufactured by reacting phthalic anhydride with alcohol(s) that range from methanol and ethanol (C1/C2) up
to tridecyl alcohol (C13), either as a straight chain or with some branching. They are divided into two distinct
groups, with very different applications, toxicological properties, and classification, based on the number of
carbon atoms in their alcohol chain. They are used primarily to soften polyvinyl chloride (PVC). Lower-
molecular-weight phthalates (3-6 carbon atoms in their backbone) are being gradually replaced in many
products in the United States, Canada, and European Union over health concerns. They are replaced by high-
molecular-weight phthalates (those with more than 6 carbons in their backbone, which gives them increased
permanency and durability). In 2010, the market was still dominated by high-phthalate plasticizers; however,
due to legal provisions and growing environmental awareness and perceptions, producers are increasingly
forced to use non-phthalate plasticizers.
Phthalates are used in a wide range of common products, and are easily released into the environment. Although
there is no covalent bond between the phthalates and plastics, they are physically bound into the plastic as a
result of the heating process used to make PVC articles. They can be removed only by exposure to severe heat
or using strong solvents. However, people are exposed to phthalates, and most Americans tested by the Centers

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for Disease Control and Prevention have metabolites of multiple phthalates in their urine. Phthalate exposure
may be through direct use or by indirect means through leaching and general environmental contamination. Diet
is believed to be the main source of di(2-ethylhexyl) phthalate (DEHP) and other phthalates in the general
population. Fatty foods such as milk, butter, and meats are a major source. In studies of rodents exposed to
certain phthalates, high doses have been shown to change hormone levels and cause birth defects.
Application
 As plasticizer in plastics (especially PVC)
 Increase softness and flexibility
 Advantage: flexibility, durability, longevity and low cost
Health effect
 Bio-cumulative
 Endocrine disruptor
 Certain phthalates as well as their metabolites and degradation products can cause adverse effects on human
health, in particular on liver and kidney for DINP and on testicles for DEHP.
Breast cancer
However, women may be at higher risk for potential adverse health effects of phthalates due to increased cosmetic use.
Diethyl phthalate and dibutyl phthalate are especially ubiquitous in cosmetics and personal care products
 Synthetic organic colorants
 In theory, azo dyes can supply a complete rainbow of colours. They have fair to good fastness properties.
 The azo compound class accounts for 60-70% of all dyes.
 These dyes may undergo in vivo reductive cleavage to aromatic amines and some of them are proven or supposed
carcinogenic.
Application
Cotton
Wool
Polyester, Polyamide (Nylon...), Polyacrylonitrile (Synthetic fibres)
Leather
Paper
Foodstuff
Hair
Wood
Technical relevance of Azodyes
More than 3000 different azo colorants (dyes+pigments) are produced.

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Approximately 50 - 150 are banned azodyes. 50-150
- banned amine components
> 50% of the dyes used nowadays are azodyes.
Percent distribution of each chemical class between major application range
Chemical
class
Acid Basic Direct Dispers
e
Mord
ent
Pigme
nt
Reac
tive
Solve
nt
Vat
Unmetalized
Azo
20 5 30 12 12 6 10 5 -
Metal complex
Azo
65 - 10 - - - 12 13 -
Thiazole - 5 95 - - - - - -
Stilbene - - 98 - - - - - 2
Anthraquinone 15 2 - 25 3 4 6 9 36
Indigoid 2 - - - - 17 - - 81
Quinophthalone 30 20 - 40 - - - 10 -
Aminoketone 11 - - 40 8 - 3 8 30
Phthalocyanine 14 4 8 - 4 - 43 15 3
Formazan 70 - - - - - 30 - -
Methine - 71 - 23 - 1 - 5 -
Percent distribution of each chemical class between major application range
Chemical
class
Acid Basi
c
Direct Disperse Mord
ent
Pigm
ent
Reactive Solve
nt
Vat
Nitro,Nitro
so
31 2 - 48 2 5 - 12 -
Triarylmet
hane
35 22 1 1 24 5 - 12 -
Xanthane 33 16 - - 9 2 2 38 -
Acridine - 92 - 4 - - - 4 -
Azine 39 39 - - - 3 - 19 -
Oxazine - 22 17 2 40 9 10 - -
Thiazine - 55 - - 10 - - 10 25

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Percent distribution of chemical classes in Reactive dye hue sectors/%
Chemical
class
Yello
w
Oran
ge
Red Violet Blue Green Brown Black % of all
reactive
dyes
Unmetaliz
ed Azo
97 90 90 63 20 16 57 42 66
Metal
complex
Azo
2 10 9 32 17 5 43 55 15
Anthraquin
one
5 34 37 3 10
Phthalocy
anine
27 42 8
Miscellane
ous
1 1 2 1
Percent distribution of chemical classes in Disperse dye hue sectors/%
10.01.2015 Corporate Presentation24
Chemical
class
Yello
w
Oran
ge
Red Violet Blue Green Brown Black % of all
disperse
dyes
Azo 48 92 73 47 27 30 100 100 59
Anthraquin
one
6 2 25 53 72 65 32
Nitro 16 3 3
Aminoketo
ne
8 2 1 1 5 2
Methine 14 2
Quinophth
alone
4 1
Miscellane
ous
4 1 1 1

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Listed of banned amines
 22 aromatic amines are forbidden in the EU Regulation 1907/2006 Annex XVII and item 43 (limit：30ppm).
These 22 amines are known to be carcinogens or potential carcinogens.
 2 additional aromatic amines (2,4-Xylidine & 2,6-Xylidine) that are forbidden for many retailers such as
Wortmann, Novi, Adidas, Deichmann …
 China also forbids the use of aromatic amines in the national standard GB 18401 with a limit of 20mg/kg.
 Forbidden in EU over 20 years
APEO/NPEO/NP/LABSA/LAS:
Alkylphenol ethoxylates (APEOs – often called
alkyphenols or alkylphenyls) are surfactants which
have an emulsifying and dispersing action, so they
have good wetting, penetration, emulsification,
dispertion, solubilizing and washing characteristics.
This makes them suitable for a very large variety of
applications: they‘ve been used for over 50 years in a
wide variety of products. In the textile industry, they
are used in detergents and as a scouring, coating or waterproofing agents, in printing pastes and adhesives, and
in dyeing. The most important APEO or alkylphenol ethoxylates for the textile industry are NPEO (nonylphenol
ethoxylates) and OPEO (octylphenol ethoxylates) due to their detergent properties, but there are a big family.
About 90% of the produced APEO are in fact NPEO.

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Toxicity
APEOs have long polyethoxylates chains which are highly polar molecules with relatively low toxicity
toward aquatic organisms. NPEs and NP are bad for the environment, bad for wild life also bad for You.
Liner alkyl benzene sulphonic acid(LABSA), Liner alkyl benzene sulphonic(LAS) is an anionic surfactant
widely wsed in the formulation of all kind of synthetic detergent powder, liquids. It is produced through an
indigenously designed reaction system. It is harmful for Health.
PAHs(polycyclic aromatic hydrocardons)
Polycyclic aromatic hydrocarbons (PAHs, also polyaromatic hydrocarbons) are hydrocarbons—organic
compounds containing only carbon and hydrogen—that are composed of multiple aromatic rings (organic rings
in which the electrons are delocalized). Formally, the class is further defined as lacking further branching
substituents off of these ring structures. Polynuclear aromatic hydrocarbons (PNAs) are a subset of PAHs that
have fused aromatic rings, that is, rings that share one or more sides.Though poly- in these cases literally means
"many", there is precedence in nomenclature for beginning this class and subclass with the two ring cases,
where biphenyl and naphthalene would therefore be considered simple examples; beginning at three rings,
examples include anthracene and phenanthrene.
16 EPA PAH(Polycyclic aromatic hydrocarbons)
1. Naphthalene (Nap)
2. Acenaphthylene (AcPy)
3. Acenaphthene (Acp)
4. Fluorene (Flu)
5. Phenanthrene (PA)
6. Anthracene (Ant)
7. Fluoranthene (FL)

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8. Pyrene (Pyr)
9. Chrysene (CHR)
10. Benz(a)anthracene (BaA)
11. Benzo(b)fluoranthene (BbF)
12. Benzo(k)fluoranthene (BkF)
13. Benzo(a)pyrene (BaP)
14. Indeno(1,2,3-cd)pyrene (IND)
15. Dibenzo(a,h)anthracene (DBA)
16. Benzo(g,h,i)perylene (BghiP)
Found for example in tobacco smoke
One reason that tobacco smoke may cause cancer
Naphthalene Nap
 was used in moth balls
 gave moths balls its typical smell
Requirement:

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Major Physical Tests for Textile product:
Dimensional Stability Test
Determination of the dimensional stability (shrinkage or growth) of woven and knit fabrics when subjected to Domestic
washing and drying procedures. - (ISO 5077, ISO 6330 & ISO 3759)
Significance
The test is to confirm that garments will perform to the user’s satisfaction if they are washing according to provided care
instructions. Any distortion like shrinkage or growth out of shape, etc., would affecting the comfort and appearance of
garments.
The specimen is conditioned in standard environment according to ISO 139 (20 ± 2°C, 65 ± 4% relative humidity).
Specimens are marked and measured with calibrated ruler, then washed and dried according to the provided care
instructions. The washed specimen is re-conditioned in standard conditions before measurement of the dimensional
change.
Number of washing cycle: 1 (ISO requirement)
Fabrics: specimen size 500mm x 500mm,
bench mark distance 350mm

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Control of shrinkage:
Origin of shrinkage in fabrics:
Fibers spun into yarn are under constant tension during the weaving process. Such action will impose internal stresses in
the fiber molecules. Without permanent fixing, fibers tend to revert to their natural state, which causes shrinkage.
In general, the factors in controlling shrinkage in fabrics are stability of the fiber and the construction of the fabric.
Construction based on the type of weave, the amount of twist in the yarn, the fabric count, and the yarn count. There are
several ways to control and reduce shrinkage in fabrics.
1. Compressive Shrinkage
2. Resin Treatment
3. stentering
Torque (Spirality)
Spirality is the measurement of twisting of fabrics after washing.
The origin of spirality arises from molecule, yarn and fabric construction.
The specimen is conditioned in standard environment according to ISO 139 (20 ± 2°C, 65 ± 4% relative humidity). A
standard square marking is put on a specimens, then washed and dried according to the provided care instructions. The
washed specimen is re-conditioned in standard conditions before measurement of spirality.
Spirality (Twisting)of Knitted Fabric
It is well known that weft knitted fabrics tend to undergo certain dimensional change that causes distortion in which there
is a tendency of the knitted loops to bend over, causing the Wales to be at diagonal instead of perpendicular to the courses
Angular relationship of course and Wales in a knitted structure
In other words, spirality occurs in knitted fabric because of asymmetric loops which turns in the wales and course of a
fabric into an angular relationship other than 90 degree. This is a very common problem in single jersey knits and it may
exist in grey, washed or finished state and has an obvious influence on both the aesthetic and functional performance of

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knitwear. However, it does not appear in interlock and rib knits because the wale on the face is counter balanced by a
wale on the back.
Course spirality is a very common inherent problem in plain knitted fabrics. Some of the practical problems arising out of
the loop spirality in knitted garments are: displacement or shifting of seams, mismatched patterns and sewing difficulties.
These problems are often corrected by finishing steps such as setting / treatment with resins, heat and steam, so that wale
lines are perpendicular to the course lines. Such setting is often not stable, and after repeated washing cycles, skewing of
the wales normally re-occurs.
Causes of generation (spirality ):
The residual torque in the component yarn caused due to bending and twisting is the most important phenomenon
contributing to spirality. The residual torque is shown by its twist liveliness. Hence the greater the twist liveliness, the
greater is the spirality. Twist liveliness of yarn is affected by the twist factor or twist multiple. Besides the torque, spirality
is also governed by fibre parameters, cross-section, yarn formation system, yarn geometry, knit structure and fabric
finishing. Machine parameters do contribute to spirality. For instance, with multi-feeder circular knitting machines, course
inclination will be more, thus exhibit spirality.
Besides marking method, measurement of the spirality in garment samples can be based on side seam twisting. Such
measurement will include not only the fabric torque but also the effect from garment structure.
Ways to reduce Spirality :
 Relaxation Finishing - This allows the individual loop structure to distort to relieve the internal stress.
 Heat Setting - for thermoplastic man made fabrics. The fabrics temperature is raised almost to the glass
transition temperature†
of the fibers in order to relieve the internal stress.
 Resination - Stabilization of the fabric through application of resin. Hand will be impaired, however
softener can improve such adverse effect.
†
Glass transition temperature is the temperature of transition between rubbery stage and glassy stage.
Appearance:
Evaluation of appearance of a product (distortion, pilling, hand feel, trim compatibility) after washing according to the
provided care instructions.

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Specimens are visually evaluated before and after washing according to the provided care instructions. Any visual
defects, such as rippling, puckering, trims damage, color loss, print loss, fabric rupture, differential shrinkage, etc., will be
reported.
Strength:
Breaking strength
The maximum tensile force recorded in extending a test piece to breaking point is called breaking strength or
tensile strength of a material.
In other word the resistance of a yarn or fabric to tensile biding is called tensile or breaking strength.
Tearing strength
The avgas force required to continue a tear previously started in a fabric is called the tensile strength.
In other word tearing strength (force) is the resistance showed by fabric against tearing.
Bursting strength
Busting is the resistance of a material to rupture when subjected to a pressure acting perpendicular to the plain
of the fabric. The load is carried by both warp & waft thread.
In tearing or breaking strength, the strength of fabric was tested by applied load is only one direction, But in
case of bursting strength the direction resistance to rupture of a circular specimen in determined.
Tensile Strength:
Determination of breaking force and elongation of textile fabrics. - (ISO 13934-2)
Significance
It indicates the potential strength of woven fabric within a product in resistance to tension.
This test method is not recommended for knitted fabrics and other textile fabrics which have high stretchability (more
than 11%).
The fabric is conditioned in a standard environment of 20 ± 2°C and 65 ± 4% relative humidity for at least 24 hours. The
fabric is cut into specific specimen sizes 200mm x 100mm. Both warpwise and weftwise directions are required. Test
specimens are mounted on a tensile tester along the long dimension and subjected to a constant rate of extension. The
loading force at point of rupture or break is recorded as tensile strength.

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General Note:
 Coarser yarn size gives a greater tensile strength
 High twist yarn gives a greater tensile strength
 Higher fabric count gives a greater tensile strength
 Different fiber possess different tensile properties
Tearing Strength:
Determination of the average force required to continue a tear from a slit in a woven fabric by means of falling
pendulum (Elmendorf) apparatus. - (ISO 13937-1)
Significance
It indicates the potential strength of woven fabric within a product in resistance to tearing action.
The method is applicable to treated and untreated woven fabrics, including those heavily sized, coated or resin-
treated. The test is not suitable for knit fabrics, felts or non-woven fabrics.
The fabric is conditioned in a standard environment of 20 ± 2°C and 65 ± 4% relative humidity for at least 4
hours. Specimens, for both warpwsie and weftwise, of specific shape are die-cut from the sample fabric. The
specimens are mounted between two clamps, precut by a knife then torn through a fixed distance by the
swinging pendulum to generate the average tearing force in pounds for both the warp and weft directions.

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Sample size for Pendulum tear
Important Note:
 Coarser yarn size gives greater tearing strength
 Looser sett gives better tearing strength
 Different surface finishes on the fabric will affecting the tearing properties
Bursting Strength
Determination of bursting strength of textile fabrics using hydraulic method. - (ISO 13938-1)
Significance
It indicates the potential strength of the knitted fabric within a product.
The fabric is conditioned in a standard environment of 20 ± 2°C and 65 ± 4% relative humidity according to
ISO 139. Test specimen is clamped over an expandable diaphragm. The diaphragm is expanded by fluid
pressure to the point of specimen rupture.
The test method is generally applicable to a wide variety of knitted goods and non-woven fabrics. It is not
recommended for general use on uncoated woven fabrics.
Bursting Strength = Total Pressure - Tare Pressure of the Specimen

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Important Note:
 Coarser yarn size gives greater bursting strength
 Higher stitch density gives higher bursting strength
 Different surface finishes on the fabric will affecting the bursting properties
Seam Slippage
Determination of the yarn slippage resistance at sewn seams in woven fabric under loading. - (ISO 13936-1 & ISO
13936-2)
Significance
It determines the tendency of the yarns to slip out of the seam and whether they would be readily repairable by re-
seaming.
Seam slippage is the separation of seam due to slippage of filling yarns over warp yarns or warp yarns over filling yarns.
In such slippage, the stitching thread is remain unbroken.

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Fabric Sample
A test specimen of 400mm x 100mm with long direction parallel to the filling yarns is cut from sample fabric, if the warp
yarns slide over the filling yarns is tested or vice versa.
The load-elongation curve of the fabric is superimposed over a load-elongation curve of the same fabric with seam sewn
being tested. Resistance to yarn slippage is reported as the load at which slippage of a specific size is seen.
This test is not intended for upholstery fabrics.

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The fabric alignment of adjacent patch of a seam may not be the same in a garment seam. Direct measurement of seam
slippage on garment seam provide a more accurate result.
Remedies for preventing seam slippage:
1. Superimposed seam type
2. Lapped seam type with tape / interlining reinforcement
3. Anti-slip finish (resin treatment)
Colour fastness
The stability of color or it fastness is one of the most important requirement of valuable customers. Color
fastness is the resistance of the color to fade or breed by these agencies. These changes occur because of
decomposition of the molecules in the fiber or because of their removal into the external medium.
Colour fastness to domestic and commercial laundering

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This test is designed to evaluate the colorfastness properties of textiles which are intended to be laundered frequently. The
fabric color loss, bleeding, and surface changes resulting from the detergent and abrasion are simulated by a 30 min.
Launder-o-meter test which approximates the action of either five typical hand washings, home launderings, or
commercial launderings, with or without bleach. Along the width the specimen (100mm x 40mm), a DW multifiber
(Acetate, Cotton, Polyamide, Polyester, Acrylic ,Wool )swatch is attached. Then they are placed in a metal jar containing
a specified number of steel balls to provide friction and abrasion. After the specimen are processed, it is removed from
the metal jar and dried. The color change and color staining are evaluated against the corresponding ISO Grey Scales.
The purpose of this test is to insure that textile products do not have excessive color loss and/or bleeding after several
times of laundering.
Relation with Care Instruction:
 Washing temperature: Warm or Cold
 Machine Wash or Hand Wash
 Warning such as Wash With Like Color, etc.
Colorfastness to Rubbing
These tests are designed to evaluate the degree of color which may be transferred from the surface of colored textile
materials to others surfaces by a rubbing action. The specimen is conditioned in a standard textile testing atmosphere of
20 ± 2°C and 65 ± 2% relative humidity for a minimum of 4 hours. The test specimen is rubbed against white crock test
cloth either at dry or wet with water under controlled conditions. Any color transfer on the white crock test cloth is
evaluated against the Gray Scale for Staining.
The purpose of this test is to insure that textile products do not excessively transfer of dye or print onto other surfaces
such as upholstery, carpeting and other wearing apparel through rubbing action.

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Colorfastness to Perspiration
This test is designed to evaluate the colorfastness property of textiles to the effects of perspiration. A specimen of colored
textile and multifiber test fabric is wet out in a simulated perspiration solution, subject to a fixed mechanical pressure and
allowed to dry slowly at a slightly elevated temperature. The change in color of the specimen and staining of the attached
multifiber test fabric is evaluated against the Gray Scale for Color Change and Staining.
The purpose of this test is to insure that colored textiles do not excessively stain clothing or change color under the action
of perspiration. This will be particularly important in underwear.

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Colorfastness to Light
This test is designed to evaluate the colorfastness property of textiles when subjected to light. A test specimen is exposed
to a specific amount of radiant energy (light). The color different of the exposed region of the specimen is compared to the
unexposed region and is evaluated against the ISO Gray Scale for Color Change.
The purpose of this test is to insure that textile products do not have excess color fading under store lighting and in direct
sunlight.
ISO 105 B02 (method 2)
Light source Xenon arc lamp
Black panel temperature 48 ± 2°C
Relative humidity 40 ± 5%
Irradiance (at 420 nm) 1.10 ± 0.03 W/m2
/nm
Irradiance (at 300 - 400 nm) 42 W/m2
Colorfastness to Saliva (DIN 53160)

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This test is designed to evaluate the colorfastness of textiles under the action of salvia. A piece of filter paper saturated
with artificial salvia solution is in contact with the sample fabric. The specimen is then placed over water in a covered jar.
The jar is keep at 37 ± 2°C for 2 hr.
If no trace of coloring can be detected on the filter paper, the sample is quoted as ―Resistant to Saliva‖ otherwise ―Not
Resistant to Saliva‖.
The purpose of this test is to insure that textile products do not have colorant transfer to the infant’s or baby’s mouth and
mucous membranes under the action of saliva.
Flammability
Burning behavior of different fiber
Cotton/Linen: Burns with a hot, vigorous flame, light colored smoke, and leaves red glowing ember after Flaming stops. Does not
melt or draw away from
Rayon/ Lyocell: Burns similarly to cotton and linen, except that it May shrink up and become tighter to the body.
Acetate :Burns with a rapid flame and melts when burning. May melt and pull away from small flames withoutIgniting. Melted area
may drip off the clothing carrying flames with it. When flames have died out, the residue is a hot, molten plastic and is difficult to
remove from any surface.
Nylon, Lastol, Olefin, Polyester, and Spandex: Burns slowly and melts when burning. May melt and pull away from small flames
without igniting. Melted area may drip off clothing carrying flames with it but not to the extent of acetate and acrylic. Residue is
molten and hot and difficult to remove. May self-extinguish.
Wool and Silk: Burns slowly and is difficult to ignite (especially in winter garments). It
May be self-extinguish.
Acrylic: a very heavy, dense, black smoke. It drips excessively.
Modacrylic and saran: Burns very slowly with melting. May melt and pull away from
small flames without igniting. It is Self-extinguishes.
Aramid, Novoloid and Vinyon: Chars, does not burn.
Flame propagation is discussed as a continuing ignition process. Only those
aspects of the flame propagation phenomenon, both in fabric strips and in
garments that are accessible through an experimental approach are dealt with.
Flammability Testing
Test Method(s):
· 16 CFR 1610
· ASTM D6413

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· NFPA 701
· 191A Method 5903
Flammability of Wearing Apparel - 16 CFR 1610
(45 Degree Flammability)
The United States Federal Government requires clothing and textiles intended to be used for clothing to have
Normal Flammability (Class 1) as tested with 16 CFR 1610 (ASTM D 1230 Standard Test Method for
Flammability of Apparel Textiles). Fabric is mounted at a 45° angle from ignition source.
Some exemptions apply:
 Certain Hats
 Gloves
 Footwear
 Interlining fabric
 Plain surface fabrics, regardless of fiber content, weighing 2.6 oz/yd2 or
more (when using ASTM D 3776 to determine the fabric weight)
 Fabric made entirely with these fibers, or blends of these fibers:
o acrylic
o nylon
o polyester
o modacrylic
o olefin
o wool
Vertical Flammability
Fabric is mounted vertically with ignition directly under fabric.
Test Methods performed:
 ASTM D6413 - Standard Test Method for Flame Resistance of Textiles (Vertical Test)
 NFPA 701 - Standard Methods of Fire Tests for Flame Propagation of Textiles and Films
 Federal Test Method Standard No 191A Method 5903 - Flame
Resistance of Cloth; Vertical
Flammability Exemption for 16 CFR 1610 by Fabric Weight
Plain surface fabrics, regardless of fiber content, weighing 2.6 oz/yd2 or more
(when using ASTM D 3776 to determine the fabric weight)Fabric is cut out,
weighed, and oz/yd2 is calculated

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Fiber Identification and Analysis
Fiber Identification - Most countries importing apparel and soft home furnishing products require fiber
identification labels indicating the fiber type and percentage of fiber components. Some countries even use fiber
composition to classify quota categories. Fiber analysis is a method of identifying and examining fibers used
by law enforcement agencies around the world to procure evidence during an investigation.
The most common use of fiber analysis is microscopic examination of both longitudinal and cross sectional
samples. While this is the most common method of undertaking fiber analysis, others do exist. These include
the burning and solubility methods. These methods are most commonly used to reveal the identity of the fiber.
Fiber analysis is usually not undertaken in university labs because of the usual lack of required solvents.
It may be Qualitative or Quantitative analysis
A number of methods are available for characterization of the structural, physical, and chemical properties of fibers.
Various methods are used for fiber identification like microscopic methods, solubility, heating and burning method,
density and staining etc. End-use property characterization methods often involve use of laboratory techniques which are
adapted to simulate actual conditions of average wear on the textile or that can predict performance in end-use.
Ty p e s o f t e s t
 The Non-technical Test
• FEELING TEST
• BURNING TEST
 The Technical Test
• MICROSCOPIC TEST
• CHEMICAL TEST
Te s t s f o r i d e n t i f i c a t i o n
 Handle/Feel Test
 Visual Examination
 Burning test
 Twist on Drying
 Floatation Test
 Microscopic analysis
 Chemical Analysis
R e q u i r e m e n t s f o r t e s t s
 Preparation of test specimen Apparatus for microscopic examination Reagents used for chemical tests Other tools
and equipment

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T h e n o n - t e c h n i c a l t e s t s
 Feeling test
 Burning test
F e e l i n g t e s t
 The feeling test requires perception if it is to be of any value.
 Skilled perception is acquired only after handling many different fabrics over a period of time.
 Limitations of this test become apparent when examining and comparing fabrics of different fiber
B u r n i n g t e s t
 To recognize the composition of fabrics by the burning test ,the sample of fiber, yarn of fabric should be moved
slowly towards a small flame and the reaction to heat carefully observed .One end of the sample should be put
directly into flame to determine its burning rate and characteristics. The burning odour should be noted and the
characteristics of the ash such as amount ,form, hardness and color should be examined
I d e n t i f i c a t i o n o f f i b e r s t h r o u g h b u r n i n g t e s t
 Cotton :
• When ignited it burns with a steady flame and smells like burning leaves. The ash lefties easily
crumbled. Small samples of burning cotton can be blown out as you would a candle.
 Linen:
• Linen takes longer to ignite. The fabric closest to the ash is very brittle. Linen is easily
extinguished by blowing on it as you would a candle.
 Silk:
• It is a protein fiber and usually burns readily, not necessarily with a steady flame, and smells like burning
hair. The ash is easily crumbled. Silk samples are not as easily extinguished as cotton or linen.

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 Wool
• It is also a protein fiber but is harder to ignite than silk as the individual "hair" fibers are shorter than silk
and the weave of the fabrics is generally looser than with silk. The flame is steady but more difficult to
keep burning. The smell of burning wool is like burning hair.
M a n M a d e F i b e r s
 Acetate:
• Acetate burns readily with a flickering flame that cannot be easily extinguished. The burning cellulose
drips and leaves a hard ash. The smell is similar to burning wood chips.
 Acrylic:
• Acrylics burn readily due to the fiber content and the lofty, air filled pockets. A match dropped on an
acrylic blanket can ignite the fabric which will burn rapidly unless extinguished. The ash is hard. The
smell is acrid or harsh
 Nylon:
• Nylon melts and then burns rapidly if the flame remains on the melted fiber. If i can keep the flame on the
melting nylon, it smells like burning plastic.
 Polyester:
• Polyester melts and burns at the same time, the melting, burning ash can bond quickly to any surface it
drips on including skin. The smoke from polyester is black with a sweetish smell. The extinguished ash is
hard.
•

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 Rayon:
• It is a regenerated cellulose fiber which is almost pure cellulose. Rayon burns rapidly and leaves only a
slight ash. The burning smell is close to burning leaves

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F I B E R B U R N T E S T

Page | 32
L i m i t a t i o n o f b u r n i n g t e s t
 It is apparent that many fibers have similar burning reactions that might cause doubt and occasional confusion.
Te c h n i c a l Te s t s
 There are certain technical tests performed for identifying various fibers. These tests require high technology
laboratory equipment and are much more reliable than the non technical fiber tests.
 Technical tests require high skilled personnel and technical know how of handling chemicals and their accurate
analysis. These tests are very valuable for those fabrics that are a blend of different yarns and also have certain
special properties including flame retardanceetc.
Ty p e s o f Te c h n i c a l Te s t
 Microscopic test
 Chemical test
M i c r o s c o p i c Te s t
 Microscopic test is a technical test that involves identifying the fabric with the help of a microscope with a
magnification of minimum 100 power.
 The test can easily distinguish between fibers.
 The test identifies the natural fibers more easily as compared to man made ones.
 Synthetic fibers are very similar in appearance and the increase in the number of varieties, makes it a little tough
to distinguish the fibers even under a microscope
M i c r o s c o p i c Te s t f o r N a t u r a l f i b e r s
 COTTON:
• It is a single elongated cell. Under the microscope, it resembles a collapsed, spirally twisted tube
with a rough surface.
• The thin cell wall of the fiber has from 200 to 400convolutions per inch.
 LINEN:
• Under the microscope, the hair like flax fiber shows several sided cylindrical filaments with fine
pointed ends.
• The fiber somewhat resembles a straight, smooth.

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 WOOL:
• Under the microscope , wool‘s cross section shows three layers- epidermis, cortex and the
medulla.
 SILK:
• It appears somewhat elliptical and triangular in cross section when we see under the microscope.
• It is composed of fibroin, consisting of two filaments, called brin which is held together by
sericin.
M i c r o s c o p i c t e s t f o r m a n m a d e f i b e r s
 RAYONS:
• Rayon fibers have a glasslike luster under the microscope and appear
to have a uniform diameter when viewed longitudinally.
 ACETATE:
• The cross sectional view has a bulbous or multi global appearance
with indentations.
These indentations appear as occasional markings
 NYLON:
• The basic microscopic appearance is generally fine ,round, smooth, and translucent.
• It is also produced in multilobal cross-sectional types.
 POLYESTERS:
• Generally, polyester fibers are smooth and straight and the cross-section is round.

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• This general characteristics may be altered to achieve certain characteristics.
 ACRYLICS: The methods of manufacturing of the acrylic fibers differ, the appearances vary accordingly.
 ACRILAN ACRYLIC: It has a bean-shaped cross section, its longitudinal appearance is straight and
smooth.
 ORLON ACRYLIC: It has a flat, nut-shaped cross section.
 CRESLAN ACRYLIC: It has an almost round cross section.
 MOD ACRYLICS: it is of two typesverel mod acrylic and SEF mod acrylic.
 SPANDEX: Spandex fibers are unique in appearance, they appear to be groups of fibers fused together.
 GLASS: The fiber is smooth, round, translucent, highly lustrous, and quite flexible.
 Asbestos fiber: This method is for the analysis of asbestos in air by Phase Contrast Microscopy. Results are
reported as fibers per cubic centimeter and depend on the volume of air sampled. PCM analysis is not asbestos
fiber specific and will count all fibers meeting the methods criteria for fiber determination.
C h e m i c a l Te s t s
 Chemical tests are another technical means of identifying fibers. But chemical tests are not intended for the
general consumers.
 Different types of chemical tests are under taken to establish the identity of the fibers used.
 These tests give accurate and precise analysis.
 The tests are conducted in research laboratories.
Ty p e s o f C h e m i c a l Te s t
 Stain Test:
• Also known as the Double Barrel Fiber Identification (DBFI), the test is based on the theory that
each fiber has its own distinct two- color reaction when treated with stain. A fiber will turn to a
particular color in the presence of dilute acetic acid and to some other specific color when stained
in the presence of a mild alkali.
 Solvent Test:
• The test involves treating the fibers in certain solvents for identifying them. The
technical test is becoming difficult to conduct as most of the manufactured fibers and
their blends are chemically similar. There is no individual chemical or solvent test for
separating or identifying the fibers in combinations.
 Distinguishing animal from vegetable fibers with an acid :

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 As strong alkali destroy animal substances, a 5%of soda lye solution in water can
be used to eliminate wool and silk fibers from a sample that contains a mixture of
fiber. The vegetable fibers will not be affected by this solution.
 Distinguishing vegetable from animal fibers with an acid
 As dilute acid destroy vegetable fibers, a 2%sulphuric acid solution can be used.
A drop of solution is placed on the sample, which is then pressed with a hot iron.
The spotted area will become charred if the sample is cotton linen or rayon.
 Distinguishing silk from wool:
• The use of concentrated cold hydrochloric acid will dissolve the silk and the wool fiber
swells.
 Distinguishing nylon from other fibres:
• If the fabric is thought to contain nylon, the fabric may be immersed in a boiling solution
of sodium hydroxide. The nylon is insoluble in such a solution
 Distinguishing polyesters from other fibres:
• Polyester is soluble in hot meta cresol; however ,unlike acetate it is not soluble in
acetone, and unlike nylon it is not soluble in concentrated formic acid.
 Distinguishing acrylics from other fibres:
• Acrylic fibers will dissolve in 70 percent solution of ammonium thiocyanate at 130
degree Celsius but the other fibers will not.
 Distinguishing Linen From Cotton
• Cotton and linen are immersed in a 1% solution of fuchsine in alcohol to give red rose
color. Later ,they are washed and immersed into ammonia, linen retains the red coloration
but cotton does not.
 Distinguishing glass fibers from other fibres:
• There are two specific solvents for quick identification of glass fibers, they are
hydrofluoric acid and hot phosphoric acid.
 Advantages:
•More reliable than the non technical tests.
•Used for both man made fibers and natural fibers.

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•Easily conducted.
 Limitations
•Certain manufacturing and finishing processes like mercerizing, affects the appearance of the
fibers under the microscope.
•Very dark colored fabrics cannot be identified under microscope.
•Dye stuffs must be removed from fabrics.
Advanced Fiber Testing Machine:
Scanning electron microscope (SEM)
Wide-angle X-ray scattering (WAXS) or wide-angle X-ray diffraction (WAXD)
Small-angle X-ray scattering(SAXS/SAXD)
Atomic force microscopy (AFM)
Scanning force microscopy (SFM)
Fourier Transform Infrared (FTIR) Spectroscopy: When infar- red radiation, composed of electromagnetic
waves with wavelengths between 1 and 15 µm, is passed through a material. It is most highly absorbed at
certain characteristic frequencies. By using an infar-red spectrometer, the variation in absorption can be found
and plotter against wavelength, or, more commonly, its reciprocal, the wave-number.

Page | 37
Infrared spectrometer
Infrared spectrometer used for analyzing polymer consist of (i) a source of radiation with a continuous
spectrum over a wide range of infrared wavelengths (ii) a means of dispersing the radiation into its
constituent wavelengths, (iii) an arrangement for allowing the radiation to pass through the sample or
to be reflected from its surface,(iv) a means of measuring intensities using a detector that responds over
the whole range of wavelengths of interest, and (v) a method of displaying, and possible performing
calculation on, the spectrum.
There are two distinct types of infrared spectrometer that record the spectrum by passing a beam of
infrared light through the sample. They are (i) dispersive IR instruments and (ii) Fourier-transform (FT)
IR (a mathematical algorithm, named after Joseph Fourier) instruments.
In dispersive IR instruments, the radiation is physically split its constituent wavelengths by a
monochromator, its passes through the sample, where upon the various wavelengths are processed in
sequence i.e. in this system; the wavelength is changed over time.
In FT-IR instrument radiation of all wavelengths passes through the sample to the detector
simultaneously i.e.it measures all wavelengths at once. A FTIR spectrometer simultaneously collects
spectral data in a wide spectral range. This confers a significant advantage over a dispersive
spectrometer which measures intensity over a narrow range of wavelengths at a time. Moreover, with
the advances in computer technology, the signal/noise ratio (S/N) in system has become quiet improve.
Hence FTIR technique has made dispersive infrared spectrometers all but obsolete and opened up new
applications of infrared spectroscopy.
In FTIR, a detector measures the total transmitted intensity as a function of the displacement of the
mirrors in a double – beam interferometer, usually of the Michelson type, and the separation of the
various wavelengths is subsequently done mathematically by performing a Fourier transform on the
intensity versus displacement data, using a dedicated computer.
The Michelson interferometer* is the most common configuration for optical interferometry, invented
by Albert Abraham Michelson. An interference ** pattern is produced by splitting a beam of light into
two paths, bouncing the beams back and recombining them. The different paths may be of different
lengths or be composed of different materials to created alternating interference fringes on a back
detector.
Working principle of Michelson interferometer
For mid –IR *** operation ,radiation of incoming light ( usually from a Nerst glower)is directed as a
collimated beams on 45 degrees incidence to a beam splitter (semi-transparent mirror usually a coated
KBr disc).approximately one half of the beam is reflected at the beam splitter and travels to the fixed
mirror. The other half is transmitted to the moving mirror .after reflection the two beams will recombine
at the beam splitter ,where on average one half of the energy will be transmitted back to the source while
the other half will be transmitted to the specimen, and so to detector.

Page | 38
*Interferometry is the technique of the diagnosing the properties o two or more waves by studying the
pattern of interference created by their superposition. The instrument used to interfere the waves
together is called an interferometer.
** In physics, interference is the addition (superposition) of two or more waves those results in a new
wave pattern. Interference usually refers to the interaction of waves that are correlated or coherent with
each other, either because they from the same source or because they have the same or nearly the same
frequency.
*** Near-infrared (NIR): 0.75- 1.4 ηm, Mid – infrared (MIR):3 8 ηm and Far –infrared (FIR) 15-1000
ηm
There are two paths from the (light) source to the detector. If these two paths differ by a whole number
(including 0) of wavelengths there is constructive interference and a strong signal at the detector. If they
differ by a whole number and a half wavelength (e.g 0.5, 1.5, 2.5) there is destructive interference and a
weak signal.
From IR a transmittance absorbance spectrum can be produced, showing at which IR wavelengths‘ the
sample absorbs. Analysis of these absorption characteristics reveals details about the molecular structure
of the sample. Where the frequency of the IR is the same as the vibrational frequency of a bond,
absorption occurs.
In spectroscopy, transmittance is the fraction of incident light at a specified wavelength that passes
through a sample. A related team is absorbance, or absorption factor, which is the fraction of light
absorbed by a sample at a specified wavelength, in equation from,
Tƛ= I/ Iₒ and Aƛ= Iₒ-I/ Iₒ
Where Iₒ is the intensity of the incident light and / is the intensity of the light coming out of the sample
and Tƛ and Aƛ are transmittance and absorbance respectively. In these equations, scattering and
reflection are considered to be close to zero .the transmittance of a sample is sometimes given as a
percentage.
Sampling techniques in FTIR spectroscopy
There are two sampling techniques in FTIR spectroscopy, namely (i) transmission and (ii) ATR (Attenuated total
reflectance)in transmission- IR, IR beam is directly passed through the sample, preferably thin film or membrane of 3 to
4 ηm thickness or powder form ,and the spectra is recorded in the detector set next to sample holder.
ATR is a sampling technique used in conjunction with infrared spectroscopy which enables samples to be
examined directly in the solid, liquid or gas state without further preparation. In this technique a beam of
infrared light is passed the ATR crystal in such a way that it reflects at least a once off the internal surface in
contact with the sample .this reflection extends into sample. The penetration depth into the sample is typically
between 0.5 and 2 micrometers, with the exact value being determined by the wavelength of light, the angle of
incidence and the indices of refraction for the ATI crystal and the medium being probed. The number of

Page | 39
reflections may be varied by varying the angle of incidence. The beam is than collected by a detector as it exits
the crystal. most modern infrared spectrometers can be converted to characterize samples via ARI by mounting
the ARI accessory in the spectrometer‘s sample compartment. The accessibility of ATR – FTIR has led to
substantial use by the scientific community. Typical materials for ATR crystals include germanium, KRS – 5
(thallium (1) mixed halides) and zinc selenide. The excellent mechanical properties of diamond make it an ideal
material for ATR, particularly when studying very hard solids.
One advantage of ATR – IR over transmission – IR is the limited path length into the sample. This avoids the
problem of strong attenuation of the IR signal in highly absorbing media, such as aqueous solutions. Since ATR
technique reflects IR mainly from the surface of the sample, hence the sample having differential sheath/core
structure cannot be observed. Transmission method provides reflection from the whole width of the sample;
hence it is suitable to obtain reliable information of the sample as a whole. But this transmission technique is
restricted for the thin film.
Group frequencies
In the spectroscopy, the oscillating electromagnetic radiation interacts with the oscillating molecular dipole to
transfer energy when the frequency of the radiation matches the resonant frequencies of the assembly balls and
springs (as stated before).for a diatomic molecule traced as a harmonic oscillator, the resonant frequency is:
𝑣 =
1
2𝜋
𝑘/𝜇
Where K is the force constant and is the reduced mass. As an example, the reduced mass of the CH moiety is
1.53x 10ˉ 27KG and so if the force constant of the CH bond is 463 N/m, then the resonant frequency is 8.75x10
ͤ13Hz, corresponding to 2919 cmˉ1. Force constants of the double bonds typically are about 1100 N/m and triple
bonds 1600 N/m.
The simplest characteristics group frequencies approximate to those of pseudo – diatomic molecules, i.e.
vibrations in which two parts of the molecule act as point masses (table 4.2). It may appear surprising at first
sight that the frequency of X – H stretching should be relatively independent of the nature of X, but this is a
direct consequence of the nature of the above equation. The reduced mass is determined largely by the lighter
atom. For instance, the C-H moiety has a reduced mass of about 1.53x10ˉ 27 Kg while the reduced mass of the
(C100 H201 )-H moiety is about 1.66x10ˉ 27 kg, which, if the force constants are the same, results is only a 4%
difference in characteristic vibration frequency after substitution in the above equation. The magnitude of the
force constant has a greater effect on the observed frequency, and this is why the O – H stretching frequency is
generally higher than the N – H stretching frequency, despite the greater mass.
Reduced mass is the ‗effective‘ inertial mass appearing in the two body problem of Newtonian mechanics. This
is a quantity with the unit of mass, which allows the two-body problem to be solved as if it were a one-body
problem. Note however that the mass determining the gravitational force is not reduced. In the computation, one
mass can be replaced by the reduced mass, if this is compensated by replacing the other mass by the sun of both
masses.

Page | 40
Given two bodies, one with mass m and the other with mass m they will orbit the barycenter of the two bodies.
The equivalent one – body problem, with the position of one body with respect to the other as the unknown‘s
that of a single body of mass, m = =m m where the force on this mass is given by the gravitational force
between the two bodies. The reduced mass is always than or equal to the mass of each body and is half of the
harmonic mean of the two masses.
A molecule can vibrate in many vibrational modes. Linear molecules (where all the atoms are in a straight line
in space, e.g. carbon dioxide) have 3N – 5 degrees of vibrational modes whereas nonlinear molecules have 3N –
6 degrees of vibrational modes (also called vibrational degrees of freedom). As an example CO a linear
molecule will have 3x3 – 5=4 degrees of vibrational freedom, or modes. Likewise, this simple approach gives
the maximum number of fundamental vibrations expected but some of these vibrations may be degenerate, i.e.
have the same frequency, or be IR or Raman inactive.
Simple diatomic molecules have only one bond and only one vibrational bond. If the molecule is symmetrical,
e.g. N the band is not observed in the IR spectrum, but only in the Raman spectrum. Unsymmetrical diatomic
molecules, e.g.CO, absorb in the IR spectrum. More complex molecules have many bonds, and their vibrational
spectra are correspondingly more complex, i.e. big molecules have many peaks in their IR spectra.
The vibrational frequency of a bond is expected (i) to increase with increase in bond strength and (ii) decrease
with increase in mass (reduced mass). For example, the stretching frequency increased in the order of C-C
(triple bonds are stronger than double and single bonds).with regard to mass, the vibrational frequency
decreases in the order H-F .it should be kept in mind that the molecules vibrate as a whole and to consider
separately the vibrations of parts of the molecules (groups of atoms) is a simplification of the true situation.
Another commonly occurring class of function group is the symmetrical triatomic moiety, such as CH2, NH2,
and CO2etc. By analogy with the CO2 molecule the stretching modes will split into a symmetric and an
antisymmetric stretch, with the antisymmetric stretch occurring at the higher frequency. Show these and other
characteristics vibrations of the methylene functionality, known by their descriptive names of scissor, wag, twist
and rock, with typical values of their observed frequencies in hydrocarbon molecules.
IR spectroscopy works almost exclusively on samples with covalent bonds. Sample spectra are obtained from
samples with few IR active bonds and high levels of purity. More complex molecular structures lead to more
complex spectra. The technique has been used for the characterization of very complex mixtures.
The infrared or Raman spectrum of any given substance is interpreted by the use of these known group
frequencies and thus it is possible to characterize the substance as one containing a given type of group or
groups. Although group frequencies occur within narrow. Limits, interference or perturbation may cause a shift
of the characteristic bonds due to (i) the electro – negativity of neighboring groups or atoms, or (ii) the spatial
geometry of the molecule.

Page | 41
Functional groups sometimes have more than one characteristic absorption band associated with them. Two or
more functional groups often absorb in the same region and can usually only be distinguished from each other
by means of other characteristics infrared bands which occur in non- overlapping regions.
Absorption bands may be regarded as having two origins, these being the fundamental vibrations of (i)
functional groups, e.g. C=O,C=C, C=N, - CH2 -, -CH3 and (ii)skeletat groups, i,e the molecular backbone or
skeleton of the molecule, e.g. C-C-C-C. Absorption bands may also be regarded as arising from (i) stretching
vibrations, i.e. .vibrations involving bond-angle changes of group. Each of these may, in some cases, be
regarded as arising from symmetric or asymmetric vibrations as illustrated before for the vibrational modes of
the methylene group. Any atom joined to two other atoms will undergo comparable vibrations, for example, any
AX group such as NH NO etc.
The vibration bonds due to the due to the stretching of a given functional group occur at higher frequencies than
those due to deformation or bending. This is because more energy is required to stretch the group than deform it
due to the bonding force directly opposing the change.
Two other types of bands may also be observed (i) overtone and (ii) combination bands. Overtone bands are
observed at approximately twice the frequency of strong fundamental absorption bands (overtones of higher
order having order having too low an intensity to be observed). Combination bands result from the combination
(addition or subtraction ) of two fundamental frequencies.
In general, many but not all of the modes of vibration of a particular type of molecule can be observed by means
of infrared spectroscopy and these are said to be infrared – active modes. Similarly, some but not all modes are
Raman- active. For example, the stretching vibrations of C=C, C=C, C=N,C=S,S=S,N=N and O=O functional
groups exhibit strong bands in Raman spectra, which are weak or inactive in the infrared. Moreover, in Raman
spectra, skeletal vibrations often give characteristic bands of medium-to-strong intensity which in infrared
spectra are usually weak. Bands due to the stretching vibrations of symmetrical groups/molecules may be
observed by using Raman that are mostly inactive in IR. For many molecules, Raman active tends to be a
function of the covalent character of bonds and so the Raman spectrum can reveal information about the
backbone of the structure of a molecule. conversely, strong IR bands are observed for polar groups. However, if
the maximum possible information is required, both types of spectroscopy should be used, but one of the two
methods is usually used for a particular type of study.
Two vibrational behaviors of molecules of poly (ether sulphone): absorption over the frequency domain of the
electromagnetic radiation and (ii) the other by inelastic light scattering are shown. This figure presents
absorption versus frequency shift (taken in Raman spectroscopy) curves of the same sample.
Many factors may influence the precise frequency of a molecular vibration. Usually it is difficult to isolate the
contribution of one effect from another. For instance, the frequency of the C=O stretching vibration in CH
COCH is lower than it is in CHCOCL. There are several factors which may influence the C=O vibrational
frequency : (i) the mass difference between CH and Cl ,(ii) the associated inductive or mesomeric influence of
CI on the C=O group ,(iii) the steric effect due to the size of the Cl atom, which affect the bong angle, and (iv) a
possible coupling interaction between the C=O and C-C1vibrations.the frequency of vibration may also be

Page | 42
influenced by phase(condensed phase, solution gas) and may also be affected by the presence of hydrogen
bonding.
The intensity of an IR absorption band is dependent on the magnitude of the dipole change during the vibration:
the large the change, the stronger the absorption band. In Raman spectroscopy, it is the change in polarisability
which determines the intensity. Hence, if both IR and Raman spectrometers are available, it is sometimes an
advantage to switch from one technique to the other. However, the intensity of the band due to a particular
functional group also depends on how many times (i.e.in how many places) that group occurs in the sample
(molecule)being studied, the phase of the sample, the solvent (if any)being employed and on neighboring
atoms/groups. The intensity may also be affected by intramolecular/intermolecular bonding.
Thermal Analysis of Textile Fibers

Page | 43
Conclusion:
Quality is a relative term. It means customer needs is to be satisfied. Quality is of prime importance in any
aspect of business. Customers demand and expect value for money. As producers of apparel there must be a
constant endeavor to produce work of good quality. To assess the quality of textile product Textile Testing is
very important work or process. Testing In response to ever-changing governmental regulations and the ever-
increasing consumer demand for high quality, softlines testing and textile testing help to minimize risk and
protect the interest of both manufacturers and consumers. It is important that testing is not undertaken without
adding some benefit to the final product. There are a number of points in the production cycle where testing
may be carried out to improve the product or to prevent sub-standard merchandise progressing further in the
cycle. So various Steps of Textile & Garments manufacturing where in-process Testing, inspection and quality
control are done to avoid reproduction, reprocessing and minimize wastage.

Textile testing & quality control

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