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Front 1

Development criteria for test methods:

Back 1

1. Test Procedure is clearly identified
2. Proposed Method undergoes inter-laboratory trails (mainly to determine precision)
3. refinement
4. method is submitted to committee vote

5. If passed, method goes to balloting by other committees ( at each level of balloting input is sought and used to improve the method)
6. once approved as a standard test method, it undergoes periodic reconsideration and re-approval in order to be retained as a standard test method

Front 2

Development criteria for Test Methods:

Back 2

1. Test Procedure is clearly identified
2. Proposed Method undergoes inter-laboratory trails (mainly to determine precision)
3. refinement
4. method is submitted to committee vote
5. If passed, method goes to balloting by other committees ( at each level of balloting input is sought and used to improve the method)
6. once approved as a standard test method, it undergoes periodic reconsideration and re-approval in order to be retained as a standard test method

Front 3

Criteria for Test Methods:

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1. Simplicity: Textile test method should be easy to read and understand. Should provide enough information, but the results should be easily interpreted.
2. Reproducibility: 2 different people who perform the same test on the same specimen should obtain the same results; results should be reproducible regardless of location.
3. Validity: The test method should be applicable to the end use.

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Precision:

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Degree of agreement within a set of test results and refers to the reproducibility of repeated measurements on the same material, that is, how close the values in the data set are to each-other.

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Accuracy:

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How close a measurement is to the true or accepted value (validity). It is usually expresed as absolute error or relative error. To determine either, the value of the material being tested must be known. (Absolute error is the difference between a measurement or several measurements and the true value. Relative error is the absolute error divided by the true value.

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Sensitivity:

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The lowest level an instrument will measure. Ex: .001g or .01in. The sensitivity of the instruments and methods being used should be noted because this affects the # of significant figures reported for a measurement.

Front 7

Determinate Error:

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are those that can be identified and corrected: 3 types--> personal, instrumental, and method. Large deviations from the expected or established value could indicate a determinate error.

Front 8

Bias

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occurs when there is a systematic error in a set of measurements that is usually the result of a Determinate error. It has replaced the accuracy in ASTM and AATCC test method statements because it is often not possible to determine accuracy of the results from a test procedure.

Front 9

Indeterminate Error:

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errors that cannot be detected and whose cause cannot be determined. These include all the little uncertainties and variations that cannot be controlled by the experimenter.

Front 10

1. What is the standard condition for testing?
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2. Why is it important to condition your fabric specimens ?

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3. Why do we need non-standard conditions?

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1. Humidity: 65+/- 1% relative humidity.
Temperature: 21 degrees C +/- 1 degree ( 70 degrees F +/- 2 degrees)
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2. To avoid the problems resulting from differential moisture absorption of different fabrics, to assume valid test results called equilibrium, & to also avoid bias and indeterminate errors.
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3. non-standard conditions for flammability tests (specimens must be bone-dry for flammability tests) and also for thermal transmittance testing and electrostatic propensity (20% RH +/- 2).

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Hysteresis:

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the fabric's moisture absorption behavior as it is influenced by it's moisture history ( wet or dry before conditioning)

Front 12

How does hysteresis or moisture history of fabric influence its properties (e.g., aesthetic, mechanical, etc.)?

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conditioning=moisture regain

wet specimen=equilibrium regain is higher H20 molecules are already in it.

dry specimen=equilibrium regain is lower

Influences on properties:
fabric density or weight; the higher the RH the heavier the fabric. Fabric content is determined by density and for this reason density should not be determined UNTIL fabric has been conditioned.

As RH increases fibers become more extensible or more easily stretched. This is because absorbed water reduces the cohesion of molecules in the amorphous regions of the fiber.(Crystalline regions are not highly affected by RH thus the effect of RH is dependent on the crystallinity of the fiber)

Elastic recovery decreases with moisture increase for cellulosic fibers but for other fibers like wool, silk, and nylon, elastic recovery increases at higher relative humidities.

Thermal conductivity increases as RH increases because the increased moisture conducts heat better than dryer fibers.
color and appearance may also be affecte

Front 13

How does moisture regain of fibers influence the performance of textiles?

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Affects fabric density, mechanical properties such as breaking strength, elongation, elastic recovery of fabrics, abrasion resistance and pilling

Higher regain = higher comfort and absorbency

Natural fibers have high regain [wool has 18% regain]; Manmade fibers have low regain [olefin has 0% regain]

Front 14

What is calibration and why it is important?

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Calibration is the comparison of 2 measurements. (To check, adjust, or determine by comparison with a standard) It is important to avoid determinate errors, bias, to attain reproducibility accuracy. It’s important for being able to convert types of measurement accurately.

Front 15

What are different statistical tools to determine the ‘precision’?

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range, standard deviation,
coefficient of variation

Front 16

What are different types of measuring scales (ordinal, ratio & interval)? Compare and contrast.

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ordinal scale: used to rank specimens; not continuous

ratio scale: zero value represents an absence; continuous

Interval scale: equal difference between scale intervals; continuous

Front 17

What are different methods of identifying generic fibers in the textile product?

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burning: identifies by ignition, odor and residue , microscopic observation, solubility

Front 18

What influences a textile product’s properties?

Back 18

1.fiber content , 2. yarn structure, 3. fabric construction

Front 19

What is the difference between staple/spun and filament yarn?

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Staple:

- dull
- fuzzy
- low in strength
- high pilling
- bulky
- low snagging
- low in stretch
- shorter

Filament:

- smooth
- longer
- lustrous
- high in strength
- low pilling
- low in bulk
- high snagging
- low stretch

Front 20

How does fiber blending influence the performance of a product for its intended end-use?

Back 20

blending can bring out both the best and worst qualities of different fibers. For example when blending cotton with polyester the cotton becomes more resilient, durable, with better dimensional stability on the other hand as the cotton may start to pill the polyester will “grab” onto those pills instead of the little balls just breaking off, like they would with 100% cotton. For example, this means if you are making an item of clothing that will encounter a lot of abrasion causing the cotton to pill, such as jeans, a polyester blend might not be the best choice because the pills will build up on the surface of the fabric.

Front 21

What is the significance of the Worth Street Textile Market Rules?

Back 21

provides classification guidelines for specifying products for particular end uses
classification based on: fiber content, yarn structure, color application, finishing state, type of fabric design
It is an effort to assure quality and honesty in the trade of textile products. It gives quality specifications for deficiency allowances in yarns and fabrics.
Bow: must be less than 2%
Skew: must be less than 2.5%
denim skew between 4-12%

Front 22

Calculate the fabric weight (ozs per square yard) of the fabric that is 5 in. by 5 in. and weighs 3.87 g.

Back 22

17.7 oz/yd^2

Front 23

If a buyer is interested in identifying a realistic breaking force specification for fabric strength, then which test specs for a printcloth should be written and why. (Hint: grab or raveled strip)

Back 23

There are two major breaking strength tests

Strip Test
a. raveled strip- the full width of the specimen is clamped so you can relate strength to width, or even to # of yarns
b. cut strip test- the specimen is cut the width of the jaws or narrower, so that all yarns will be gripped during the test. Accuracy depends on exact alignment and deviation will result in error

Grab test: the specimen is cut wider than the jaws and gripped in the middle; this test gives “effective strength” not the strength of yarns actually gripped. Samples are simpler to prepare and thus this test takes less time than the strip test.

Probably use the grab test because it gives the effective strength and is also less time consuming?

Front 24

Breaking Strength:

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force in pounds required to break many warp or filling yarns at once

Front 25

Elongation:

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The increase in length or deformation of a fiber as a result of stretching. Elongation is measured as a percentage of the original length.

Front 26

Young’s Modulus:

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also known as tensile modulus; the slope of the initial straight line of the curve; elastic limits
-steep slope yields higher resistance

Front 27

Toughness:

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work of rupture; the area under the stress-strain or force-elongation curve and represents the total amount of energy required to break a material

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Yield:

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point of curve where slope deviates from the straight line (permanent deformation)

Front 29

21. Calculate following for a cotton/polyester blend fabric:

Back 29

a) percentage of cotton fiber dissolved
original dry specimen mass=4.3821 g
extracted dry residual mass of polyester=2.2787 g
** percentage of cotton fiber is 52 %: (4.3821-2.2787)/(4.3821)= 48 % polyester ( 52% cotton)
(pg. 78 in book)

b) yarn number (CC or denier?) for a single spun yarn.
mass of yarn: 0.0602 lb = 27.3063 g
length of yarn: 2.48 yards
**Since the yarn is single ply & spun instead of filament, use CC.
= (2.48 yd/27.3063 g) x (454 g/1 lb) x (1 hank/840 yd) = 0.0491

c) yarn twist (tpi):
specimen length: 7.75 inches
turns counted: 231
= (231 twists/7.75 in)= 29.81 tpi

d) fabric weight in oz/yd2
weight of specimen: 10.7881 g
width of specimen: 11 inches
length of specimen: 9 inches
= 10.7881g/20 inches x 1 oz/28.4g x 1296 in/1 yd^2 = 24.6 oz/yd^2

*Can someone provide the full equation for this? Where does 1296 come from?
1296 is 36^2, or number of inches in a square yard

The [1 oz/28.4g x 1296 in/1 yd^2] part of the equation

Front 30

How does ‘fabric count’ influence durability and comfort of woven textiles?

Back 30

An increased fabric count increases the strength of the fabric and also increases the comfort as a high fiber count usually means finer fibers and smaller yarns.

Front 31

The ASTM has established performance standards for textiles. Why are these minimum standards?

Back 31

minimum standards because they are the tests on performance characteristics for apparel that will allow for the lowest performance yet still be a functional fabric

Front 32

How can a breaking strength test be used to determine the effects of sunlight (hint: UV resistance)?

Back 32

-Maybe if the fabric is not resistant to UV exposure, breaking strength is lower when fabric is exposed to sunlight/UV rays?

Front 33

Why does the tearing strength test give the lowest test result compared to breaking strength?

Back 33

Because in tearing strength only one or a few yarns are broken at a time and in breaking strength many yarns are broken at one time therefore resulting in a higher # than tearing strength.

Front 34

How can two woven fabrics of the same weight possess different breaking strengths?

Back 34

Fiber content can greatly affect the tearing strength of fabrics so one of the woven fabrics might have a higher breaking strength (polyester?) than another (cotton?)
Another consideration is the weave type. Plain weaves have a high breaking strength with low tearing strength while satin weaves have a lower breaking strength and high tearing strength. Twills have a higher tearing strength than plain weaves but a lower breaking strength but their breaking strength is higher than satins’ because more interlacings.
Fabric count also determines differences in breaking strength. A high fabric count has a high breaking strength with a low tearing strength and vice versa for a low fabric count.
Lastly the degree of yarn twist and whether it is simple, plied, etc affects fabric strength. For spun yarns the greater the twist the better the strength and ply yarns are stronger than simple.

Front 35

Two fabrics, one plain weave and other twill weave, are made of the same size yarns, have the same fiber content and possess the same yarn count. Which one has a higher tearing strength and breaking strength? Why?

Back 35

Twill weaves have a higher tearing strength because the floats in the weave make it harder to tear by making more opportunity for yarns to move together to resist tearing. While plain weaves have no floats making it fairly easy to tear the fabric after a small cut in the fabric has been made.

Plain weaves have a higher breaking strength than twills because they have more interlacings which means they have more opportunity to share the applied force evenly across the fabric.

Front 36

For each of the following fabrics, list two tests you feel should be performed to evaluate its potential performance. Also, list two tests you feel need not be performed. Briefly explain the reasons for your choices.

Back 36

a. A tightly constructed woven fabric made of 100% nylon, with large pigment print, is to be used as a boy’s outerwear jacket.
WANT TO DO
- Abrasion Resistance Testing should be used
-Tearing strength should be tested because children’s clothing needs to be durable.

DONT WANT TO DO
-Colorfastness should be tested because children’s clothing are washed and dried
repeatedly and ease of care is a primary factor to the consumer.
- Electrostatic propensity doesnt matter

b. A solution-dyed, filament yarn, woven fabric made of 100% silk, with large jacquard design, is to be made into a summer dress.
WANT TO DO
- moisture regain/ absorbency test is needed because it is a summer dress
- breathability test ( depending on geographic location) or resilency

DONT WANT TO DO
- no colorfastness or abrasion resistance or breaking strength necessary / no flammability test or electrostatic propensity

c. A brown knit fabric made of 100% cotton, is to be made into a man’s pullover s

Front 37

You would like to develop the dress fabric that is strong, very drapable, and highly lustrous. Describe how you would construct this fabric (e.g., fiber content, yarn type, weave type). Do not describe any finishes.

Back 37

silk and polyester are both fibers that are strong, drapable, and can be highly lustrous (polyester depends on the cross section, trilobal is the most lustrous)
I would use a 2 ply yarn so that there is strength while the thickness of the yarn will not impede on the drapability and since both are filament fibers in most cases there should be low or no twist to maximize strength.
while satin weave is the most lustrous weave type, it is also the weakest. Since twill is not lustrous, I would choose plain because, although not the most lustrous or strongest, it has the ability to show luster and is strong because of all the interlacings. This weave can also allow the fabric to be drapable.

Front 38

What are different types and categories of abrasion? Explain briefly.

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Fabric Against Fabric Abrasion: occurs in instances such as sleeves rubbing against the body or shirts rubbing against a jacket or when clothes rub against each other during washing and drying.
Fabric Abrasion against a Non Textile Surface: any time that fabric comes into contact with a non textile surface such as a table or chair or wall it is abraded by that surface depending on the texture of the surface. For example, if fabric rubs over cement or asphalt it will abrade much more than if the same fabric rubs across metal or plastic.
Abrasion Between Fabric Components: abrasion that occurs as fibers or yarns within a fabric rub against each other. for example when fabric is flexed repeatedly, the pulling and compression forces are alternately applied and released, causing the component fibers and yarns to slide and rub back and forth against each other, resulting in abrasion and eventually rupture.
Abrasion By Foreign Materials Within the Fabric: particles of dust, sand, and other foreign substances

Front 39

What is the effect of fabric count on abrasion resistance?

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The higher the fabric count the less abrasion resistant because fibers and yarns are usually smaller and therefore more likely to wear down faster

Front 40

What are different ways of assessing abrasion?

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1. Microscopic evaluation, 2. Visual evaluation 3. Rate of abrasion
4. Change in physical property (original-flawed/original x 100%)
5. Endpoint determination: # of cycles until fabric rupture

Front 41

American Society for Testing and Materials (ASTM); dry methods

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annual book of volumes, largest non governmental associations textile testing, post test method and specifications, more towards physical attributes and performance of textiles using dry procedures,
use materials of all industry

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American Association of Textile Chemists and Colorists (AATCC); wet methods

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focus on physical and biological, test colorfastness,
identification and analysis

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ISO- International Organization for Standardization

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2 categories: 9000 and 14000

9000 insures quality

14000 insures business turn in forms for environmental protection

Front 44

test methods

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Best practices to measure and evaluate qualities and characteristics of fiber, yarn or fabric which have been approved by specific organizations (takes 2 - 5 years to develop)

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tolerance

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to work within given limits.

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Specifications (via ASTM):

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a precise statement of a set of requirements to be satisfied by a material, product, system, or service that indicates the procedures for determining whether each of the requirements is satisfied.

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Standards:

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A required or agreed level of quality or attainment

Front 48

Why is textile testing important?

Back 48

textile testing is important because it helps us determine the different attributes, qualities, chemical structure, performance, and characteristics that will determine what end uses are appropriate and inappropriate for the textile. It also helps protect and inform consumers.

It is used for: assessment of product performance, research and development, quality control, comparative testing, analyzing product failure, and government regulations

Front 49

textile analysis:

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Analysis in textile testing means the study of the individual characteristics of a textile material in order to determine how each contributes to the overall performance properties of the textile product