Txmi 3500 Exam 2

Front 1

What are the care instructions for a woman's dark blue blouse made from 100% viscose rayon?

Back 1

1) Dry cleaning is usually recommended for regular viscose fabrics because of their low strength, abrasion resistance, and dimensional stability.
2) Caution should be observed in laundering because the fiber is weaker when wet and can be damaged more easily by rough handling.
3) Drying in an automatic dryer may accentuate rayon's tendency to shrink.
4) When pressing rayon fabrics, use lower ironing temperatures.
5) Chlorine bleaches must be controlled carefully to avoid fabric deterioration. Oxygen (or perborate) bleaches are safer for rayon fabrics, if bleaching must be done.

Front 2

In what ways are cotton and viscose rayon different?

Back 2

1) In viscose rayon, the cellulosic chains are much shorter.
2) The degree of polymerization is only about four hundred to seven hundred, compared to six thousand to ten thousand for cotton. T
3) The molecules are also less ordered.
4) The crystalline areas are smaller in size.
5) The fiber has a higher amount of amorphous material.

Front 3

What advantages do Modal, a high-wet modulus (HWM) rayon and Tencel, a Lyocell rayon, offer over regular viscose rayon?

Back 3

1) Greater resistance to deformation when wet
2) High tenacity
3) High modulus
4) Better wrinkle resistance
5) Wet abrasion increases fibrillation

Front 4

Why is lyocell considered a green fiber?

Back 4

1) The process is self-contained. 2) The solvent is not toxic and also has low volatility during processing, so there are almost no harmful emissions.
3) The NMMO is reclaimed from the spinning bath and recycled.

Front 5

Why do lyocell fibers fibrillate? What effect does this have on the fibers?

Back 5

Because of the manner in which the fibers form during spinning, they are highly crystalline, and as a result, small fibrils tend to splinter off from the surface. This fibrillation, which is enhanced under conditions of wet abrasion, gives lyocell a fuzzy appearance and reduces the luster of the fibers. It also makes dyeing the fabric challenging.

Front 6

What are the applications of cuprammonium rayon fibers?

Back 6

1) Lightweight fabrics
2) Linings
3) Warm-weather clothing
4) Artificial kidneys

Front 7

Regenerated cellulose fibers

Back 7

1) Viscose: "regular," high-wet-modulus (HWM), and high-tenacity rayon
2) Cuprammonium
3) Lyocell

Front 8

Derivative cellulosic fibers

Back 8

1) Acetate
2) Triacetate

Front 9

What is the difference between the chemical composition of acetate and triacetate? Briefly explain the differences in their properties.

Back 9

1) Both are spun: acetate is dissolved in acetone; triacetate is dissolved in methylene chloride. Also, acetate has two acetate ester groups per ring, and triacetate has three acetate ester groups per ring.
2) Properties are desirable aesthetics but low strength and abrasion resistance.Triacetate has better wrinkle resistance and better recovery than acetate, while acetate has a slightly higher moisture regain and a lower melting point.

Front 10

What properties of nylon make it especially useful in (a) women's hosiery & (b) carpet?

Back 10

a) Nylon has long been a major importance in the manufacture of women's hosiery because it is strong and stretches and recovers easily.
b) Because it is resilient and abrasion resistant, it dominates the carpet and rug market.

Front 11

What are some of the outstanding properties of acrylic and mod-acrylic fibers?

Back 11

1) Acrylic properties: Bulk, warmth at low weight, low strength, and high elongation are similar to wool. Other properties are low moisture regain and good sunlight resistance.
2) Modacrylic is flame resistant.

Front 12

Different types of polyesters

Back 12

1) PTT (polytrimethylene terephthalate): high resilience, stretch, and recovery
2) PEN (polyethylene napthalate): very high strength
3) PBT (polybutylene terephthalate)
4) PLA (polyactic acid): biodegradability

Front 13

Why have acrylic fibers replaced wool fibers in many types of apparel?

Back 13

1) Acrylic is a lower-cost competitor for wool.
2) It has similar mechanical properties: low strength and modulus, high elongation, and moderate recovery.

Front 14

Why is polyethylene not manufactured as a fiber?

Back 14

1) Low melting point (300°F, or 147°C).
2) Tendency to "creep," or elongate, under load over a long period of time.

Front 15

Which generic fiber is used for making Coolmax fabric?

Back 15

Polyester (PET)

Front 16

Elastomeric fiber

Back 16

"A natural or synthetic polymer which at room temperature can be stretched repeatedly to at least twice its original length and which after removal of the tensile load will immediately and forcibly return to approximately its original length."

Front 17

Generic elastomeric fibers:

Back 17

Spandex, rubber, anidex, and elastoester.

Front 18

What is so special about Spandex fiber?

Back 18

Spandex was the first commercially successful synthetic elastomeric fiber. It has very high elongation and excellent recovery, as well as good chemical and environment resistance.

Front 19

Why do white nylon fabrics need to be washed separately?

Back 19

It has a tendency to "scavenge" colors, picking up surface color easily from other fabrics.

Front 20

Why is nylon commonly found in sportswear along with spandex?

Back 20

Spandex/nylon blends can be dyed with the same dye at a lower temperature and give better stretch and recovery properties as well.

Front 21

How can you distinguish acetate from viscose rayon fibers?

Back 21

Burning test: Viscose rayon fabrics continue to burn after the source of the flame has been removed, and burning fabrics have the odor of burning paper. A soft, gray ash remains after burning. If ignited, acetate and triacetate burn with melting. When the flame has been put out, a small, hard, beadlike residue remains at the edge of the burned area.

Front 22

Properties of nylon fibers:

Back 22

1) High strength
2) Low modulus
3) Good elasticity and recovery
4) Good resilience
5) More expensive than other synthetics

Front 23

Properties of aramids:

Back 23

1) High thermal stability for meta-aramids.
2) High strength and modulus for para-aramids
3) Used mainly in industrial and specialty products.

Front 24

What difference in the properties of Kevlar and Nomex aramid fibers account for the different kinds of products in why the are used?

Back 24

Para-aramids (EX: Kevlar), with high strength and modulus, are used in protective apparel such as safety gloves, boots, clothing, chain saw chaps, and bullet-resistant vests.

Meta-aramids (EX: Nomex), with their excellent thermal stability, are fabricated into clothing for firefighters, race car drivers, petrocehmical and refinery workers, power and utility workers, military flight personnel, and astronauts. The fiber's light weight, lower modulus, and moderate absorbency make it more comfortable than other materials that might be used.

Front 25

Why doesn't polyester crystallize as easily as nylon?

Back 25

Because of its aromatic rings, which are bulky and inhibit alignment of the molecules. In addition, there are no polar groups in the polyester polymers to form hydrogen bonds between the polymers.

Front 26

How can the heat setting process be useful in taking advantage of polyester's heat sensitive nature?

Back 26

Not only will heat setting stabilize and shape, but wrinkle resistance of polyesters is enhanced by heat setting.

Front 27

If you had three fabrics that were the same in all other aspects but one was made of polyester, one of nylon, and one of rayon, rank their weight from heaviest to lightest. Why such difference?

Back 27

1) Rayon
2) Polyester
3) Nylon

Specific gravity

Front 28

Care procedures for 100% polyester

Back 28

Polyesters have been given heat-setting treatments have excellent dimensional stability, so long as the heat-setting temperature is not exceeded. Because of its low moisture regain, polyester does not shrink when wet and can stabilize fabrics when it is blended with other fibers.

Front 29

Which properties of polyproylene fibers contribute to their use in the following products: carpet, carpet backing, diapers, thermal underwear, and geotextiles?

Back 29

1) Carpets: Being nonabsorbent and having good weather resistance, polypropylene can be made into carpets that will withstand exposure to outdoor conditions in areas where sunlight is not intense or prolonged. When polypropylene is used for traditional indoor carpets, soil- and waterborne stain resistance are exceptional, and the carpets have good lightfastness and resistance to moths.
2) Carpet backing: It has virtually replaced jute in carpet backing because of its resistance to microorganisms.
3) Diapers: Polypropylene nonwovens, as diaper liners, wick moisture away from the skin to the inner absorbent layer of the diaper.
4) Thermal underwear: Batting provides good insulation because the high surface area and low density of the material trap air. The fine size and light weight of the fibers contribute to warmth without excessive bulk or size.
5) Geotextiles: Polypropylene geotextiles are placed under the soil or roadbeds, where their strength and chemical resistance are advantages and they will not be

Front 30

Which properties of high-strength Spectra polyethylene fibers contribute to their use in products, such as cut-resistant clothing, composite materials for industry.

Back 30

1) Ultra high strength (fifteen times stronger than steel and more than twice the strength of para-aramids)
2) Low specific gravity
3) Low moisture absorbency

Front 31

The fiber producer salesperson is trying to convince you to use 100% polyester when you develop the summer blouse fabric you are designing. State two reasons why you might reject polyester for this fabric?

Back 31

1) If polyester fabrics have not been heat-set, they may shrink at high temperatures.
2) Fibers will degrade after long exposure to sunlight.

Front 32

The same salesperson is wearing down your resistance to use polyester for the blouse fabric. State two good reasons why you WOULD use 100% polyester for that fabric?

Back 32

1) Good wicking ability increases polyester's comfort in warm weather as perspiration is carried along the surface of the fiber and evaporated.
2) Polyesters are resistant to attack by microorganisms.

Front 33

Why are acrylic fibers extensively used in products, such as carpets, hand-knitting yarns, sweaters, and high pile fabrics?

Back 33

1) Carpets: resistance to degradation by sunlight, low moisture absorbency, and antimicrobial and antistatic properties
2) Hand-knitting yarns and sweaters: wool-like hand and bulk combined with easy-care characteristics
3) High-pile fabrics: good resilience and abrasion resistance

Front 34

Why is polyester frequently used in fiberfill for apparel and home furnishing items?

Back 34

Easy-care, non-allergenic substitutes for goose down; hollow polyester fibers are said to offer advantages in this use over traditional polyester fiber forms.

Front 35

Discuss why rayon is such a popular fiber for women's apparel but is not often used for children's wear and menswear.

Back 35

Viscose rayon is used in fashionable wearing apparel. Its use is dictated by its aesthetic rather than its durability properties. Because rayon is among the denser of the commonly used fibers and has a lower modulus, the weight of the fabric and its low stiffness help to develop the pleasing folds associated with good drapability.

Front 36

Why is olefin used so extensively in industrial products?

Back 36

It is inexpensive and light weight.