TMS 211 Test 2

In order to be formed into filaments using melt spinning, a polymer must be:

-Capable of being melted -Have a large degree of polymerization in order for the filament to be strong enough and not break

Match the term with the definition: Decomposition temperature Glass transition temperature Melting Point

Decomposition temperature - temperature at which the polymer begins to degrade into components Glass transition temperature - Temperature at which portions of polymer chains not crystallized become mobile Melting Point - Temperature at which the portions of polymer chains embedded in crystals become mobile

Cotton is stronger than polyester. True or False?

False

During a tensile test, wool has a very low elongation at the breaking point: True or False?

False

Wool is stronger than cotton: True or False?

False

What naturally occurring fiber has the greatest initial modulus (stiffness)? a. Silk b. Cotton c. Wool d. Flax

Flax

Besides cotton, other plant fibers made from cellulose include?

Flax Ramie Jute

If you are a fisherman working in the Bering Strait do you want your clothing to be made of a fiber that is hydrophobic or hydrophilic?

Hydrophobic

Cotton and wool have no melting temperature because the polymers will decompose into other molecules before they become liquid: True or False?

True

Cotton fiber length is highly variable due to processing of the fiber beginning with ginning: True or False?

True

Cotton fiber properties are highly variable because it is a natural fiber with variability in growing conditions: True or False?

True

Cotton is highly flammable unless treated with a flame-retardant finish: True or False?

True

Cotton will absorb moisture and physically swell: True or False?

True

During a tensile test, cotton has a very low elongation at the breaking point: True or False?

True

Most natural and manufactured fibers have greater breaking strength than wool: True or False?

True

Silk fibers may be up to 600 meters in length: True or False?

True

Silk is similar in strength to cotton: True or False?

True

Wool and silk are less flammable than cotton: True or False?

True

Wool and silk will absorb moisture and physically swell: True or False?

True

Wool fiber length is highly variable due to the fact that wool on a sheep's leg is shorter than wool on the sheep's back: True or False?

True

Consumers find wool fabrics to be comfortable:

When dry Because wool is a hydrophilic fiber

The color of wool is:

White, gray, brown (All of the above)

The melting point of wool and silk are:

Wool and silk will decompose before melting

What was the tenacity of the 70 denier polyester in the lesson? a. 3.71 gf/denier b. 37.1 gf/denier c. 26 inches d. 26 gf/denier

a. 3.71 gf/denier

Standard laboratory conditions for the mechanical testing of a textile product includes: Select one or more: a. 70 + / -2 degrees fahrenheit b. 65 + / -2% relative humidity c. 30 degrees centigrade d. 72% relative humidity

a. 70 + / -2 degrees fahrenheit b. 65 + / -2% relative humidity

The moisture regain of cotton at standard laboratory conditions is: a. 8.5% b. 16% c. 4% d. 10%

a. 8.5%

A hydrophilic fiber is one which a. Absorbs moisture readily b. Retains oil on its surface or inside the fiber c. Repels water d. Absorbs oil readily

a. Absorbs moisture readily

Olefin has high tenacity compared to what other fiber(s)? a. Acrylic b. Rayon c. Polyester Correct d. Nylon

a. Acrylic b. Rayon c. Polyester Correct d. Nylon

Consumers find silk fabrics to be comfortable: Select one or more: a. Because fabrics made from silk have excellent drape characteristics b. When wet c. Because it is difficult to dry d. When dry e. Because silk is a hydrophilic fiber

a. Because fabrics made from silk have excellent drape characteristics d. When dry e. Because silk is a hydrophilic fiber

Glass transition temperature is: a. Dependent upon moisture regain b. The temperature at which the polymer begins to decompose into small units c. The point at which crystalline regions begin to melt d. Temperature at which polymer chains in the amorphous part of the fiber become mobile

a. Dependent upon moisture regain d. Temperature at which polymer chains in the amorphous part of the fiber become mobile

Wool is a. Hydrophilic b. Hydrophobic

a. Hydrophilic

Wool is a. Hydrophilic b. Hydrophobic

a. Hydrophilic

Polyester is a. Hydrophobic b. Hydrophilic

a. Hydrophobic

Polypropylene is a. Hydrophobic b. Hydrophilic

a. Hydrophobic

Which fiber is better suited for a parachute rope? a. Nylon b. Polyester c. Rayon d. Cotton

a. Nylon

Acetate has low tenacity compared to what other fiber(s)? a. Nylon b. Rayon c. Olefin d. Acrylic

a. Nylon b. Rayon c. Olefin d. Acrylic

Which manufactured fibers are stiffest as determined by the initial modulus? a. Olefin b. Nylon c. Polyester d. Acrylic

a. Olefin c. Polyester

What fiber has the lowest melting temperature? a. Polypropylene b. Cotton c. Polyester d. Nylon

a. Polypropylene

"Resilience" is a measure of: Select one or more: a. The ability of a fiber to return to its original shape b. The area under the load - elongation curve up to the yield point c. Measure of recoverable work d. The work required to deform a fiber

a. The ability of a fiber to return to its original shape b. The area under the load - elongation curve up to the yield point c. Measure of recoverable work

Consumers find cotton fabrics to be comfortable: Select one or more: a. When dry b. When wet c. Because it is difficult to dry d. Because cotton is a hydrophilic fiber

a. When dry d. Because cotton is a hydrophilic fiber

The yield point refers to: Select one or more: a. found by using Meredith's Method for viscoelastic materials b. the point where the fiber breaks c. the point where elastic deformation turns to plastic deformation d. a specific point on the load - elongation diagram

a. found by using Meredith's Method for viscoelastic materials c. the point where elastic deformation turns to plastic deformation d. a specific point on the load - elongation diagram

The moisture regain of silk at standard laboratory conditions is: a. 18% b. 11% c. 4% d. 7%

b. 11%

Cotton fibers are made primarily from what polymer? a. Cuticle b. Cellulose c. Keratin d. Aramid

b. Cellulose

The fiber in the burn test video is: (whole fiber becomes enflamed, turns to ash) a. Kevlar b. Cotton c. Nylon d. Polyester

b. Cotton

The melting point of cotton is: a. 125 C b. Cotton will decompose before melting c. 350 F d. 500 F

b. Cotton will decompose before melting

Heat of wetting is: a. Greater for hydrophobic fibers compared to hydrophilic fibers b. Heat generated when a fiber absorbs moisture

b. Heat generated when a fiber absorbs moisture

Wool is Select one: a. Hydrophobic b. Hydrophilic

b. Hydrophilic

When a fiber is tied into a knot: Select one or more: a. The knot makes the fiber stronger b. The knot acts to increase the stress on the fiber c. The knot causes the stress to be reduced d. The fiber becomes weaker

b. The knot acts to increase the stress on the fiber d. The fiber becomes weaker

"Work of Rupture" describes what important characteristic of a fiber? Select one or more: a. The work required to cause a fiber to deform b. The total work absorbed by a fiber before it breaks c. The force required to rupture a fiber d. Force times distance of an elongation curve

b. The total work absorbed by a fiber before it breaks

The elastic stiffness of a fiber is determined from what calculated parameters? a. Tenacity b. Yield stress c. Yield strain d. Ultimate elongation

b. Yield stress c. Yield strain

What was the yield stress for the 150 denier rayon in the lesson? a. 21.6 inches b. 2.15 inches/inch c. 1.15 gf/denier d. 3.15 gf/denier

c. 1.15 gf/denier

The moisture regain of wool at standard laboratory condition is: a. 4% b. 7% c. 14% d. 10%

c. 14%

Relative humidity affects the properties (mechanical, electrical, etc.) of ____ fibers a. Oleophobic b. Hydrophobic c. Hydrophilic

c. Hydrophilic

The melting temperature of acrylic is approximately. a. 140 C b. 250 C c. it decomposes before it melts d. 480 C

c. It decomposes before it melts

An oleophilic fiber is one which a. Absorbs moisture readily b. Repels water c. Tenaciously absorbs and holds oil d. Releases oil when laundered

c. Tenaciously absorbs and holds oil

Which natural fiber has the greatest ultimate strain? a. Cotton b. Silk c. Wool d. Flax

c. Wool

Cotton is most damaged by: a. Grease b. Bases (high pH) c. Organic solvents d. Acids (low pH)

d. Acids (low pH)

The color of cotton is: a. White b. Gray c. Light yellow d. All of the above

d. All of the above

The fiber in the burn test video is: (shrinks away from flame, black think smoke, burns completely) a. Nylon b. Kevlar c. Cotton d. Polyester

d. Polyester

Protein based fibers are most damaged by: a. grease b. organic solvents c. acids (low ph) d. bases (high ph)

d. bases (high ph)