Test 2

Question 1

What fiber is best suited for parachute rope?

Answer 1

Nylon

Question 2

Which manufactured fibers are stiffness according to inital modulus?

Answer 2

olefin and polyester

Question 3

which natural fiber has the greatest ultimate strain?

Answer 3

wool

Question 4

which natural fiber has the greatest inital modulus (Stiffness)?

Answer 4

flax

Question 5

the elastic stiffness of a fiber is determined from what parameters?

Answer 5

yield stress and yield strain

Question 6

Work of Rupture describes what important characterisitcs of fiber

Answer 6

the total work absorbed by a fiber before it breaks

Question 7

Resilience is a measure of what?

Answer 7

a measure of recoverable work and the ability of a fiber to return to its orginial shape

Question 8

When a fiber ties into a knot..?

Answer 8

the fiber becomes weaker and the knot acts to increase the stress on the fiber

Question 9

standard laboratatory conditions for the mechanical testing is

Answer 9

65 +/- 2% relative humidity and 70+/- 2 degrees fahrenheight

Question 10

the yield point refers to…?

Answer 10

found by Merediths method for viscoelastic materials and the point where elastic deformation turns to plastic deformation.

Question 11

If you are a fisherman do you want your clothes to be hydrophobic or hydrophilic?

Answer 11

hydrophobic

Question 12

Is wool hydrophobic or hydrophilic?

Answer 12

hydrophilic

Question 13

which fiber has the lowest melting temp?

Answer 13

polypropylene

Question 14

glass transition temp is ..?

Answer 14

dependent on mositure regain and temp at which polymer chains in the amorphous part of fibers to be mobile

Question 15

heat of wetting is?

Answer 15

heat generated when a fiber absorbs mositure

Question 16

a hydrophilic fiber is one that…?

Answer 16

absorbs mositure readily

Question 17

An oleophilic fiber is one that…?

Answer 17

tenaciously absorbs or holds oil

Question 18

Is polyester hydrophobic or hydrophilic?

Answer 18

hydrophobic

Question 19

Is polypropylene hydrophobic or hydrophilic?

Answer 19

hydrophobic

Question 20

Relative humidty affects the properties of _ fibers.

Answer 20

hydrophillic

Question 21

T or F: Cotton and wool have no melting temp because the polymers will decompose into other molecules before they become liquid.

Answer 21

True

Question 22

Cotton is more damaged by …

Answer 22

Acids (low pH)

Question 23

Consumers find cotton to be comfortable because…

Answer 23

when dry and because cotton is hydrophillic

Question 24

The color of cotton is…

Answer 24

white, grey, light yellow

Question 25

Cotton fibers are primarly from what polymer?

Answer 25

cellulose

Question 26

the mositure regain of cotton at standard lab settings is...

Answer 26

8.5%

Question 27

the melting point of cotton is ...

Answer 27

cotton will decompose before it melts

Question 28

T or F: cotton fiber length is highly variable due to the processing of the fiber beginning with ginning.

Answer 28

true

Question 29

T or F: Cotton is highly flammable unless treated with a flame retardant finsihing

Answer 29

true

Question 30

T or F: cotton is stronger than polyester

Answer 30

false

Question 31

T or F:during a tensile test, cotton has a very low elognation at the breaking point.

Answer 31

true

Question 32

T or F: cotton will absorb moisture and phyiscally swell

Answer 32

true

Question 33

T or F: cotton fiber properties are highly variable because it is a natural fiber with varying growing conditions.

Answer 33

true

Question 34

T or F: wool fiber length is highly variable due to the fact that wool on a sheep's leg is shorter than wool on the sheeps back.

Answer 34

true

Question 35

T or F: wool and silk will absorb mositure and phyiscally swell

Answer 35

true

Question 36

T or F: during a tensile test, wool has a very low elongation at the breaking point

Answer 36

false

Question 37

mositure regain of silk at standard lab conditions is

Answer 37

11%

Question 38

consumers find silk fabrics to be comfortable

Answer 38

because it is hydrophilic fiber, when dry, because silk fabrics have excellent drape characterisitcs

Question 39

T or F: most natural and manufactured fibers have greater breaking strength than wool.

Answer 39

true

Question 40

T or F: individual silk filaments can have a length of several hundred meters.

Answer 40

true

Question 41

The melting point of wool and silk

Answer 41

they don't have a melting point because they will decompose before melting

Question 42

the color of wool is

Answer 42

white, grey, brown

Question 43

During melt spinning the spinneret provides what value to the process?

Answer 43

It creates the filament cross sectional shape

Question 44

What part of the melt spinning extrusion unit forces the melted polymer to the metering pump?

Answer 44

the screw

Question 45

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

Answer 45

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

Question 46

what part of the melt spinning extrusion unit forces the melted polymer to the spinneret with a uniform flow rate?

Answer 46

metering pump