Unit 1 - Lecture 5 Topic 2

Question 1

Heat/Thermal Retention:

Answer 1

Ability of a textile to hold heat. Low retention is good in hot weather, and high retention is good in cold weather.

Question 2

Electrical Conductivity:

Answer 2

The ability of a fibre to carry or transfer electrical charges. Most fibres are poor conductors of electricity – except for metallic or carbon fibres. Differences in conductivity between common fibres is related to moisture regain but also influenced by environmental humidity. Conductivity is often shown through lint attraction and fabric cling.

Question 3

Heat Sensitivity:

Answer 3

The way a fibre reacts to heat by softening, melting, or resisting the heat. Many synthetic fibres will soften and melt. Many fibres have a heat resistant temperature in which any temperature above will cause the fibres to begin to degrade.

Question 4

Chemical Reactivity determines:

Answer 4

Laundering and care procedures, along with the selection of dyes and finishes usable.

Question 5

Chemical Resistance:

Answer 5

Certain chemicals can break bonds in polymer chains
of some fibres which is related to reactive groups on polymer, types of bonding, and fibre crystallinity. For example, acids degrade cotton and bases degrade wool.

Question 6

Biological Resistance:

Answer 6

Ability of a textile to resist deterioration or discolouration by microorganisms and insects. When there is a high amount of microorganisms and insects, their wastes may lead to bio-deterioration - a period of heavy mildew growth and textile rotting. Mild growth of microorganisms may lead to discolouration. Moths and carpet beetles degrade protein fibres, while silverfish degrade cellulosic fibres. Natural fibres and rayon are susceptible to biological attack. Synthetic fibres tend to be resistant to biological attack.

Question 7

Textile resistance to light:

Answer 7

The ability to withstand degradation from natural and artificial light. Degradation occurs via photo-oxidation due to ultraviolet (UV) exposure. Polyester and acrylic have high UV resistance, whereas nylon doesn’t.

Question 8

Dimensional Stability:

Answer 8

Ability of a textile to retain its original dimensions after wetting, drying or exposure to high humidity. Felting, tension or swelling can all result in fabric shrinkage.

Question 9

Felting Shrinkage:

Answer 9

Some animal hair fibres shrink when washed due to interlocking & tangling of fibres.

Question 10

Relaxation Shrinkage:

Answer 10

Tension introduced during fabric manufacture is relaxed when washed.

Question 11

Swelling:

Answer 11

Some fibres increase in fibre diameter when wet and cause a reduction in length.