polymers and fibres

Question 1

what are polymers

Answer 1

large molecules with linked monomer units

Question 2

what are 4 types of polymers

Answer 2

natural (biopolymers)
semi-synthetic (cellophane)
synthetic (polystyrene)
co-polymers

Question 3

what are 3 possible organisation of monomer units in co-polymers

Answer 3

random
alternating
graft co-polymers

Question 4

what are some examples of linear co-polymers

Answer 4

PVC, polystyrene and nylon

Question 5

what are some examples of cross linked co polymers

Answer 5

rubber. epxoy resin

Question 6

what are some examples of branched polymer chains

Answer 6

LDPE, HDPE

Question 7

What is a dendrimer

Answer 7

specialised polymers with branching points, core and termini

Question 8

what are some characteristics of thermoplastics as synthetic polymers

Answer 8

hard at room temp, soft and viscous at higher temp which means they can be shaped and moulded

Question 9

what is an example of thermoplastics

Answer 9

Polystyrene

Question 10

what ae some characteristics of thermosetting polymers

Answer 10

on heating become highly cross-linked and cant be reshaped

Question 11

what are 2 examples of thermosetting polymers

Answer 11

car top coats and bakelite

Question 12

what is the classification of elastomers

Answer 12

• ability to stretch and return to original shape

Question 13

what is an example of elastomers

Answer 13

rubber, tyres

Question 14

what are fibres

Answer 14

thin threads

Question 15

why are fibres important

Answer 15

for transfer and trace evidence used in homicide, assault cases etc.

Question 16

what is a cellulose fibre

Answer 16

natural fibre

Question 17

what are 3 characteristics of cellulose fibres

Answer 17

dicot fibre-
- transparent
- colourless
-curve twisted fibres

Question 18

what shape is the cross section of cellulose fibres

Answer 18

circular cross section with surface striations

Question 19

what is an example of cellulose fibres

Answer 19

cotton (found in some clothing)

Question 20

what are 3 characteristics of the natural fibre Kapok

Answer 20

seed fibre
- smooth hollow thin walled cylinders
- 2-3cm
-surface irregularities and twisting and sharp bends

Question 21

can natural fibres be synthetic or semi-synthetic

Answer 21

yes- can be both, can also be from minerals, animal and plant sources

Question 22

what are kapok seed fibres used for

Answer 22

boyancy aids- they are brittle and inelastic

Question 23

what is a flax (Linen) natural fibre, and what is its shape

Answer 23

Dicot fibre
- transverse nodes shaped I, X, V and Y

Question 24

What are some examples of flax fibres

Answer 24

• skin
• vegetable

Question 25

what is hemp fibre

Answer 25

dicot fibre

Question 26

what are some characteristics of hemp fibre

Answer 26

- colourless transparent cylinders - surface irregularities - polygonal in cross sections