1.3 enhancement

Question 1

lubricants

Answer 1

addition of wax or calcium reduces the viscosity of the molten polymer, making it less sticky

Question 2

thermal antioxidants

Answer 2

help prevent the polymer oxidising or discolouring due to excessive heat during processing

Question 3

pigments

Answer 3

tiny particles mixed into the polymer in its molten state to give colour

Question 4

antistatics

Answer 4

improves the surface conductivity by attracting moisture from the room surrounding therefore reducing static charge

Question 5

flame retardants

Answer 5

bromine, chlorine or metal can be added to polymers to reduce the likelihood of combustion or the spread of fire

Question 6

plasticisers

Answer 6

allow plastics to become less hard and brittle at normal temperature use

Question 7

antioxidants

Answer 7

reduce environmental deterioration of the polymer from exposure to oxygen in the air

Question 8

uv light stabilisers

Answer 8

prevent the polymer chains from being broken down by sunlight

Question 9

biodegradable plasticisers

Answer 9

make the polymer more flexible, softer and easier to break down

Question 10

bio batch additives

Answer 10

oxy-degradable, photo-degradable, hydro-degradable

Question 11

work hardening

Answer 11

involves cold working metals through applications such as bending, rolling, hammering
the crystals in the metals are distorted and changed leading to improved tensile strength and hardness

Question 12

annealing

Answer 12

used to make the work hardened metal less brittle and more ductile
the metal is heated and then very slowly cooled, allowing the metal crystals to grow and slowly move into place

Question 13

case hardening

Answer 13

hardening the surface of sheets
produces steel with an outer casing of greater hardness

Question 14

carburising

Answer 14

changes the chemical composition of the surface of low carbon steel so it can absorb more carbon to increase surface hardness
placed in a ceramic box and heated to about 940 so the carbon atoms can diffuse

Question 15

quenching

Answer 15

red hot metal is quenched in water
fast cooling process which seals the hard surface case while not affecting the properties of the inner core

Question 16

hardening

Answer 16

process of heating medium and high carbon steel to alter the structure
hold them at temperature for a given time and then quench them in water, oil or saltwater baths

Question 17

tempering

Answer 17

heat treatment process for medium and high carbon steels that is carried out after hardening to reduce some of the excess hardness and increases the toughness

Question 18

fillers

Answer 18

add bulk, dont then have to use as much raw polymer