Plastics, Polymers and Composites

Question 1

What is the main difference between thermosets and thermoplastics?

Answer 1

Thermosets retain their form whereas thermoplastics can melt under heat after curing

Question 2

How are thermoplastic and thermosets polymer structures different?

Answer 2

Thermoplastic: weak intermolecular forces between polymer chains, no cross-links
Thermoset: strong covalent bonds between polymer chains

Question 3

What does it mean when thermoplastics become soft when heated due to crossing the “glass transition temperature” (Tg)?

Answer 3

The temperature at which a polymer changes from a hard state to a soft state

Question 4

What are some examples of thermoplastics?

Answer 4

Polyethylene (PE)
Polycarbonate (PC)
Polyvinyl chloride (PVC)

Question 5

What are some examples of thermosets?

Answer 5

Polyester resin
Polyurethanes
Bakelite

Question 6

What are Fibre-Reinforced Polymers (FRPs)?

Answer 6

Composites made from a polymer matric reinforced with another material (a matrix)

Question 7

What is an elastomer?

Answer 7

A material with loosely crosslinked polymers, examples being rubber and neoprene

Question 8

What does composites being “anisotropic” mean?

Answer 8

The material properties change depending on the placement and number of layers of reinforcement material (fibres)

Question 9

What is flexural strength?

Answer 9

A material’s ability to withstand bending

Question 10

What are some composite properties?

Answer 10

Tensile strength
Shear strength
Compressive strength

Question 11

What are some examples of composites?

Answer 11

MDF
Plywood
GRP
CRP (Carbon fibre Reinforced Plastic)