2 - Classification of materials - Polymers

Question 1

What is a thermoplastic?

Answer 1

A material which can be repeatedly reheated and reshaped, allowing it to be recycled after its initial use.

Thermoplastics have long linear chain molecules, held together by van der Waals forces

Question 2

Examples of thermoplastics

Answer 2

LDPE, HDPE, PP, HIPS, ABS, PMMA, PET, PVC

Question 3

What is a thermosetting polymer?

Answer 3

A material that, when heated, undergoes a chemical change whereby the molecules form rigid cross links.

Cannot be reheated and reshaped

Question 4

Examples of thermosetting polymers

Answer 4

Urea Formaldehyde (UF), Melamine Formaldehyde (MF), Polyester resin, Epoxy resin

Question 5

What is an elastomer?

Answer 5

A material which at room temperature can be deformed under pressure, but will return to its original shape once the pressure is removed.

Elastomers have weak bonds which allow them to stretch easily. They can be stretched repeatedly and will always return to original length and shape

Question 6

Examples of elastomers

Answer 6

Natural rubber, polybutadiene, neoprene, silicone