chapter 4 plastics

Question 1

Properties and definition of thermoplastics

Answer 1

During processing the chemical composition remains unchanged and the material can be reshaped many times

Question 2

Properties and definition of Thermosetting plastics

Answer 2

Changes chemically during the moulding process and cannot be reshaped any further

Question 3

Properties of polystyrene

Answer 3

2 forms: expanded and ridged, transparent, colours well, has impact resistance, light and buoyant, good insulator. Used for food containers, packaging and insulation

Question 4

Properties of nylon

Answer 4

good resistance to extreme temperatures, tough, mechanically durable and has high chemical resistance, nylon has many uses like gears bearings, washers and clothing

Question 5

Properties of acrylic

Answer 5

Good light transmitting properties, hard and ridged and is available in lots of colours. Used for display signs and jewellery

Question 6

Properties of abs

Answer 6

Good shock absorbance, tough, stability under load is excellent, 2x cost of producing polystyrene although it has better hardness, gloss, toughness and electrical insulation properties. Some products- automotive body parts, head gear

Question 7

Properties of PVC

Answer 7

Biologically and chemically resistant, cheap, durable and easy to assemble. Water proof and used in clothing

Question 8

properties of polythene

Answer 8

there are two types, high density polythene and low density polythene, polythene is cheap flexible durable and chemically resistant. ldpe is used for plastic bags and hdpe is used to make containers

Question 9

properties of polyethylene terephthalate (pet)

Answer 9

a plastic resin which is the most common type of polyester. used for bottles and food packaging, safe strong transparent and versatile, lightweight shatter resistance and recyclable

Question 10

properties of melamine formaldehyde

Answer 10

a very hard strong plastic used for kitchen utensils and furniture making like kitchen cupboards, laminate flooring, it waterproof and helps to protect surfaces

Question 10

properties of epoxy resins

Answer 10

used in coatings and adhesives in general epoxies are known for their excellent adhesion, chemical and heat resistance, excellent mechanical properties and very good electrical insulating properties