Polymers, Ceramics, and Composites

Question 1

Plastics that soften with increasing temperature and regain rigidity as the temperature is decreased are called

Answer 1

Thermoplastic

Question 2

Plastic materials that cannot be returned to the original state after they have been exposed to higher temperature during the manufacturing process are referred to as

Answer 2

Thermosetting

Question 3

The greatest variety of plastics compromises

Answer 3

Synthetic material

Question 4

The most important area of plastic processing is

Answer 4

Matched die molding

Question 5

Compression molding, cold molding, transfer molding, and injection molding are all examples of what type of plastic processing

Answer 5

Matched die molding

Question 6

___________materials may be held in the softened condition for prolonged periods of time with little or no chemical change

Answer 6

Thermoplastic

Question 7

The high pressures required by compression molding, together with the low viscosity of most thermosetting materials, require that the mold halves have fitting clearances on the order of

Answer 7

0.025 mm(0.001 in.)

Question 8

The sprue and runner system, or “cull” that is produced during the transfer molding process

Answer 8

Must be removed and cannot be reused

Question 9

The injection molding process for thermosetting plastics is referred to as

Answer 9

Jet, flow, or offset molding

Question 10

A low tooling cost procedure restricted to thermosetting resins used for low production of jewelry, novelty items, laboratory specimens, and similar parts is called

Answer 10

Casting of plastics

Question 11

Thin plastic film is produced either by extruding the plastic through a slit of the appropriate size or by

Answer 11

The expanded tube method