Deck 23: Plastics

Question 1

What is rotational molding?

Answer 1

Rotational molding forms hollow one-piece items from polyethylene powders. The resin is placed inside the mold, which is heated as it rotates about two axes. The resin is distributed to the surfaces of the mold by centrifugal force and fused by the heat.

Question 2

What is blow molding?

Answer 2

Blow molding involves placing a heated, preformed plastic tube called a paison in a forming die. Air pressure is raised inside the plastic tube, forcing it to conform to the shape of the die. When it cools, the die is opened and the part is removed. Most bottles are formed this way.

Question 3

____ is a process in which several layers of material are bonded together to form a single sheet.

A) Laminating
B) Thermoforming
C) Injection molding
D) Form molding

Answer 3

A

Question 4

Describe the two common cellulosics.

Question 5

____ are plastics that cannot be reheated and reformed once they have been softened, constituted, and cured.

A) Bioplastics
B) Thermosets
C) Thermoplastics
D) Polymers

Question 6

____ is a measure of how easily something will ignite or burn.

A) Flammability
B) Arc resistance
C) Weatherability
D) Density

Question 7

Explain the weatherability of plastics.

Question 8

____ is used as an inner layer in safety glass and as a protective coating on fabrics.

A) Polypropylene
B) Polystyrene
C) Polyvinyl butyral
D) Polyvinyl acetate

Question 9

What are the two major factors to consider when examining thermal properties?

Question 10

Describe the optical properties of plastics and give examples.

Question 11

What are thermosetting plastics?

Question 12

____ is measured by the modulus of elasticity.

A) Toughness
B) Tensile strength
C) Creep
D) Stiffness

Question 13

____ involves moving a plastic material in a liquid state through a series of rollers, which creates a thin plastic film as the material solidifies.

A) Blow molding
B) Casting
C) Compression molding
D) Calendaring

Question 14

What is polypropylene?

Question 15

Some ____ are used to reduce a plastic's cost by providing bulk.

A) plasticizers
B) stabilizers
C) fillers
D) colorants

Question 16

____ are tough, high in strength, and have good chemical resistance.

A) Cellulosics
B) Nylons
C) Polycarbonates
D) Fluorocarbons

Question 17

____ have good chemical and moisture resistance but are mainly used because of their excellent adhesive qualities.

A) Formaldehyde plastics
B) Vinyls
C) Polyesters
D) Epoxies

Question 18

Explain the mechanical property of stiffness as it relates to plastics.

Question 19

A single molecule is known as a ____.

A) monomer
B) polymer
C) bond
D) molecule

Question 20

What are stabilizers?