CET 312 (Civil Engineering Materials: Plastics and Rubbers)

These flashcards cover key concepts, definitions, and applications related to plastics and rubbers as discussed in the CET 312 lecture.

What are plastics?

Plastics are considered to be amorphous or crystalline polymers that are hard and brittle at ordinary temperatures and primarily made from organic substances.

What are the two main processes to produce plastics?

Polymerisation and polycondensation.

What is the composition of plastics?

Organic polymers + Carbon + Oxygen + Nitrogen + Sulphur.

What are thermoplastics?

Thermoplastics are materials that can be softened and molded upon heating and are reversible to their original state when cooled.

What is an example of a thermoplastic and its application?

Nylon, used in parachutes, vehicle tires, garments, fabrics, and footwear.

What are the properties of polyethylene?

Low strength, high ductility, corrosion resistant, relatively low melting point.

What is high-density polyethylene (HDPE) used for?

Milk jugs, detergent bottles, garbage containers, and water pipes.

How is polypropylene characterized?

Tough, flexible, lightweight, durable, with good resistance to fatigue and chemical corrosion.

What is polyvinyl chloride (PVC) derived from?

Salt (57%) and oil or gas (43%).

What are some applications of phenol formaldehyde resins?

Laminated panels, handles, knobs, electrical components, and insulators.

What are the properties of natural rubber?

Flexibility, strength, and resistance to cutting, tearing, while being vulnerable to environmental conditions.

How does synthetic rubber differ from natural rubber?

Synthetic rubber is made from petrochemicals and can be molded and vulcanized like natural rubber.

What is the use of polyurethane in construction?

Insulation of refrigerators and freezers, and cushioning for furniture.

How are thermosetting plastics described?

They do not become soft on heating and never melt once set.

What is acrylonitrile butadiene styrene (ABS)?

A tough, opaque thermoplastic made from acrylonitrile, butadiene, and styrene, known for its durability and glossy finish.