Page 84 - Mechanical Behavior of Materials

Section 3.5 Polymers 85

Table 3.8 Classes, Examples, and Uses of Representative Polymers

Polymer Typical Uses
(a) Thermoplastics: ethylene structure
Polyethylene (PE) Packaging, bottles, piping
Polyvinyl chloride (PVC) Upholstery, tubing, electrical insulation
Polypropylene (PP) Hinges, boxes, ropes
Polystyrene (PS) Toys, appliance housings, foams
Polymethyl methacrylate Windows, lenses, clear shields, bone cement
(PMMA, Plexiglas, acrylic)
Polytetrafluoroethylene Tubing, bottles, seals
(PTFE, Teflon)
Acrylonitrile butadiene Telephone and appliance housings,
styrene (ABS) toys
(b) Thermoplastics: others
Nylon Gears, tire cords, tool housings
Aramids (Kevlar, Nomex) High-strength fibers
Polyoxymethylene (POM, Gears, fan blades, pipe fittings
acetal)
Polyetheretherketone (PEEK) Coatings, fans, impellers
Polycarbonate (PC) Safety helmets and lenses
(c) Thermosetting plastics
Phenol formaldehyde Electrical plugs and switches, pot handles
(phenolic, Bakelite)
Melamine formaldehyde Plastic dishes, tabletops
Urea formaldehyde Buttons, bottle caps, toilet seats
Epoxies Matrix for composites
Unsaturated polyesters Fiberglass resin
(d) Elastomers
Natural rubber; Shock absorbers, tires
cis-polyisoprene
Styrene-butadiene rubber Tires, hoses, belts
(SBR)
Polyurethane elastomers Shoe soles, electrical insulation
Nitrile rubber O-rings, oil seals, hoses
Polychloroprene (Neoprene) Wet suits, gaskets

molecular structures of some of the simpler polymers of this type are illustrated by giving their
repeating unit structures in Fig. 3.12.
Polyethylene (PE) is the simplest case, in that the only modification to the ethylene molecule
is the rearranged carbon-to-carbon bond. In polyvinyl chloride (PVC), one of the hydrogen atoms
is replaced by a chlorine atom, whereas polypropylene (PP) has a similar substitution of a methyl
(CH 3 ) group. Polystyrene (PS) has a substitution of an entire benzene ring, and PMMA is based
on two substitutions, as shown. Polytetrafluoroethylene (PTFE), also known as Teflon, has four