Everything Science Grade 12

2.5 CHAPTER 2. ORGANICMACROMOLECULES

Name Formula Monomer Properties Uses

Polyethene

(low density)

-(CH 2 -CH 2 )n- CH 2 =CH 2 soft, waxy

solid

film wrap

and plastic

bags

Polyethene

(high den-

sity)

-(CH 2 -CH 2 )n- CH 2 =CH 2 rigid electrical

insulation,

bottles and

toys

Polypropene -[CH 2 -CH(CH 3 )]n- CH 2 =CHCH 3 different

grades:

some are

soft and

others hard

carpets and

upholstery

Polyvinyl-

chloride

(PVC)

-(CH 2 -CHCl)n- CH 2 =CHCl strong, rigid pipes, floor-

ing

Polystyrene -[CH 2 -CH(C 6 H 5 )]n CH 2 =CHC 6 H 5 hard, rigid toys, pack-

aging

Polytetra-

fluoro-

ethylene

-(CF 2 -CF 2 )n- CF 2 =CF 2 resistant,

smooth,

solid

non-stick

surfaces,

electrical

insulation

Table 2.1: A summary of the formulae, properties and uses of some common plastics

Exercise 2 - 2

1. It is possible for macromolecules to be composed of more than onetype of re-
   peating monomer. Theresulting polymer is called a copolymer. Varying the
   monomers that combineto form a polymer, is one way of controlling theproper-
   ties of the resulting material. Refer to the table below which shows a number of
   different copolymers ofrubber, and answer thequestions that follow:

Monomer A Monomer B Copolymer Uses

H 2 C=CHCl H 2 C=CCl 2 Saran films and fi-

bres

H 2 C=CHC 6 H 5 H 2 C=C-CH=CH 2 SBR (styrene

butadiene

rubber)

tyres

H 2 C=CHCN H 2 C=C-CH=CH 2 Nitrile rubber adhesives and

hoses

H 2 C=C(CH 3 ) 2 H 2 C=C-CH=CH 2 Butyl rubber inner tubes

F 2 C=CF(CF 3 ) H 2 C=CHF Viton gaskets

(a) Give the structural formula for each of the monomers of nitrile rubber.

(b) Give the structural formula of the copolymerviton.

(c) In what ways wouldyou expect the properties of SBR to be different from

nitrile rubber?

(d) Suggest a reason why the properties of thesepolymers are different.