Advices For Studying Organic Chemistry

3. Polyethylene has been produced commercially since 1943.
   
   
   1. PE is used in manufacturing flexible bottles, films, sheets, and insulation for
      electric wires.
   
   
   2. PE produced by radical polymerization has a softening point of about 110°C.
   
   
   
   


4. PE can be produced using Ziegler-Natta catalysts (organometallic complexes of
   transition metals) in which no radicals are produced, no back biting occurs, and,
   consequently, there is no chain branching.
   
   
   1. The PE is of higher density, has a higher melting point, and has greater strength.
   
   
   
   

Table 10.2 Other Common Chain-Growth Polymers

Monomer Polymer Names

CH 2 =CHCH 3

CH 2 CH

CH

( )n

(^3)
Polypropylene
CH 2 =CHCl
CH 2 CH
Cl
( )n
Poly(vinyl chloride), PVC
CH 2 =CHCN
CH 2 CH
CN
( )n
Polyacrylonitrile, Orlon
CF 2 =CF 2 (CF 2 CF 2 )n Polytetrafluoroethene, Teflon
H 2 C CCO 2 CH 3
CH 3
( )CH C
CH 3
2
CO 2 CH 3
n
Poly(methyl methacrylate),
Lucite, Plexiglas, Perspex

10.11 OTHER IMPORTANT RADICAL CHAIN REACTIONS

10.11A MOLECULAR OXYGEN AND SUPEROXIDE

1. Molecular oxygen in the ground state is a diradical with one unpaired electron on
   each oxygen.

1. As a radical, oxygen can abstract hydrogen atoms just like other radicals.