ch.26 Flashcards
definition of a polymer
a large molecule composed of many spaller repeating units
Who first postulated polymers?
Hermann Staudinger
What is the difference between addition and condensation polymers?
addition = chain growth
condensation = step growth
What are the 3 kinds of addition polymer intermediates?
free radicals, carbocations, and carbanions
When does chain branching occur?
when the growing end of a chain abstracts a hydrogen atom from the middle of a chain
chain branching makes the polymer _____.
soft
what does ATRP stand for?
atom transfer radical polymerization
what are good monomers for cationic polymerization?
styrene or isobutylene
what are poor monomers for cationic polymerization?
ethylene or acrylonitrile
The _____ polymerization reaction is initiated by a Grignard or organolithium reagent.
anionic
In anionic polymerization, the alkene must have an electron withdrawing group like what?
C=O or NO2
Why are isotactic and syndiotactic polymers stronger?
stronger and stiffer due to their regular packing arrangement
What usually gives isotactic or syndiotactic polymers?
anionic intermediate
Free-radical polymerization is nearly random, giving branched ______ polymers.
atactic
The Ziegler-Natta catalyst polymerization is completely __________.
stereospecific
