c****n
发帖数: 134 | 1 By definition (Szwarc), a living polymerization involves only initiation and
propagation. there is no chain breaking reactions such as termination and
chain transfer. (Perhaps only chain polymerization is considered in the realm
of living polymerization. An important criterion of a living polymerization is
that the number of chains doesn't change with conversion.)
The living nature of a polymerization doesn't guarantee the narrow molecular
weight distribution. P. J. Flory reasoned that when init | t*******n
发帖数: 66 | 2 Actually another one important characterication about living polymierzation is
that block compolymer should be formed upon adding another monomer.
realm
is
RAFT,
is
【在 c****n 的大作中提到】
: By definition (Szwarc), a living polymerization involves only initiation and
: propagation. there is no chain breaking reactions such as termination and
: chain transfer. (Perhaps only chain polymerization is considered in the realm
: of living polymerization. An important criterion of a living polymerization is
: that the number of chains doesn't change with conversion.)
: The living nature of a polymerization doesn't guarantee the narrow molecular
: weight distribution. P. J. Flory reasoned that when init
| c****n
发帖数: 134 | 3 This criterion was listed in Quirk's book "Anionic polymerization",
but personally I don't think it is a good criterion.
Block copolymer may not be formed if you add propylene to living anionic
polystyrene...
block copolymer will be formed only when two monomer are similar in reactivity
in a specific polymerization (such as styrene and butadiene in anionic
polymerization). when the two monomers are quite different in reactivity, the
block copolymer may not be formed or there may be contaminatio
【在 t*******n 的大作中提到】
: Actually another one important characterication about living polymierzation is
: that block compolymer should be formed upon adding another monomer.
:
: realm
: is
: RAFT,
: is
|
|
