| 159. Litvinenko, G. I.; Müller, A.H.E.: Molecular weight averages and degree of branching in self-condensing vinyl copolymerization in the presence of multifunctional initiators, Macromolecules 35, 4577 (2002) | |
| Abstract: The averages of the molecular weight distribution (MWD) and the degree of branching (DB) are calculated for hyperbranched copolymers obtained in the self-condensing vinyl copolymerization (SCVCP) of AB* initiator-monomers ("inimers") with a monomer M in the presence of an f-functional initiator, G*f. Two cases are considered: (a) batch polymerization when all components are mixed simultaneously; (b) semibatch polymerization, i.e., slow addition of the comonomer mixture to the system. The presence of initiator leads to a considerable narrowing of the MWDs, the nonuniformity of the distribution (U =  w/n
-1) decreasing with initiator functionality, f, similar to normal
self-condensing vinyl polymerization (SCVP): U 
f-2 in the batch mode and U = f-1 in
the semibatch mode. In the semibatch process, the presence of comonomer
does not further decrease the polydispersity, as compared to the homopolymerization
of AB* inimers in the presence of polyinitiator. The degree of branching
is only slightly affected by the presence of polyinitiator and is mostly
governed by the comonomer content. In contrast to semibatch SCVP with initiator,
there is no increase in DB. The calculations are also applied to polymerizations
from surface-bound initiators. |
Prof. Dr. Axel Müller
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