Patent ID: 7691954

Claim:
A process to control the molecular weight of bromostyrene polymers in which α-methyl styrene dimer is used as a chain transfer agent, comprising the steps of: (a) providing an essentially solventless blend of: (i) ar-bromostyrene monomers having the following general structure where R is H and x is 3, where the polymers have an assigned weight average molecular weight (MW) compared with a polystyrene standard as measured by gel permeation chromatography of from about 11,000 to about 60,000; (ii) a polymerization initiator; and (iii) α-methyl styrene dimer, (b) feeding the monomer/polymerization initiator blend into a reaction vessel; (c) reacting the monomer/polymerization initiator blend under conditions effective to polymerize at least about 80% of the monomers in a time of between about 1 minute and about 20 minutes; and (d) removing the polymerized bromostyrenes from the reaction vessel.