Polymers of bromostyrenes having controlled molecular weight
AssigneeChemtura Corporation
InventorsWayne Meyer, Jennifer Bohan, Larry Timberlake, James Siebecker
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Abstract
A controlled molecular weight polymer of styrene is provided having bromine substituted thereon. Control of molecular weight is achieved by the use of alpha-methyl styrene dimer as a chain transfer agent. The brominated polymer of styrene is useful as a flame retardant, particularly for polyamides giving improved properties including color retention after molding.
Claims19
Polymers of ar-bromostyrene monomers and brominated polystyrene having the following general structure
- where R is H or CH3 and x is an integer of 1 to 5, 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, wherein the polymers further comprise residues of α-methyl styrene dimer.
Polymers of ar-bromostyrene monomers having the following general structure
- where R is H or CH3 and x is an integer of 1 to 5, where the polymers have an assigned weight average molecular weight of from about 11,000 to about 60,000, wherein the polymers retain at least 88% of their mass after 20 minutes and at least 85% of their mass after 30 minutes when a 10 mg specimen is held at 330° C. under a nitrogen atmosphere.
A process to control the molecular weight of bromostyrene polymers in which a-methyl styrene dimer is used as a chain transfer agent, comprising the steps of:
- (a) providing an essentially solventless blend of:
- (i) monomers of brominated styrenes;
- (ii) a polymerization initiator;
- and
- (iii) a-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 bromostyrene from the reaction vessel.
A process to control molecular weight of styrene polymers in which the a-methyl styrene dimer is used as a chain transfer agent, comprising the steps of:
- (a) providing an essentially solventless blend of:
- (i) monomers of styrene;
- (ii) a polymerization initiator;
- and
- (iii) a-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;
- (d) adding bromine to react with the polymerized styrene under conditions effective to brominate the polymerized styrene and
- (e) removing the polymerized bromostyrene from the reaction vessel.
Dependencies are inferred from the claim text.