Method of directing grafting by controlling the location of high vinyl segments in a polymer

A method comprising the steps of:

• a. forming a living prepolymer high vinyl initiator with a vinyl content greater than about 45% using a vinyl modifier,
• b. adding a R1R2R3aluminum or R1R2R3boron compound to nullify the effect of the vinyl modifier, and
• c. initiating polymerization of diene monomers using said living prepolymer high vinyl initiator so as to form a polymer product with a block A high vinyl end segment and a block B segment,
• d. adding the polymer containing at least one high vinyl end segment to a solvent comprising at least one vinyl aromatic monomer;
• e. optionally adding at least one additional inert solvent;
• f. optionally adding additives selected from the group consisting of extender oils, modifiers, and antioxidants,
• g. initiating polymerization of the vinyl aromatic monomer by the use of an initiator and/or heat,
• where R1,R2,and R3 are selected from the group consisting of C1-C12 alkyl, C2-C12 alkene, C2-C12 alkyne, phenyl, and alkyl-substituted phenyl and may all be identical or may all be separately selected but cannot be H
• wherein steps (d), (e) and (f) can be performed in any order;
• whereby the result of steps (a)-(g) is production of an engineered plastic;
• wherein the engineered plastic is selected from the group consisting of high impact polystyrene, styrene-maleic anhydride copolymer, methylmethacrylate-butadiene-styrene copolymer, transparent impact polystyrene, and acrylonitrile butadiene styrene copolymer;
• and
• wherein the block A high vinyl end segment of the polymer has a 1,2-vinyl bond content of greater than about 45% and a number average molecular weight of about 100 to about 20.000;
• wherein said block B has a vinyl content of less than about 45%;
• wherein said polymer has an overall number average molecular weight of about 40,000 to about 300,000.

A method comprising the steps of:

• (a)adding a polymer containing at least one block A and at least one additional block selected from the group consisting of a block B, a block C, and combinations thereof to a solvent comprising styrene;
• (b)optionally adding at least one additional inert solvent;
• (c)optionally adding additives selected from the group consisting of extender oils, modifiers, and antioxidants,
• (d)initiating polymerization of the styrene by the use of an initiator and/or heat,
• wherein steps (a), (b) and (c) can be performed in any order;
• whereby the product resulting from steps (a)-(d) is high impact polystyrene;
• wherein said block A has a 1,2-vinyl bond content of greater than about 45% and a number average molecular weight of about 100 to about 20,000;
• wherein said block B has a vinyl content of less than about 45% and said block C comprises one or more aromatic vinyl monomers;
• wherein said polymer has an overall number average molecular weight of about 40,000 to about 300,000;
• and
• wherein the presence of the at least one high vinyl segment in the polymer allows direction of the grafting site during preparation of the high impact polystyrene.