Process for preparation of block copolymers

专利名称：Process for preparation of block

copolymers

发明人：Adel F. Halasa,James E. Hall,Adolph Para申请号：US05/776048申请日：19770309公开号：US04291139A公开日：19810922

摘要：The process described herein involves the preparation of block copolymers ofthe S-B-S type wherein S represents a block of polystyrene and B represents a block ofpolybutadiene. In order to have the initial polystyrene block soluble in the

polymerization medium, cyclohexane and aromatic hydrocarbons have been used as thediluent or solvent in these polymerizations. The present process permits the use ofhexane as diluent by first preparing a \"foot\" or small block of homopolydiene to whichthe initial polystyrene block is thereafter attached. This small block of homopolydienerepresents no more than 12 parts, preferably no more than 10 parts by weight ofhomopolydiene per 100 parts by weight of the block of polystyrene to which it isattached. Generally therefore this block has a molecular weight of 200-5000 dependingon the size of the attached polystyrene block and is not large enough to alter theproperties of the resultant S-B-S block copolymer except to give the initial polystyreneblock greater dispersibility in hexane, heptane, etc.

申请人：THE FIRESTONE TIRE & RUBBER COMPANY

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