Process for preparation of block copolymers

Details Process for preparation of block copolymers Process for preparation of block copolymers

1977-03-09

1981-09-22

Michl, Paul R.

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Mixing of two or more solid polymers; mixing of solid...

260 336A, C08F29704

Patent

active

042911397

ABSTRACT:
The process described herein involves the preparation of block copolymers of the S-B-S type wherein S represents a block of polystyrene and B represents a block of polybutadiene. In order to have the initial polystyrene block soluble in the polymerization medium, cyclohexane and aromatic hydrocarbons have been used as the diluent or solvent in these polymerizations. The present process permits the use of hexane as diluent by first preparing a "foot" or small block of homopolydiene to which the initial polystyrene block is thereafter attached. This small block of homopolydiene represents no more than 12 parts, preferably no more than 10 parts by weight of homopolydiene per 100 parts by weight of the block of polystyrene to which it is attached. Generally therefore this block has a molecular weight of 200-5000 depending on the size of the attached polystyrene block and is not large enough to alter the properties of the resultant S-B-S block copolymer except to give the initial polystyrene block greater dispersibility in hexane, heptane, etc.

REFERENCES:
patent: 3231635 (1966-01-01), Holden
patent: 3427364 (1969-02-01), Shaw
patent: 3937760 (1976-02-01), Cole
patent: 4089913 (1978-05-01), Miki
Smith Defensive Publication T953011, published Dec. 7, 1976 (pp. 1-13 of Smith SN431531, parent case of T953011 enclosed).

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