| 摘要 |
Elastomeric polymers are made by hydrogenating a block copolymer of the formula A-B-A in which each A is an independently selected polymerized alkenyl aromatic hydrocarbon block having an average molecular weight of 4000 to 115,000 and in which B is a polymerized conjugated diene hydrocarbon block having an average molecular weight of 20,000 to 450,000, block A constituting 2 to 35% of the block copolymer, the residual unsaturation, both ethylenic and benzenoid, being less than 30% of its original value. The block copolymer starting materials are made by the sequential polymerization of alkenyl aromatic monomers and conjugated dienes. The hydrogenation of the block copolymers is carried out with the aid of known catalysts, e.g. nickel on kieselguhr. The hydrogenated products may be used as moulding materials and may be modified by the presence of silicone and mineral oils, chlorinated biphenyl, polyethylene, polypropylene, polystyrene, asphalt, wax and natural and synthetic rubbers. The examples describe the hydrogenation of polystyrene-polyisoprene-polystyrene block copolymers. |
