| 摘要 |
A thermoplastic elastomer composition comprising a polymer of an alpha -olefin containing from 2 to 5 carbon atoms, a 4-methyl-1-pentene polymer and a selectively hydrogenated block copolymer comprising at least two polymeric blocks predominantly polymerized from monoalkenyl aromatic hydrocarbon monomer units and at least one polymeric block predominantly polymerized from conjugated diolefin monomer units which at least one polymeric block is selectively hydrogenated after polymerization. The thermoplastic elastomer composition is particularly useful in the preparation of an IPN having a higher service temperature than similar structures known in the prior art. In general, the thermoplastic elastomer composition will comprise from about 20 to about 70 wt % of the alpha -olefin polymer, from about 20 to about 70 wt % of the 4-methyl-1-pentene polymer and from about 5 to about 25 wt % of the block copolymer. In a preferred embodiment, the alpha -olefin polymer will be an isotactic polypropylene having a crystallinity of at least 50%, the 4-methyl-1-pentene polymer will be a copolymer and the selectively hydrogenated block copolymer will comprise two polymeric blocks predominantly polymerized from monoalkenyl aromatic hydrocarbon monomer units and at least one polymeric block predominantly polymerized from conjugated diolefin monomer units that has been hydrogenated after polymerization. In a most preferred embodiment, the selectively hydrogenated block copolymer will contain terminal polymeric blocks which are styrene homopolymers and a central polymeric block which is a homopolymer of butadiene that has been hydrogenated after polymerization.
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