| 摘要 |
PURPOSE:To produce a block copolymer excellent in moldability, adhesiveness, heat resistance, water repellency, etc., by saponifying a polyvinyl ester polymer/ polysiloxane block copolymer. CONSTITUTION:Saponified is a block copolymer obtained by reacting (A) a polyvinyl ester having a group of formula I (wherein X is a halogen, and R<1> and R<2> are each a hydrocarbyl group) on a molecular terminal with (B) a polyvinyl ester having a group of formula II, wherein Y is OM, OH, OR, or X (wherein M is an alkali metal, R is a 1-6C alkyl, and X is a halogen) and R<3> and R<4> are each a hydrocarbyl group. The polyvinyl ester portion is converted into PVA, and a block copolymer of PVA with the polysiloxane is produced. In this block copolymer, the bond between the both consists of a C-Si bond, so that the block copolymer is excellent in hydrolysis resistance, and the bonds are never cleaved. Because of excellent mechanical properties of a molding, the block copolymer is useful as a functional material such as a separation membrane.
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