Method for preparing improved polyalphamethyls tyrene-polydiorganosiloxane block copolymers and products thereof
US4107227A · kind A · utility
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11Claims
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Key dates
| Filing date | Dec 9, 1976 |
| Grant date | Aug 15, 1978 |
| Priority date | — |
| Expiry date | Dec 9, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31663
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Block copolymers are prepared by coupling a poly-.alpha.-methylstyrene block with a polydiorganosiloxane block through a small amount of coupling units of the formula ##STR1## where R denotes an alkyl radical of 1 to 4 carbon atoms. The resulting block copolymers have an improved glass transition temperature, reaching a value of approximately the glass transition temperature of an analogous poly-.alpha.-methylstyrene when R is tertiary-butyl.
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