| 摘要 |
Polymers having the general formula R113SiO(R12SiRSiR12O)nSi R113, wherein R is <FORM:1009964/C3/1> or <FORM:1009964/C3/2> each R1 is a monovalent hydrocarbon radical free from aliphatic unsaturation, each R11 is a monovalent hydrocarbon or halohydrocarbon radical and n is an integer of at least 2, can be made (1) by cohydrolysing and condensing a mixture of R113SiX and XR12SiRSiR12X, wherein X is halogen, alkoxy, acyloxy or hydroxy, and acid acceptor being used where X is halogen, or (2) when R11 is free from aliphatic unsaturation, by equilibrating a mixture of R113SiOSiR113 and XR12SiR SiR12X. In a typical Example (1) p-bis-(dimethylhydroxysilyl) benzene and tetramethylguanidine were dissolved in benzene by refluxing for 3 hours; further benzene and (CH3)3SiOOC.CH3 were added and refluxing continued to yield a polymer having the formula <FORM:1009964/C3/3> wherein n=</>t125. Uses.-they can be drawn into fibres, cast in moulds, or form films on surfaces either from melts/sHor solutions; used as heat transfer media; or can be mille into silicone rubber stocks to produce heat-shrinkable silicone rubbers as set forth in Specification 1,009,009. |
