| abstract |
The silacyclobutane functional polydiorganosiloxane copolymers of the invention have the following structure: ##STR1## wherein M is selected from ##STR2## wherein R a , R b , R c , R d , R e , and R f are independently monovalent radicals selected from the group consisting of hydrogen, hydrocarbon, or substituted hydrocarbon; m and x are integers of from 0 or more; n is equal to 1; and p is an integer greater than 0; with the proviso that there is at least one silacyclobutane group in the copolymer. The copolymer can be made by reacting a hydroxyl endblocked polydiorganosiloxane with either a difunctional chain extending silacyclobutane or with a monofunctional chain stopper, or a mixture of chain extender and chain stopper. The copolymer can be made into curable compositions by use of suitable catalyst. |