Patent attributes
This invention discloses a process for synthesizing a dendrimer of a rubbery polymer comprising: (a) reacting a lithium terminated rubbery polymer with a halogenated silicon containing compound to produce a polymer which is terminated with halogenated silicon moieties, wherein the halogenated silicon contain compound has at least four halogen atoms which are bonded directly to silicon atoms, wherein the ratio of the lithium terminated rubbery polymer to halogen atoms in the halogenated silicon containing compound is within the range of 2:n to (n−1):n, wherein n represents the number of halogen atoms that are bonded directly to silicon atoms in the halogenated silicon containing compound, wherein the halogenated silicon containing compound contains at least three halogen atoms which are bonded directly to a silicon atom; (b) reacting the polymer which is terminated with halogenated silicon moieties with a molar excess of a tertiary alcohol to produce a polymer which is terminated with hydroxy silyl moieties; and (c) allowing the polymer which is terminated with the hydroxy silyl moieties to couple under conditions sufficient to produce a dendrimer containing siloxane linkages. It has also be found that similar dendrimers having improved processability can be make utilizing halogenated tin containing compounds in stead of the halogenated silicon containing compound.
