the process of this invention can be utilized to stabilize tin - coupled rubbery polymers . it is particularly useful for stabilizing rubbery polymers that do not contain bound styrene . this invention more specifically discloses a process for improving the stability of a tin - coupled rubbery polymer which comprises adding 0 . 1 phr to about 4 phr of styrene to a living rubbery polymer to produce a styrene capped rubbery polymer , adding a tin halide to the styrene capped living rubbery polymer to produce the tin - coupled rubbery polymer , and optionally , adding a tertiary chelating alkyl 1 , 2 - ethylene diamine or a metal salt of a cyclic alcohol to the tin - coupled rubbery polymer . the use of metal salts of cyclic alcohols is preferred because they do not lead to recycle stream contamination . this is because cyclic alcohols do not co - distill with hexane or form compounds during steam - stripping which co - distill with hexane . in other words , the boiling points of these metal salts of cyclic alcohols are very high , so they do not co - distill with hexane and contaminate recycle streams . additionally , metal salts of cyclic alcohols are considered to be environmentally safe . in fact , sodium mentholate is used as a food additive .