Hydrolysable silanes and polymeric materials modified by silanes

A process for modifying a polymeric material having a carbon backbone containing carbon-to-carbon unsaturation by reaction with a hydrolysable silane, characterised in that the hydrolysable silane has the formula wherein each R represents a hydrolysable group; each R" represents a hydrocarbyl group having 1 to 8 carbon atoms; n = 1 to 3; Y represents a divalent organic spacer linkage having 1 to 20 carbon atoms; z = 1 to 8; y = 0 or 1; x = 0 or 1; x+y= 0 or 1; R1 represents hydrogen or a hydrocarbyl or substituted hydrocarbyl group having 1 to 8 carbon atoms; and R2 represents a hydrocabyl or substituted hydrocabyl group having 1 to 20 carbon atoms. In another aspect, a diene elastomer composition comprising a diene elastomer, a curing agent and the above hydrolysable silane. The hydrolysable silanes are useful in the modification of elastomers, and as coupling agents for diene elastomer compositions containing a filler. In particular, hydrolysable silanes containing a keto group and the preparation of such hydrolysable silanes, to a process for modifying a polymeric material by reaction with a hydrolysable silane, to diene elastomer compositions containing a hydrolysable silane and to the use of the hydrolysable silanes as coupling agents for diene elastomer compositions containing a filler.