A moisture curable composition capable of cure to an elastomeric body, comprising a polymeric material having not less than two hydroxyl or hydrolyzable groups an alkoxysilane curative and a catalyst comprising:

• a mixture and/or reaction product of a compound (i) M[OR]₄ and compound (ii) M[OR]_x[Z]_z, wherein M represents a metal having a valency of 4 selected from Group IVB of the Periodic Table, preferably titanium or zirconium. Each R and R may be a primary, secondary or tertiary aliphatic hydrocarbon or the group SiR⁹₃; and a compound iii) of the general formula

  A-C(O)R¹—C(O)—B

  wherein R¹ is a methylene group or a substituted methylene radical, A is selected from —(CX₂)_nC(R²)₃ wherein n is from 0 to 5, and an adamantyl group or a derivative thereof; B is selected from the group of —(CX₂)_tC(R²)₃ wherein t is from 0 to 5; a monovalent alkyl group having from 1 to 6 carbon atoms and; OR³, wherein R³ is selected from the group of —(CX₂)_tC(R²)₃ and a monovalent alkyl group having from 1 to 6 carbon atoms; wherein each X is the same or different and is selected from the group of a halogen radical and hydrogen, each R² is the same or different and is selected from the group of a halogen radical and an alkyl radical having one to eight carbon atoms, and when n is greater than 0 at least one of X or R² is a halogen radical