A method for quenching a polymerisation process is described. The reaction of carbon dioxide with an epoxide in the presence of a bimetallic metal complex catalyst to produce a polymer comprises the quenching step of deactivation of the catalyst by contacting the catalyst with an acid effective to deactivate the catalyst. The deactivated catalyst may be removed from the polymer product by contacting the catalyst and polymer product with a solid phase and/or by precipitation; and the catalyst may also be optionally reactivated by contacting the deactivated catalyst with an anion. The acid may contain an anion effective to initiate the polymerisation process and effective to deactivate the catalyst and the molar ratio of acid to catalyst in the deactivation step may be less than or equal to 20:1 of the acid to catalyst mole ratio for the reaction.