Abstract: A process for reclaiming elastomeric material from elemental sulphur-cured elastomeric material having a vulcanized network without using hexamethylene tetramine, by treating the sulphur-cured elastomeric material having a vulcanized network with one or more rubber delinking accelerators selected from the group of zinc salts of thiocarbamates and zinc salts of dialkyl dithiophosphates, 2-mercaptobenzothiazole or derivatives thereof, thiurams, guanidines, 4,4'-dithiomorpholine and sulphenamides, and a zinc oxide activator in an amount sufficient to act as an activator for the accelerator(s) to delink the elastomeric material at a temperature below 70.degree. C., whereby the vulcanized network is opened up or delinked to provide a curable reclaimed elastomeric material capable of being vulcanized without adding rubber vulcanizing chemicals.

Abstract: A method for the preparation of polyalkenamer which comprises in an polymerization with ring opening of the alicyclic unsaturated compound in the presence of a catalyst comprising three components:A. a compound of a transition metal of Groups IV-VIII of the Periodic System;B. a compound of a metal of Groups I-VI of the Periodic System; andC. quinone or its halogen derivative or an acid halide of sulfur-containing acid having the general formula R.sub.k SO.sub.n Q.sub.t wherein R is halogen, aryl, alkyl, nitro- or amino-group; S can be sulfur; O represents oxygen; Q stands for halogen; k = 0-1; n = 1-2; t = 1-2; The aforespecified component c makes the catalyst more active.