Crosslinking reaction of rubber with aldehydes

Abstract

SynopsisThe reactions of rubber with aldehydes have previously been studied in latex or in solutions and the reaction products formed by cyclization, condensation, or addition, have been reported. In the present study, solid-state reactions of rubber with aldehydes were carried out. It was found that crosslinked rubbers may be obtained by press curing in the presence of aldehydes with acidic catalysts. Polychloroprene and Hypalon especially undergo these reactions without a catalyst or with a small amount of catalyst. In the experiments using various aldehydes, some improvements in the properties of the crosslinked rubber were observed when aldehydes such as paraformaldehyde or a-polyoxymethylene were used. Some Lewis acids such as SnClz.2HzO were found to be more effective catalysts than the above, and it was found that organic acids such as ptoluenesulfonic acid could also be used.The physical properties of the crosslinked rubber are similar to these of sulfur-cured rubbers.The curing seemed to be an ionic reaction.

Hexamethylene-N,N1 bis (tertbutyl peroxycarbamate) as crosslinking agent in elastomers

“…Butadiene and some of its copolymers have been reported to undergo thermal vulcanization although vulcanizates obtained from this method were poor (122). Other vulca'nizing agents/systems are amine-boranes(123), aldehydes (124), bisperoxycarbamates (125,126), bisazoesters (127)(128)(129), bisazidoformates (130), aromatic diazoaminocompounds(131), diamines for fluoropolymers (122), selenium and tellerium (40) and nasc:ent sulphur(132) • The list is by no means exhaustive as information on different crosslinking systems for different elastomers is scattered in the literature and further treatment of vulcanization and vulcanizing agents could be found elsewhere(40,88) •…”