The chemical structures of aged dicumyl peroxide(DCP)-crosslinked EPDMs were investigated with FT-IR and ¹³C high-resolution solid state NMR. The mechanism of degradation induced by residual DCP was studied in DCP-crosslinked EPDMs.
The thermal degradation of DCP-crosslinked EPDMs occurred with the disappearance of C=C bond of ethylidene norbornene and generation of carbonyl, carboxy and hydroxy groups and the scission of polymer chains. It can be considered that the residual DCP in DCP-crosslinked EPDMs accelerated the production of peroxide and hydroperoxide. The peroxide and hydroperoxide are extremely unstable, thereby causing various degradation reactions such as production of radicals, chain scission, and oxidation reactions of EPDM polymer.

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In this paper, the adhesion of epichlorohydrin rubber (CHR) compounds to polyamide 6 (PA6) using a molecular adhesive (6-triethoxysilylpropylamino-1,3,5-triazine-2,4-ditiol, TES) has been investigated to clarify the relation between TES concentration on the PA6 surface and the peel strength of CHR/PA6 adherends. TES contains two functional groups, one is dithiol triazinyl group and the other is alkoxysilyl group. The former reacts with the chloromethyl group of CHR, the latter reacts with the OH group linked PA6 which was formed by the corona discharge treatment. The introduction of TES on the PA6 surface was analyzed by X-ray photoelectron spectroscopy (XPS). As a result, TES concentration on the PA6 surface and peel strength of CHR/PA6 adherends were influenced by the concentration and reaction temperature of TES in solution.
In addition, TES concentration on the PA6 surface correlated closely with the peel strength of CHR/PA6 adherends. The failure pattern in CHR/PA6 adherends varied from interfacial failure to cohesive failure by the way of apparent interfacial failure, with the increase of TES concentration on the PA6 surface.

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