Crosslinking by metallic oxides

The vulcanization of polychloroprene (Neoprene) is carried out in different ways. Vulcanization by sulfur, even with an accelerator, is not practiced to a large extent. Vulcanizations by metal oxides (without diamine), either alone or in combination with sulfur (sometimes together with an accelerator), give the best physical properties for the crosslinked product. Halogenated butyl rubber is crosslinked in a similar manner. The mechanism for crosslinking by metal oxide alone is not established [Stewart et al., 1985 Vukov, 1984]. 

Polychloroprene is crosslinked by metallic oxides. Zinc oxide and magnesium oxide are generally used. Chlorosulfonated polyethylene is crosslinked with litharge (PbO), PbO/MgO, and MgO/pentaerythritol. 

CR can be crosslinked by metal oxides alone. Thus, there is a major difference between general purpose diene rubbers and CR. Suitable accelerators help to achieve a sufficient state of crosslinking under the desired conditions. 

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See also in sourсe #XX -- [ ]

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