Ethylene—propylene-diene monomer cure systems

Mechanical Properties and Cure Rate Index of the Mixes—Role of Dry Bonding System on the Reinforcement of Ethylene-Propylene-Diene Monomer (EPDM) Rubber with Melamine Fiber ... 

FIGURE 12.16 Plots of tan S versus temperature of maleated ethylene-propylene-diene monomer (EPDM) rubber-melamine fiber composites cured by using mixed cross-bnking system. (From Rajeev, R.S., Bhowmick, A.K., De, S.K., and Bandyopadhyay, S., J. Appl. Polym. Sci., 89, 1211, 2003. With permission.)... 

Cure Systems in Ethylene-Propylene Diene Monomer (EPDM)... 

Over the years, much of the research on accelerated-sulfur vulcanization was done by using natural rubber as a model substrate. Natural rubber was the first elastomer and therefore the search for the understanding of vulcanization originated with work on natural rubber. Most of the work cited in the previous sections is related to natural rubber. However, some rather early studies have been directed to the vulcanization of butadiene 1,4-polymers (Skinner and Watson, 1969 Wolfe et al, 1329 Gregg and Katrenick, 1970). More recent is the work of Pellicioli and coworkers. Early basic work on the vulcanization of ethylene-propylene-diene-monomer rubber (EPDM) has been carried out (van den Berg et al., 1984a,b). Recently, Kuno and coworkers did basic work on EPDM networks. They found that, essentially, the vulcanizate properties depend only on the crosslink density, not on the type of curing system (Dijkhuis et al., 2009). 

Since EPR rubber molecules do not contain unsaturation, they can be vulcanized only by organic peroxide curing systems. If a third monomer is added during the polymerization, i.e., a diene monomer (wherein only one of the two double bonds takes part in the polymerization), unsaturation can be introduced into the molecule, and it can then be vulcanized by accelerated sulfur curing systems. A chemical structure for ethylene-propylene-diene-monomer (EPDM) rubbers can be expressed as follows ... 

A.S.Z. Naseri, A. JalaU-Arani, A comparison between the effects of gamma radiation and sulfur cure system on the microstructiire and crosslink network of (styrene butadiene rubber/ethylene propylene diene monomer) blends in presence of nanoclay. Radiation Physics and Chemistry, ISSN 0969-806X 115 (October 2015) 68-74. http //dx.doi. org/10.1016/jjadphyschem.2015.05.037. 

EPDM is a terpolymer of ethylene, propylene, and a small amount of an unsaturated diene as a third monomer to provide a cure site. Unlike the elastomers previously discussed, the unsaturation in EPDM is not in the main chain, but it is pendent to the chain. Peroxide-based cure systems afford better aging resistance and low compression set. A comparison of a sulfur-based cure to two different peroxides in EPDM is shown in Table 21 (4). Initial properties for these three compounds are reasonably close. However, after air aging, the advantages of peroxide curing are apparent. Most dramatic is the improved compression set... 

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