Apolar rubbers

Hot vulcanization is carried out in presses heated by steam or by electricity. It can also be done with microwaves, and then it is fast with polar rubbers and slow with apolar rubbers. The rate of this vulcanization is increased by carbon black such an effect by light-colored fillers is not known. 

The newest vulcanization process under discussion uses microwaves. The heating effect induced by microwaves is rapid with polar rubbers and slow with apolar rubbers. The rate of heating can be increased by the incorporation of carbon black. However, no suitable light-colored filler is known for this microwave heating process. 

The polarity of the network also can be varied by manipulation of the side chains of the reactive diluent. Both apolar rubbers and polar hydrogels can be obtained through the correct choice of side chain substituent. 

As a result of its saturated polymer backbone, EPDM is more resistant to oxygen, ozone, UV and heat than the low-cost commodity polydiene rubbers, such as natural rubber (NR), polybutadiene rubber (BR) and styrene-butadiene rubber (SBR). Therefore, the main use of EPD(M) is in outdoor applications, such as automotive sealing systems, window seals and roof sheeting, and in under-the-hood applications, such as coolant hoses. The main drawback of EPDM is its poor resistance to swelling in apolar fluids such as oil, making it inferior to high-performance elastomers, such as fluoro, acrylate and silicone elastomers in that respect. Over the last decade thermoplastic vulcanisates, produced via dynamic vulcanisation of blends of polypropylene (PP) and EPDM, have been commercialised, combining thermoplastic processability with rubber elasticity [8, 9]. 

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