Rubber Compounds with Special Mechanical Properties

For polyethylene and polyvinyl chloride blends, dibenzoylperoxide, which induces crosslinking, is used for impact strength improvement [35]. 

5-dimethyl-2,5-di(t-butylperoxy)hexane is used for blends of mixed polymers containing polyethylene, polypropylene, polyvinyl chloride, polystyrene, and poly(ethylene terephthalate) at low dosage [36]. 

Maleic anhydride-grafted polypropylene mixed with styrene-acrylonitrile-glycidylmethacry-late copolymer is used for the compatibiHzation of polypropylene and acrylonitril-butadiene-styrene blends [37]. 

Maleic anhydride-grafted recycled polypropylene is used for the compatibilization of polyamide-6 and polypropylene blends, and it leads to improved impact strength and tensile properties [38]. 

Maleic anhydride or maleic anhydride-grafted polypropylene are used for improving mechanical properties of cellulose fiber-filled compounds [39 to 42]. 

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Rubber Compounds with Special Mechanical Properties... 

One may ask why all this is necessary, since SBR (cross-linked) is almost an ideal rubber as defined earlier. The trouble with this ideal material is that it does not extrude smoothly, it degrades rapidly on exposure to warm air, and it has a tensile strength of about 500 psi (3.5 MPa). Proper compounding changes SBR to a smoothprocessing, heat-stable rubber with a tensile strength of over 3000 psi (20 MPa) However, theoretical equations no longer describe its mechanical behavior. The compounder then must be part scientist, part artist, and part statistician if he or she is to develop optimnm properties in a material. It is virtually impossible to optimize all properties at once, so compounders have developed specialized recipes for swim-snits, tires, fan belts, tarpaulins, electrical insulation, and so on. Over 9000 such recipes were published between 1948 and 1957 alone ... 

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