Mineral-reinforced rubber

The mechanism (iii) has been largely the domain of the silanes over the last 30 years. The class of compounds has demonstrated outstanding performance advantages, most notably in the fiberglass industry, but also in other varied applications including mineral filled/reinforced rubber, plastics, and high performance adhesives. Nonetheless, the silanes are not without their deficiencies specifically, high cost, severe hydrolytic instability, and nonoptimal performance on many nonsiliceous substrates. 

This year s U.S. production of thermoplastics, thermosets, and synthetic rubber is expected to be 29 billion pounds. About 80% of this is based on only a few common monomers. To improve performance, the polymer industry rarely changes to a new, probably more expensive polymer, but instead it shifts from mere homopolymers to copolymers, polyblends, or composites. These three types of multicomponent polymer systems are closely inter-related. They are intended to toughen brittle polymers with elastomers, to reinforce rubbers with active fillers, or to strengthen or stiffen plastics with fibers or minerals. 

Thermoplastic polyolefin (TPO) is a generic name that refers to polyolefin blends usually consisting of some fraction of polypropylene (PP), polyethylene (PE) or polypropylene block copolymer (PP-b-EP or BCPP ), and a thermoplastic olefinic rubber, with or without a mineral reinforcing filler such as talc or wollastonite. Common rubbers include ethylene propylene rubber (EPR), EPDM rubber, ethylene-octene (EO) copolymer mbber, ethylene-butadiene (EB), and styrene-ethylene-butadiene-styrene (SEBS) block copolymer rubbers. Currently, there are a great variety of commercial polypropylene homopolymers, PP block copolymers, and olefinic rubbers available to make a wide range of TPO blends with densities ranging from 0.92 to 1.1. 

Engelhard Corporation (2002) Performance mineral reinforcements for plastics and rubber. Technical Brochure, Engelhard Corp., Isebn, NJ, www.engelhard.com,... 

The PP-based formulations now have the largest share of the European market. They contain a carefully balanced mix of mineral reinforcement (usually talc, at between 20 and 40%), and rubber (usually EPDM). Glove-box outers, and other parts potentially in passenger contact, are similarly... 

Basically a polymer composite contains a polymer and a nonpolymer. While polymer composites include such compositions as foams and some types of gels, this chapter will be restricted to compositions of one or more polymers and one or more nonpolymers in the bulk state. There are a few points of overlap between blends and composites polymer-impregnated wood (where wood itself is a natural polymer blend), and organic fiber (e.g., polyester) reinforced plastics constitute examples. Compositions of special interest to this chapter include glass fiber reinforced plastics, carbon black reinforced rubber, and mineral-pigmented coatings. 

Byers, J. T., Meeting of Rubber Division, ACS, Cleveland, October 17-20, 1995, paper B. Ruiz, R A., Modifying Film Conversion and End-use Characteristics with Mineral Reinforcement. 

One could be tempted to overcome the modulus loss in PBT-rubber blends by adding glass or mineral to the rubber-modified blends. While this works to some extent, the effect of the filler or reinforcement is to limit the ductility of the blend. 

---