Olefinic thermoplastic vulcanizate

Results given in Table VII show that the viscosity versus shear rate variation of these three Santoprene grades fits the power law over the entire range from 10 to 5200 s . Both the viscosity and the extrudate swell at constant shear rate increase with decreasing rubber particle content (or increasing hardness). Thus, these olefinic thermoplastic vulcanizates essentially behave like highly filled fluids in flow. When compared with unvulcanised rubber (see previous sections) or polypropylene - EPDM blends (32), the extrudate swell appears low and there is no Newtonian viscosity plateau. 

By a suitable treatment of these MPT data, it is however possible to derive some more information on flow behaviour and morphological effects of these olefinic thermoplastic vulcanizates (OTV). 

Thermoplastic Vulcanizates. These are a surprising improvement over conventional thermoplastic olefins. Vulcanized ethylene/... 

TOE Catalyst turnover frequency TPE Thermoplastic elastomer TPO Thermoplastic olefinic elastomer TPU Thermoplastic urethanes TPV Thermoplastic vulcanizate TR Tubular reactor... 

COPs differ from simple polyester thermoplastics, which are typically hard crystalline polymers of organic dibasic acids and diols. COPs have an excellent combination of properties and are accordingly priced higher than thermoplastic elastic olefins (TEOs) or thermoplastic vulcanizates (TPVs). 

TPEs which are prepared by physical blending of an elastomer with a thermoplastic. Such TPEs are categorized into two types depending on rubber vulcanization (i) thermoplastic olefins (TPOs) or thermoplastic elastomer polyolefins (TEOs) (ii) thermoplastic vulcanizates (TPVs). 

EPDM is a terpolymer produced from ethylene, propylene, and a diene monomer that is usually 5-ethylidene-2-norbornene (ENB), see Eigure 3.12. Good EPDM properties are attainable because the stereospecific Ziegler-Natta catalysts and the newer metallocene-type catalysts are used in the polymerization of these elastomers. Much proprietary knowledge is applied with the latest catalysts to help the EPDM producers achieve a competitive advantage in the marketplace. Today, about 20% of all EPDM goes into the production of TPOs (thermoplastic olefins) or TPVs (thermoplastic vulcanizates), mainly for nontire automobile uses. (About 13% of EPDM production is used in TPO manufacture while about 7% is consumed in TPV production.)... 

The use of thermoplastic olefins or TPOs is growing at a faster rate than the styrenic block copolymers (SBC) just discussed, or the thermoplastic vulcanizates (TPVs), which are discussed in the next section. The TPO growth rate is currently about 10% annually worldwide. Unlike the SBCs, certain TPOs can sometimes be used at higher service temperatures. Unlike the TPVs (which are derived through dynamic vulcanization), the TPOs are usually used uncured or are only very slightly vulcanized, if at all. This means that the TPOs are usually less costly than the TPVs. The TPOs have been very successful in the automotive industry in replacing the soft polyvinyl chloride compounds used in car interiors. TPOs are commonly available in softness ranges from 60 Shore A to 60 Shore D. A major use for TPOs is in the manufacture of automotive fascias, where appearance is very important. 

Figure 2 Compression set (elastic recovery under compressive deformation) at 70 °C for an E-LAO random copolymer, flexible polyvinylchloride (f-PVC), thermoplastic polyurethanes (TPUs), and thermoplastic vulcanizates (TPVs). Reproduced with permission from Wenzel, T. T. Arriola, D. J. Carnahan, E. M. et at. In Metal Catalysts in Olefin Poiymerization. Topics in Organometallic Chemistiy, Guan, I., Ed. Springer-Verlag Berlin, Germany, 2009 Vol. 26. ...

Brookfield, CT, SPE, 2003, p.45-52, 27 cm, 012 NEW MIXING STRATEGIES FOR THE REACTIVE COMPOUNDING OF THERMOPLASTIC OLEFINS AND THERMOPLASTIC VULCANIZATES FORMULATIONS Mack M H Uphus R... 

In addition to the above-mentioned fields of application, functionahzation of blends of olefin polymers and copolymers has been widely employed in the manufacture of thermoplastic dynamic vulcanizates (71,72). 

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