Thermoplastic elastomeric olefins

Thermoplastic Elastomeric Olefins (TPOs). EPDM rubber and PP are the constituents of the most common TPOs. An EPDM/PP TPO has a near that of the hard PP phase and a rubber-phase Tg close to that for the soft EPDM (plus additives) phase. These TPOs thus melt in the range of 150 to 165°C and can be processed above these temperatures. They show excellent low-temperature performance with brittle points often below -60°C. The clearly determines the upper theoretical service temperature limit of these TPOs. The maximum long-term service temperature is usually 25 to 50°C below the depending in part on the resistance of the polymers to oxidative attack. 

System for Automotive Thermoplastics Elastomeric Olefins (TEO) System for Automotive PolyfMethyl methacrylate) (PMMA) Plasticsl System for Automotive Polyester Plastics ... 

PVDC polyvinylldene chloride TEO thermoplastic elastomeric olefin... 

Reith RL, Eaton FR, Coates WG. Polymerization of ureidopyrimidinone-functionalized olefins by using late-transition metal Ziegler-Natta catalysts synthesis of thermoplastic elastomeric polyolefins. Angew Chem Int Ed 2001 40 2153-2156. 

Very recently, Coates et al. used a vinyl-substituted Upy-unit to be part of an olefin polymerization using the Brookhart catalyst. With small amounts of Upy-units incorporated, the polyolefins showed thermoplastic elastomeric properties.120... 

Another remarkable character of this class of Ni complexes is their tendency to promote living polymerization of a-olefins at low temperatures and with low concentrations of the monomer. Thus, the low-temperature polymerization of propylene leads to a material whose number average molecular weight (Mn) increases almost linearly as a function of time and propylene consumption, reaching values of M = 160 000 Daltons and polydispersities of ca. 1.13. This character allows these Ni catalysts to produce A-B-A type block copolymers composed of semicrystalline and amorphous segments, which is used to prepare thermoplastic elastomeric polymers. The Ni catalysts can also polymerize internal cyclic... 

The living nature of the nickel-catalyzed a-olefin polymerizations coupled with the propensity for chain straightening of longer a-olefins can be utilized to prepare block copolymers with well-defined architectures. For example, the synthesis of a-olefin A—B—A block copolymers where the semicrystalline A blocks are made up of poly(l-octadecene) and the B block is composed of a more highly branched, amorphous, random copolymer of propylene and 1-octadecene enabled the preparation of thermoplastic elastomeric polyolefins. ... 

Olefins or alkenes are defined as unsaturated aliphatic hydrocarbons. Ethylene and propylene are the main monomers for polyolefin foams, but dienes such as polyisoprene should also be included. The copolymers of ethylene and propylene (PP) will be included, but not polyvinyl chloride (PVC), which is usually treated as a separate polymer class. The majority of these foams have densities <100 kg m, and their microstructure consists of closed, polygonal cells with thin faces (Figure la). The review will not consider structural foam injection mouldings of PP, which have solid skins and cores of density in the range 400 to 700 kg m, and have distinct production methods and properties (456). The microstructure of these foams consists of isolated gas bubbles, often elongated by the flow of thermoplastic. However, elastomeric and microcellular foams of relative density in the range 0.3 to 0.5, which also have isolated spherical bubbles (Figure lb), will be included. The relative density of a foam is defined as the foam density divided by the polymer density. It is the inverse of the expansion ratio . 

Cavitation in the rubber particles of PS/high-impact PS (HIPS) was also identified as a heterogeneous nucleation site, using batch-foam processing [15, 16]. The experimentally observed cell densities as a function of the temperature, the rubber (HIPS) concentration, the rubber particle size, and saturation pressure were found to be in good agreement with the proposed nucleation model. Similar nucleation mechanisms of elastomeric particles were claimed for acrylic and di-olefinic latex particles in various thermoplastics [17, 18]. 

Polyolefin - Polyolefins are a large class of carbon-chain elastomeric and thermoplastic polymers usually prepared by addition (co)polymerization of olefins or alkenes such as ethylene. The most important representatives of this class are polyethylene and polypropylene. There are branched and linear polyolefins and some contain polar pendant groups or are halogenated. Unmodified polyolefins are characterized by relatively low thermal stability and a nonporous, nonpolar surface with poor adhesive properties. Processed by extrusion, injection molding, blow molding, and rotational molding. Other thermoplastic processes are used less frequently. This class of plastics is used more and has more applications than any other. Also called olefinic resin, olefinic plastic. 

The blends of EPDM terpolymers and isotactic PP with curing agents, such as peroxide, phenol resins, and sulfur, are termed as thermoplastic vulcanized elastomer (TPV) since the rubber domains are vulcanized. Polyolefin copolymers, such as random copolymer of propylene with ethylene, copolymers of other olefins, elastomeric PP, and elastomeric PE, are developed with recent advances of... 

A final word in this short summary of impact modification concerns the amount of imagination compounders and polymer scientists continue to invest in the development of rubber-modified compoimds. Efforts are being made to decrease their compounding costs, to enhance their paintability, and to formulate them to replace more competing materials such as ABS, thermoset rubber, and PVC—thereby allowing more recyclable "aU-olefin" automotive interiors, for example. Recent efforts have even been made to incorporate ground vehicle tire rubber or other "ultrafine rubber particles into PP to create vulcanized elastomeric thermoplastics that cost less than half as much as standard TPVs. Similar concepts will continue to push impact-modified POs into new applications [7-26, 7-27, 7-28]. 

FTIR step-scan photoacoustic spectroscopy was used to study the composition of thermoplastic olefin films, as a function of depth below the surface. Experiments were completed at various modulation frequencies, enabling a stratification model to be developed. The uppermost layer (0-3 im) showed large changes in talc and PP concentration, while the layer below showed a significant decrease in both the phases. In the third layer (6-9 pm), all three phases showed the maximum values. In the fourth layer (9-12 pm), the talc concentration reduced, whilst concentrations of elastomeric copolymer of ethylene and propylene (EPR) and PP were observed, decreasing with depth (44). 

Montell s in-reactor Catalloy ( catalytic alloy ) polymerization process alloys propylene with comonomers, such as EPR and EPDM, yielding very soft, very hard, and rigid plastics, impact grades or elastomeric TPOs, depending on the EPR or EPDM % content. The term olefinic for thermoplastic olefinic elastomers is arguable, because of the generic definition of olefinic. TPVs are composed of a continuous thermoplastic polypropylene phase and a discontinuous vulcanized rubber phase, usually EPDM, EPR, nitrile rubber, or butyl rubber. 

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