Commodity resins and their blends

Five large-volume polymeric groups belong to this category polyethylenes, polypropylenes, styrenics, acrylics and vinyls. Their world market share remains relatively stable — the commodity resins represent 71% of all consumed plastics. 

Simon in 1839 named the distillate of Storax officinalis a styrol. By 1845, the thermal polymerization of styrene as well as the thermal depolymerization of PS were known. In 1915 I. G. Farbenindustrie started commercial production of PS, Trolitul . Until the 1950 s, PS was produced in small quantities — the resin was brittle, thermally unstable, with poor solvent and scratch resistance. The main use of styrene was in the manufacture of styrenics, viz. Buna-S, SBR, or ABS. 

Common PS is atactic and amorphous. It has good optical clarity, low dielectric loss factor, modulus E = 3.2 GPa, strength o = 45-65 MPa, density p = 1050 kg/m and CUT = 50-70°C. Because of brittleness and low chemical resistance the demand for neat PS has decreased, and except for foaming, PS is rarely used. PS can also be polymerized into crystalline forms isotactic (iPS) or syndiotactic (sPS) with T = 230 or 272°C, respectively. The former was polymerized using Ziegler-Natta catalyst [Ishihara et al., 1986], while the latter using a single-site metallocene titanium-based catalyst [Imabayashi et ah, 1994]. 

The high-impact PS, HIPS, has been known since 1911 [Matthews, 1911, 1913]. In the USA, Ostromislensky [1924, 1926-28] patented copolymerization of styrene with rubber, balata or other elastic and plastic gum . Production of HIPS, Victron , by the Naugatuck Chemical started in 1925, but soon it was discontinued. 

PS is miscible with several polymers, viz. polyphenyleneether (PPE), polyvinylmethylether (PVME), poly-2-chlorostyrene (PCS), polymethylstyrene (PMS), polycarbonate of tetramethyl bisphenol-A (TMPC), co-polycarbonate of bisphenol-A and tetramethyl bisphenol-A, polycyclohexyl acrylate (PCHA), polyethylmethacrylate (PEMA), poly-n-propyl methacrylate (PPMA), polycyclohexyl methacrylate (PCHMA), copolymers of cyclohexyl methacrylate and methyl methacrylate, bromobenzylated- or sulfonated-PPE, etc. Other miscible blends are listed in Appendix 2. 

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The worldwide commercialization of polymer blends has been directed at the replacement of traditional materials, such as metals and ceramics. Even though plastics can be more costly than other types of materials on a weight basis, they are often more economical in terms of production and manufacturing cost, mainly attributed to the less complex assembly of plastic parts that can be easily formed in complex-finished shapes [1, 21-26], Blending is a convenient route to the time-efficient and cost-effective upgrading of commodity resins and to the tailoring of these resins to specific performance profiles for the desired application. The most common polymer blends and their applications are described below. 

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