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plasticizer
Plasticizers (UK: plasticisers) or dispersants are additives that increase the plasticity or fluidity of a material. The dominant applications are for plastics, especially polyvinyl chloride (PVC). The properties of other materials are also improved when blended with plasticizers including concrete, clays, and related products.
==For plastics==
Plasticizers for plastics are additives, most commonly phthalate esters in PVC applications. Almost 90% of the market for plasticizer is for PVC, giving this material improved flexibility and durability.〔David F. Cadogan and Christopher J. Howick "Plasticizers" in Ullmann's Encyclopedia of Industrial Chemistry 2000, Wiley-VCH, Weinheim. 〕 The majority is used in films and cables.〔(Market Study Plasticizers, 3rd ed., Ceresana, Nov. 2013 )〕 It was commonly thought that plasticizers work by embedding themselves between the chains of polymers, spacing them apart (increasing the "free volume"),〔(1) Maeda, Y.; Paul, D. R. J. Polym. Sci. Part B Polym. Phys. 1987, 25, 957–980.〕〔(1) Maeda, Y.; Paul, D. R. J. Polym. Sci. Part B Polym. Phys. 1987, 25, 1005–1016.〕 and thus significantly lowering the glass transition temperature for the plastic and making it softer; however it was later shown that the free volume explanation could not account for all of the effects of plasticization.〔(1) Casalini, R.; Ngai, K. L.; Robertson, C. G.; Roland, C. M. J. Polym. Sci. Part B Polym. Phys. 2000, 38, 1841–1847.〕 For plastics such as PVC, the more plasticizer added, the lower their cold flex temperature will be. This means that the plastic will be more flexible and its durability will increase as a result of it. Plasticizers evaporate and tend to concentrate in an enclosed space; the "new car smell" is caused mostly by plasticizers evaporating from the car interior.
Plasticizers make it possible to achieve improved compound processing characteristics, while also providing flexibility in the end-use product. Ester plasticizers are selected based upon cost-performance evaluation. The rubber compounder must evaluate ester plasticizers for compatibility, processibility, permanence and other performance properties. The wide variety of ester chemistries that are in production include sebacates, adipates, terephthalates, dibenzoates, gluterates, phthalates, azelates, and other specialty blends. This broad product line provides an array of performance benefits required for the many elastomer applications such as tubing and hose products, flooring, wall-coverings, seals and gaskets, belts, wire and cable, and print rolls. Low to high polarity esters provide utility in a wide range of elastomers including nitrile, polychloroprene, EPDM, chlorinated polyethylene, and epichlorohydrin. Plasticizer-elastomer interaction is governed by many factors such as solubility parameter, molecular weight, and chemical structure. Compatibility and performance attributes are key factors in developing a rubber formulation for a particular application.〔()〕
Plasticizers also function as softeners, extenders, and lubricants, and play a significant role in rubber manufacturing.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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