Applications of Polymer Alloys and Blends
Since their widespread commercialization, the applications of polymer blends have been directed at replacement of traditional materials, most commonly, metals. Although plastic raw materials can be more costly than metals on a weight basis, they are often
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APPLICATIONS OF POLYMER ALLOYS AND BLENDS
J.J. Scobbo, Jr.1 and Lloyd A. Goettler2
1
General Electric Plastics, Mt. Vernon, IN, USA
2
University of Akron, Department of Polymer Engineering, Akron, OH, USA
13.1
General Principles for the Use of Polymer Blends
Since their widespread commercialization, the applications of polymer blends have been directed at replacement of traditional materials, most commonly, metals. Although plastic raw materials can be more costly than metals on a weight basis, they are often more economical in terms of final manufactured cost [Paul and Newman, 1978; Legge et al., 1987; Utracki, 1989, 1998; Datta and Lohse, 1996; Louise, 1997]. This is because plastic parts can consolidate many functions into fewer parts, usually require less complex assembly (e.g., they are amenable to snap fitting and ultrasonic welding) and can be easily formed (by injection molding) into complex finished shapes, even incorporating textured or high gloss surfaces. In use they are more corrosion resistant as well as lighter in weight than metals, which is especially important for fuel economy in automotive applications. There is a trend toward specialization in the polymer products industry. Since the industry is expanding globally, a sufficient market is available for these products. Blending is a convenient route to time-efficient and cost-effective upgrading of commodity resins and to tailoring these resins to specific performance profiles for the desired application. The time to commercialization can now be reduced to less than one year for PAB’s vs. 8-10 or more years for the synthesis of new polymers. The development of the latter can exceed $10 MM. After development, modifications can also be more easily implemented. For example, flame retardant (FR) grades of PAB’s have been developed for the business machine and electronics markets. These materials combine high modulus, heat resistance, and impact strength in addition to FR. Costs can be reduced by blending engineering thermoplastics (ETPs) with less expensive commodity resins. Also, the distinction between plastics and elastomers can be breached by PAB’s and is in fact narrowing. Advantages of PAB’s blends for meeting application requirements can be summarized as follows: • lower development costs • faster development • recycling issues (post-consumer) • regulatory considerations L.A. Utracki (Ed.), Polymer Blends Handbook, 951-976. © 2003 Kluwer Academic Publishers. Printed in the Netherlands.
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J.J. Scobbo and L.A. Goettler
• reduced manufacturing costs, e.g., lower capital required (vs. metal conversion) • JIT (just-in-time) inventory • part size reduction, thinner walls • parts consolidation • tailored properties to meet performance specifications. Furthermore, the beneficial PAB properties for general applications include: • better processing: e.g., PA/ABS vs. PA for blow molding • enhanced performance over single resin systems • mechanical (creep, impact, stiffness, strength) • heat resistance • lower cost • optical • electrical properties • fla
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