Showing papers on "Commodity plastics published in 1993"

7 Toughened polymers

Abstract: Commodity plastics such as polyethylene (PE), polypropylene (PP), poly­ styrene (PS), and polyvinylchloride (PVC) make up a large of proportion of the total tonnage of plastic currently being used mainly for non-Ioadbearing ap­ plications (e.g. consumer products). However, with the ever-increasing use of plastics in the areas dominated by the use of metal or ceramics, e.g. in the auto­ mobile industry, new engineering plastics, both thermoplastics and thermoset resins, have been developed which provide the combinations of lightness and good balance of stiffness, and some also in toughness, over a wide range of temperature applications. While the development of new polymers with novel primary chain struc­ tures has continued, in parallel established materials are repeatedly modified and improved in the form of alloys or blends, largely by the innovation in synthesis and compounding. The blends and alloys of these plastics and rubbers constitute one of the most rapidly evolving areas of engineering plastics. For ease of discussion, the blends or modified polymers discussed here refer mainly to heterogeneous (two-phase) polymers but do not include modified elastomers and glass or carbon-fibre reinforced polymers. The intention ofthis chapter is to highlight some of the progress which has been made on toughened polymers and their blends. The areas of work described in this chapter are of current interest. 7.2 Toughened thermoplastics Over the last decade, there has been some progress in the development of novel thermoplastics, especially in the area of engineering plastics. An example of this is the aromatic group of thermoplastics, e.g. polyetherether ketone (PEEK), polyarylsulfone (PAS) and polyetherketoneketone (PEKK), which is used in high temperature applications. These polymers can be represented with a general formula as (- Ar 1 - X - Ar 2 - Y -). Their physical and mechanical properties are determined by the choice of the X, Y and the aromatic Ar 1 and Ar 2 groups, and their distribution along the molecular chain