Commodity plastics tolerances

In the decades after their discovery, radicals were viewed as too reactive for precision synthesis and their reactions were viewed by many chemists as messy, unpredictable, unpromising, and essentially mysterious. ° Despite this initial pessimism, free-radical polymerization rapidly became an important industrial process, responsible for the production of approximately half of all commodity plastics. Compared with other more sophisticated polymerization processes, free-radical polymerization has the often imderstated advantages of being highly robust and versatile, as the neutral radical-hased propagating species is tolerant of a variety of solvent and/ or monomer impurities and can facilitate the (co)polymerization of a wide-airay of monomer... 

However, plastics processors must continually update their procedures and/or acquire additional knowledge on how to process plastics. New developments in this field are unlimited. This book has emphasized that it is not difficult to process plastics, and has reviewed the many fabricating processes used to produce many different sizes and shapes of thermoplastic and thermoset commodity and engineering resins, which are used either unreinforced or reinforced (in composites). As explained, process selection depends basically on product performance requirements, shape, required dimensional tolerances, plastics processing characteristics, production volume, and cost (1-3, 317-326). 

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