Thermoplastic materials, guidelines

This book puts a wealth of information at your fingertips. It represents an exhaustive compilation of data on how chemicals and other exposure environments affect the properties and characteristics of thermoplastic materials. How a plastic will perform in its end use environment is a critical consideration and the information presented here gives useful guidelines. However, this or any other information resource should not serve as a substitute for actual testing in determining the applicability of a given part or material in a given end use environment. 

A route to compatibility involving ionomers has been described recently by Eisenberg and coworkers [250-252]. The use of ionic interactions between different polymer chains to produce new materials has gained tremendous importance. Choudhury et al. [60] reported compatibilization of NR-polyolefin blends with the use of ionomers (S-EPDM). Blending with thermoplastics and elastomers could enhance the properties of MPR. The compatibility of copolyester TPE, TPU, flexible PVC, with MPR in aU proportions, enables one to blend any combination of these plastics with MPR to cost performance balance. Myrick has reported on the effect of blending MPR with various combinations and proportions of these plastics and provided a general guideline for property enhancement [253]. 

Within the field of engineering thermoplastics, in-plant recycling has only recently been adopted due to stringent performance specifications. There are no general guidelines on maximum regrind content. Feasible levels depend on the application requirements and on material characteristics. 

The benefits of new materials will only be fully expressed in products if weak spots, such as weld lines in injection molded products, can be properly addressed. Weld lines may be critical with regard to product quality for some thermoplastics. Therefore, research into the effects of variations in injection molding settings, combined with mechanical testing, will be helpful for developing design guidelines for injection molded bioplastics products. 

An example of the latter is the boost in the development of thermoplastic elastomers in the last decade of the Twentieth Century, driven by product applications obtained by multi-component injection molding. The design guidelines for such products originally included recommendations to make the material components mutually enclose each other so as not to rely on adhesion between dissimilar materials only. Later grades of thermoplastic elastomers have been improved with respect to the adhesion to thermoplastics, allowing more design flexibility and processability improvements. 

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