Plastics, characterization/classification

Keywords Characteristics of Plastics, Characterization, Classification, Economic data. Environmental Polymer Engineering... 

The overall picture emerging in the course of this field study was that clay smears are formed consistently on all scales in the Frechen exposures, where they represent a universal phenomenon. This would suggest that the conditions necessary for the emplacement of clay smears in minor shear bands are the same as those met along the major faults. Among the factors that are likely to determine the thickness, length and continuity of a smear, the thickness of the source bed and the fault throw are readily identified in the field. The requirement that the shales possess the necessary plasticity is also clearly met, i.e., the shale source bed material may be characterized as highly plastic, fat clay in accordance with the standard soil mechanics classification (Bowles, 1984). 

Careful characterization of moisture interactions in cellulose derivatives has been reported for HPMC films, both unplasticized and plasticized. Using various techniques (a radiotracer technique involving the use of tritiated water, DSC and TGA), some authors [73] proposed the classification of the water present into three categories the tightly bound water present in plain HPMC films was located in the ordered regions of the polymer and was absent in plasticized films. The moderately bound water (detectable by TGA) was in the rank order of the hydrophilicity of the polymer additives and this order was reversed for the calculated free water content. 

It is not possible to discuss here the special properties of all the different types of plastic materials that can occur within these three groups. The plastics industry today, by employing copolymerization or chemical modification, is capable of producing an extraordinary number of combinations of properties, making the identification of corresponding plastics more complicated. Its physical appearance and its classification as a thermoplastic, thermoset, or elastomer therefore permit us to draw conclusions about the chemical nature of the plastic only in simple cases. But they often provide a useful additional way of characterizing the material. 

Table 11 [8] compares the properties of TPE classes. See Table 6 in Chapter Plastics Classification, Characterization, and Economic Data for the abbreviations. 

In standard classification for vinyl plastics used in biomedical applications, a plasticizer is specified with prefix letter The letter is followed by a number from 1 to 14 which characterizes the type of plasticizer (e g., 1 - none, 2 - adipic acid derivative, 3 -azelaic, 4 - benzoic, 5 - citric, 6 - isophthalic, 7 - myristic, 8 - phosphoric, 9 - phthalic, 10 - sebacic, 11 - terephthalic, 12 - poly ether, 13 - polyethylene glycol, 14 - polyesters, 999 - other). The second letter specifies secondary plasticizer (e.g., A - none, B - alkyl epoxy stearates, C - epoxidized tall oil, D - epoxidized soybean oil, E - epoxidized linseed oil, F - epoxidized sunflower oil, Z - other). This classification is used to guide design engineers. Classification is not applicable to long-term implants. If there is a conflict between provisions of this standard and detailed specification for a particular device, the latter takes precedence. 

A more convenient scheme, first proposed by Mascia [14] for plastic additives, is to classify fillers according to their specific function, such as their ability to modify mechanical, electrical, or thermal properties, flame retardancy, processing characteristics, solvent permeability, or simply formulation costs. Fillers, however, are multifunctional and may be characterized by a primary function and a plethora of additional functions (see Table 1.4). The scheme adopted in this book involves classification of fillers according to five primary functions, as follows ... 

As it is known, the work of fracture U, characterizing expenditure of energy on material deformation up to failure, is one of the most important plasticity characteristics. In paper [5] it was shown, that the fracture character of solids is determined by the fractal dimension df of their structure at 4-2. 50 brittle fracture is realized, at 4 2.50-2.67 - quasibrittle (quasiductile) fracture and at 4 2.70 - ductile fracture. This classification allows to suppose plasticity increase characterized by value U at raising df. Actually, the dependence U dj) shown in Fig. 3 confirms this assumption. This dependence is linear, the increase U is observed at raising df and zero value U is reached at 4=2.50, i.e., at brittle fracture. Since limiting (maximal) value df for real solid is equal to 2.95 then this allows to estimate... 

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