Thermoplastics classification

The outdated standard DIN 16776-1 84 Polyethylene and Ethylene Copolymer Thermoplastics Classification and Designation and the replacing European standard EN ISO 1872-1 1999 Plastics Polyethylene (PE) Moulding and Extrusion Materials Part I Designation System and Basis... 

DIN 16776-1 1984 Polyethylene and Ethylene Copolymer Thermoplastics Classification and Designation... 

The diversity of release products and the wide range of release problems make classification difficult. One approach is by product form, with subdivisions such as emulsions, films, powders, reactive or iaert sprays, reactive coatings, and so on. Another approach is by appHcation, eg, metal casting, mbber processiag, thermoplastic iajection mol ding, and food preparation and packagiag. 

The classification given in Table 1 is based on the process, ie, thermosetting or thermoplastic, by which polymers in general are formed into usehil articles and on the mechanical properties, ie, rigid, flexible, or mbbery, of the final product. AH commercial polymers used for molding, extmsion, etc, fit into one of these six classifications the thermoplastic elastomers are the newest. 

Chapters 10 to 29 consisted of reviews of plastics materials available according to a chemical classification, whilst Chapter 30 rather more loosely looked at plastics derived from natural sources. It will have been obvious to the reader that for a given application plastics materials from quite different chemical classes may be in competition and attempts have been made to show this in the text. There have, however, been developments in three, quite unrelated, areas where the author has considered it more useful to review the different polymers together, namely thermoplastic elastomers, biodegradable plastics and electrically conductive polymers. 

ISO 4433-3 1997 Thermoplastics pipes - Resistance to liquid chemicals - Classification -Part 3 Unplasticized poly(vinyl chloride) (PVC-U), high-impact poly(vinyl chloride) (PVC-HI) and chlorinated poly(vinyl chloride) (PVC-C) pipes ISO 6259-2 1997 Thermoplastics pipes - Determination of tensile properties - Part 2 Pipes made of unplasticized poly(vinyl chloride) (PVC-U), chlorinated poly(vinyl chloride) (PVC-C) and high-impact poly(vinyl chloride) (PVC-HI)... 

ISO 4433-4 1997 Thermoplastics pipes - Resistance to liquid chemicals - Classification -Part 4 Poly(vinylidene fluoride) (PVDF) pipes ISO 9393-2 1997 Thermoplastics valves - Pressure test methods and requirements - Part 2 Test conditions and basic requirements for PE, PP, PVC-U and PVDF valves ISO 10931-1 1997 Plastics piping systems for industrial applications - Poly(vinylidene fluoride) (PVDF) - Part 1 General... 

ISO 3934 2002 Rubber, vulcanized and thermoplastic - Preformed gaskets used in buildings - Classification, specifications and test methods ISO 4649 2002 Rubber, vulcanized or thermoplastic - Determination of abrasion resistance using a rotating cylindrical drum device ISO 4664-1 2005 Rubber, vulcanized or thermoplastic - Determination of dynamic properties - Part 1 General guidance... 

Table 6.26 and Figure 6.19 display some property examples for various thermoplastic composites. These are examples, some other figures exist and the classification is arbitrary but, as already noted, the mechanical performances at room temperature are especially influenced by the nature, form and size of the reinforcements. 

Polymers are often divided according to whether they can be melted and reshaped through application of heat and pressure. These materials are called thermoplastics. The second general classification comprises compounds that decompose before they can be melted or reshaped. These polymers are called thermosets. While both thermoset and thermoplastic polymers can be recycled, thermoplastic recycling is easier and more widespread because thermoplastic materials can be reshaped simply by application of heat and pressure. 

The phenomenological ordering of polymers projected for use as constructing materials is not an easy matter. Sometimes the temperature stability is used as a criterion, i.e., the temperature up to which the mechanical properties remain more or less constant. Another attempt for classification, uses the E modulus or the shape of the curve of stress-strain measurements (see Sect. 2.3.5.1). In general one can say that semicrystalline thermoplastics are stiff, tough, and impact-resistant while amorphous thermoplastics tend to be brittle. Their E... 

An increase in heat deflection temperature of some thermoplastic polymers can be achieved by the addition of polyfunctional aromatic cyanates (BPA/DC in particular) and trimerization catalysts. A rigid network is formed as a resul t of the cyanate trimerization. The polymer material consists of a linear polymer and a crosslinked network and belongs to the class of semi-IPNs (semi-interpenetrating Polymer Networks) the corresponding classification is given in [34-37]. 

The broadest classification for plastics is the old thermoplastic and thermosetting . Examples of the former group are polyethylene, polystyrene, and poly-(methyl methacrylate) examples of the latter are urea-formaldehyde condensation polymers, powder coatings based on polyesters, epoxy resins, and vulcanized synthetic elastomers. 

Figure 12 represents all steps of craze formation in crystalline polymers in a single model. It is based on Hornbogen s model for a crack tip in a polymer crystal, under the utilization of individual block drawings by Schultz for the fine scale nature of plastic deformation in semicrystalline thermoplastics. The classification into four regions A to D (after ) helps to describe and imderstand the influence of molecular parameters on craze strength and craze breakdown. 

Since the molecular backbone can be linear, branched, or network type, this aspect is also important for polymer structure. It is known that most polymers with a linear backbone are thermoplastics, while those with network backbone are thermosetting polymers. However, for classification from a chemical point of view, this differentiation is less significant. Many polymers with linear backbone are obtained from bifunctional monomers (e.g. terephthalic acid and glycol). If the polymer is obtained from similar monomers but with more than two functionalities (e g. terephthalic acid and ethylene glycerin), the polymer will have thermosetting characteristics. For this reason, this feature is not necessarily used for a classification from the chemical point of view. 

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