Plastic classification thermosets

Classification Thermosetting resin Definition Plastic derived from furfuryl alcohol or from furfural or reaction prods, of furfural and a ketone cured resins char, by heat/fire/chem. resist. 

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. 

Table 1 shows a classification of thermosetting foams. Among the foams listed in this table, polyurethane foams have the largest market share in the thermosetting-plastic-foam market. 

Polymers can be classified in many ways, such as by source, method of synthesis, structural shape, thermal processing behavior, and end use of polymers. Some of these classifications have already been considered in earlier sections. Thus, polymers have been classified as natural and synthetic according to source, as condensation and addition (or step and chain) according to the method of synthesis or polymerization mechanism, and as linear, branched, and network according to the structural shape of polymer molecules. According to the thermal processing behavior, polymers are classified as thermoplastics and thermosets, while according to the end use it is convenient to classify polymers as plastics, fibers, and elastomers (Rudin, 1982). 

In the broad classification of plastics there are two generally accepted categories thermoplastic resins and thermosetting resins. 

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. 

The family of plastics is classified several ways. The two major classifications are thermoplastics (TPs) and thermosets (TSs). Over 90wt% of all plastics used are TPs. The TPs and TSs in turn are classified as commodity or engineering plastics (CP and EP). Commodities such as polyethylenes (PEs), polyvinyl chlorides (PVCs), polypropylenes (PPs),... 

As technology advances, materials have been developed which evade the above classification. Mixtures of thermoplastics and thermosetting resins have been developed in which the thermoplastics material acts as a toughening agent for the thermosetting resin. Alloys or blends of two or more thermoplastics, or of plastics and rubbers, are becoming commonplace. 

Synonyms Condensation prods., epoxy Epoxides, polymers, epoxy resins Epoxy compds. Ethers, cyclic, epoxides, polymers Plastics, epoxy Polyethers, epoxy resins Classification Polymer Definition A thermosetting resin based on the reactivity of the epoxide group Toxicology LD50 (oral, rat) 2200 mg/kg strong skin irritant in uncured state poison by inhalation moderately toxic by ingestion little or no toxicity in cured state Hazardous Decomp. Prods. Heated to decomp., emits toxic fumes of Cr... 

We will conform to Carothers classification in the sections devoted to the preparation of synthetic polymers. However, when considering the application of polymers it is more useful to consider the following three categories (1) plastics, which include thermosetting resins, such as urea resins, polyesters, or epoxies, and thermoplastic resins, such as poly-... 

Industrialists and technologists often classify polymers as either thermoplastics or thermoset plastics rather than as addition or condensation polymers. This classification takes into account their thermal properties. 

These two major classifications of thermoplastics (TPs) and thermosets (TSs) in turn have different classifications such as virgin or recycled plastics. Virgin plastics have not been subjected to any fabricating process. NEAT plastics identify plastics with Nothing Else Added To. They are true virgin polymers since they do not contain additives, fillers, etc. However they are rarely used since they do not provide the best performances. Thus the technically correct term to identify the materials is plastics. Of the 35,000 types available worldwide there are about 200 basic types or famihes that are commercially recognized with less than 20 that are popularly used. Examples of these plastics are shown in Table 1.2. 

Chemical Resistance of Thermoplastics also includes introductory chapters which will enhance the usefiilness of the information to a broader audience. The first of these chapters introduces polymer chemistry, physics and engineering at a fairly elementary level that is easy to read and accessible to technically informed readers without a background in plastics. The chapter begins by providing definitions and a history of polymers. It continues with the classification of different types of polymers, including thermoplastics, thermosets and elastomers. Also covered are properties, stmctures, and examples of commercial polymers as well as processing and polymerization techniques. The chapter ends with a discussion of applications and common trademarks of plastics. 

The classification of plastics can generally be combined into two major groups thermoplastics, which are moldable and fusible, and thermosets, which are cross-linked and infusible. In addition to these broad categories, polymers can be classified in terms of their structure, for example, crystalline, amorphous, and liqnid crystalline. Other classes of plastics commonly referred to are copolymers, alloys, and elastomers. Finally, additives, reinforcements, and fillers, play a major role in modifying properties. 

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