Polyvinyl chloride thermoplastic plastic

Fig. 1. US total sales and captive use of selected thermoplastic resins by major market for 2001. Major market volumes are derived from plastic resins sales and captive use data as compiled by VERIS Consulting, LLC and reported by the American Plastics Council s Plastic Industry Producers Statistics Group. Selected thermoplastics are low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, nylon, polyvinyl chloride, thermoplastic polyester, engineering resins, acrylonitrile-butadiene-styrene, styrene-acrylonitrile, other styrenics, polystyrene, and styrene butadiene latexes. (Data from ref. 25.)...

Hot-gas welding can be used to join most thermoplastics including polypropylene, polyethylene, acrylonitrile butadiene styrene, polyvinyl chloride, thermoplastic polyurethane, high-density polyethylene, polyamide, polycarbonate, and polymethylmethacrylate. For polyolefins and other plastics that are easily oxidized, the heated gas must be inert (e.g., nitrogen or argon) because hot air will oxidize the surface of the plastic. 

In terms of tonnage the bulk of plastics produced are thermoplastics, a group which includes polyethylene, polyvinyl chloride (p.v.c.), the nylons, polycarbonates and cellulose acetate. There is however a second class of materials, the thermosetting plastics. They are supplied by the manufacturer either as long-chain molecules, similar to a typical thermoplastic molecule or as rather small branched molecules. They are shaped and then subjected to either heat or chemical reaction, or both, in such a way that the molecules link one with another to form a cross-linked network (Fig. 18.6). As the molecules are now interconnected they can no longer slide extensively one past the other and the material has set, cured or cross linked. Plastics materials behaving in this way are spoken of as thermosetting plastics, a term which is now used to include those materials which can in fact cross link with suitable catalysts at room temperature. 

Polyvinyl chloride (p.v.c.) P.V.C. is one of the two most important plastics in terms of tonnage and shows many properties typical of rigid amorphous thermoplastics. More individually, it softens at about 70°C, burns only with difficulty and is thermally unstable. To reduce this instability, stabilisers are invariably compounded into the polymer. 

Thermoplastic Polymers. Most thermoplastic polymers are used in high-volume, widely recognized applications, so they are often referred to as commodity plastics. (We will elaborate upon the distinction between a polymer and a plastic in Chapter 7, but for now we simply note that a plastic is a polymer that contains other additives and is usually identified by a variety of commercial trade names. There are numerous databases, both in books [1] and on the Internet [2], that can be used to identify the primary polymer components of most plastics. With a few notable exceptions, we will refer to most polymers by their generic chemical name.) The most common commodity thermoplastics are polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC) and polystyrene (PS). These thermoplastics all have in common the general repeat unit -(CHX-CH2)-, where -X is -H for PE, -CH3 for PP, -Cl for PVC, and a benzene ring for PS. When we discuss polymerization reactions in Chapter 3, we will see that all of these thermoplastics can be produced by the same type of reaction. 

There is every indication that the next several years will witness a continued rapid increase in the use of petroleum raw materials in the production of elastomers and plastics, and that the petroleum companies will become increasingly active, not only in providing the starting materials, but also in operating the chemical processes of converting them to the required monomers and polymers. The current increase in production of thermoplastic resins such as polystyrene, polyvinyl chloride, polyethylene, and acrylonitrile polymers is based on the development of widespread new applications at the consumer level, and the outlet for plastic materials in many of these uses is presently limited by the capacity to produce and process the resins rather than by consumer demand. 

Plastisols are used for molding thermoplastic resins, chiefly polyvinyl chloride. See also Plasticizers. 

THERMOPLASTIC. A high polymer that softens when exposed to heat and returns to its original condition when cooled to room temperature. Natural substances that exhibit this behavior are crude rubber and a number of waxes however, the term is usually applied to synthetics such as polyvinyl chloride, nylons, fluorocarbons, linear polyethylene, polyurethane prepolymer, polystyrene, polypropylene, and cellulosic and acrylic resins. See also Plastics. 

Coal and pine tar are examples of common nonreactive diluents from natural substances. These are interesting nonreactive diluents because of their relatively low cost. They are often used as extenders in epoxy systems to reduce the cost. Coal tar is widely used because of its excellent compatibility with epoxy resins and relatively small sacrifice in cured properties. Nonyl phenol, furfural alcohol, and dibutyl phthalate are also common nonreactive diluents for epoxy systems. Dibutyl phthalate is also used as a plasticizer in many thermoplastics, such as polyvinyl chloride. 

Very Low Density (VLDPE) and Ultra Low Density (ULDPE) Polyethylenes. These are made by copolymerization with increasing amounts of comonomers, especially 1 -octene, reducing regularity/crystallinity (density 0.91- 0.86) down toward ethylene/propylene rubber. These are soft and flexible enough to compete with plasticized polyvinyl chloride and thermoplastic elastomers in some applications. 

Polyvinyl Chloride. (Table 15.5) this is the most versatile of the commercial thermoplastic polymers. It is used mainly for rigid and flexible plastics, for rubberlike products, for coatings on steel, cloth, and paper, and in smaller amounts for specialty fibers. It is processed mainly by extrusion and calendering, and in smaller amounts by injection, compression, and... 

Plasticized polyvinyl chloride can be regarded as the first thermoplastic elastomer, as it is used in an uncross-linked form. Because of the lack of cross-linking, this material exhibits high rates of creep and stress relaxation. As with other thermoplastic elastomers, these disadvantages worsen as the temperature is... 

Polyvinyl chloride (PVC) A thermoplastic material composed of polymers of vinyl chloride a colorless solid with outstanding resistance to water, alcohols, and concentrated acids and alkalis. It is obtainable in the form of granules, solutions, lattices, and pastes. Compounded with plasticizers it yields a flexible material superior to rubber in ageing properties. It is widely used for cable and wire coverings, in chemical plants, and in the manufacture of protective garments. 

The important thermoplastics used commercially are polyethylene, acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC), cellulose acetate butyrate (CAB), vinylidene chloride (Saran), fluorocarbons (Teflon, Halar, Kel-F, Kynar), polycarbonates, polypropylene, nylons, and acetals (Delrin). Important thermosetting plastics are... 

Plastic polymers make up a high proportion of waste and the volume and range used is increasing dramatically. The two main types of plastic are thermoplastics which soften when heated and harden again when cooled and thermosets which harden by curing and cannot be remoulded. The six main plastics in municipal solid waste are, high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC) and polyethylene terephthalate (PET). In addition there are... 

Plastic wastes may be the remains of production or post-consumer wastes, the latter being classified as municipal, packaging, agricultural, automotive and electrical. Packaging wastes are the major category [33, 52-54]. These are mainly thermoplastics such as polyethylene, polypropylene, polystyrene and polyvinyl chloride [28, 33, 55-56]. 

All plastics emit toxic and irritant fumes with increasing temperatures. However, the evolution rate and composition of the fumes emitted vary for different plastics and are strongly temperature dependent. Some common examples include thermoplastics such as polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polystyrene (PS), ABS copolymer, and polytetrafluoroethylene (PTFE). When... 

Over a period of many years polymeric materials have gradually replaced metals in many applications. Among the five leading thermoplastics low and high density polyethylene, polyvinyl chloride, polypropylene, and polystyrene polyethylene is the largest volume plastic in the world. Polyethylene was initially made in the United States in 1943. In 1997, the estimated combined worldwide production of both low and high-density polyethylene was 1.230 x 1010 kg (2.712 x 1010 lb) [10]. Low density polyethylene is produced at pressures of 1030 to 3450 bar (1020 to 3400 atm) whereas high density polyethylene is produced at pressures of 103 to 345 bar (102 to 340 atm) [11]. 

The general purpose thermoplastics introduced in the 1930 s and 1940 s were readily fabricated by extrusion and injection molding techniques. Thermoplastics, such as polyvinyl chloride, polystyrene and polyethylene were resistant to mineral acids at temperatures up to 60OC but they could not be used at higher temperatures, such as that of boiling water. These large volume plastics had other characteristic deficiencies which were overcome by the use of additives. 

Polyethylene, polyvinyl chloride and polypropylene are easily worked utilizing ordinary wood or metal working hand and power tools. Being thermoplastic, these materials can be easily thermo-formed as well as cut, sawed, drilled and tapped. In the heat forming process, electric ovens are generally used which can maintain good thermal control. Of the three thermoplastics, polypropylene requires the more finite thermal control. Table III provides approximate time and temperature relationship required for thermoforming these three plastics. 

In their processible mixture, these one-component products, also belonging to physically setting adhesives, consist of two components PVC (polyvinyl chloride-) particles and plasticizers (Section 9.2.9). The solid PVC particles are disperged in the high-viscosity plasticizer. The adhesive layer formation occurs by heating (120-180 °C), when the thermoplastic PVC swells and is thus able to absorb the plasticizer (no chemical reaction ). This process is called a sol-gel process. The formerly two-phase system (sol) is turned into a single-phase system (gel) by the inclusion of the plasticizer. 

---