Plastics ethylene based

The family of FPs, also called fluorocarbon plastics, is based on polymers made of monomers composed of fluorine and carbon may also include chlorine atoms in their structure. Specific types include polytetrafluoroethylene (PTFE), polytetrafluoroethylene-cohexafluoro-propylene or fluorinated ethylene propylene (FEP), polytrafluoroethylene-coperfluoropropylvinyl ether (PFA), ethylenetetrafluoroethylene (ETFE). polychlorotrifluoroethylene (PCTFE), ethylene-chlorotri-fluoroethylene (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), perfluoromethylvinylether (PFMV), perfluoroalkoxy (PFA), etc. 

Plastics are based on repeating units of a monomer, such as ethylene, to create a polymer (e.g., polyethylene). The principal limitations of plastics compared with metals are their relatively low strength at elevated temperatures and limited ductility. Many plastics have outstanding chemical resistance. 

The most widely used thermoplastic polymer is the ethylene—vinyl acetate copolymer, which is obtainable in a wide range of molecular weights as well as in a variety of compositions. Often flexibilizers or plasticizers are added in order to improve both the mechanical shock resistance and the thermal properties of the adhesive. Polybutenes, phthalates, and tricresyl phosphate have been used as plasticizers. Tackifying agents can also be added. Because hot-melt adhesives are frequendy ethylene-based, they are subject to oxidation if, as in a typical situation, the adhesive sits in an applicator for long periods before use. Thus, antioxidants such as hindered phenols are often used, as are fillers. Fillers are added to opacify or to modify the adhesive s flow characteristics, as well as to reduce cost. Wax is also a very important component. Wax alters surface characteristics by decreasing both the liquid adhesive s surface tension and its viscosity in the melt. Upon solidification, however, the wax acts to increase the strength of the adhesive. Both paraffin and microcrystalline wax are used (see Waxes). 

Butylene carbonate Dibutoxyethoxyethyl phthalate Ethylene carbonate N-(2-Hydroxypropyl) benzenesulfonamide plasticizer, PU foam Pentaerythrityl trioleate Tris (2,3-dichloropropyl) phosphate plasticizer, PU resins Triethylene glycol plasticizer, PU sealants Polypropylene glycol dibenzoate plasticizer, PU-based sealants Benzyl phthalate plasticizer, pulp/paper Oleyl alcohol Propylene glycol laurate plasticizer, PVA emulsion paints s-Dioctyl phthalate plasticizer, PVAc Butyl oleate Butyl ricinoleate Dibutoxyethoxyethyl adipate Dibutoxyethoxyethyl glutarate Dibutyl adipate... 

Acrylonitrile-butadiene rubber, NBR, styrene-aciylonitrile rubber, SAN, ethylene-vinyl acetate copolymer, EVA, and acrylic copolymers are helpful modifications of polyvinylchloride that change its processing characteristics and elastomeric properties. Blending with these copolymers helps to reduce the requirement for low molecular weight plasticizers. Ethylene-vinyl acetate copolymer plays a role of high molecular weight plasticizer in production of vinyl hose. This reduces the amount of DOP used in flexible hose applications. Ethylene copolymer is used plasticize PVC that reduces gel. "" Phthalate plasticizers can be eliminated from water based adhesives because of utilization of vinyl acetate ethylene copolymer as a high molecular plasticizer/modifier. " ... 

Lei Y, Wu Q. Wood plastic composites based on microfibrillar blends of high density polyeth-ylene/poly (ethylene terephthalate). Bioresour Technol 2012 101 (10) 3665-3671. 

Lee KY, Bharadia P, Blaker JJ, Bismarck A (2012c) Short sisal fibre reinforced bacterial cellulose polylactide nanocomposites using hairy sisal fibres as reinforcement. Compos A 43 2065-2074 Lei Y, Wu Q (2010) Wood plastic composites based on microfibrillar blends of high density polyethylene/poly(ethylene terephthalate). Bioresour Technol 101 3665-3671 Liu D, Zhong T, Chang PR, Li K, Wu Q (2010) Starch composites reinforced by bamboo cellulosic crystals. Bioresour Technol 101 2529-2536 Liu H, Xie F, Yu L, Chen L, Li L (2009) Thermal processing of starch-based polymers. Prog Polym Sci 34 1348-1368... 

A.luminum Jilkyl Chain Growth. Ethyl, Chevron, and Mitsubishi Chemical manufacture higher, linear alpha olefins from ethylene via chain growth on triethyl aluminum (15). The linear products are then used as oxo feedstock for both plasticizer and detergent range alcohols and because the feedstocks are linear, the linearity of the alcohol product, which has an entirely odd number of carbons, is a function of the oxo process employed. Alcohols are manufactured from this type of olefin by Sterling, Exxon, ICI, BASE, Oxochemie, and Mitsubishi Chemical. 

High density polyethylene (HDPE) is defined by ASTM D1248-84 as a product of ethylene polymerisation with a density of 0.940 g/cm or higher. This range includes both homopolymers of ethylene and its copolymers with small amounts of a-olefins. The first commercial processes for HDPE manufacture were developed in the early 1950s and utilised a variety of transition-metal polymerisation catalysts based on molybdenum (1), chromium (2,3), and titanium (4). Commercial production of HDPE was started in 1956 in the United States by Phillips Petroleum Company and in Europe by Hoechst (5). HDPE is one of the largest volume commodity plastics produced in the world, with a worldwide capacity in 1994 of over 14 x 10 t/yr and a 32% share of the total polyethylene production. 

Transesterification has a number of important commercial uses. Methyl esters of fatty acids are produced from fats and oils. Transesterification is also the basis of recycling technology to break up poly(ethylene terephthalate) [25038-59-9] to monomer for reuse (29) (see Recycling, plastics). Because vinyl alcohol does not exist, poly(vinyl alcohol) [9002-89-5] is produced commercially by base-cataly2ed alcoholysis of poly(vinyl acetate) [9003-20-7] (see Vinyl polymers). An industrial example of acidolysis is the reaction of poly(vinyl acetate) with butyric acid to form poly(vinyl butyrate) [24991-31-9]. 

There are 12 producers of ethylene oxide ia the United States. Table 9 shows the plant locations, estimated capacities, and types of processes employed. The total U.S. production capacity for 1992 was ca 3.4 x 10 metric tons. The percentages of total domestic production made by the air- and oxygen-based processes are ca 20 and 80%, respectively. The largest producer is Union Carbide Corp. with approximately one-third of the United States ethylene oxide capacity. About 94% of domestic ethylene oxide capacity is located on the Gulf Coast near secure and plentiful ethylene suppHes. Plans for additional U.S. production ia the 1990s have been announced by Union Carbide (incremental expansions), Eormosa Plastics (at Pt. Comfort, Texas), and Shell (at Geismar, Louisiana) (101). 

The most chemical-resistant plastic commercially available today is tetrafluoroethylene or TFE (Teflon). This thermoplastic is practically unaffected by all alkahes and acids except fluorine and chlorine gas at elevated temperatures and molten metals. It retains its properties up to 260°C (500°F). Chlorotrifluoroethylene or CTFE (Kel-F, Plaskon) also possesses excellent corrosion resistance to almost all acids and alkalies up to 180°C (350°F). A Teflon derivative has been developed from the copolymerization of tetrafluoroethylene and hexafluoropropylene. This resin, FEP, has similar properties to TFE except that it is not recommended for continuous exposures at temperatures above 200°C (400°F). Also, FEP can be extruded on conventional extrusion equipment, while TFE parts must be made by comphcated powder-metallurgy techniques. Another version is poly-vinylidene fluoride, or PVF2 (Kynar), which has excellent resistance to alkahes and acids to 150°C (300°F). It can be extruded. A more recent development is a copolymer of CTFE and ethylene (Halar). This material has excellent resistance to strong inorganic acids, bases, and salts up to 150°C. It also can be extruded. 

The inability to process PTFE by conventional thermoplastics techniques has nevertheless led to an extensive search for a melt-processable polymer but with similar chemical, electrical, non-stick and low-friction properties. This has resulted in several useful materials being marketed, including tetrafluoro-ethylene-hexafluoropropylene copolymer, poly(vinylidene fluoride) (Figure 13.1(d)), and, most promisingly, the copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether. Other fluorine-containing plastics include poly(vinyl fluoride) and polymers and copolymers based on CTFE. 

Since the last edition several new materials have been aimounced. Many of these are based on metallocene catalyst technology. Besides the more obvious materials such as metallocene-catalysed polyethylene and polypropylene these also include syndiotactic polystyrenes, ethylene-styrene copolymers and cycloolefin polymers. Developments also continue with condensation polymers with several new polyester-type materials of interest for bottle-blowing and/or degradable plastics. New phenolic-type resins have also been announced. As with previous editions I have tried to explain the properties of these new materials in terms of their structure and morphology involving the principles laid down in the earlier chapters. 

Among the different pressure sensitive adhesives, acrylates are unique because they are one of the few materials that can be synthesized to be inherently tacky. Indeed, polyvinylethers, some amorphous polyolefins, and some ethylene-vinyl acetate copolymers are the only other polymers that share this unique property. Because of the access to a wide range of commercial monomers, their relatively low cost, and their ease of polymerization, acrylates have become the dominant single component pressure sensitive adhesive materials used in the industry. Other PSAs, such as those based on natural rubber or synthetic block copolymers with rubbery midblock require compounding of the elastomer with low molecular weight additives such as tackifiers, oils, and/or plasticizers. The absence of these low molecular weight additives can have some desirable advantages, such as ... 

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