Engineered plastics Poly

Figure 4.22 High temperature size-exclusion liquid chromatography of an engineering plastic, poly (phenyl sulfate). Column, SSC GPS-3506, 50 cm x 8 mm i.d. eluent, 1-chloronaphthalene flow rate, 1.0 ml min-1 column temperature, 210 °C detector, refractive index detector.

Diazotization in the presence of boron trifluoride enables diazonium tetrafluoroborates to be isolated from the reaction mixture and purified. Subsequent controlled decomposition produces the required fluoroaromatic. Although explosion hazards and the toxicity of the isolated salts are significant concerns with this process, known as the Balz-Schiemann process, 4,4 -di-fluorobenzophenone (BDF. 6) has been prepared by this route as a monomer for the production of the engineering plastic poly(ether ether ketone) , or PEEK , by condensation with 1,4-dihydroxybenzene in the presence of potassium carbonate. BDF 6 is superior to its chlorine analog because in aromatic systems the nucleophilic displacement of fluorine is more facile than that of chlorine, leading to a shorter polymerization time and a better quality product containing less degradation impurities. 

Kakimoto et al. 43h have reported the preparation of hyperbranched engineering plastic, poly(phenylene sulfide)(PPS) dendrimers via the polymerization of methyl 3,5-bis-(phenylthio)-phenyl sulfoxide. The degree of polymerization and weight average molecular weight were determined to be 80 and 25,700 amu, respectively T% values were determined to increase (102 to 124 °C) proportionately relative to molecular weight. 

Commercial production of Ryton , the engineering plastic poly(phenylene... 

MDI Azelaic acid Semicrystalline engineering plastic poly( amide)... 

Polyoxyethylene. Synthetic polymers with a variety of compositionaHy similar chemical stmctures are as follows. Based on polarity, poly(oxymethylene) (1) would be expected to be water soluble. It is a highly crystalline polymer used in engineering plastics, but it is not water-soluble (see... 

Butanediol. 1,4-Butanediol [110-63-4] made from formaldehyde and acetylene, is a significant market for formaldehyde representing 11% of its demand (115). It is used to produce tetrahydrofuran (THF), which is used for polyurethane elastomers y-butyrolactone, which is used to make various pyrroHdinone derivatives poly(butylene terephthalate) (PBT), which is an engineering plastic and polyurethanes. Formaldehyde growth in the acetylenic chemicals market is threatened by alternative processes to produce 1,4-butanediol not requiring formaldehyde as a raw material (140) (see Acetylene-derived chemicals). 

Acrylic ESTER POLYMERS Acrylonitrile POLYMERS Cellulose esters). Engineering plastics (qv) such as acetal resins (qv), polyamides (qv), polycarbonate (qv), polyesters (qv), and poly(phenylene sulfide), and advanced materials such as Hquid crystal polymers, polysulfone, and polyetheretherketone are used in high performance appHcations they are processed at higher temperatures than their commodity counterparts (see Polymers containing sulfur). 

Hydroformylation. Hydroformylation of aEyl alcohol is a synthetic route for producing 1,4-butanediol [110-63-4] a raw material for poly(butylene terephthalate), an engineering plastic (qv) many studies on the process have been carried out. 

Not only ate ABS polymers useful engineering plastics, but some of the high mbber compositions are excellent impact modifiers for poly(vinyl chloride) (PVC). Styrene—acrylonitrile-grafted butadiene mbbers have been used as modifiers for PVC since 1957 (87). 

The forecasts made in 1985 (77) of 8—8.5% worldwide aimual growth have not materialized. The 2 x lOg + /yr engineering plastic production reported for 1985—1986 has remained fairly constant. Whereas some resins such as PET, nylon-6, and nylon-6,6 have continued to experience growth, other resins such as poly(phenylene oxide) have experienced downturns. This is due to successhil inroads from traditional materials (wood, glass, ceramics, and metals) which are experiencing a rebound in appHcations driven by new technology and antiplastics environmental concerns. Also, recycling is likely to impact production of all plastics. 

With the expiry of the basic ICI patents on poly(ethylene terephthalate) there was considerable development in terephthalate polymers in the early 1970s. More than a dozen companies introduced poly(butylene terephthalate) as an engineering plastics material whilst a polyether-ester thermoplastic rubber was introduced by Du Pont as Hytrel. Polyfethylene terephthalate) was also the basis of the glass-filled engineering polymer (Rynite) introduced by Du Pont in the late 1970s. Towards the end of the 1970s poly(ethylene terephthalate) was used for the manufacture of biaxially oriented bottles for beer, colas and other carbonated drinks, and this application has since become of major importance. Similar processes are now used for making wide-neck Jars. 

Special mention must be made of poly(lactic acid), a biodegradable/bio-resorbable polyester, obtained from renewable resources through fermentation of com starch sugar. This polymer can compete with conventional thermoplastics such as PET for conventional textile fibers or engineering plastics applications. Hie first Dow-Cargill PLA manufacturing facility is scheduled to produce up to 140,000 tons of Nature Works PLA per year beginning in 200245 at an estimated price close to that of other thermoplastic resins U.S. l/kg.46 Other plants are planned to be built in the near future.45... 

In 2002, the world production of polymers (not including synthetic libers and rubbers) was ca. 190 million metric tons. Of these, the combined production of poly(ethylene terephthalate), low- and high-density polyethyelene, polypropylene, poly(vinyl chloride), polystyrene, and polyurethane was 152.3 milhon metric tons [1]. These synthetic, petroleum-based polymers are used, inter alia, as engineering plastics, for packing, in the construction-, car-, truck- and food-industry. They are chemically very stable, and can be processed by injection molding, and by extrusion from the melt in a variety of forms. These attractive features, however, are associated with two main problems ... 

Poly(2,6-dimethyl-l,4-oxyphenylene) (poly(phenylene oxide), PPG) is a material widely used as high-performance engineering plastics, thanks to its excellent chemical and physical properties, e.g., a high 7 (ca. 210°C) and mechanically tough property. PPO was first prepared from 2,6-dimethylphenol monomer using a copper/amine catalyst system. 2,6-Dimethylphenol was also polymerized via HRP catalysis to give a polymer exclusively consisting of 1,4-oxyphenylene unit, while small amounts of Mannich-base and 3,5,3, 5 -tetramethyl-4,4 -diphenoquinone units are always contained in the chemically prepared PPO. 

Poly(3-hydroxyalkanoate)s have potential for application to engineering plastics endowed with biodegradable nature. One of the synthetic approaches to the polyesters is the ring-opening polymerization of -substituted /3-lactones which can be effectively produced by ring-expansion carbonylation of epox-... 

Copoly(ether ester)s consisting of short-chain crystalline segments of PBT and amorphous poly(ether ester) of poly(tetramethylene terephthalate) exhibit a two-phase structure and can be used for the production of high-impact-strength engineering plastics. These very interesting materials with their outstanding properties understandably require stabilization to heat and UV exposure [45],... 

The industrial synthesis of polyformaldehyde [poly(oxymethylene)] occurs by anionic polymerization of formaldehyde in suspension. For this the purification and handling of monomeric formaldehyde is of special importance since it tends to form solid paraformaldehyde. After the polymerization the semiacetal end groups have to be protected in order to avoid thermal depolymerization (Example 5-13). This is achieved by esterfication with acetic anhydride (see Example 5-7). As in the case of trioxane copolymers (see Sect. 3.2.3.2) the homopolymers of formaldehyde find application as engineering plastics. 

Nylon, polyacetal, polycarbonates, poly(2,6-dimethyl)phenylene oxide (PPO), polyimides, polyphenylene sulfide (PPS), polyphenylene sulfones, polyaryl sulfones, polyalkylene phthalates, and polyarylether ketones (PEEK) are stiff high-melting polymers which are classified as engineering plastics. The formulas for the repeating units of some of these engineering plastics are shown in Figure 1.15. 

Uses. A principal use of thionyl chloride is in the conversion of acids to acid chlorides, which are employed in many syntheses of herbicides (qv), surfactants (qv), drugs, vitamins (qv), and dyestuffs. Possible laiger-scale applications are in the preparation of engineering thermoplastics of the poly aryl ate type made from iso- and terephthaloyl chlorides, which can be made from the corresponding acids plus thionyl chloride (186) (see Engineering plastics). 

Poly(trimethylene terephthalate). Poly(trimethylene terephthal-ate) (PIT) is a crystalline polymer that is used for fibers, films, and engineering plastics. The polymer has an outstanding tensile elastic recovery, good chemical resistance, a relative low melting temperature, and a rapid crystallization rate. It combines some of the advantages of poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT). Disadvantageous are the low heat distortion temperature, low melt viscosity, poor optical properties, and pronounced brittleness low temperatures. 

Poly(styrene) (PS) belongs to the largest volume thermoplastic resins (1). Unmodified PS is well suited to applications, where its brittleness is acceptable. In contrast, certain engineering plastics have been used in applications, where less brittleness is required. 

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