Aliphatic Engineering Plastics

Fluorinated rubbers, copolymers of hexafluoropropylene and vinylidene-fluorides, have excellent resistance to oils, fuels and lubricants at temperatures up to 200°C. They have better resistance to aliphatic, aromatic and chlorinated hydrocarbons and most mineral acids than other rubbers, but their high cost restricts their engineering applications. Cheremisinoff et al. [54] provide extensive physical and mechanical properties data on engineering plastics. A glossary of terms concerned with fabrication and properties of plastics is given in the last section of this chapter. 

This class of polyesters consists of four major commercial polymers and their copolymers, namely PET, PTT, PBT, and PEN (see Table 2.1). They compete for engineering thermoplastics, films, and fibers markets with other semicrystalline polymers, such as aliphatic polyamides, and for some other applications with amorphous engineering plastics such as polycarbonate. The syntheses of PET and PBT, detailed in numerous reviews and books,2-5 are described in Sections 23.2.2 and 2.3.2.1. 

You can use analogies to put adipic acid in its right place. Acetic acid is the most important aliphatic monocarboxylic acid adipic is the most important aliphatic dicarboxylic acid. (You remember, of course, that carboxylic is the contraction for carbonyl and hydroxyl, -C-O and -OH, or together, -COOH. Right ) Also, adipic acid is to Nylon 66 what cumene is to phenol. About 95% of the adipic acid ends up as Nylon 66, which is used for tire cord, fibers, and engineering plastics. 

Aromatic—Aliphatic Polyester Resins. Unlike most other classes of engineering plastics, which are made by only a few manufacturers, aromatic-aliphatic polyester resins are produced and compounded by several dozen firms (66). The aliphatic polyester resin marketplace is characterized by wide product differentiation and competition. Some firms make only a few hundred tons per year and presumably retain profitability because of the availability of low cost monomer and the simplicity of the processes employed. Low investment and low manufacturing costs are possible even for small-volume operations. 

Nevertheless, further detailed information was unavailable on the polyimide synthesis from nylon-salt-type monomers that is referred to as salt monomer method , and this method was not really recognized as a simple synthetic method of both aromatic and aliphatic polyimides. In addition, many polyimide investigations have mainly been concentrated on aromatic polyimides, and little information is available about aliphatic polyimides [13-18] that are also potential candidates for engineering plastics. 

Linear aliphatic chols are widely used as raw materials for polymers. Polymers synthesized from even-carbon diols tend to show excellent polymer properties. 1,4-Butanediol is very important as raw material for various polymers such as urethanes and polybutylene terephthalate (PBT), which is an engineering plastic. Since Celanese Corporation described a PBT resin in 1970, the demand for PBT resin, which is mainly used for automotive, electrical, and electronic equipment parts, has been expanding rapidly [1]. THF is also a major 1,4-butanediol derivative as a raw material for poly(tetramethylene ether) glycol used for artificial leather and elastic fibers in addition to being a high-performance solvent. Significant growth in demand for these 1,4-butanediol derivatives is expected in Asia, primarily in China. 

These materials are an important group of engineering plastics. Aliphatic polysulfones were first synthesized at the end of the last century. That synthesis was based on reactions of SO2 with olefins ... 

Primary amides, calciiun stearate, ethylene bis-stearamide, erucamide, fluoropolymers and silicones can be employed in polymers other than PVC. PTFE can also be used in polyamide processing, improving the friction and wear properties of gears and other engineering components. ABS and SAN benefit from the addition of zinc stearate or a secondary bis-amide, sometimes in combination with glyceryl monostearate or a fatty acid amine. Engineering plastics can be lubricated by secondary amides, aliphatic esters such as palmitates and sebacates, and silicones. 

Since their discovery by Carothers [181], aliphatic polyamides such as nylon-6,6 and nylon-6 are important textile fibers and plastics. Similar polyamides produced by melt reaction of aliphatic diacids - - diamines, or by hydrolytic polymerization of lactams, have some interest as engineering plastics, and will also be discussed in this section. 

Making monomeric and polymeric organic carbonates by using CO as one of the raw materials is important for two reasons. Aromatic polycarbonates are well established as engineering plastics with an annual worldwide production of about 2 million tons. Aliphatic polycarbonates are under vigorous developmental efforts as they may have similar potential applications. 

Polyamides (PAs, except for those that are fully aromatic) represent a versatile group of plastics that have been successful for 70 years in the market of fibers, engineering plastics and specialties. Aliphatic polyamides and copolyamides (Scheme 7.1), obtained by a classical polycondensation of diamines and diacids, or a-amino acids (PA 66, PA 612, PA 610, PA 46, PA 11) or by the hydrolytic polymerization of lactams (PA 6, PA 12), belong to the group of highly valued semicrystalline plastics that are widely used in most branches of industry in some applications they are, as yet, irreplaceable. 

---