Engineering thermoplastic, high

Commodity (and engineering) thermoplastics High density polyethylenes (HOPE), polypropylenes (PP), ethylene vinyl acetates (EVA), ionomers, polyvinyl chlorides (PVC). 

Triphenyl phosphate [115-86-6] C gH O P, is a colorless soHd, mp 48—49°C, usually produced in the form of flakes or shipped in heated vessels as a hquid. An early appHcation was as a flame retardant for cellulose acetate safety film. It is also used in cellulose nitrate, various coatings, triacetate film and sheet, and rigid urethane foam. It has been used as a flame-retardant additive for engineering thermoplastics such as polyphenylene oxide—high impact polystyrene and ABS—polycarbonate blends. 

The typical mechanical properties that qualify PCTFE as a unique engineering thermoplastic are provided ia Table 1 the cryogenic mechanical properties are recorded ia Table 2. Other unique aspects of PCTFE are resistance to cold flow due to high compressive strength, and low coefficient of thermal expansion over a wide temperature range. 

The largest use for 2,4-dicumylphenol is in a production of a uv stabilizer of the benzotriazole class, 2-(2 -hydroxy-3, 5 -dicumylphenyl)benzotriazole [70321-86-7] which is used in engineering thermoplastics where high molding temperatures are encountered (67). The high molecular weight of... 

Polyurethane engineering thermoplastics are also manufactured from MDI and short-chain glycols (49). These polymers were introduced by Upjohn/Dow under the trade name Isoplast. The glycols used are 1,6-hexanediol and cyclohexanedimethanol. 1,4-Butanediol is too volatile at the high processing temperatures used in the reaction extmsion process. Blends of engineering thermoplastics with TPU are also finding uses in many appHcations... 

COLLYER, A. A., A Practical Guide to the Selection of High Temperature Engineering Thermoplastics, Elsevier Advanced Technology, London (1990)... 

The presence of the either linkages is sufficient to allow the material to be melt processed, whilst the polymer retains many of the desirable characteristics of polyimides. As a consequence the material has gained rapid acceptance as a high-temperature engineering thermoplastics material competitive with the poly-sulphones, poly(phenylene sulphides) and polyketones. They exhibit the following key characteristics ... 

Highly aromatic thermoplastic polyesters first beeame available in the 1960s but the original materials were somewhat difficult to process. These were followed in the 1970s by somewhat more processable materials, commonly referred to as polyarylates. More recently there has been considerable activity in liquid crystal polyesters, which are in interest as self-reinforeing heat-resisting engineering thermoplastics. 

Phillips, L.N. (ed.) Design with Advanced Composite Materials, Design Council, London (1989). Strong, B.A. High Performance Engineering Thermoplastic Composites, Technomic Lancaster, PA (1993). 

Many engineering thermoplastics (e.g., polysulfone, polycarbonate, etc.) have limited utility in applications that require exposure to chemical environments. Environmental stress cracking [13] occurs when a stressed polymer is exposed to solvents. Poly(aryl ether phenylquin-oxalines) [27] and poly(aryl ether benzoxazoles) [60] show poor resistance to environmental stress cracking in the presence of acetone, chloroform, etc. This is expected because these structures are amorphous, and there is no crystallinity or liquid crystalline type structure to give solvent resistance. Thus, these materials may have limited utility in processes or applications that require multiple solvent coatings or exposures, whereas acetylene terminated polyaryl ethers [13] exhibit excellent processability, high adhesive properties, and good resistance to hydraulic fluid. 

Materials with totally new property combinations may be achieved by blending two or more polymers together. Through blending of thermotropic main-chain LCPs with engineering thermoplastics, the highly ordered fibrous structure and good properties of LCPs can be transferred to the more flexible matrix polymer. LCPs are blended with thermoplastics mainly in order to reinforce the matrix polymer or to improve its dimensional stability, but LCP addition may modify several... 

Polyesters are one of the most versatile classes of polymers ever produced, covering a wide range of properties and applications. Polyesters are present in fibers, engineering thermoplastics, and high-performance polymers as well as in thermosetting resins and elastomers. Table 2.1 lists the chemical structure, abbreviations, and uses of some commercially important thermoplastic polyesters. 

Aromatic-aliphatic polyesters, in which either R1 or R2 is aromatic, are generally high-melting (150-270°C) semicrystalline materials that find applications as engineering thermoplastics, films, or fibers. 

Alkanesulfonates act as an external lubricant in PVC, polystyrene, and engineering thermoplastics. They have a good release effect and assist flow. Addition is in the concentration range between 0.1 and 2.0 parts per 100 parts resin (phr). Because of their low volatility, alkanesulfonates are also used as a processing aid for high-melting engineering thermoplastics. 

Engineering polymers generally comprise a high performance segment of synthetic plastic materials that exhibit premium properties. In this paper, engineering thermoplastics developed for advanced applications, and particularly for enhanced thermal stability are considered. 

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