Engineering plastics acetal

The most stable polyacetal polymer is polyformaldehyde (or polyoxymeth-ylene, POM) this is the only polyacetal that has reached commercial production. This resin has unique properties (e.g., selflubrication) and is very widely used in automotive applications such as engineering plastics. Acetals are widely used engineering thermoplastics with high load-bearing characteristics and low coefficients of friction. Currently, over 200 million lb of acetals are molded and extruded in the United States. 

Plaslube . [Akzo Engineering Plastics] Acetal, nylon 6, 6/6,6/12, PC, or PPS resins lubricated widi PIPE, silicone, molybdenum disulfide, or carbon. internally lubricated engineering thermoplastics. 

Through counted as one of the engineering plastics, acetal resins with their comparatively high cost cannot, however, be considered as general-purpose thermoplastics in fine with polyethylene, polypropylene, PVC, and polystyrene... 

In the 1980s, there was a major effort among the major resin suppliers to seek out new applications by replacing parts and systems that had been traditionally made out of metal with parts and systems that were injection molded from engineering plastics (acetal, nylon, polycarbonate, polyester, etc.). These applications were in a wide range of industries, including automobiles, industrial equipment, household appliances, and office furniture [2],... 

Cyclic ether and acetal polymerizations are also important commercially. Polymerization of tetrahydrofuran is used to produce polyether diol, and polyoxymethylene, an excellent engineering plastic, is obtained by the ring-opening polymerization of trioxane with a small amount of cycHc ether or acetal comonomer to prevent depolymerization (see Acetal resins Polyethers, tetrahydrofuran). 

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). 

Acrylonitrile-butadiene-styrene (ABS). ABS materials have superior strength, stiffness and toughness properties to many plastics and so they are often considered in the category of engineering plastics. They compare favourably with nylon and acetal in many applications and are generally less expensive. However, they are susceptible to chemical attack by chlorinated solvents, esters, ketones, acids and alkalis. 

Most of the engineering plastics reproduce faithfully and easily conform to the mold configuration, and when processing parameters are appropriately controlled, they will repeat with excellent accuracy tolerance wise, etc. As an example for the past many decades, we see plastic gears and other precision products made of acetal, nylon, polycarbonate,... 

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. 

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. 

Engineering plastics are most frequently thought of as the acetals, nylons, fluorocarbons, phenolics, polycarbonate, and polyphenylene oxide, to name just a few. These are indeed engineering materials and for such applications are usually used in relatively small... 

Polyethers. Acetal Resins. These stabilized polyoxymethy-lenes were introduced dramatically by DuPont and Celanese as engineering plastics to replace non-ferrous metals. Good mechanical strength, resilience, fatigue-resistance, lubricity, abrasion-resistance, heat distortion temperature, water and solvent-resistance can approach the behavior of metals on a volume basis, while processability, color possibilities, and corrosion-resistance are superior. Major weakness is sensitivity to thermal, oxidative, and ionic degradation. 

Engineering plastics are those to which standard metal engineering equations can be applied they are capable of sustaining high loads and stresses and are machinable and dimensionally stable. They are used in construction, as machine parts, automobile components, etc. Among the more important are nylon, acetals, polycarbonates, ABS resins, PPO/styrene, and polybutylene terephthalate. 

Performance Coatings and Polymers nylon, acetal, polyester, polyimide and EPDM engineering plastics and elastomers industrial and powder coatings and inks ... 

The Performance Coatings Polymers business is involved in the production of nylon, acetal, polyester, polyimide and EPDM engineering plastics and elastomers and industrial and powder coatings and inks. The Wuppertal sites are primarily involved in the production of automotive coatings and refinishes, electrical insulation and adhesives. 

Both CAP and CAB have superior properties to plain acetate, particularly with reference to toughness and impact strength. Their main uses are as engineering plastics and occasionally for pharmaceutical devices and administration aids. Hard, gas-permeable contact lenses may be made from CAB. 

Spin/friction welding primarily finds usage with engineering plastics such as acetal. It is occasionally used with plastic components found in packaging. 

Many of the practical examples of miscible blends involve poly(vinylchloride) including those with butadiene-acrylonitrile copolymers2), possibly the first put into use, and various poly acrylates and vinyl acetate copolymers3,4) which are extensively used in PVC formulations at present. Others involve high performance engineering plastics such as blends of polystyrene with poly(2,6-dimethyl-1,4-phenylene oxide) (Noryl )5). In some cases a useful compromise or averaging of properties can be obtained whereas in others a useful combination of different desirable properties can be achieved. 

Though useful polymers can be made by these reactions, their low ceiling temperatures (see p. 599) and consequent tendency to undergo facile depolymerization by an unzipping mechanism pose serious limitations. To overcome this problem the technique of end-capping or end-blocking may be used. Thus poly-oxymethylene (polyacetal), an engineering plastic, prepared from the cyclic acetal... 

---