Engineering resins and plastics

Nearly all cyclohexane is used to make three intermediate chemicals. About 85% goes for caprolactam, and adipic acid. Another 10% goes for hexamethylene diamine (HMD). All three are the starting materials for Nylon 6 or Nylon 66 synthetic fibers and resins. Nylon fiber markets include the familiar applications hosiery, upholstery, carpet, and tire cord. Nylon resins are engineering plastics and are largely used to manufacture gears, washers, and similar applications where economy, strength, and a surface with minimum friction are important. 

Electrical and electronic products such as computers, cell phones, TVs, and stereos are becoming a more visible part of the MSW. Some of the resins used in electronic products are PS, HIPS, ABS, PC, PP, PU, PV, PVC, polyamides, phenol formaldehyde, and blends of some of these polymers. Several technologies are being developed for the separation of different plastic types. Since the electronic parts are made from many engineering plastics, and with many different additives, it is more difficult to identify and separate the individual resins. 

Aromatic polyesters having an amorphous molecular structure. Compared with other amorphous engineering plastics in terms of heat resistance, polyarylates are generally positioned between polycarbonate on the low side and sulfone and polyether polymers on the high side. Compared with crystalline and semi-crystalline engineering plastics, polyarylate resins offer better resistance to warping, and generally comparable mechanical properties. 

Formaldehyde (CH20) is an important compound in the synthesis of various chemicals on an industrial scale. One of the first industrial applications was in the production of artificial Indigo. The variety of end products produced from formaldehyde include resins or glues (produced by the condensation of formaldehyde with urea, phenol, or melamine) as well as rubber, paper, fertilizers, explosives, engineering plastics, and specialty chemicals like acrolein, methacrylic acid, methyl methacrylate, etc. Because it is nearly impossible to handle in its pure gaseous form, formaldehyde is almost exclusively produced... 

Durd . (Hoechst Ceianese/Engineering Plastics] Polyarylate resin engineering therW)plastic for glazing and lifting applies., lenses, automotive panels, appliance parts, solar collection panels. 

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... 

Thermoset composite systems of phenol and formaldehyde, some of which can he substituted for a number of structural applications can also be considered as engineering plastics and they have been in use for a very long time. In recent applications, improved urea - melamine resins have been used as matrices more and more for composite systems, because of their non-melting, high thermal and chemical resistances, hardnesses, mechanical-dimensional stabilities and low flammabilities. 

These resins are expected to bridge the performance gap between advanced polyolefin resins and engineering plastics, and are therefore, truly "Specialty Polyolefins". 

Engineering polymer blends (EPB) can be roughly divided into blends of an engineering plastic or resin (ER) with a commodity plastic, blends of an engineering plastic with another engineering plastic, blends of an engineering plastic with an elastomer and, blends which contain three or more polymers. We can therefore get combinations such as PPO/PS PPO/PA PC/ABS PET/PBT PBT/PC/SAN etc. each of the blends may in turn be filled. When blends are made the objective is to simultaneously optimize blend formulations, in respect of several properties important for a particular application, sacrificing those which are not important. 

Polyarylamide resins n. Synthesized by melt polymerization of m-xylenediamoine with adipic acid. It is used as a high stiffness, high softening point engineering plastic. Polyarylamide resins have higher modules and yield stress values than nylon 66, however, its water sensitivity has precluded a wider usage. 

Many factors are responsible for closing the performance gap between composites of engineering plastics and polypropylene (PP) resins. Enhanced mechanical properties of GFRP composites are primarily due to practical utilization of... 

Drying. Although modified PPE resin has the lowest moisture absorption of any engineering plastic and may be molded as received in many applications, it is a good practice, particularly where surface appearance is critical, to dry modified PPE resin before molding. Modified PPE resins should not be dried longer than 8 h. Excessive drying may result in loss of physical properties, color shift, loss of processability, or a combination of the three. 

Fig. 20. FCP rates vs AK for several engineering plastics and metal alloys (39). A, LDPE B, epoxy C, PMMA D, polysulfone E, polystyrene F, PVC G, pol3Kphenylene oxide) H, polycarbonate I, nylon-6,6 J, HI-nylon-6,6 K, poly(vinylidene fluoride) L, acetal resins M, 2219-T851 aluminum alloy N, 300M steel alloy.

In these expressions, Ef, and Er are the moduli of the composite, fiber, and resin, is the volume fraction of fiber, A is the average aspect ratio of the fiber, and W is the maximum packing fraction. Application of the equation is limited to small strains. (Natural fibers, plastics and composites. Wallenberger FT, Weston NE (eds). Springer, New York, 2003 Murphy J (1998) Reinforced plastics handbook. Elsevier Science and Technology Books, New York Engineering plastics and composites. Pittance JC (ed), SAM International, Mate-rials Park, OH, 1990) L... 

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