Crystalline Engineering

Polyetheretherketone PEEK is a high-temperature, crystalline engineering TP used for high performance applications such as wire and cable for aerospace applications, military hardware, oil wells and nuclear plants. It holds up well under continuous 450°F (323° C) temperatures with up to 600°F (316° C) limited use. Fire resistance rating is UL 94 V-0 it resists abrasion and long-term mechanical loads. 

SPS has high a melting point almost comparable to those of other engineering plastics (Table 18.2). In comparison with other crystalline engineering thermoplastics, of particular interest is that SPS has the lowest specific gravity and dielectric constant. 

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. 

Polyketones PK are crystalline engineering TPs that provide high performing thermal [240-245C (465-475F)], mechanical,... 

PIT Incorporation of other adipic acids, such as sebacic acid, trimethylene isophthalate, p-cetoxybenzoic acid, and ethylene glycol units Seo et al. (2006), Chen et al. (2007), Wei et al. (2006), Ou (2002) Blended with polyesters to develop high-performance materials, including crystalline engineering thermoplastic polymers, amorphous engineering thermoplastic polymers, and thermoplastic elastomers Nadkami and Rath (2002), Run et al. (2007), Krutphan and Supaphol (2005), Jafari et al. (2005), Yavari et al. (2005)... 

High melt viscosity compared to crystalline engineering polymers such as PA-6, PBT. 

The study of relaxation processes in Semicrystalline Polymers (qv) is a subject of continuing technological interest because of its practical importance. This is based on the observation that the stiffness of typical crystalline engineering thermoplastics at room temperature may be only one-third to one-fifth that of the same material at a low temperature. The drop in stiffness or modulus takes place in regions of temperature associated with a relaxation process. 

PPS is a crystalline engineering plastic especially known for its high heat performance with heat deflection temperatures in excess of 260 °C. It has exceptional processability when injection moulded on conventional equipment. It also has outstanding dimensional stability and so is particularly suitable for precision moulding to severe tolerances. It can also be used as a replacement for high performance thermosets or metal, especially brass, in some applications. 

Many of the polymer blends containing crystalline polymers involve crystalline polyolefins (e.g., polyethylene, polypropylene) and these blends will be discussed in Section 4.5. Additionally, crystalline engineering polymer blends, such as nylon 6,6, poly(butylene terephthalate), poly(aryl ether ketones), and poly(ethylene terephthalate), are blended with other engineering polymers (either amorphous or crystaUine) and these will also be discussed separately (see Section 4.6). Blends of the crystaUine engineering polymers with non-engineering polymers wiU be discussed in this section. AdditionaUy, crystaUine polyolefin blends with non-olefin polymers wiU be covered in this section. 

Polyphthalamide (PPA) is a semi-crystalline engineering polymer that bridges the cost-performance gap between traditional engineering thermoplastics such as polycarbonate (PC), polyamides (PA polyester (PET, PBT), acetals (POM) and higher-cost speciality pol5nners such as liquid crystal polymers (LCP), polyphenylene sulfide (PPS) and polyetherimide (PEI). 

PBT is one of the partially crystalline engineering plastics. It is used primarily on account of its good dimensional stability hardness, rigidity, and strength good temperature resistance and good electrical properties. 

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