Polyether-imide plastic

An engineering plastic core was found preferable examples included polyetherether ketone (PEEK), polyphenylene sulfide (PPS), and polyether imide (PEI). Polytetrafluoroethylene bearers were placed in the mold to keep the core material away from the walls of the mold. No special cavity modifications were required. Any hot-melt fluoroplastic could be molded surrounding the insert examples include PVDF, FEP, ETFE, PFA, ECTFE, and PCTFE. 

The term HT-thermoplastics is used for polymers, which in the absence of fillers, have a continuous-use temperature above approx. 200 °C. In contrast, standard plastics, such as PVC, polyethylene or polystyrene, have continuous-use temperatures of the order of 100 °C. In addition to their high temperature stability, HT-thermoplastics, in general, possess good resistance to chemicals and usually also low flammability. Among the most important HT-thermoplastics are polyphenylene sulfides (PPS), polysul-fones (PSU), polyether sulfones (PES), polyether imides (PEI), polyetherether ketones (PEEK) and polyarylates (PAR). 

Polyether-imide (PEI) is an amorphous thermoplastic, with an excellent balance of physical properties and dimensional stabilities. PEI can be nsed with the fnll spectrum of sterilisation methods. Surgical probes that are subjected to repeated cleaning and sterilisation are their typical preferred application as a medical plastic. 

Polyetherimide molding compounds are commercially available in extmsion and injection molding grades. The major suppliers of this material include GE Plastics (JJltem), Compound Technologies, DSM Engineering, LNP, and RTF A polyether-imide-polycarbonate alloy and a polyetherimide-silicone alloy are also available from GE Plastics. 

Although polyimides can have an open-chain structure, cyclic polyimides have found more use because they are more thermally stable than open-chain polyimides. The polyether-imide prepared from pyromellitic dianhydride and 4,4 -diaminodiphenyl ether has found use in high temperature coatings, adhesives, and structural plastics. The reaction involves rapid formation of the polyamide, called polyamic acid, followed by a high-temperature ring closure step. 

Polypropylene is generally used as oriented polypropylene. Polyvinyl chloride film is commonly used in plasticized form. Polyvinylidene chloride is often known as Saran and is generally used in copolymer form with acrylonitrile. Polyethylene terephthalate is a thermoplastic polyester. Polystyrene is sometimes used in biaxially oriented form. Polycarbonates, polysulfones, polyether sulfones, poly-imides, polyetherimides, and several fluoropolymers are also used for specialty applications. 

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