Corrosion-resistance copolymers

Polyoxymethylene (POM) is commonly used as a direct replacement for metals due to its stiffness, dimensional stability and corrosion resistance. Copolymers including ethylene oxide are quite common, primarily because they reduce the propensity for depolymerization at normal processing temperatures. Some typical properties are Glass Transition Temperature, Tg = -30 C Melting Temperature, Tm = 183 C Amorphous density at 25 C = 1.25 g/cc Crystalline density at 25 C = 1.54 g/cc Molecular weight of repeat unit = 30.03 g/mole. There are a number of grade variations of this material commercially available. 

FEP plastics Copolymers of tetrafluoro-ethene and hexafluoropropene. Inert and corrosion resistant as Teflon but can be processed by melt techniques. 

As a tme thermoplastic, FEP copolymer can be melt-processed by extmsion and compression, injection, and blow molding. Films can be heat-bonded and sealed, vacuum-formed, and laminated to various substrates. Chemical inertness and corrosion resistance make FEP highly suitable for chemical services its dielectric and insulating properties favor it for electrical and electronic service and its low frictional properties, mechanical toughness, thermal stabiUty, and nonstick quaUty make it highly suitable for bearings and seals, high temperature components, and nonstick surfaces. 

The most chemical-resistant plastic commercially available today is tetrafluoroethylene or TFE (Teflon). This thermoplastic is practically unaffected by all alkahes and acids except fluorine and chlorine gas at elevated temperatures and molten metals. It retains its properties up to 260°C (500°F). Chlorotrifluoroethylene or CTFE (Kel-F, Plaskon) also possesses excellent corrosion resistance to almost all acids and alkalies up to 180°C (350°F). A Teflon derivative has been developed from the copolymerization of tetrafluoroethylene and hexafluoropropylene. This resin, FEP, has similar properties to TFE except that it is not recommended for continuous exposures at temperatures above 200°C (400°F). Also, FEP can be extruded on conventional extrusion equipment, while TFE parts must be made by comphcated powder-metallurgy techniques. Another version is poly-vinylidene fluoride, or PVF2 (Kynar), which has excellent resistance to alkahes and acids to 150°C (300°F). It can be extruded. A more recent development is a copolymer of CTFE and ethylene (Halar). This material has excellent resistance to strong inorganic acids, bases, and salts up to 150°C. It also can be extruded. 

The evaluation of the components of the tinplate container showed that the preferred enamel for irradiation processing was the epoxy phenolic the preferred end-sealing compound was the blend of cured and uncured isobutylene—isoprene copolymer. Component testing of tinplate and solder for possible changes in mechanical properties, microstructure, and corrosion resistance indicated that the radiation caused... 

One of the most chemical-resistant plastics commercially available today is tetrafluoroethylene or TFE (Teflon). This thermoplastic is practically unaffected by all alkalies and acids except fluorine and chlorine gas at elevated temperatures and molten metals. It retains its properties up to 260°C. Chlorotrifluo-roethylene or CFE (Kel-F) also possesses excellent corrosion resistance to almost all acids and alkalies up to 175°C. FEP, a copolymer of tetrafluoroethylene and hexafluoropropylene, has similar properties to TFE except that it is... 

Hydrolysis of acyl fluoride end groups on hexa-fluoropropylene-tetrafluoroethylene copolymer with 1% water in a corrosion-resistant 28-mm intermeshing twin-screw extruder at 360°C. 

Low molecular weight copolymers of styrene with maleic or acrylic acid have been used as their N,N-dimethylethanolamine salts to prevent corrosion of zinc and aluminum in coatings applied from water.103 Corrosion-resistant binders for magnetic tapes have been prepared from diaminoquinones (13.21).104... 

The utility of polyaniline in corrosion resistant coatings has been noted [McAndrew et al., 1996]. The addition of polyaniline to acid containing polymers e.g., polyamic acid precursor of poly-imides, styrene-acrylic acid copolymers) allowed for polymeric doping and intermediate corrosion protection of the blends compared to the constituents. Epoxy addition and diisocyante terminated... 

Acetal polymers and copolymers are engineering materials and are competitive with a number of plastics materials, nylon in particular, and with metals. Acetal resins are being used to replace metals because of such desirable properties as low weight (sp. gr. 1.41-1.42), corrosion resistance, resistance to fatigue, low coefficient of friction, and ease of fabrication. 

This elastomer is sold under the trade name Tefzel by DuPont. ETFE is a modified partially fluorinated copolymer of ethylene and polytetrafluor-oethylene (PTFE). Since it contains more than 75% TEE by weight, it has better resistance to abrasion and cut-through than TEE while retaining most of the corrosion resistance properties. 

Uses Mfg. of block copolymers incl. polyamides, PU, PC mfg. of silicone-modified epoxy resins in corrosion-resist, coatings and polishes Features Improved adhesion to painted and unpainted metal surfs. Properties Liq. sp.gr. 0.98 vise. 50 cSt 98% solids PS513 [United Chem. Tech.]... 

Lipaton SB 4520 Slyrene/buladlene/ acryKc add copolymer binder, corrosion-resistance coatings... 

Ethylene chlorotrilluoroethylene (ECTFE) is an alternating copolymer of chlorotrifluo-roethylene and ethylene. It has better wear properties than PTFE along with good flame resistance. Applications include wire and cable jackets, tank linings, chemical process valve and pump components, and corrosion-resistant coatings. ... 

This material has excellent barrier properties and is frequently used in food packaging applications. Films made from PVDC have good cling properties, which is an advantage for food wraps. Commercial polymers are all copolymers of vinylidene chloride with vinyl chloride, acrylates, or nitriles. Copolymerization of vinylidene chloride with other monomers reduces the melting point to allow easier processing. Corrosion-resistant materials should be considered for use when processing PVDC. 

Combinations of zinc dust (particle diameter 12-20 xm) and extrafine zinc dust (particle diameter 3-6 p,m) yield optimal corrosion resistance. Small amounts of aluminum paste or powder, added to obtain a more silvery appearance, will however decrease corrosion resistance—as found in comparative weathering tests by Van Eijnsbergen (personal communication). Generally, nonsaponifiable binders, such as vinyl copolymers, chlorinated mbber, methacrylic resins, and epoxy resins, are used. For welding zinc-rich primers, epoxy-polyamide binders are widely used. They allow a wider range of sealers and top coatings. 

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