Polymer chemical resistance

Beilin, D., and Figovsky, O. Stress-Strain State of Polymer Chemical-Resistant Coatings Curing and under Operating Conditions, J. Composite Structures 31 (1995) 253-256. 

PEEK energised seals Trelleborg Sealing Solutions High purity, all polymer, chemical resistance versus metal... 

Polymers—Chemical resistance. 2. Stabilizing agents. I. Pongratz, Sonja,... 

The components of any particular resin and the proportions of these components vary with the intended use of the resins. By suitable variations, the polymer chemist can achieve a wide range of physical properties and performance characteristics, including viscosity, colour, hardness, toughness, adhesion, solubility, compatibility with other polymers, chemical resistance, colour and gloss retention and durability. The choice of different components in alkyd synthesis and their influence on paint properties has recently been comprehensively reviewed. ... 

Tetralluoroethylene polymer has the lowest coefficient of friction of any solid. It has remarkable chemical resistance and a very low brittleness temperature ( — 100°C). Its dielectric constant and loss factor are low and stable across a broad temperature and frequency range. Its impact strength is high. 

It possesses outstanding barrier properties to gases, especially water vapor. It is surpassed only by the fully fiuorinated polymers in chemical resistance. A few solvents dissolve it at temperatures... 

The principal monomer of nitrile resins is acrylonitrile (see Polyacrylonitrile ), which constitutes about 70% by weight of the polymer and provides the polymer with good gas barrier and chemical resistance properties. The remainder of the polymer is 20 to 30% methylacrylate (or styrene), with 0 to 10% butadiene to serve as an impact-modifying termonomer. 

The high degree of crystallization and the thermal stability of the bond between the benzene ring and sulfur are the two properties responsible for the polymer s high melting point, thermal stability, inherent flame retardance, and good chemical resistance. There are no known solvents of poIy(phenyIene sulfide) that can function below 205°C. 

PVC polymer plus special plasticizers are used to produce flexible tubing which has good chemical resistance. 

An extensive new Section 10 is devoted to polymers, rubbers, fats, oils, and waxes. A discussion of polymers and rubbers is followed by the formulas and key properties of plastic materials. Eor each member and type of the plastic families there is a tabulation of their physical, electrical, mechanical, and thermal properties and characteristics. A similar treatment is accorded the various types of rubber materials. Chemical resistance and gas permeability constants are also given for rubbers and plastics. The section concludes with various constants of fats, oils, and waxes. 

The industrial value of furfuryl alcohol is a consequence of its low viscosity, high reactivity, and the outstanding chemical, mechanical, and thermal properties of its polymers, corrosion resistance, nonburning, low smoke emission, and exceUent char formation. The reactivity profile of furfuryl alcohol and resins is such that final curing can take place at ambient temperature with strong acids or at elevated temperature with latent acids. Major markets for furfuryl alcohol resins include the production of cores and molds for casting metals, corrosion-resistant fiber-reinforced plastics (FRPs), binders for refractories and corrosion-resistant cements and mortars. 

Blends of PET and HDPE have been suggested to exploit the availabiUty of these clean recycled polymers. The blends could combine the inherent chemical resistance of HDPE with the processiag characteristics of PET. Siace the two polymers are mutually immiscible, about 5% compatihilizer must be added to the molten mixture (41). The properties of polymer blends containing 80—90% PET/20—10% HDPE have been reported (42). Use of 5—15% compatbiLizer produces polymers more suitable for extmsion blow mol ding than pure PET. 

Chemical Properties. The hydrolysis of PET is acid- or base-catalyzed and is highly temperature dependent and relatively rapid at polymer melt temperatures. Treatment for several weeks in 70°C water results in no significant fiber strength loss. However, at 100°C, approximately 20% of the PET tenacity is lost in one week and about 60% is lost in three weeks (47). In general, the hydrolysis and chemical resistance of copolyester materials is less than that for PET and depends on both the type and amount of comonomer. 

Many challenging industrial and military applications utilize polychlorotriduoroethylene [9002-83-9] (PCTFE) where, ia addition to thermal and chemical resistance, other unique properties are requited ia a thermoplastic polymer. Such has been the destiny of the polymer siace PCTFE was initially synthesized and disclosed ia 1937 (1). The synthesis and characterization of this high molecular weight thermoplastic were researched and utilized duting the Manhattan Project (2). The unique comhination of chemical iaertness, radiation resistance, low vapor permeabiUty, electrical iasulation properties, and thermal stabiUty of this polymer filled an urgent need for a thermoplastic material for use ia the gaseous UF diffusion process for the separation of uranium isotopes (see Diffusion separation methods). 

Uses. Neopentyl glycol is used extensively as a chemical intermediate in the manufacture of polyester resins (see Alkyd resins), polyurethane polyols (see Urethane polymers), synthetic lubricants, polymeric plasticizers (qv), and other polymers. It imparts a combination of desirable properties to properly formulated esterification products, including low color, good weathering and chemical resistance, and improved thermal and hydrolytic stabiUty. 

Polyimides (PI) were among the eadiest candidates in the field of thermally stable polymers. In addition to high temperature property retention, these materials also exhibit chemical resistance and relative ease of synthesis and use. This has led to numerous innovations in the chemistry of synthesis and cure mechanisms, stmcture variations, and ultimately products and appHcations. Polyimides (qv) are available as films, fibers, enamels or varnishes, adhesives, matrix resins for composites, and mol ding powders. They are used in numerous commercial and military aircraft as stmctural composites, eg, over a ton of polyimide film is presently used on the NASA shuttle orbiter. Work continues on these materials, including the more recent electronic apphcations. 

Polymers. Ion implantation of polymers has resulted in substantial increases of electrical conductivity (140), surface hardness (141), and surface texturing (142). A four to five order of magnitude increase in the conductivity of polymers after implantation with 2 MeV Ar ions at dose levels ranging from 10 -10 ions/cm has been observed (140). The hardness of polycarbonate was increased to that of steel (141) when using 1 MeV Ar at dose levels between 10 -10 ions/cm. Conductivity, oxidation, and chemical resistance were also improved. Improvements in the adhesion of metallizations to Kapton and Teflon after implantation with argon has been noted (142). 

Carboxyhc acids react with aryl isocyanates, at elevated temperatures to yield anhydrides. The anhydrides subsequently evolve carbon dioxide to yield amines at elevated temperatures (70—72). The aromatic amines are further converted into amides by reaction with excess anhydride. Ortho diacids, such as phthahc acid [88-99-3J, react with aryl isocyanates to yield the corresponding A/-aryl phthalimides (73). Reactions with carboxyhc acids are irreversible and commercially used to prepare polyamides and polyimides, two classes of high performance polymers for high temperature appHcations where chemical resistance is important. Base catalysis is recommended to reduce the formation of substituted urea by-products (74). 

The chemical resistance and excellent light stabiUty of poly(methyl methacrylate) compared to two other transparent plastics is illustrated in Table 5 (25). Methacrylates readily depolymerize with high conversion, ie, 95%, at >300° C (1,26). Methyl methacrylate monomer can be obtained in high yield from mixed polymer materials, ie, scrap. 

Polymers are used as inserts for pins and contacts. Important properties of the commonly used insert materials have been compiled (31). Polysulfones are high temperature thermoplastics that have high rigidity, low creep, excellent thermal stabiHty, flame resistance, low loss tangents, and low dielectric constants. The principal weakness of polysulfones is their low chemical resistance. 

Nylon-12,12. Nylon-12,12 [36497-34-4] [36348-71-7] was introduced into the marketplace by Du Pont in the late 1980s (174). This polymer possesses very low moisture absorption, high dimensional stabihty, and excellent chemical resistance, with a moderately high melt point (T = 185° C)... 

Chemical Resistance of LGPs. Ceitain liquid crystal polymers (eg, Vectra) have extremely high chemical resistance to a variety of aggressive chemicals and solvents. Table 18 shows the chemical stabiUty of Vectra test-bars to various agents (244). 

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