Polyamide-imide coatings

TrimeUitic anhydride is converted to PVC plasticizers, polyesters, water-soluble alkyd coatings, and polyamide—imide resias. The trimellitate plasticizers have a lower volatility than those derived from phthaUc anhydride (see Plasticizers). 

Dual Constructions. In addition to the "basic" magnet wire insulations in which the conductor wire is coated with a single enamel, there are a number of cases where two different enamels are used one overcoated over the other. Examples include polyurethane-base insulation overcoated with poly(vinyl butyral) or with nylon, or polyester-base insulation overcoated with nylon or with polyamide imide. 

Linear polymers such as polyamide imides and polyimides are sometimes used as varnishes however, they produce coatings that are not cross-linked. For some applications for which rework and repairs have to be made, cross-linked coatings have a disadvantage. Soluble polymer systems that can be repaired are to be preferred in such cases. 

Chem. Descrip. Polyamide imide resin (44%) in N-methyl pyrrolidone Uses Binder for formulation of stoving can coatings Features Highly flexible yields very hard glossy paint films which do not have thermoplastic props. produces coatings resist, to boiling water and soivs. 

Hydrogenated cottonseed oil Hydrogenated palm oil Hydrogenated vegetable oil Octyidodecyl stearoyl stearate binder, surface coatings Epoxy, bisphenol A Polyamide-imide resin Poly (vinyl propionate) binder, suspension polymerization Methyl hydroxyethylcellulose binder, swimming pool paints Rubber, chlorinated... 

Polyamide-imide resin plastics, reinforced Dipropylene glycol Polypropylene plastics, surface-coating Bismuth subsalicylate plastics, vinyl Ammonium acetate plastisols... 

Another important group are the polyamide imides and polyimides. The substitution of tricarboxylic acid anhydride for dicarboxylic acids during synthesis results in thermally more stable polyamide imides. The polycondensation reaction proceeds in two steps, with the solution of the intermediate polycarboxylic acid used in applications where the final product can be generated by a thermal or baking process. Uses include heat-resistant wire and cable coatings. The basic synthesis of polyamide imides is as follows ... 

Polyamide-imides enjoy, as the name suggests, a positive synergy of properties from both polyamides and poljdmides, such as flexibility, melt processability, elongation, dimensional stability, and toughness. Polyamide-imide polymers can be processed into a wide variety of forms, from injection- or compression-molded parts and ingots to coatings, films, fibers, and adhesives. Generally these articles reach their maximum properties with a subsequent thermal cure process. 

The polyamide-imide achieved at the end of this process is a high-molecular-weight, fully imidized polymer in solvent with no condensation by-products, since the carbon dioxide gas is easily removed. This convenient form makes it especially beneficial for the manufacturer where the primary end use is wire enamel or another coating application. The solution viscosity is thus controlled by stoichiometry, monofunctional reagents, and polymer solids. The typical polymer sohds level is 35 to 45% and it may be diluted further by the supplier or customer with diluents. 

Torlon AI-50 is another water-soluble polyamide-imide similar to Torlon AI-30 in solids composition and coating performance. Because of a slightly different polymer backbone, it also does not have the MDA handling restrictions, plus it has a lower viscosity at the same solids level compared to AI-30. 

Several workers have proposed new combinations of materials in an attempt to overcome wear. Studies involving polyimides, polyamide-imides, and poly-tetrafluoroethylene-filled polyoxymethylene demonstrated that although wear characteristics were good in dry conditions, the presence of lubricants (blood plasma, water) decreased the wear resistance. Results obtained with reinforcing materials such as carbon fibre and with an aluminium oxide ceramic ball used in conjunction with a polyethylene socket have been presented, Examples of other types of reconstructive surgery involving hard tissue replacement are the use of poly(methyl methacrylate) in chest wall reconstruction and repair of depressed skull fractures, the repair of major crano-orbital defects with the aid of a polyurethane-coated poly(ethylene terephthalate) mesh, and the use of silicone rubber in total finger joint and carpal bone replacement. 

Metal coated polyamide (ASTM) Poly(acrylic acid) (ASTM) p-Aminobiphenyl Polyaminobismaleimide Poly(acrylonitrile) fiber (DIN, lUPAC) see also PAN, PC Phthalate ester plasticizer Polyamide-imide (ASTM)... 

Polyamide-imides (PAIs) are thermoplastic amorphous polymers prepared by the condensation of an aromatic diamine, such as methylene diamine, and an anhydride, such as trimellitic add chloride. PAIs have good mechanical, thermal, chemical resistance, high strength, melt processability, and high heat capacity. They can be processed into a variety of forms, such as injection or compression molded articles, coatings, films, fiber, and adhesives. The typical heat deflection temperature for neat molded PAI is 278°C,but reinforcements are often used to improve mechanical properties. PAIs are generally soluble in strong aprotic solvents such as NMP and DMAc, and thus misdble blends with PBI are feasible. 

Plastics for which the adhesion of coatings may be improved by plasma pre-treatment are reported to be polyethylene, polypropylene, polycarbonates, polyacetals, polyaromatic esters, polyimides, polyamides, polyphenylene ether, polyacrylates, acetal homopolymer, and poly(ether imide). 

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