Polycarbonate chemicals, resistance

Bisphenol A. One mole of acetone condenses with two moles of phenol to form bisphenol A [80-05-07] which is used mainly in the production of polycarbonate and epoxy resins. Polycarbonates (qv) are high strength plastics used widely in automotive appHcations and appHances, multilayer containers, and housing appHcations. Epoxy resins (qv) are used in fiber-reinforced larninates, for encapsulating electronic components, and in advanced composites for aircraft—aerospace and automotive appHcations. Bisphenol A is also used for the production of corrosion- and chemical-resistant polyester resins, polysulfone resins, polyetherimide resins, and polyarylate resins. 

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). 

In general, polycarbonate resins have fair chemical resistance to aqueous solutions of acids or bases, as well as to fats and oils. Chemical attack by amines or ammonium hydroxide occurs, however, and aUphatic and aromatic hydrocarbons promote crazing of stressed molded samples. Eor these reasons, care must be exercised in the choice of solvents for painting and coating operations. Eor sheet appHcations, polycarbonate is commonly coated with a sihcone—sihcate hardcoat which provides abrasion resistance as well as increased solvent resistance. Coated films are also available. 

Polypropylene has a chemical resistance about the same as that of polyethylene, but it can be used at 120°C (250°F). Polycarbonate is a relatively high-temperature plastic. It can be used up to 150°C (300°F). Resistance to mineral acids is good. Strong alkalies slowly decompose it, but mild alkalies do not. It is partially soluble in aromatic solvents and soluble in chlorinated hydrocarbons. Polyphenylene oxide has good resistance to ahphatic solvents, acids, and bases but poor resistance to esters, ketones, and aromatic or chlorinated solvents. 

The chemical resistance of polyester materials is well recognised to be limited because of the comparative ease of hydrolysis of the ester groups. Whereas this ease of hydrolysis was also observed in aliphatic polycarbonates produced by... 

Polycarbonate is blended with a number of polymers including PET, PBT, acrylonitrile-butadiene-styrene terpolymer (ABS) rubber, and styrene-maleic anhydride (SMA) copolymer. The blends have lower costs compared to polycarbonate and, in addition, show some property improvement. PET and PBT impart better chemical resistance and processability, ABS imparts improved processability, and SMA imparts better retention of properties on aging at high temperature. Poly(phenylene oxide) blended with high-impact polystyrene (HIPS) (polybutadiene-gra/f-polystyrene) has improved toughness and processability. The impact strength of polyamides is improved by blending with an ethylene copolymer or ABS rubber. 

ABS foam provides properties that include impact, heat, and chemical resistance low mold shrinkage rates good long-term dimensional stability and platability. Improved flammability characteristics are possible either by alloying (blending) with PVC or polycarbonate, or by... 

Although polycarbonate is an engineering thermoplastic material which provides high toughness, flexibility and thermal stability, it suffers from certain limitations due to poor chemical resistance and low flow characteristics in injection moulding. These shortcomings can be circumvented by blending PC... 

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