Showing papers on "Polycarbonate published in 1978"

Polycarbonate transesterification process

Abstract: A polycarbonate process comprising contacting in the presence of a base, a β-fluoroaliphatic carbonate, and a polyhydroxy compound selected from alcohols and/or phenols. The resulting polycarbonates are useful as polycarbonates per se, or useful in the preparation of high molecular weight polycarbonates which can be molded or formed into films, laminates or reinforced plastics by conventional techniques.

Polyester–polycarbonate blends. I. Poly(butylene terephthalate)

Abstract: Melt blends of bisphenol A polycarbonate with poly(butylene terephthalate) were studied by DTA and dynamic mechanical behavior to determine their state of miscibility. Both techniques showed multiple glass transitions indicative of incomplete miscibility in the amorphous phase. However, these transitions in some cases did not correspond to those in the pure components and varied with overall blend composition in some instances. This indicates that there are amorphous phases containing both components, i.e., partial miscibility. This view was supported by the crystallization behavior of the polyester. Two crystallization exotherms were observed for quenched samples, which is interpreted as polyester crystallization from two separate phases, one richer in this component than the other. Other interpretations of these results are discussed.

Polyester/polycarbonate blends. I. Poly(butylene terephthalate)

Abstract: Melt blends of bisphenol A polycarbonate with poly(butylene terephthalate) were studied by DTA and dynamic mechanical behavior to determine their state of miscibility. Both techniques showed multiple glass transitions indicative of incomplete miscibility in the amorphous phase. However, these transitions in some cases did not correspond to those in the pure components and varied with overall blend composition in some instances. This indicates that there are amorphous phases containing both components, i.e., partial miscibility. This view was supported by the crystallization behavior of the polyester. Two crystallization exotherms were observed for quenched samples, which is interpreted as polyester crystallization from two separate phases, one richer in this component than the other. Other interpretations of these results are discussed.

Water sorption of polycarbonate and its effect on the polymer’s dielectric behavior

Abstract: Polycarbonate absorbs water in two stages: in the initial period of absorption at an elevated temperature all of the water was found in an unassociated state when cooled to room temperature; and, in the second stage, most of the additional water absorbed by the polymer was identified in a separate liquid phase (clustered water). From water sorption studies on polycarbonate bars, we advance the following model for the formation of clusters. After the polymer is saturated with water at an elevated temperature and cooled, its solubility is lowered and water condenses in the form of microscopic water‐filled cavities, providing the internal pressure which is generated by the excess water exceeds the strength of the polymer. Below Tg the clusters are formed only after the polycarbonate (Mw=26 600) has been hydrolytically degraded; whereas, above Tg, clusters can be formed without degradation. Cluster regions were found by SEM to be spherical cavities, usually measuring from 0.1 to 1.0 μ across. In addition, the glass temperature of polycarbonate was lowered as the molecular weight decreased due to hydrolysis and the amount of water in the polymer increased. Unassociated water was found to enhance the low‐temperature dielectric loss of polycarbonate. Frozen clustered water produced an additional secondary loss peak about 40 °C below the β transition. In addition, the liquid clustered water produced a loss mechanism in the kHz region that was interpreted as a Maxwell‐Wagner effect.

In-mold coating compositions containing functional group terminated liquid polymers

Abstract: Fully cured reinforced molded resins such as polyesters, polyurea urethanes, polyureas, polyurethanes, polyisocyanurates, polyepoxies and polycarbonate resins can be in-mold coated to cover surface defects such as sink marks and microcracks with an improved coating composition comprising reactive liquid polymers, a vinyl monomer, and certain cross-linkable unsaturated ester resins as co-polymers.

Modified polyester composition

Abstract: Modified thermoplastic polyester compositions are provided which comprise (a) a poly(1,4-butylene terephthalate) resin and, optionally, a poly(ethylene terephthalate) resin and (b) a modifier therefor comprising (i) a silane-treated clay; (ii) acicular calcium metasilicate, (iii) a combination of segmented copolyester and an aromatic polycarbonate; or (iv) novaculite or a combination thereof. The modifiers provide easier processability and enhanced resistance to warpage in articles molded from the compositions.

Blends of a polycarbonate resin and interpolymer modifier

Abstract: Blends of a polycarbonate resin and an interpolymer modifier comprising crosslinked (meth)acrylate, crosslinked styrene-acrylonitrile, and uncrosslinked styrene-acrylonitrile polymeric components are disclosed. The blends have improved processing as compared to the processing characteristics of the polycarbonate resin alone and are impact resistant. They are more weather resistant than blends of the polycarbonate resin and ABS graft copolymers.

Ester interchange of carbonate

Abstract: PURPOSE: To obtain a carbonate, which cannot be easily manufactured, from an available carbonate, by effecting the ester interchange of the carbonate using a silicatitania solid acid catalyst prepared according to a specific method. CONSTITUTION: A carbonate is reacted with an organic compound having a hydroxyl group in the presence of a silica-titania solid acid catalyst, prepared by a coprecipitation from an aqueous solution of a titanium compound, e.g. titanium tetrachloride, and a silicon compound, e.g. silicon tetrachloride, with an aqueous ammonia, by washing the precipitate, and by drying and calcining, to effect the ester interchange. Dibutyl carbonate can be obtained from inexpensive ethylene carbonate; polycarbonate, from dimethyl carbonate and bisphenol A. COPYRIGHT: (C)1979,JPO&Japio

Impact and yield properties of polycarbonate as a function of strain rate, molecular weight, thermal history, and temperature

Abstract: A study has been made on the impact and yield properties of polycarbonates from two manufacturers as a function of strain rate, melt flow rate, notch radius, thermal history, and test temperature. The yield stress increases with the strain rate and annealing time in exactly the way predicted by a recently proposed theory on nonlinear viscoelasticity of glassy polymers. The critical molecular weight for the transition from a ductile to a brittle break increased at higher rate of strain and also with the longer annealing times.

Delayed yielding of polycarbonate under constant load

Abstract: The time-dependent yielding of glassy polycarbonate subjected to constant tensile loads has been studied. Application of a constant stress of a magnitude between the yield stress and the stress required for propagation of a neck in constant strain tests results in inhomogeneous yielding after a well-defined time lag. This delay time increases with decreasing stress and temperature. The critical stress for slowly cooled material is greater than that for quenched material in which the delay time is divided in two regions. The delay time is regarded as the time required for the initiation of inhomogeneous yielding at either edge of the specimen and growth over a certain distance across the specimen. Geometrical observations revealed that the inhomogeneous yielding is shear yielding which is initiated due to stress inhomogeneities caused by mechanical imperfections at the edge of the specimen. The Eyring treatment of delayed yielding can describe fairly well the stress and temperature dependence of the delay time.

Effects of polar group incorporation on crazing of glassy polymers: Styrene–acrylonitrile copolymer and a dicyano bisphenol polycarbonate

Abstract: The degree of swelling and attendant reduction in the glass transition temperature have been determined for a 70% styrene–30% acrylonitrile copolymer in a large number of organic liquids. The critical strain ϵc for crazing or cracking has been determined also in air and in each agent. Limited crazing data have been obtained also on a dicyano bisphenol polycarbonate in which the CN groups take the place of the methyl groups in bisphenol A (BPA) polycarbonate. The two resins are compared with polystyrene and BPA polycarbonate, respectively, in terms of crazing resistance, swelling, and other properties. In both systems CN incorporation raises ϵc (air) and reduces susceptibility to liquids of low solubility parameter δ; Tg and shear yield stress are raised in the polycarbonate but not in the styrene system. The volume efficiency of CN in raising ϵc (air) is greater in the polycarbonate system than the styrene system; for the rise in polymer solubility parameter, CN efficiency is apparently reversed. These changes are discussed in terms of the differences in molecular architecture of the two systems. For glassy polymers, ϵc (air) is shown to depend in semiquantitative fashion on polymer Tg, δ, and resistance to shear deformation.

Translucent, flame-retardant polycarbonate compositions

Abstract: Translucent and flame-retardant polycarbonate compositions comprising an admixture of an aromatic polycarbonate, minor amounts of a partially fluorinated polyolefin, and minor amounts of an organic alkali metal salt or an organic alkaline earth metal salt or mixtures thereof.

On the structure of glassy polymers. VI. Electron microscopy of polycarbonate, poly(ethylene terephthalate), poly(vinyl chloride), and polystyrene

Abstract: High-resolution electron microscopy studies have been carried out on four glassy polymers examined in previous small-angle x-ray scattering (SAXS) investigations. The polymers include polycarbonate, poly(ethylene terephthalate), poly(vinyl chloride), and polystyrene. For all four polymers, both bright field and dark-field observations indicate the general absence of microstructural features of a size down to the resolution limit of the electron microscope. Only “pepper and salt” features on a scale ca. 5 A are seen as characteristic of the structures. These features reflect simple interferences as the resolution limit is approached, and are seen for single crystal and oxide glasses as well as for the polymers. The present results, taken together with structural information from light scattering, SAXS, and small-angle neutron scattering, indicate that glassy polymers should be regarded as having rendom structures. The combined results are inconsistent with heterogeneous microstructures having regions of locally high order present in large volume fractions.

Branched polyaryl-sulphone/polycarbonate mixtures and their use for the production of extruded films

Abstract: The present invention is concerned with mixtures of branched polyaryl-sulphone and aromatic polycarbonates having Mw in excess of about 60,000. These mixtures are particularly suitable for the production of extruded film although the polycarbonate itself is of too high a molecular weight to be conveniently extruded by itself. These films display superior stress-cracking properties and resistance to unsaturated polyester resins compared to similar blends with lower molecular weight polycarbonates.

Organoboron plasticized polycarbonate composition

Abstract: A plasticized polycarbonate composition comprising an admixture of a high molecular weight aromatic polycarbonate and a plasticizing amount of an organoboron plasticizer.

Flame retardant blend comprising a polyalkylene terephthalate, an organo polysiloxane-polycarbonate block copolymer, and a halogenated copolycarbonate

Abstract: A polymer blend comprising a polyalkylene terephthalate, an organopolysiloxane-polycarbonate block copolymer, and a halogenated copolycarbonate having improved impact, heat distortion and flame retardant properties. The polymer blends can be molded or formed into films, sheets, fibers, laminates, or other improved molded articles of manufacture, including reinforced articles by conventional techniques.

Polyalkylene terephthalate and organo-polysiloxane-polycarbonate block copolymer blends

Abstract: A blend comprising a polyalkylene terephthalate resin and an organopolysiloxane-polycarbonate block copolymer having improved impact and heat distortion properties. The polymer blends can be molded or formed into films, sheets, fibers, laminates, or other improved molded articles of manufacture including reinforced articles by conventional techniques.

Flame retardant polycarbonate polyblends

Abstract: The present invention pertains to a halogen-containing, copolycarbonate blend having improved critical thickness and flammability properties comprising an aromatic copolycarbonate comprising the reaction product of an aromatic diphenol, an aromatic thiodiphenol and a carbonic acid derivative, such as phosgene or carbonyl bromide, blended with an effective amount of a halogen-containing compound. In a preferred embodiment, the copolycarbonate blend also contains small amounts of a perfluoro sulfonic or carboxylic acid salt.

High-molecular weight, segmented, polycarbonate elastomers

Abstract: High-molecular weight polycarbonate elastomers are produced by reacting polymer segments having an average molecular weight (Mn) of more than 600 and carboxyl groups with diphenols and phosgene according to the two-phase boundary polycondensation process at a pH value between about 9 and about 14 and a temperature between about 0° C. and 80° C. and, thereafter, either heat-treating the resulting reaction products at temperatures between about 40° C. and about 100° C. or gelling the resulting reaction products in solution in organic solvents.

Blends of low molecular weight polyalkylene terephthalate resins and organopolysiloxane-polycarbonate block copolymers

Abstract: A blend comprising a low molecular weight polyalkylene terephthalate resin and an organopolysiloxane-polycarbonate block copolymer having improved impact and heat distortion properties. The polymer blends can be molded or formed into films, sheets, fibers, laminates, or other improved molded articles of manufacture including reinforced articles by conventional techniques.

Non melt-drip flame retardant polycarbonate composition

Abstract: A coated non melt-drip and non-opaque flame retardant polycarbonate article having improved abrasion, scratch and chemical resistance, comprising an admixture of an aromatic carbonate polymer and a metal salt of a monomeric or polymeric unsubstituted or substituted aliphatic, aromatic or heterocyclic sulfonic acid, said article having deposited on the surface thereof a coating comprised of a certain aminoplast adhesion promoter and levelling agent, a diol, a certain melamine, and a polyol.

Study of molecular relaxations in aliphatic polycarbonates by the method of thermally stimulated currents

Abstract: The method of thermally stimulated currents has been used to study the molecular relaxations in a homologous series of aliphatic polycarbonates varying in monomeric unit size from four to twelve methylene groups. The secondary β relaxation has especially been analyzed considering the complex relaxations often observed at low temperatures in other linear polyesters. In unsubstituted aliphatic polycarbonates, a significant structure in β relaxation is observed only in samples containing water; in perfectly dry samples, it appears that the TSC β peak cannot be resolved in discrete components, even by a fractional polarization technique, and is only characterized by a continuous distribution of relaxation times. On the other hand, in a substituted aliphatic polycarbonate, the β relaxation clearly appears to be structured, showing the important role played by branches for the appearance of a complex relaxation.

Impact resistant safety glass panel

Abstract: Impact resistant glass laminates formed of at least one silicate glass panel and at least one polycarbonate panel bonded together by a methacrylate resin formed from at least 50% by weight of the polymerizable mixture of 2-ethylhexyl methacrylate.

Polycarbonate mixtures which can be processed as thermoplastics

Abstract: The present invention relates to mixtures comprising about 60% by weight to 5% by weight of aromatic polycarbonates which have a Mw between about 60,000 and 120,000 (component A) and about 40% by weight to 95% by weight of aromatic polycarbonates which have a Mw between about 28,000 and 40,000 (component B), as well as to processes for their preparation and their use for the production of shaped articles. The melt which can be prepared from the mixtures according to the invention has a high stability and the films obtainable therefrom have a high resistance towards stress cracking.

Blends of reticulated polyarylsulfones and polycarbonates and their application during the manufacture of extruded films

Abstract: Mixts., consisting of 95-30 (90-60) esp. 85-70 wt. % branched polyarylsulphone, (I), and of 5-70 (10-40) esp. 15-30 wt.% polycarbonate, (II), having Mw, >60000 pref. 65000-120000 esp. 75000-95000, are claimed and are pref. used for film extrusion. The extruded films are partic. suitable for electrical sector. The films have high strength, resistance to stress corrosion on heating and to organic liqs., high resistance to heat deformation and to constant heating, and high resistance to unsaturated polyester resin solns.

Thermally stable translucent polycarbonate compositions

Abstract: Thermally stable translucent polycarbonate compositions comprising an admixture of an aromatic polycarbonate and a minor amount of a partially fluorinated polyolefin.

Polycarbonate films of low flammability and improved stress crack resistance

Abstract: The present invention relates to polycarbonate films, and in particular extruded films and cast films, but preferably extruded films, which are characterized in that they contain about 0.01% to 2% by weight of a NH4 salt, alkali metal salt or alkaline earth metal salt of a perhalogenoalkanesulphonic acid, preferably a perfluoroalkanesulphonic acid.