Showing papers on "Polycarbonate published in 1981"

Process for the preparation of modified polycarbonate molding compositions

Abstract: This development is concerned with an improved process of preparing polycarbonate molding compositions and molded articles having superior hydrolysis resistance, stress crack resistance and flame retardancy, by thermoplastically processing a partially crosslinked aromatic polycarbonate. A crosslinkable aromatic thermoplastic polycarbonate is subject to irradiation to cause crosslinking on its surface such that between about 5 and 50 wt. % of the polymer is crosslinked and it is then thermoplastically processed. This partially crosslinked polycarbonate may be blended with uncrosslinked thermoplastic aromatic polycarbonate or known flame retardant agents. This development is also concerned with the compositions or articles so produced.

Characteristics of submicron pores obtained by chemical etching of nuclear tracks in polycarbonate films

Abstract: Calibrated pores in the range 102–2×103 A have been obtained by chemical etching of polycarbonate thin films irradiated with high energy krypton ions (500 MeV, Kr25+). Both the amorphous and the crystalline forms of polycarbonate (Makrofol, Bayer), further designated by their respective trade names N and KG, have been investigated up to thicknesses of 60 μm, close to the theoretical ion range of 77 μm. From conductivity studies, three different domains have been separated around the ion track: A highly damaged core of radius ?50 A with a fast etching rate vT ≊104 A/min, an intermediate zone of radius ?500 A with an etching rate vI = 0.9 A/min, an outer region with an etching rate equal to that of the undamaged material, vG = 0.47 A/min. These observations are compatible with the delta ray model for track formation in plastic materials. Scanning electron microscope investigations have revealed that the pores formed in the N material are straight cylinders with a narrow distribution of the pore entrance dia...

Chemistry of miscible polycarbonate–copolyester blends

Abstract: Blends of polycarbonate and the copolyester based on 1,4-cyclohexanedimethanol and a mixture of terephthalic and isophthalic acids are known to be completely miscible. This study was concerned with various chemical events which may occur in this system, particularly during melt processing. Degradation reactions were studied by both TGA and dilute viscometry techniques, and some indications of component interaction were noted. The residual titanium catalyst from the copolyester formation was found to produce color formation by interaction with phenolic end groups in the polycarbonate and to promote interchange reactions. Both events could be suppressed by deactivation of the residual catalyst with appropriate additives. An indication of the extent of interchange reactions was obtained by following the crystallizability of the copolyester component using differential scanning calorimetry.

Diffusion and induced crystallization in polycarbonate

Abstract: The study of the effect of thickness on the mass uptake is shown to be quite helpful in the understanding of the complexities of polymer/organic penetrant sorption behavior. Isothermal diffusion results for methanol, acetone, and carbon tetrachloride in polycarbonate plates and films of various thicknesses ranging from 12 mils (0.030 cm) to 1/4 in. (0.633 cm) are presented. The diffusion is purely Fickian only in the case of methanol, which is a poor solvent for polycarbonate and has a low level of saturation in it (0.06 g/g). Methanol does not lead to a detectable swelling or any appreciable crystallization of the polymer during the diffusion process. Acetone and carbon tetrachloride are much better solvents and lead to much higher saturation levels; they crystallize polycarbonate, and their mass uptake is anomalous. The diffusion of carbon tetrachloride exhibits initially a case II diffusion behavior followed for thicker plates by an intermediate behavior between case II and Fickian diffusion. The anomalous diffusion in the case of acetone appears to be associated primarily with surface effects.

Rheological and extrusion characteristics of glass fiber-reinforced polycarbonate†

Abstract: An experimental investigation of the rheological properties of glass fiber-reinforced polycarbonate melts and the extrusion of such compounds through capillary and slit dies is presented. The viscosity–shear rate function seems independent of instrument for cone-plate and capillary investigations. The presence of fibers increases the level of the viscosity. Normal stresses at fixed shear stress are also increased by the presence of fibers. The extrudate swell is decreased by the presence of fibers and surface roughness is increased. Fiber orientation increases and surface roughness decreases with increasing extrusion rate.

Coated shaped article of polycarbonate type resin

Abstract: A coated shaped article of a polycarbonate type resin of improved abrasion resistance, which comprises: (I) a shaped substrate of a polycarbonate type resin, (II) an undercoat layer applied to and cured on said substrate, an (III) an overcoat layer applied to and cured on the undercoat layer, which overcoat is formed of a composition containing: (A) at least one hydrolyzate selected from the group of epoxy group-containing silicon compounds, (B) at least one member selected from the group consisting of hydrolyzates of organic silicon compounds colloidal silica and organic titanium compounds, and (C) a curing catalyst.

High-pressure sorption of carbon dioxide in solvent-cast poly(methyl methacrylate) and poly(ethyl methacrylate) films

Abstract: Carbon dioxide sorption isotherms in poly(methyl methacrylate) (PMMA) and poly(ethyl methacrylate) (PEMA) are reported for pressures up to 20 atm. Temperatures between 35 and 80°C were studied for PMMA and temperatures between 30 and 55°C were studied for PEMA. Typical dual mode sorption isotherms concave to the pressure axis were observed in all cases. The measured Langmuir sorption capacities of both polymers extrapolated to zero at the glass transition (Tg) consistent with the behavior of other glassy polymer/gas systems. Sorption enthalpies for CO2 in the Henry's law mode for PMMA and PEMA are in the same range (−2 to −4 kcal/mole) as has been reported for a variety of other glassy polymers such as poly(ethylene terephthalate), polycarbonate, and polyacrylonitrile. Some of the data suggest that postcasting treatment of the PEMA films left a small amount of residual solvent in the film. the presence of the trace residual solvent during quenching from the rubbery to the glassy state after annealing appears to cause a dilation of the Langmuir capacity and an alteration in the apparent Langmuir affinity constant of the PEMA film. These results suggest the possibility of tailoring physical properties of glassy polymers such as sorptivity, permeability, impact strength, and craze resistance by doping small amounts of selected residuals into polymers prior to quenching to the glassy state from the rubbery state.

Blend of polycarbonate and wholly aromatic polyester

Abstract: A polymer blend which is capable of exhibiting an anisotropic melt phase and the ability to form shaped articles having improved mechanical properties is provided. The polymer blend comprises approximately 5 to approximately 75 percent by weight, based upon the total weight of the blend, of a polycarbonate and approximately 25 to approximately 95 percent by weight, based upon the total weight of the blend, of a melt processable wholly aromatic polyester which is capable of forming an anisotropic melt phase apart from the blend.

Ultraviolet radiation stabilized coated polycarbonate article

Abstract: A coated ultraviolet radiation stabilized polycarbonate article having improved abrasion, mar, scratch, and chemical solvent resistance comprising a polycarbonate article with its surface layers impregnated with an ultraviolet radiation absorbing compound having at least one surface thereof coated with (i) an adhesion promoting primer layer comprised of a thermoset acrylic polymer; and (ii) a top coat disposed on said primer layer comprised of a colloidal silica filled thermoset organopolysiloxane.

Limiting oxygen indices of silicone block polymer

Abstract: The limiting oxygen index (LOI) has been determined for each of a large number of silicone-containing resins, principally dimethylsiloxane (DMS) block polymers varying widely in DMS content and hard block type. A synergistic enhancement in LOI of varying strength is seen in several families of resins. For the major families explored, the synergism varies with hard block type in roughly the following order: bisphenol-A carbonate and bisphenol fluorenone carbonate > styrene and 2,6-diphenyl-1,4-phenylene oxide > bisphenol chloral polycarbonate > methyl methacrylate and phenolphthalein carbonate, the enhancement being nil in the last case. Strength of the synergism is discussed in terms of DMS degree of dispersion, char-forming tendencies, melt viscosity, and other factors.

A new method for data evaluation of small angle neutron scattering experiments and its application to amorphous polycarbonate

Abstract: The conformation of single chains in bulk polymer materials can be evaluated from coherent neutron scattering on mixtures of normal and deuterated polymers. It is shown that the single-chain structure factor can be also obtained from measurements of highly concentrated mixtures and the procedure of evaluation is described. The application to amorphous polycarbonate demonstrates the advantages of the method.

Thermoplastic polycarbonate resins reinforced with silane treated fillers

Abstract: A thermoplastic polycarbonate molding composition containing a particulate filler coated with a silane.

Ultrathin polymer membranes

Abstract: An ultrathin polyphenylene oxide/organopolysiloxane-polycarbonate copolymer film is described wherein the film contains from about 10 to about 35 percent by weight of the organopolysiloxane-polycarbonate copolymer.

Interfacial Synthesis Part II: Phase-Transfer Catalyzed Synthesis of Polycarbonate/Polysiloxane Block Copolymers

Abstract: A phase transfer catalyzed (PTC) method for the preparation of bisphenol-A polycarbonate/polydimethylsiloxane multi-block or segmented copolymers of the structure shown below has been investigated. The synthesis route involves the reaction of a preformed carboxypropyl-terminated polydimethylsiloxane oligomer of various molecular weights with bisphenol-A, base, phosgene, and the PTC. The final copolymer contains a direct [tbnd]Si-C- link between the block structures as compared to the relatively hydrolytically unstable [tbnd]Si-O-C bond discussed previously by the authors and others. A phosgenation “pre-step” to the interfacial reaction was found to be desirable. This procedure involves bubbling phosgene through an anhydrous concentrated solution of the carboxypropyl-terminated polydimethylsiloxane in methylene chloride. Subsequently, a two-phase CH2 Cl2/H2O reaction medium with the phase transfer catalyst is employed in the interfacial step. The phosgenation pre-step is believed to enhance the co...

Method for making silicon coated polycarbonates and article obtained therefrom

Abstract: A method is provided for improving the weatherability of a polycarbonate substrate by initially treating the surface of the polycarbonate substrate with a solution of a hydrolyzed silylated organic U.V. screen followed by the application of a curable silicone hardcoat composition onto the treated substrate.

Composition of polycarbonate, an ABS resin and an acrylate-methacrylate interpolymer

Abstract: This application discloses novel thermoplastic molding compositions of a polycarbonate, a copolymer which comprises acrylonitrile-butadiene-alkenyl aromatic compound and a multiphase acrylic interpolymer.

Ternary polycarbonate compositions containing polyacrylate and thermoplastic polyester.

Abstract: Des compositions ternaires comprennent un melange d'un polycarbonate aromatique thermoplastique de poids moleculaire eleve, un copolymere d'acrylate et un polyester thermoplastique. Ternary compositions comprise a mixture of a thermoplastic aromatic polycarbonate of high molecular weight acrylate copolymer and a thermoplastic polyester.

Electrically conductive polycarbonate

Abstract: ELECTRICALLY CONDUCTIVE POLYCARBONATE Abstract of the Disclosure An antistatic and electrically conductive moulding composition comprising from 99 to 99.99 % by weight of an aromatic polycarbonate and from 1 to 0.01 % by weight of carbon or graphite fibres having a ratio of length to cross section of at least 10:1. Le A 20 076 -

Light scattering of bisphenol-A polycarbonate in the amorphous state and at the beginning of thermal crystallization

Abstract: Depolarized light scattering of amorphous polycarbonate (PC) is angular independent. The amount of scattering did not give any evidence for the existence of a liquid crystal type of phase, consisting of regions with a strong orientation correlation between chain segments. Annealing of PC belowTg does not affect its scattering behaviour. Therefore, observed changes in physical properties such as the mechanical behaviour cannot be interpreted by an appreciable increase of intermolecular orientation correlation. If PC is heated at 190 °C for several days, an angular dependent scattering component appears. This component arises from the formation of spherulites with a sheaf-like structure.

Moldable resin compositions containing polycarbonate styrene polymer and three phase graft polymer

Abstract: A moldable resin composition comprising: (A) an aromatic vinyl-type polymer; (B) a polycarbonate; and (C) a three-stage polymerization product produced by three-stage emulsion polymerizations of an aromatic vinyl-type monomer, butadiene, alkyl methacrylate, etc.

Glass-filled polycarbonate of improved impact strength

Abstract: A glass fiber reinforced polycarbonate composition having an improved level of impact strength and decreased notch sensitivity, comprising an aromatic polycarbonate, glass fibers and a polyanhydride resin which is a copolymer of α-olefin and maleic anhydride is provided.

Polycarbonates with impact strength

Abstract: The invention provides polycarbonates having improved impact resistance in the form of a mixture of a polycarbonate resin and an acrylic rubber interpolymer compound.

Plasmapheresis membrane and process for the preparation thereof

Abstract: Plasmapheresis membranes of hydrophilic polycarbonates are disclosed, comprising polycondensates of bisphenol A and a polyalkylene oxide. These membranes which have a regular pore structure with smoothly rounded pores with openings without sharp edges, have an average pore diameter of about 0.01 to 0.8μ, a porosity preferably above 65%, and a thickness of between about 50 and 300μ. Processes for preparing these membranes are also disclosed, including casting a 3 to 20 weight percent polycarbonate polymer solution onto a smooth surface, contacting the layer with a gelling medium prior to precipitation of the membrane, and subsequent precipitation of the gelled layer to form the membrane.