Showing papers on "Polycarbonate published in 1974"

Process for preparing aromatic carbonate polymers

Abstract: A process for preparing a polycarbonate, which polycarbonate has improved resistance to thermal degradation and improved impact resistance and consists of reacting at least 70 weight percent of a stoichiometric amount of a carbonate precursor such as phosgene with a dihydric phenol such as bisphenol-A while simultaneously adding to the reaction medium an alkali metal hydroxide such as sodium hydroxide to maintain a pH of 6.0 to about 10.0. The pH is then raised to 11.0 by adding sufficient alkali metal hydroxide.

Films and sheets of polyester-polycarbonate blends

Abstract: This invention provides a film or sheet capable of being thermoformed into a shaped article and being formed from a blend of about 60 to 85 parts by weight of a polyethylene terephthalate having an intrinsic viscosity of at least about 0.90, about 15 to 40 parts by weight of a polycarbonate and about 5 to 20 parts by weight of a non-acidic silica filler, such as novaculite, the polyethylene terephthalate portion of the film or sheet having a degree of crystallinity in the range of about 20 to 40%. The present invention also provides compositions for forming such films and sheets and shaped articles thermoformed from such films or sheets, such as cook-in-trays. This invention also provides a process of forming such films or sheets.

The effect of densification on the mechanical properties of amorphous glassy polymers

Abstract: Four polymers, viz. polystyrene, polycarbonate, poly(methyl methacrylate), and poly-(vinyl chloride), were cooled from the melt to room temperature under hydrostatic pressures of 30 and 1000 atm. Cooling under high pressure increased the density by 0.4–0.6%, and the effect of this has been examined for the torsional creep properties, the dynamic properties at 1 Hz, the Charpy impact strength, the thermal expansivity, and the torsional yield stress. It turned out that, in general, densification affects the thermomechanical properties only slightly.

Thermoplastic blended composition comprising polyphenylene ether, aromatic polycarbonate and styrene resin

Abstract: A thermoplastic blended composition comprising 15-80% by weight of polyphenylene ether, 5-60% by weight of a styrene resin and 2-15% by weight of an aromatic polycarbonate. The composition has superior heat resistance, fatigue resistance and processability.

Process for the preparation of polycarbonate with weatherproof property

Abstract: A process is provided for preparing a polycarbonate composition with excellent weatherproof properties. The process comprises adding an ultraviolet absorbing compound having a hydroxy group which contributes at least partially to the molecular weight modifier to an oligomeric polycarbonate which is obtained by the reaction of a dioxy compound with phosgene, and then condensing said oligomeric polycarbonate to polymerize the same. The invention also concerns a process for preparing a polycarbonate with excellent weatherproof properties which process comprises introducing a dioxy compound in alkaline solution and an organic solvent for the polycarbonate into a tubular reactor continuously to form a turbulent flow, feeding phosgene concurrently to the reactor with cooling outside of the reactor to produce an oligomeric polycarbonate as the solution of organic solvent, adding an aqueous alkaline solution of dioxy compound, molecular weight modifier, which is contained at least in part ultraviolet absorbing compound having an hydroxy group, and catalyst selected from the group consisting of tertiary amine and quaternary ammonium salt and, if desired, antioxidant to said oligomeric polycarbonate solution and condensing said oligomeric polycarbonate to polymerize the same.

Modified polycarbonate resin

Abstract: A polycarbonate resin having an acidic additive for providing improved resistance to stress cracking under humid conditions while retaining tensile and impact strength at elevated temperatures.

Thermoplastic molding compositions of rubber-reinforced styrene/maleic anhydride resins and polycarbonate resins

Abstract: Thermoplastic compositions with improved physical properties are obtained by blending from 12 to 40 weight percent of a polycarbonate resin with from about 88 to 60 weight percent of a rubber-reinforced styrene/maleic anhydride copolymer.

Secondary structural motions in polycarbonate. I. dielectric properties

Abstract: Polycarbonate has three secondary dielectric losses in the temperature range between –200°C and the glass transition. The effects of crystallinity and orientation on these secondary losses are considered, and related to the structural entities involved in these motions. In addition, a stress relaxation peak was found in oriented polycarbonate.

Moulding compositions of graft polycarbonate and graft polymer rubbers

Abstract: Thermoplastic moulding compositions of 1. 70 - 20 % by weight of graft polycarbonates whose graft stock is a vinyl polymer with a molecular weight of from 10,000 to 100,000, containing from 3 to 10 side chains attached by carbon, each of which contains a hydroxyphenyl group, on which aromatic polycarbonate chains are condensed, and 2. 30 - 80 % by weight of graft polymer rubbers obtained by polymerizing a mixture of 2.1. 50 - 90 % by weight styrene, α-methylstyrene, methylmethacrylate or mixtures thereof, and 2.2. 10 - 50 % by weight acrylonitrile, methacrylonitrile, methylmethacrylate or mixtures thereof on a diene or acrylate rubber.

Origin of Impact Strength in Polycarbonate: I. Effect of Crystallization and Residual Solvent

Abstract: The high impact strength of glassy polycarbonate has been suggested to be related to an excess free volume, a large low temperature beta transition, or a unique morphology. To determine how crystallization affects free volume, molecular motion and morphology, samples of amorphous and partially crystalline polycarbonate have been studied by means of specific volume and dynamic mechanical measurements, electron microscopy and x-ray diffraction techniques. Previous studies have given conflicting results concerning the effect of crystallization on the low temperature beta transition below Tg . Our results clarify this matter by showing that crystallization and residual solvent give different effects on the beta transition. Crystallization is shown to decrease the intensity of the beta loss peak suggesting that the beta motion occurs in the “non-crystalline” regions of the polymer. Solvent not only decreases the beta peak intensity, but also shifts the peak maximum to lower temperatures and causes an ...

Process for the manufacture of stabilized polyester-polycarbonate copolymers

Abstract: The melt phase reaction and/or solid phase reaction for the manufacture of polyesters is accelerated by adding a polycarbonate and a phosphorus containing stabilizer to the reaction mixture before completion of the reaction.

Molecular motions in bisphenol a polycarbonates as measured by pulsed NMR techniques. I. Homopolymers and copolymers

Abstract: Molecular motions in homopolymers and copolymers based on bisphenol A polycarbonate (BAP) were investigated over a wide temperature range by means of two pulsed nuclear magnetic resonance methods: the spin-lattice relaxation time T1 and the spin-lattice relaxation time in rotating frame, T1ρ. Nuclear magnetic relaxation measurements of bisphenol A polycarbonate indicated the existence of four transitions in the solid amorphous state. This included the glass transition Tα, two transitions associated with localized motions of the main chain, Tβ and Tγ, and a transition due to side-group motion, Tδ. The results offer new evidence for the transition Tβ, which is ascribed to localized segmental motions of the polycarbonate chain. The physical properties of the polymer (high impact strength and a large fractional free volume in the glassy state) can be explained by the presence of the two secondary transitions Tβ and Tγ, which are both associated with main-chain motions. The presence of the bulky bromine on a bisphenol A unit of a polymer chain in a position ortho to the carbonate groups restricts all motions of the main chain, thus increasing Tα, Tβ, and Tγ. As a result of an increase in the secondary transition temperatures, impact strength is reduced at least 20-fold as compared with the unsubstituted material. The results for tetrabromobisphenol A polycarbonate and copolymers of bisphenol A with tetrabromobisphenol A and bisphenol A with tetrachlorobisphenol A polycarbonate confirm the idea that the impact strength of the polymer is related to the secondary transitions (T < Tg) arising from the main-chain motions. Copolymers of bisphenol A polycarbonate with tetrabromobisphenol A polycarbonate showed a single glass transition temperature whose value lay between those of the homopolymers. The results indicated multiple secondary transitions which corresponded to the transitions of the homopolymers with magnitudes proportional to the comonomer content.

Continuous production of polycarbonates

Abstract: High molecular weight linear polycarbonates are prepared by continuous condensation of organic dihydroxy compounds and phosgene in two reaction zones, a mixture of an aqueous-alkaline solution of the organic dihydroxy compound and an aqueous catalyst solution being introduced at the rate of from 1 to 50 meters per second and the phosgene at the rate of from 30 to 300 meters per second into the first reaction zone and condensed, an organic solvent being incorporated into the resultant reaction mixture containing oligomer and polycarbonate and the condensation of the aqueous-organic reaction mixture carried to completion in the second reaction zone by the two-phase interfacial method.

Thermoplastic blend composition

Abstract: A thermoplastic blend composition having especially superior impact strength and fatigue resistance comprising 15 ro 80% by weight of a polyphenylene oxide, 16 to 75% by weight of a rubber-modified polystyrene, 2 to 15% by weight of an aromatic polycarbonate and 2 to 15% by weight of a high styrene rubber, the sum total of the proportions of these ingredients being 100% by weight.

Bisphenol-A polycarbonate prepn. - by melt transesterification of molten bisphenol and diphenyl carbonate

Abstract: An aromatic polycarbonate of high mol.wt. is prepd. from diphenyl carbonate and Bisphenol A according to the known melt transesterification process, but using raw matls., which as pure substances have never passed through the solid phase, in proportions by wt. of between 30:70 and 70:30 (pref. 45:55 and 55:45). Previous process using crystalline diphenyl carbonate and Bisphenol A led to difficulties in excluding O2 and consequently poor coloured prodt. Use of molten, never crystallised raw matls. makes O2 exclusion much easier giving prodt. of pale colour.

Transparent fire resistant polymeric structures

Abstract: Transparent impact-, heat- and fire-resistant polymeric materials for making windows, windshields and plane canopies are provided wherein the polymeric materials comprise an exposy resin cured with an alkoxy boroxine catalyst and a polycarbonate resin, preferably a polyphenolphthalein carbonate resin. Laminates including the advantages of both resins comprise a transparent layer of epoxy resin and a transparent layer of a polycarbonate resin joined together with a transparent adhesive interlayer.

Process for the crystallization of polycarbonates and products obtained

Abstract: The invention concerns a process for crystallizing a polycarbonate polymer which consists in incorporating to said polycarbonate polymer a finely divided nucleating agent and/or a plasticizer for said polycarbonate polymer, and crystallizing the mixture thus obtained at a temperature higher than the vitreous transition temperature. The semi-crystalline polymer material obtained can be reinforced by adding inorganic fibers.

Thermally stable translucent polycarbonate composition

Abstract: A thermally stable translucent polycarbonate composition comprising in admixture an aromatic carbonate polymer and a minor amount of a mixture of a poly(dimethylsiloxane) gum and divided silica.

Origin of impact strength in polycarbonate. III. Effect of liquids and orientation

Abstract: The effects of Arochlor 5442 (a chlorinated terphenyl) dibutyl phthalate, butyl stearate, a high molecular weight polyester plasticizer, acetone, methyl ethyl ketone, isopropyl alcohol, carbon tetrachloride, and water on the dynamic mechanical properties of polycarbonate have been studied. Results show that all liquids except water and carbon tetrachloride suppress the low-temperature β-transition loss peak and shift the temperature of maximum loss to lower temperatures. Water causes the β loss peak to broaden and be more asymmetrical. Nonpolar carbon tetrachloride causes a splitting of the β loss peak which may indicate a selective suppression of local segmental motions in nonpolar regions of the polymer. Polycarbonate liquid blends may also exhibit additional loss peaks at temperatures above or below the β loss peak. Volume losses are observed for all blends whose specific volume has been measured. Electron microscopy of etched polycarbonate blends indicates 600 to 1100 A structures exist in br...

Polycarbonate resin having improved electrical tracking resistance

Abstract: A polycarbonate plastic having improved electrical tracking resistance is provided by including in the polycarbonate a substance which is normally an oxidation or combustion catalyst such as a transition metal having a positive oxidation potential of >+0.2 volt.

Thermally stable positive polycarbonate electron beam resists

Abstract: Electron beam positive resists which are sensitive to electron beam radiation and simultaneously thermally stable are prepared using polycarbonates.

Thermally stable polycarbonate composition

Abstract: A thermally stable polycarbonate composition comprising in admixture, an aromatic carbonate polymer and a stabilizing amount of an additive which is a combination of an epoxy compound prepared from an epichlorodydrin and the reaction product of an alkyl phosphite and the chlorine containing contaminant in said epoxy compound.

Morphology of crazes in glassy polycarbonate

Abstract: The craze morphology of amorphous polycarbonate in bulk samples and thin films has been examined using electron microscopy techniques. Results indicate polycarbonate crazes induced by heat or solvent have a “lamellar” texture oriented nearly perpendicular to the tensile stress direction. However, the craze texture of polycarbonate blended with antiplasticizer is observed to be fibrillar, similar to polystyrene, whereas the craze texture of polycarbonate blended with plasticizers is observed to contain crystallites. Transmission electron microscopy studies demonstrate that craze initiation does not occur by void formation or cavitation but rather by a local thinning or yielding at the craze tip. The initial stage of craze development appears similar for crazes in both polystyrene and polycarbonate.

Cold rolling of polymers 3. Properties of rolled crystallized polycarbonates

Abstract: Amorphous polycarbonate sheets up to 1/4 inch in thickness have been crystallized both thermally and by acetone vapor sorption. For thick sheets acetone vapor sorption is the superior technique and a method has been developed for assuring homogeneous crystallized sheets. The crystallized polycarbonate can be cold rolled providing there is a residual acetone content to act as a plasticizer for the sheet. The tensile stress strain characteristics of the as-crystallized sheets as well as the rolled crystallized sheets have been determined as a function of the residual acetone content. It is shown that a crystallized polycarbonate whose thickness is reduced by 74 percent can achieve a true stress at fracture of 27,180 psi and a strain of 33 percent. These values are significantly greater than the values obtained for rolled amorphous polycarbonates.

Polycarbonate plastics having improved tracking resistance

Abstract: The resistance to tracking paths for electric currents of polycarbonate plastics is improved by dispersing from about 10 to about 50% by weight of a hydrophobic TiO2 or Cr2O3 therein. The polycarbonate composition may be used for making components which are associated with electrical conductors.

Glass bonding - by thermoplastic film by heat and pressure

Abstract: Designed to bond two layers of glass for use as liquid crystal display devices, the thermoplastic film to form the bonding seal is e.g., selected from polyester of dicarbonic acid with glycolene or phenolene, polycarbonate, polyurethane and acrylic bonds. The purpose is to give an even and consistent bonding, without uneven zones, which will not dissolve with the liquid crystal material.