Showing papers on "Polycarbonate published in 1968"

Thermal degradation of polycarbonate

Abstract: A comparison is drawn between the thermal behaviour of poly-[2,2-propane-bis-(4-phenyl carbonate)] and the model compound diphenyl carbonate. On this basis a rearrangement mechanism is suggested to account for the main chemical and physical features of the degradation of the polymer between 300 and 389°.

Ultraviolet light stabilized polycarbonate article

Abstract: AN ULTRAVIOLET LIGHT RESISTANT POLYCARBONATE ARTICLE CONSISTING OF A POLYCARBONATE SUBSTRATE HAVING BONDED TO AT LEAST ONE SURFACE THEREOF AN ACRYLATE COPOLYMER FILM OF 1 TO 10 MILS THICKNESS WHEREIN THE ACRYLATE COPOLYMER FILM AHS UNIFORMLY DISPERSED THROUGHOUT 0.25-5.0 WEIGHT PERCENT OF AN ULTRAVIOLET LIGHT ABSORBENT BASED ON THE WEIGHT OF THE ACRYLATE COPOLYMER FILM. THE ULTRAVIOLET LIGHT ABSORBENT MAY BE ANY OF THE KNOWN ULTRAVIOLET LIGHT ABSORBENTS. THE ARTICLE IS PARTICULARLY RESISTANT TO ULTRAVIOLET LIGHT AND PROTECTS THE POLYCARBONATE FROM ATTACK FROM ULTRAVIOLET LIGHT. IN ADDITION, A PROCESS IS ALSO DISCLOSED FOR PREPARING AN ULTRAVIOLET LIGHT RESISTANT POLYCARBONATE ARTICLE, WHICH PROCESS CONSISTS OF BRINGING AN ACRYLATE COPOLYMER FILM INTO CONTACT WITH A POLYCARBONATE SHEET AT ELEVATED TEMPERATURES AND AT A PRESSURE OF AT LEAST 20 P.S.I. AND THEN COOLING THE ARTICLE TO ROOM TEMPERATURE.

Laminated assembly of polycarbonate and polyacrylate resin sheets and method of making the same

Abstract: Transparent globe for street lighting luminaires comprises a laminated assembly of superposed sheets of polycarbonate resin and polyacrylate resin having an ultraviolet absorbing compound incorporated preferably in the polyacrylate resin sheet.

Polycarbonate modified polyester reinforcing elements and rubber structures made therefrom

Abstract: RELATES TO AN IMPROVED RUBBER STRUCTURE REINFORCED WITH AN IMPROVED POLYESTER REINFORCING FIBER MODIFIED WITH EITHER AN ISOCYANATE OR IN COMBINATION WITH A POLYCARBONATE PRESENT IN THE POLYESTER PRIOR TO FIBER FORMATION.

Reinforced polymers containing a matrix of pvc or abs with a carrier of styrene-acrylonitrile reinforced with any of a polycarbonate,nylon 66 or polyoxymethylene

Abstract: DISCLOSED HEREIN ARE MATRIX POLYMERS AND COPOLYMERS REINFORCED WITH IN SITU FORMED POLYMERIC FIBERS OF HIGH SOFTENING POINT. THESE FIBERS ARE INTRODUCED INTO THE MATRIX POLYMER BY MEANS OF A POLYMERIC CARRIER HAVING A HIGH HEAT STABILITY AND A LOW FLOW TEMPERATURE RELATIVE TO THE MATRIX POLYMER. COMPOSITIONS FORMED THEREBY CAN BE MOLDED INTO ARTICLES HAVING INCREASED RESISTANCE TO DEFORMATION UNDER LOAD AT HIGH TEMPERATURES. THE MATRIX RESIN MAY BE EITHER POLYVINYL CHLORIDE OR AN ACRYLONITRILBUTADIENE-STYRENE RESIN. THE CARRIER POLYMER IS EXEMPLIFIED BY A STYRENE-ACRYLONITRILE INTERPOLYMER REINFORCED WITH ANY OF POLYCARBONATE, NYLON 66, OR POLYOXYMETHYLENE.

Polycarbonate/polyacetal thermoplastic resin compositions

Abstract: BLENDS OF POLYCARBONATES WITH POLYACATALS WHEREIN THE POLYACETAL IS PRESENT IN THE BLEND AT A CONCENTRATION SUFFICIENT TO IMPART THERETO A RESISTANCEL TO ENVIRONMENTAL STRESS CRAZING AN CRACKING GREATER THAN THAT POSSESSED BY THE POLYCARBONATE ITSELF.

Process for preparing color and melt viscosity stable polycarbonate resins

Abstract: A PROCESS FOR PREPARING AN AROMATIC CARBONATE POLYMER HAVING EXCELLENT RESISTANCE TO THERMAL DISCOLORATION AND THERMAL DEGRADATION, WHICH PROCESS INVOLVES INCORPORATING 0.1-5.0 WEIGHT PERCENT OF WATER, BASED ON THE WEIGHT OF THE TOTAL COMPOSITION WITH THE AROMATIC CARBONATE POLYMER, AND THEN EXTRUDING THE MIXTURE THROUGH A HEATED, VACUUM VENTED EXTRUDER. A VACUUM IS APPLIED TO THE MIXTURE WHILE IN THE MOLTEN STATE.

Correlation of physical and polymer chain properties

Abstract: An idealized polymer model is used to examine the magnitude of the catastrophic tensile breaking energy and stress in terms of primary and secondary bonding forces. Computed strengths for primary and secondary bonding are respectively 8000 and 500 times larger than observed values of a common thermoplastic. From other considerations, the glass transition temperature for both elastomeric and thermoplastic polymers is found to show a linear dependence on the cohesive energy per unit length of polymer chain. In special polymer model, the influence of polymer chains on unidirectional elongation is shown to be a function of chain size. Elongation data reported on a series of modified polycarbonates exhibit a correlation with chain size as described by the model. Published data on the polycarbonate series are used to evaluate the correlation between observed deformation breaking energies and cohesive energies calculated from glass transition temperatures.

Effects of molding conditions on properties of injection‐molded polycarbonates

Abstract: Statistically designed experiments were carried out to study the effects of molding conditions on the properties of two types of polycarbonate, which were synthesized by the solvent process and the melt process, respectively. The properties tested in this study were classified into two groups with respect to the effect of molding conditions. One, which included birefringence, heat shrinkage at 180°C, and surface resistance to Taber abrasion, was mainly affected by stock temperature and was slightly affected by holding pressure. The other, which included resistance to solvent crack, Rockwell hardness, density, and heat shrinkage at 120°C, was affected by mold temperature and holding pressure. Mechanically isotropic moldings with a low degree of frozen orientation could be molded at a high stock temperature and at a low holding pressure, where stock temperature was more effective than holding pressure. Moldings with low residual stresses could be molded at a high mold temperature and at a low holding pressure. Essentially there was no difference in the molding conditions and properties by the method of synthesis. However, under the same molding conditions polycarbonate synthesized by the melt process gave a higher degree of frozen orientation and somewhat more rigid moldings.

Glass fiber reinforced polycarbonates

Abstract: THE INVENTION MEETS WITH A PROCESS FOR THE PRODUCTION OF GLASS FIBER REINFORCED POLYCARBONATES BY INTRODUCING MILLED, FILAMENTIZED, WATER-SIZED GLASS FIBERS INTO A SOLUTION OR A MELT OF POLYCARBONATE RESIN, REMOVING THE SOLVENT IF NECESSARY AND EXTRUDING THE GLASS FIBER CONTAINING MELT THROUGH A NOZZLE.

Discontinuous polycarbonate coatings

Abstract: A METHOD OF PROVIDING A DISCONTINUOUS POLYCARBONATE COATING ON A THERMOPLASTIC SUBSTRATE COMPRISING THE STEPS SOLVENT, APPLYING THE RESULTING SOLUTION TO A THERMOPLASTIC SUBSTRATE, EVAPORATING THE SOLVENT TO FORM A CONTINUOUS POLYCARBONATE COATING, AND SUBSEQUENTLY TREATING THE COATING WITH A DEVELOPING SOLVENT TO FORM A DISCONTINUOUS COATING.

Chlorination of polyesters

Abstract: By photochemical chlorination chlorine was substituted on the gem-dimethyl groups of the polyterephthalate and polycarbonate of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, the polyterephthalate of 2,2-dimethyl-1,3-propanediol, and the polycarbonate of 4,4′-isopropylidenediphenol (bisphenol A). The factors affecting polyester degradation, the efficiency of chlorination, and the degree of chlorination were investigated, and the effects of chlorine content on the solubility, flammability, density, hydrolytic stability, thermal stability, tensile properties, electrical properties, and heat-distortion temperatures of cast films were determined. The chlorinated polyesters of particular interest, because of their properties, are the polycarbonates of 2,2,4,4-tetramethyl-1,3-cyclobutanediol and bisphenol A.

Thermal Analyses of Polymers. I. Polycarbonate and Polyethylene Terephthalate

Abstract: Polyethylene terephthalate (PET) and polycarbonate (PC) are two individual aromatic polyesters which have been used for rather different commercial applications. The former is used abundantly in film and fiber applications because of its high strength and ability to crystallize, whereas the latter has found use primarily in applications requiring excellent clarity, high heat distortion, and high impact strength.