Showing papers on "Polycarbonate published in 1973"

Flame retardant polycarbonate composition

Abstract: A flame retardant polycarbonate composition comprising in admixture an aromatic carbonate polymer and a flame retardant additive which may be the metal salts of either monomeric or polymeric aromatic sulfonic acids, or mixtures thereof.

Morphology-property studies of amorphous polycarbonate

Abstract: The relationship between morphology and several physical properties (tensile, thermal, dielectric, and dynamic mechanical properties) of amorphous poly-bisphenol-A-carbonate was examined as a function of annealingtime at temperatures below the glass transition temperature (Tg). The change in structure of the amorphous films was studied by means of X-ray diffraction and with electron diffraction using a rotating sector in an electron microscope as well as by electron micrographs of replicas of surfaces prepared by etching with dilute aqueous NaOH solutions. The changes in morphology and physical properties caused by annealing below Tg are, in general, closely related. The relationship cannot be explained only by changes in free volume; it is proposed that changes in the degree and type of order (nodular structure) also play a role. The design and application of the rotating sector is described in an Appendix.

Transparent moulding composition of a polycarbonate and a resin

Abstract: A transparent moulding composition comprising a bisphenol polycarbonate having a low refractive index due to a content of alkyl substitution and a rubber and/or a resin.

Crazing, yielding, and fracture in polycarbonate and polyethylene terephthalate at low temperatures

Abstract: Tensile behavior over the temperature range 4.2 to 350°K is reported for amorphous polyethylene terephthalate and polycarbonate. Three regimes in tensile behavior are distinguished and the transitions between these regimes are correlated with molecular relaxation processes. The [dtilde]-process at about 50°K is associated with the onset of anelasticity in the stress strain behavior. Below the β-temperature, fracture stresses fall off markedly with decreasing temperature, suggesting that stress concentration effects are active. The effect of the [dtilde]-relaxation on tensile properties is more pronounced in polycarbonate than in polyethylene terephthalate and agrees with the relative relaxation peak intensities. Over the gamma relaxation region, 170 to 200°K, there occurs a broad drop in yield stress in polycarbonate. In polyethylene terephthalate a transition from brittle to yield behavior is observed. Crazing occurs in both polymers over two distinct temperature regimes, one over an approximate...

Tailoring the interface in graphite-reinforced polycarbonate

Abstract: : Pronounced effects of thermal treatment on the properties of graphite fiber/ polycarbonate and glass fiber/polycarbonate composites have been demonstrated and explained. At 20 volume percent loading of random-in-a-plane, discontinuous fibers, both specimen strength and modulus in both fiber systems were found to increase dramatically upon molding above 260-265 C, whereas only the graphite system was further improved by subsequent annealing. In the latter case, property improvement is due to generation of a crystalline inner layer at the interface, which apparently transfers the stresses more effectively from fiber to fiber. Regardless of the type of fiber, molding at 275 C (slightly above 260-265 C, the melting point of crystalline polycarbonate) results in improved properties due to better wetting of the fibers by the resin. Hot forming of graphite reinforced polycarbonate composites between the molding and annealing steps takes advantage of the higher process-ability of the unannealed material in addition to providing increased modulus and strength in the final molded article.

Regulating the Interface in Graphite/Thermoplastic Composites

Abstract: Among the many engineering thermoplastics available today, there exists a large subgroup of difficult-to-crystallize or amorphous polymers which possess a rather unique micronodular morphology in their normally produced solid state. When these polymers are processed in the unfilled state, changes in process thermal history have little effect on mechanical properties; but when reinforcement such as graphite is added, pronounced effects of thermal treatment arise which are relatable to the nodular polymer morphology. These effects will be documented and explained for graphite fiber-filled polycarbonate and poly(phenylene oxide). The practical application of these results to hot-forming techniques will also be described. Finally, extension of these techniques to the more easily crystallized thermoplastics such as polypropylene will be considered.

Water-clear hydrolytically stable polycarbonate composition containing an aromatic or aliphatic epoxy stabilizer

Abstract: An improved water clear polycarbonate composition consisting in admixture an aromatic polycarbonate and a stabilizing amount of a particular epoxy compound which may be either an aromatic epoxy or an aliphatic epoxy compound and mixtures thereof.

Process for stabilizing moldings of high molecular weight thermo-plastic polycarbonates

Abstract: Articles of high molecular weight thermoplastic polycarbonates having high resistance to ultraviolet radiation while retaining good mechanical properties prepared by applying to the surface of the articles a liquid mixture containing 2 - 20 percent by weight of an ultraviolet absorber in a mixture of 10 to 80 parts by weight of one or more aliphatic C1 - C3 halogenohydrocarbons, 20 to 80 parts by weight of one or more lower aliphatic C1 - C4 alcohols, which may be halogen-substituted, and 0 to 25 parts by weight of water The mixtures are applied to the polycarbonate at room temperature and subsequently dried at 70 DEG - 100 DEG C

Process for preparing aromatic polycarbonates

Abstract: A process for preparing aromatic polycarbonates from diphenyl carbonate and bisphenol A which comprises effecting preliminary polymerization under limited operational conditions to produce specific polycarbonate prepolymers and then subjecting the specific prepolymers to further polymerization for a shorter residence time thereby obtaining high molecular weight polycarbonates.

Flameproof polycarbonates containing an alkali metal salt soluble in the polycarbonate melt

Abstract: HIGH MOLECULAR WEIGHT THERMOPLASTIC POLYCARBONATES OF LOW INFLAMMABILITY ARE PROVIDED WHICH CONTAIN ALKALI SALTS SOLUBLE IN THE POLYCARBONATE MELT IN AMOUNTS OF FROM ABOUT 0.2% BY WEIGHT TO ABOUT 0.00005% BY WEIGHT BASED ON THE WEIGHT OF THE POLYCARBONATE.

Thermoplastic moulding compositions of a polycarbonate and a graft copolymer of styrene and acrylonitrile on an acrylic acid ester polymer

Abstract: Thermoplastic moulding compositions and mouldings of: A. FROM 95 TO 5% BY WEIGHT OF POLYCARBONATES OF DIHYDRIC PHENOLS, AND B. FROM 5 TO 95% BY WEIGHT OF A GRAFT COPOLYMER OF STYRENE AND ACRYLONITRILE ON AN ACRYLIC ACID ESTER HOMOPOLYMER AND/OR COPOLYMER.

Thermoplastic moulding composition and mouldings of polycarbonate,having improved ease of mould release when injection moulding

Abstract: THE INVENTION RELATES TO THERMOPLASTIC MOUNDING COMPOSITIONS MADE OF POLYCARBONATES BASED ON AROMATIC BISHYDROXY COMPOUNDS WHICH MAY CONTAIN FILLERS DYESTUFFS, PIGMENTS, STABILISERS AND/OR GLASS FIBRES, CHARACTERISED IN THAT THEY CONTAIN 0.1 TO 2% BY WEIGHT, RELATIVE TO POLYCARBONATE, OF ONE OR SEVERAL ESTERS OF SATURATED ALIPHATIC LONGCHAIN MONOCARBOXYLIC ACIDS AND UNIVALENT ALIPHATIC LONGCHAIN ALCOHOLS.

Oxidatively stable polycarbonate composition

Abstract: AN OXIDATIVELY STABLE AROMATIC POLYCARBONATE COMPOSITION WHICH IS STABILIZED AGAINST DEGRADATION DUE TO ELEVATED TEMPERATURES BY EMPLOYING THEREWITH A MATERIAL WHICH MAY BE EITHER A HEAVY METAL SALT OR HYPOPHOSPOROUS ACID OR THE METAL SALT OF HYPOPHOOROUS ACID IN COMBINATION WITH A PARTICULAR EPOXY COMPOUND. THE AMOUNT OF THE METAL OF THE HYPOPHOSPHOROUS ACID EMPLOYED HEREIN CAN RANGE FROM ABOUT 0.005 TO ABOUT 2.0 WEIGHT PERCENT AND THE AMOUNT OF EPOXY CAN RANGE FROM 0.01 TO 1.0 WEIGHT PERCENT ALL BASED ON THE WEIGHT OF THE AROMATIC POLYCARBONATE COMPOSITION.

Thermoplastic resin composition comprising methyl methacrylate resins

Abstract: A thermoplastic resin composition consists essentially of from 10 to 95 parts by weight of a methyl methacrylate resin and from 90 to 5 parts by weight of a styrene-methyl methacrylate copolymer resin with or without from 5 to 150 parts by weight of a polycarbonate resin. A molded product from the composition has a beautiful, pearlescent luster and a high impact strength.

Mixture of a polycarbonate and a styrene maleic acid anhydride copolymer

Abstract: Thermoplastic moulding compositions and shaped articles made therefrom of mixtures of A. 5 TO 95 PERCENT BY WEIGHT OF A POLYCARBONATE OF DIVALENT PHENOLS AND B. 95 TO 5 PERCENT BY WEIGHT OF A STYRENE/MALEIC ACID ANHYDRIDE COPOLYMER HAVING IMPROVED STABILITY TO BOILING WATER AND IMPROVED FLOW PROPERTIES.

The Viscoelastic-Plastic Behavior of a Ductile Polymer

Abstract: A brief discussion of the use of polymers in general and polycarbonate in particular in experimental mechanics is presented both from the viewpoint of materials for use in photomechanics and as materials for use in the validation of continuum constitutive equations. Experimental data are presented showing polycarbonate to be a ductile material with elastic, viscoelastic, and plastic behavior regimes. Using constant-head-rate tests (0.002 in./min to 20 in./min), the rate-dependent yield behavior of polycarbonate is described and is compared with that proposed for metals by Ludwik. By means of creep tests, the time-dependent yield behavior of polycarbonate is also described and compared with viscoelastic-plastic theories of Nagdi and Murch and of Crochet. Finally, possible application of the results to photoplasticity and ductile fracture are discussed.

Review of Properties of Polycarbonate Resins

Abstract: I. INTRODUCTION The polycarbonate characterized in this review refers to the commercially available poly(4,4-dioxydiphenyl-2,2-propane carbonate).

Process for preparing polycarbonates

Abstract: Extruded films having reduced proneness to stress-cracking, good resistance to casting resins of unsaturated polyesters and no blocking effect and produced from branched aromatic polycarbonates which are the reaction products of aromatic dihydroxy compounds and branching agents having more than three phenolic hydroxyl groups, with polycarbonate precursors. The films are useful as insulating films in the electrical industry.

Mechanical relaxation in polycarbonate–polysulfone blends

Abstract: Lexan polycarbonate and polysulfone P-1700 were blended to various weight percentages by dissolution in methylene chloride. The blended material was reclaimed in the form of evaporated thin films which were dried, ground, and molded. Low-frequency mechanical relaxation tests were run on specimens machined from this material as a function of composition and thermal treatment. In addition to the β-peak, a second peak, β′, was resolved in unannealed 75 wt/o P-1700 specimens. These results are presented and a possible interpretation is discussed and compared with previously proposed mechanisms.

An aromatic polycarbonate/polyalkylene naphthalate resin composition having a marble-like appearance

Abstract: A resin composition having a marble-like appearance is disclosed, comprising 5 to 90% by weight, based on the weight of the composition, of an aromatic polycarbonate, and a polyalkylene naphthalate consisting of polytetramethylene-2,6-naphthalate, polyhexamethylene-2,6-naphthalate and a mixture thereof.

Glass fibre reinforced thermoplastics laminate prodn. - by heating above softening pt. and cooling under compression

Abstract: The sandwich is heated to a point above the m. pt. of the cladding and then pressed together while cooling. The cladding is selected from polyethylene, polypropylene, polystyrene or copolymers of styrene with acrylonitrile or maleic acid anhydride or methyl methacrylate, PVC, PVdC, polyamide, polycarbonate, polymethyl methacrylate reinforced with glass fibres, asbestos, carbon fibres and natural and/or synthetic fibres. The foam core is of polyurethane, urea - formaldehyde resin or phenol - formaldehyde resin. Provides a single - stage process for developing a sandwich laminate for boat or vehicle shells, giving a curved moulding, without adhesives.

Luminescent diode - with housing of transparent plastics contg glass powder

Abstract: Luminescent semiconductor element has the semiconductor encapsulated in a housing of a transparent plastics material, which is mixed with glass powder. The light is scattered partic. widely and evenly distributed, allowing use of the luminescent diode at a large angle of view. The glass powder has particle size 100 mu m and is used in an amt. of 0.5-4% with a casting resin or injectable plastics, esp. a polycarbonate or an acrylic resin.

Gas‐filled polymers. III. Mechanical behavior of polycarbonate and poly(vinyl chloride)

Abstract: Gasification behavior and its effects on mechanical properties were determined for amorphous polycarbonate (PC) and poly(vinyl chloride) (PVC). Nitrogen-gasified PC and PVC exhibit interior regions containing gas bubbles surrounded by surface layers of void-free polymer, while in the helium-gasified polymers no gas bubbles could be observed. Scanning electron microscope (SEM) observations of the bubbles in nitrogengasified PC indicate that the bubble walls are smooth and featureless (in contrast to the diffuse walls with fibrils of polymer extending into the bubbles observed previously in gasified polyethylene). For both PC and PVC, neither the yield stress nor the elongation to fracture showed any appreciable variation between gasified and ungasified material. The lack of a significant effect of gas bubbles on the drawing behavior in these glassy polymers stands in contrast with the pronounced effect noted with semicrystalline polyethylene. The origin of this difference in behavior and its relation to the crystallization process in polyethylene are discussed.

Acrylic fiber of improved properties

Abstract: There are disclosed a process for preparing acrylic fibers of improved hot-wet properties and improved elastic recovery by finely dispersing in the spin dope prior to spinning a solution of a polycarbonate resin in a solvent immiscible with the spin dope The acrylic fibers so produced contain elongated fibrils of the polycarbonate resin of 005 to 50 microns diameter and up to several centimeters long

Thin, non-porous polycarbonate films

Abstract: Non-porous, thin, polycarbonate films and a process for their production. Solutions of polycarbonates in concentrations of less than 5 parts solids per 100 parts solvent are applied to the surface of liquids immiscible, or sparingly miscible with, the solvent for the polycarbonate. The solvent is then evaporated, and the resultant film removed. The films are useful for the separation of gas and liquid mixtures and for electrical insulating purposes.

Process for the manufacture of polycarbonate solutions

Abstract: Process for the preparation of polycarbonate solutions that are particularly suitable for the production of filaments and films. The solutions are prepared by precipitating polycarbonates, in a largely crystalline form, from their solutions in polycarbonate solvents by adding specified precipitants to the solutions and thereafter redissolving the precipitated polycarbonates in their solutions by evaporating off the precipitants.