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Showing papers on "Polycarbonate published in 1987"


Journal ArticleDOI
TL;DR: In this article, the extrusion, fiber spinning, compression, and injection molding of blends of polycarbonate and two thermotropic liquid crystal polymers based on wholly aromatic copolyesters have been studied.
Abstract: Rheological properties, extrusion, fiber spinning, compression, and injection molding of blends of polycarbonate and two thermotropic liquid crystal polymers based on wholly aromatic copolyesters have been studied. Blends were prepared using an internal Banbury mixer and static Koch mixer. Based upon differential scanning calorimetry and dynamic mechanical measurements, these blends have been shown to be incompatible in the entire range of concentrations. During extrusion and injection molding at high strain rates, it has been observed that thermotropic liquid crystal polymer at concentrations 2.5, 5, and 10 percent by weight in situ forms high modulus and high strength fibers within the polycarbonate matrix leading to self-reinforced polymer composites. The tensile strength of the composite containing 10 percent of liquid crystal polymer exceeds that of the pure components. In addition, anisotropy of properties of the injection molded parts has been found to substantially reduce in a comparison with that of liquid crystal polymer. The processing conditions and technique for the production of self-reinforced polymer composite during processing of the blends have been identified. This has been done by measurements of mechanical properties, direct observation of morphology, and by theoretical calculation using simplified composite theory for the unidirectional continuous fiber-reinforced composites. At the high concentrations, 25 and 50 percent by weight, thermotropic liquid crystal polymer forms large spherical droplets inside polycarbonate leading to highly brittle material. This is in distinction from the fibrous, high modulus tough composites formed at the lower concentrations.

228 citations


Journal ArticleDOI
TL;DR: In this article, the effects of molecular structure manipulation of polycarbonates on sorption and transport of various gases were studied using tetramethyl, tetrachloro, and tetrabromo substitutions onto the aromatic rings of bisphenol A polycarbonate.
Abstract: The effects of molecular structure manipulation of polycarbonates on sorption and transport of various gases were studied using tetramethyl, tetrachloro, and tetrabromo substitutions onto the aromatic rings of bisphenol A polycarbonate. Solubility and permeability measurements were made at 35°C over the pressure range of 1–20 atm for a variety of gases, namely CO2, CH4, O2, N2, and He. A threefold to fourfold increase in permeability was caused by the tetramethyl substitution, whereas the tetrachloro and tetrabromo substitutions reduced the permeability relative to the tetramethyl substitution. Lower activation energies for transport were found for the tetramethyl polycarbonate relative to the unsubstituted polycarbonate. Permeability coefficients were factored into solubility and diffusion coefficients. Sorption levels increased for all substitutions, but among the substituted polymers the levels remain practically the same. Solubility data were analyzed in terms of the dual sorption model. The Henry's law solubility coefficients obtained from this analysis were found to be consistent with a predictive equation developed for rubbery polymers. The usual correlation for predicting the Langmuir sorption capacity of the model overestimates the values for the substituted polycarbonates, and a proposal for the cause of this is offered. Thermal expansion of these polymers was measured using dilatometry, and the results are used in the interpretation of the sorption data. Diffusion phenomena are explained by segmental mobility and free volume considerations. The effects of CO2 exposure history on sorption and transport were also investigated.

155 citations


Journal ArticleDOI
TL;DR: In this paper, supercritical carbon dioxide readily induces crystallization in bisphenol A polycarbonate and the degree of crystallinity increases sharply as the CO2 pressure is raised from 100 to 300 atm but levels off thereafter.
Abstract: Supercritical carbon dioxide readily induces crystallization in bisphenol A polycarbonate. Crystallization begins within one h of exposure to the CO2 at temperatures and pressures as low as 75°C and 100 atm. The degree of crystallinity increases sharply as the CO2 pressure is raised from 100 to 300 atm but levels off thereafter. This behavior is likely due to a minimum in the Tg of the polycarbonate/CO2 mixture owing to the opposite effects of the pressure on the Tg of the polymer and on the equilibrium weight fraction of CO2 absorbed. Percent crystallinities of over 20%, comparable to that achieved using acetone or other organic liquids, have been obtained after 2 h exposure to supercritical CO2. Since polycarbonate degasses quickly and quantitatively at ambient temperature and pressure, the high Tg of bisphenol A polycarbonate can be regained in the crystallized material without further vacuum treatment.

116 citations



Journal ArticleDOI
TL;DR: Melange polycarbonate du bisphenol A/PMMA prepare par coulee d'une solution ou extrusion a vis as discussed by the authors, which is a combination of PMMA and polycarbonates.
Abstract: Melange polycarbonate du bisphenol A/PMMA prepare par coulee d'une solution ou extrusion a vis

103 citations


Patent
Walt H. Bassett1
31 Dec 1987
TL;DR: In this paper, a mixture of polyester and polycarbonate resins with a transesterification reaction hindering the amount of metaphosphate fiber was used to constrain a polyester fiber.
Abstract: A composition comprising a blend of a polyester resin and a polycarbonate resin are provided with a transesterification reaction hindering amount of a metaphosphate fiber.

80 citations


Journal ArticleDOI
TL;DR: The balance between the rate and the selectivity of transport of various gas pairs in a series of polycarbonates has been examined in this paper, where the four available hydrogens on the aromatic rings of the bisphenol-A unit with CH3, Cl, or Br groups gave materials with a better balance of these two characteristics than the unsubstituted polycarbonate (PC).

75 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated pure and binary mixture permeabilities for the C0 2 /CH 4 system in polycarbonate and silicone rubber. But they did not investigate the effect of perturbation with CO 2 on permselection properties.

72 citations


Journal ArticleDOI
TL;DR: In this article, bisphenol-A polycarbonate (PC) and polystyrene (PS) blends were investigated with screw extrusion and solution casting with weight fractions of PC in the blends varying from 0.95 to 0.004 for extruded blends at 250°C.
Abstract: Blends of bisphenol-A polycarbonate (PC) and polystyrene (PS) prepared by screw extrusion and solution casting have been investigated with weight fractions of PC in the blends varying from 0.95 to 0.05. From the measured glass transition temperatures (Tg) and specific heat increments (ΔCp) at the Tg, the polystyrene appears to dissolve more in the PC phase than does the PC in the PS phase. The blend appears to be near eqilibrium under extrusion conditions so that the polymer–polymer interaction parameter of PC/PS blends was calculated and found to be 0.038±0.004 for extruded blends at 250°C. Scanning electron microscopy supports the conclusion that the compatibility increases more in the region of PS-rich compositions than in the regions of PC-rich compositions of the PC/PS blends.

64 citations


Patent
20 Aug 1987
TL;DR: A polymer blend containing a polycarbonate and a siloxane-polyetherimide copolymer was proposed in this paper, which improved impact strength, particularly thick section impact strength over the unmodified polycarbonates.
Abstract: A polymer blend containing a polycarbonate and a siloxane-polyetherimide copolymer. The blends of the invention have improved impact strength, particularly thick section impact strength, over the unmodified polycarbonates. In addition the blends have good physical properties, relatively low flammability and are resistant to environmental stress cracking and crazing.

53 citations


Patent
R. P. Kambour1
25 Sep 1987
TL;DR: Transparent blends of polymethyl methacrylate and BPA polycarbonate are provided in this paper resulting from solution casting and melt blending procedures, which are useful as glazing materials and for making optical disks and other injection moldable articles for which an easy flow poly-carbonate is desirable.
Abstract: Transparent blends of polymethyl methacrylate and BPA polycarbonate are provided resulting from solution casting and melt blending procedures. The blends are useful as glazing materials and for making optical disks and other injection moldable articles for which an easy flow polycarbonate is desirable.

Journal ArticleDOI
TL;DR: In this paper, the effects of CO2 driving pressure and CO2 exposure history on transport properties for two polycarbonates and two acrylic polymers are described, and the effects may be important for membrane separation processes involving CO2 at high pressures.

Journal ArticleDOI
TL;DR: Differential scanning calorimetry (DSC) measurements have been carried out on a number of poly(butylene terephthalate) (PBT)/BPA polycarbonate (PC) blends prepared by melt compounding and solution casting from hexafluoroisopropanol (HFIP).
Abstract: Differential scanning calorimetry (DSC) measurements have been carried out on a number of poly(butylene terephthalate) (PBT)/BPA polycarbonate (PC) blends prepared by melt compounding and solution casting from hexafluoroisopropanol (HFIP). The results clearly indicate that appreciable mixing of the two polymers takes place in the melt phase whereas complete separation is observed in cast films. The failure of the casting procedure to mimic the melt blending results is related in part to liquid-liquid phase separation and to crystallization of both polymers from the casting solvent.

Journal ArticleDOI
TL;DR: The tensile properties of coextruded multilayer composites comprised of predominantly 49 alternating layers of polycarbonate (PC) and polystyrene- acrylonitrile (SAN) were investigated in the bulk and microscopically as discussed by the authors.
Abstract: The tensile properties of coextruded multilayer composites comprised of predominantly 49 alternating layers of polycarbonate (PC) and polystyrene- acrylonitrile (SAN) were investigated in the bulk and microscopically. The bulk was characterized by three types of behaviour: brittle fracture at low strains, ductile yielding with fracture during neck formation, and formation of a stable neck followed by drawing to high extension. Optical microscopy was utilized to correlate deformation mechanisms within each phase to the observed modes of deformation in the bulk. Optical microscopy showed that in all cases the initial irreversible deformation event was the formation of cracks or crazes in the SAN layers. Good adhesion between the layers resulted in the subsequent initiation of shear bands in the polycarbonate layers at the craze tips. Interaction of crazes and shear bands produced an expanded damage zone ahead of the propagating crack which delocalized the stress and delayed fracture. The ultimate mode of fracture depended on the relative thickness of the SAN and PC layers, as determined by the composition, and the strain rate.

Patent
17 Jul 1987
TL;DR: In this paper, cyclic polycarbonate (or thiol analog) oligomer mixtures are prepared by the reaction of bishaloformates or their thio analogs, or mixtures thereof with dihydroxy or dimercapto compounds, with alkali metal hydroxides and various amines.
Abstract: Cyclic polycarbonate (or thiol analog) oligomer mixtures are prepared by the reaction of bishaloformates or their thio analogs, or mixtures thereof with dihydroxy or dimercapto compounds, with alkali metal hydroxides and various amines. The oligomer mixtures may be converted to polycarbonates or their thiol analogs by a method which is particularly adaptable to integration with polycarbonate processing operations. Polymerization may be conducted simultaneously with molding, extrusion and the like. The oligomer mixtures are adaptable to the preparation of filled prepregs.

Patent
05 Nov 1987
TL;DR: In this paper, a process comprising exposing to radiation a branched aromatic polycarbonate at least partially capped with a structure of the formula is described, which increases the organic solvent resistance of the polycarbonates.
Abstract: A process comprising exposing to radiation a branched aromatic polycarbonate at least partially end­ capped with a structure of the formula - - = - R Figure 1 wherein R is hydrogen or alkyl of one to three carbon atoms inclusive, the radiation of sufficient intensity and time duration to cause crosslinking of the branched aromatic polycarbonates which increases the organic solvent resistance of the polycarbonates.

Journal ArticleDOI
TL;DR: In this paper, the miscibility of poly(methyl methacrylate) (PMMA) with bisphenol chloral polycarbonate (BCPC) has been studied using differential scanning calorimetry (DSC), optical indication of phase separation on heating (i.e., lower critical solution temperature (LCST) behavior), density measurement, and gas permeation.
Abstract: The miscibility of poly(methyl methacrylate) (PMMA) with bisphenol chloral polycarbonate (BCPC) has been studied using differential scanning calorimetry (DSC), optical indication of phase separation on heating (ie, lower critical solution temperature (LCST) behavior), density measurement, and gas permeation All evidence indicates that PMMA is miscible with BCPC over the whole blend composition range Single composition-dependent glass transition temperature and LCST behavior have been observed for each blend The specific volumes of the blends follow closely the simple additivity rule indicating the interaction between PMMA and BCPC is weak Gas permeability coefficients for He, H2, O2, Ar, N2, CH4, and CO2 measured at 35°C under 1 to 2 atm upstream pressure are lower than those calculated from the semilogarithmic additivity rule The difference between this calculated permeability and the measured one increases with gas molecular size As a result, the ideal gas separation factors for He/CH4, CO2/CH4, and O2/N2 gas pairs estimated from the ratio of pure gas permeabilities are higher than predicted from the semilogarithmic additivity rule These permeation results were interpreted in terms of the free volume theory and the activated state theory, which have been proposed to describe gas transport behavior in polymer mixtures

Patent
30 Nov 1987
TL;DR: In this article, a compsn. was proposed to lower birefringence without detriment to characteristics such as light transmittance, heat distortion temp, etc., by blending an arom. polycarbonate resin with a specified amount of a specified arom.
Abstract: PURPOSE:To lower birefringence without detriment to characteristics such a light transmittance, heat distortion temp. etc., and to provide a compsn. suitable for use as a material for optical disc bases, by blending an arom. polycarbonate resin with a specified amount of a specified arom. vinyl copolymer resin. CONSTITUTION:58-88wt% arom. vinyl monomer (e.g., styrene) is copolymerized with 40-12wt% (meth)acrylonitrile and 30-0wt% copolymerizable vinyl monomer (e.g., methyl acrylate) to produce an arom. vinyl copolymer resin. 50-3wt% said arom. vinyl copolymer resin is blended with 50-97wt% arom. polycarbonate resin as essential ingredients to obtain the desired polycarbonate resin compsn. The compsn. is useful in the field of plastic molding materials which must have low optical distortion.

Journal ArticleDOI
TL;DR: Structure cristalline de l'analogue structural du poly(oxycarbonyloxy phenylene isopropylidene-1,4 phenylene-1.4) (polycarbonate du bisphenol A)
Abstract: Structure cristalline de l'analogue structural du poly(oxycarbonyloxy phenylene isopropylidene-1,4 phenylene-1,4) (polycarbonate du bisphenol A)

Patent
17 Dec 1987
TL;DR: Novel polycarbonate homopolymers and implantable bioresorbable medical devices fabricated therefrom are described in detail in this article and the references therein are discussed in Section 2.1.
Abstract: Novel polycarbonate homopolymers and implantable bioresorbable medical devices fabricated therefrom.

Patent
05 Nov 1987
TL;DR: A resinous composition comprising: (i) at least one aromatic polycarbonate resin, (ii) polyester resin, and (iii) a minor amount of a mixture of polyol and epoxide is defined in this paper.
Abstract: A resinous composition comprising: (i) at least one aromatic polycarbonate resin; (ii) at least one polyester resin; and (iii) a minor amount of a mixture of at least one polyol and at least one epoxide.

Journal ArticleDOI
TL;DR: In this article, the results of a series of recent studies of the morphology and deformation behavior of toughened poly(butylene terephthalate) (PBT)/BPA polycarbonate (PC) blends are briefly summarized.
Abstract: In this communication the results of a series of recent studies of the morphology and deformation behavior of toughened poly(butylene terephthalate) (PBT)/BPA polycarbonate (PC) blends are briefly summarized. Several papers containing a more detailed account are currently in press (1–3). Among the unique morphological features of these blends are the consistent isolation of the core/shell impact modifier (IM) in the PC phase and the crystallization and phase separation of the PBT from the partially miscible PBT/PC melt on slow cooling. DSC studies provide corroborating evidence for melt miscibility of the two resins. The blends deform through a combination of cavitation and shear processes. In all cases cavitation occurs exclusively within the IM particles and is suppressed at higher PC concentrations and elevated temperatures.

Journal ArticleDOI
01 Jul 1987-Polymer
TL;DR: In this article, a model of three parallel segments each of two monomer units in a trans-trans conformation was proposed for low-wavevector wide-angle neutron scattering experiments on differently deuterated versions of polycarbonate.

Patent
06 Nov 1987
TL;DR: In this article, a process for the preparation of a POWADIR membrane consisting of bisphenol-based polycarbonates was described, where at least 25 percent by weight of the polycarbonate moieties are tetrahalogenated, and the halogen is Cl or Br.
Abstract: The invention is a process for the preparation of a POWADIR membrane comprising bisphenol-based polycarbonates wherein at least 25 percent by weight of the bisphenol moieties are tetrahalogenated wherein the halogen is Cl or Br, and the membrane prepared by such process. The process generally comprises: forming a mixture comprising (i) a bisphenol-based polycarbonate wherein at least 25 percent by weight of the bisphenol moieties are tetrahalogenated, wherein the halogen is Cl or Br, (ii) a solvent for such polycarbonate, and (iii) a non-solvent for such polycarbonate, wherein the mixture has a sufficient viscosity to allow extrusion at temperatures at which the mixture is homogeneous; heating the mixture to a temperature at which the mixture is a homogeneous fluid and extrudable; extruding the heated mixture into a shape suitable for membrane use; passing the formed membrane through a quench zone wherein the mixture undergoes phase separation, and the major portion of the solvent and non-solvent are removed from the formed membrane; wherein the membrane formed is a POWADIR membrane with a discriminating region capable of separating oxygen from nitrogen.

Patent
23 Jun 1987
TL;DR: In this paper, a graft copolymer having an elastomeric core and a block copolymers of a polycarbonate and a polysiloxane was proposed.
Abstract: The invention relates to polymer mixtures which comprise a polycarbonate resin, a graft copolymer having an elastomeric core, and a block copolymer of a polycarbonate and a polysiloxane These polymer mixtures have only a small tendency to delamination and a good impact strength


Journal ArticleDOI
TL;DR: In this paper, polycarbonates were synthesized from phosgene and three different diphenols under phase transfer conditions, using quarternary ammonium and phosphonium salts and dichloromethane as solvent.

Patent
04 Nov 1987
TL;DR: In this article, thermoplastic blends of polyamide with at least one resin selected from the group consisting of polycarbonate, poly(ester carbonate) and polyarylate are compatibilized with an effective amount of a polyamide-polyarylate block copolymer and molded into articles having excellent physical properties.
Abstract: Thermoplastic blends of polyamide with at least one resin selected from the group consisting of polycarbonate, poly(ester carbonate) and polyarylate are compatibilized with an effective amount of a polyamide-polyarylate block copolymer and molded into articles having excellent physical properties with little or no evidence of delamination.

Patent
14 Dec 1987
TL;DR: In this paper, it was shown that copolymer polycarbonate can be used to produce smooth surfaces without any sign of carbon deposits thereon by using polycarbonates prepared from cyclohexene oxide, cyclopentene oxide or cycloheptene oxide.
Abstract: The evaporative casting of molten metals has been shown to produce castings having smooth surfaces without any sign of carbon deposits thereon by using a copolymer polycarbonate prepared from cyclohexene oxide, cyclopentene oxide, cycloheptene oxide, or isobutylene oxide and carbon dioxide

Journal ArticleDOI
Abstract: The optical properties of bisphenol-A polycarbonate resin as described by the complex index of refraction, N = n – ik, are derived by Kramers-Kronig analysis of experimental absorption and reflectance data obtained in the range 40μm ≥ λ ≥ 105 nm. Electronic absorption processes in polycarbonate are characterized by two broad absorption peaks centered at ∼200 and ∼100 nm.