Showing papers on "Polycarbonate published in 1991"

Acrylic coated thermoplastic substrate

Abstract: An ultraviolet radiation curable silica coating composition containing (a) acrylic monomers, (b) functionalized colloidal silica, (c) acrylated urethanes, (d) an ultraviolet radiation absorber, and (e) a photoinitiator. The coating composition once applied to and cured on a thermoplastic substrate provides a coating which exhibits improved flexibility and weathering. The coatings are useful for providing abrasion resistance and weatherability to thermoplastic, for example polycarbonate, substrates.

Structure development during flow of polyblends containing liquid crystalline polymers

Abstract: The microstructure development during capillary flow of polyblends containing Liquid Crystalline Polymers (LCPs) was studied. In the present investigation the wholly aromatic LCP constituent was the minor phase suspended in polycarbonate (PC), poly(butyleneterephthalate) (PBT) or Nylon 6 (N-6), in addition to previously studied amorphous nylon matrix Experimental results showed that the viscous forces acting at the components' interface are predominating the elongational deformation and the resulting structure development of the LCP phase. In cases where the viscosity of the suspending matrix was higher than the LCP one (PC, amorphous nylon) scanning electron micrographs indicated that fibrillar structure developed. In cases where the viscosity of the matrix polymers was lower than the LCP suspended phase, fibrous structures developed only at very high shear rates. Due to velocity rearrangement effects at the capillary exit a skin core morphology was observed. Since the polymers viscosity depends both on shear rate and temperature, the in situ composite structure development depends on the specific processing methods and conditions that the LCP containing polyblends experience.

Secondary relaxation motion in bisphenol A polycarbonate

Abstract: The nature of the molecular motion responsible for the mechanical secondary relaxation process of bisphenol A polycarbonate (BPA-PC) was studied. Dynamic mechanical behaviors of an alternating copolymer and alternating multiblock copolymers of BPA-PC and tetramethylbisphenol A polycarbonate (TMBPA-PC) were investigated. The results suggest that the secondary relaxation of BPA-PC is due to the cooperative motion of several repeating units along the chain. The results of dynamic mechanical analyses of the blends of BPA-PC and TMBPA-PC indicate that the molecular motion has contributions from intermolecular interactions

Polycarbonate/aromatic polyester blends containing an olefinic modifier

Abstract: A polycarbonate blend of good impact and flexural strength, good heat distortion and weldline properties, low gloss, and good solvent resistance prepared by admixing with polycarbonate an aromatic polyester, an olefinic epoxide-containing modifier, and one or more members of the group conssisting of a thermoplastic elastomer and a rubber-modified styrene/acrylonitrile copolymer. Optionally, a graft copolymer of the core-shell type may be used as an additional impact modifier.

Preparation of branched polycarbonate composition from cyclic aromatic polycarbonate oligomer, polyhydric phenol and polycarbonate

Abstract: Branched polycarbonates are prepared by melt equilibration of aromatic cyclic polycarbonate oligomes with a polyhydric phenol having more than two hydroxy groups per molecule, preferably 1,1,1-tris-(4-hydroxyphenyl)ethane, in the presence of a carbonate equilibration catalyst, preferably tetrabutylammonium tetraphenylborate. In an additional embodiment of the invention, a linear aromatic polycarbonate is added to the reaction mixture. Branched polycarbonates prepared according to this invention have high melt strength and high shear sensitivity characteristics and are useful in extrusion and injection molding processing applications and particularly useful in blow molding applications for preparing relatively large articles and panels.

Effect of isopropylidene replacement on gas transport properties of polycarbonates

Abstract: The gas sorption and transport properties of a series of polycarbonates in which the isopropylidene unit of bisphenol A polycarbonate has been replaced with another molecular group are presented. Two new materials, bisphenol of norbornane polycarbonate (NBPC) and bisphenol Z polycarbonate (PCZ), are compared with several polymers which have been studied previously in this laboratory, including bisphenol A polycarbonate (PC), hexafluorobisphenol A polycarbonate (HFPC), and bisphenol of chloral polycarbonate (BCPC). The effect of molecular structure on chain mobility and chain packing is related to the gas transport properties. Dynamic mechanical thermal analysis and differential scanning calorimetry are used to judge chain mobility, while x-ray diffraction and free volume calculations give information about chain packing. Permeability measurements were made for He, H2, O2, N2, CH4, and CO2 at 35°C over a range of pressures up to 20 atm. Sorption experiments were also done for N2, CH4, and CO2 under the same conditions. The permeability coefficients of these polymers rank in the order HFPC ≫ NBPC>PC>BCPC ≫ PCZ for all of the gases. With the exception of BCPC, this order correlates well with fractional free volume. The low gas permeability of BCPC is attributed to a polarity effect. In general, bulky and relatively immobile substituents, as in HFPC and NBPC, can yield improved separation characteristics. The polar group of BCPC and the flexible cyclohexyl substituent of PCZ result in relatively low gas permeability.

The aqueous phase in the interfacial synthesis of polycarbonates. Part 1. Ionic equilibria and experimental solubilities in the BPA-sodium hydroxide-water system

Abstract: The BPA−NaOH−H 2 O system for polycarbonate synthesis is analyzed by solving the simultaneous chemical equilibria, material balances, and ionic charge balance to yield the aqueous-phase composition under arbitrary 2,2-bis(4-hydroxyphenyl) propane (BPA) loadings and pH levels

Surface properties of commercial polymer films following various gas plasma treatments

Abstract: Surface properties of a number of commercial thermoplastic polymer films were investigated before and after brief exposures to RF induced, low temperature gas plasmas. Water wettability and adhesion of vapor deposited aluminum to thin films (8–12 micron) of polyethylene, polypropylene, polyester, polysulfone, polycarbonate, and polyvinylidene fluoride films were studied before and after treatments with oxygen, 96% CF4/4% O2, and helium plasmas. Treatment with oxygen plasmas showed the greatest change in water wettability for polyvinylidene fluoride and polypropylene films, while treatment with 96% CF4/4% O2 showed dramatic changes in wettability of polycarbonate, polysulfone, and polystyrene. Excellent adhesion of aluminium was found for polymers that had been previously exposed to gas plasmas.

Gas transport in halogen‐containing aromatic polycarbonates

Abstract: The gas permeability and permselectivity of a series of halogen-containing polycarbonates are discussed in terms of the fundamental solubility and diffusivity factors. These materials have structural features that hinder interchain packing and intrachain rotational mobility. Both diffusion and solubility coefficients are higher in materials with higher fractional free volumes. Diffusivity selectivities tend to increase with increasing restriction of intrachain torsional mobility. The materials with four bromine atoms substituted on the phenyl rings ortho to the carbonate linkages display a significantly increased diffusivity selectivity relative to conventional polycarbonate. This improvement in the ability of the polymer matrix to discriminate between gas molecules of different sizes is due to a reduction in intrachain torsional mobility. The reduction in chain mobility is indicated by higher glass transition and higher sub-Tg transition temperatures in the bromine-substituted materials. The materials with hexafluoroisopropylidene moieties have high fractional free volumes and exhibit a very significant increase in permeability relative to conventional bisphenol-A polycarbonate. The material with both the hexafluoro and the tetrabromo substitutions displays significant simultaneous increases in permeability and permselectivity relative to conventional polycarbonate.

Evaluation of the interfacial tension between high molecular weight polycarbonate and PMMA resins with the imbedded fiber retraction technique

Abstract: The interfacial tension between molten, high molecular weight samples of polycarbonate and poly(methyl methacrylate) was measured using the imbedded fiber retraction (IFR) technique. A value of 1.44 ± 0.16 dyn/cm was measured at 240 °C. This value was obtained on commercial resins with zero‐shear bulk viscosities and at a temperature typically encountered in the processing of blends and/or composites. Refinements to the IFR method were implemented which reduced the experimentation time. Consequently, measurements of the interfacial tension can now be routinely obtained in several hours for materials with zero‐shear bulk viscosities on the order of 104 Pa s.

Glass transition and dynamics of phosphate esters dissolved in two glassy polymer matrices

Abstract: Etude par analyse dynamomecanique et RMN 31 P de melanges 50:50 polystyrene/poly(oxyde de 2,6-dimethyl-1,4-phenylene) et du polycarbonate du bisphenol A contenant le phosphate de triphenyle ou de trioctyle ou le tetraxylyl diphosphate de l'hydroquinone

Coextruded double walled sheet of linear polycarbonate resin

Abstract: The invention relates to a process for coating moldings via co-extrusion with a UV-absorber-containing layer containing special dimeric UV absorbers and to the moldings coated with a corresponding layer.

Coating composition for fibers

Abstract: An aqueous coating composition for glass fibers is provided which contains a polycarbonate precursor material and a water soluble film former or binder. The resulting coated glass fibers have excellent flexibilty with little or no powdering of the coating composition off the fibers.

Polyamide resin composition

Abstract: PURPOSE:To obtain a composition having excellent dispersibility and impact resistance by blending a mixture of a polyamide resin and thermoplastic resin having compatibility with poly epsilon-caprolactone with a specific copolymer at a specific amount. CONSTITUTION:The composition obtained by uniformly blending (A) 70-99.5wt.% mixture consisting of A1: 5-95wt.% polyamide resin and A2 95-5wt.% thermoplastic resin (e.g. aromatic polycarbonate, ABS resin and/or AS resin or polyvinyl chloride) having compatibility with poly epsilon-caprolactone with (B) 0.5-30wt.% copolymer obtained by polymerizing an aromatic vinyl compound with alpha,beta-unsaturated carboxylic acid compound and hydroxyl group-containing compound and then subjecting epsilon-caprolactone to ring opening polymerization using hydroxyl groups of the resultant polymer as initiation points and having 10-94wt.% aromatic vinyl compound content, 1-20wt.% alpha,beta-unsaturated carboxylic acid compound content and 5-70wt.% poly epsilon-caprolactone content.

Thermoplastic polycarbonate moulding compositions with flame retarding properties

Abstract: A flame resistant molding composition containing a polycarbonate resin, a graft polymer and, as a flame retarding agent a phosphoric acid ester of novolak in combination with an anti drip agent is disclosed. The composition may further contain a thermoplastic copolymer and/or polyalkylene terephthalate. A process for the preparation of the composition is also disclosed.

Atomic force microscopy on polymers and polymer related compounds: 4. Polytetrafluoroethylene and polycarbonate

Abstract: SummarySurface morphology and molecular arrangement have been recorded by atomic force microscopy (AFM) on polytetrafluoroethylene (PTFE) and on polycarbonate (PC) films. In a thin layer of PTFE deposited by rubbing polymer on hot glass substrate unidirectional orientation of polymer has been revealed. Individual polymer chains have been visualized. An interchain distance of .53 nm and several periodicities along the chain contours have been found-.44 nm, .62 nm and .82 nm-in accordance with a 13/6 helix.The monitoring of surface changes during thermal treatment of amorphous-bis-phenol A-PC film has been realized by AFM. Different types of surface morphology were revealed. Spherulites are formed during polymer crystallization. In most cases, however, numerous nanocrystallites appeared after thermal treatment. On their surfaces well-ordered atomic scale AFM images have been received. The arrangement of AFM patterns can be characterized by periodicities of .50 nm and .52 nm in the orthogonal directions. Polycarbonate oligomers-as the product of surface degradation-effectively might form the observed nanocrystallites.

Blends of polycarbonates and aliphatic polyesters

Abstract: BLENDS OF POLYCARBONATES AND ALIPHATIC POLYESTERS ABSTRACT OF THE DISCLOSURE The present invention concerns a thermoplastic molding composition comprising a homogeneous blend of (i) a polycarbonate resin and (ii) a polyester resin derived from neopentyl glycol and an aliphatic diacid. The components of the blend were found to be completely miscible and the blend to exhibit a single glass transition temperature. The composition of the invention is suitable for the preparation of useful molded articles having improved optical properties.

Polyester/polycarbonate blends having improved clarity and impact strength

Abstract: Disclosed are clear thermoplastic molding compositions comprising an aromatic polycarbonate, a polyester of terephthalic acid and 1,4-cyclohexane-dimethanol, and the copolymeric transesterification product of the polycarbonate and polyester.

Polymer blends of polycarbonate, PETG and ABS

Abstract: Polymer blends useful as thermoplastic molding resins comprise polycarbonate, PETG and ABS or ASA exhibit enhanced moldability, heat resistance and thick section impact resistance not available in binary blends of the components.

Studies on a diphenylether modified poly(phenyl‐1,4, phenylene terephthalate) liquid crystalline polymer and its blends with polycarbonate and polysulfone

Abstract: Blends of a thermotropic liquid crystalline polymer, LCP, (4,4′-dicarboxy diphenyl ether modified poly(phenyl-1,4-phenylene terephthalate)) with polycarbonate and polysulfone were prepared and characterized with respect to their thermal properties, viscoelastic behavior, processability and mechanical properties. The processability of the thermoplastics was significantly improved by the addition of small amounts of LCP. This was also reflected by decreases in the steady shear viscosities, though the dynamic complex viscosities of the blends were generally similar or higher than those of the individual component polymers. Composite fibers were spun from the blends and the tensile moduli and strengths were consistent with a morphology of highly oriented LCP microfibrils with high aspect ratios dispersed in the thermoplastic fiber. The properties increased with increasing draw ratio.

Processing and Properties of Polycarbonate/Liquid Crystal Polymer Blends

Abstract: Rheological and mechanical properties, structural characteristics, extrusion and injection molding behavior of blends of polycarbonate (PC) with a thermotropic, wholly aromatic copolyesteramide have been investigated. The processability of polycarbonate is remarkably improved by addition of small contents of liquid crystal polymer. All the flow curves of the blends lie between those of the pure components. In the processing conditions adopted, the LCP particles are easily elongated in the flow direction. In this direction the elastic modulus rises remarkably with LCP content. The modulus-composition curve is, however, lower than that expected on the basis of an additive rule due to the incompatibility and poor adhesion between the two phases. Finally, injection molding of this extrusion grade PC has been easily performed by adding small contents of LCP. The impact strength values of the injection molding samples of these blends are only slightly lower than that of the pure PC.