Showing papers on "Polycarbonate published in 2000"

Synthesis of Polycarbonate-Layered Silicate Nanocomposites via Cyclic Oligomers

Abstract: A partially exfoliated bisphenol A polycarbonate nanocomposite has been prepared by using carbonate cyclic oligomers and ditallow dimethyl exchanged montmorillonite (B34). Wide-angle X-ray diffraction (WAXD) indicated that exfoliation of this organically modified layered silicate (OLS) occurs after mixing with the cyclic oligomers in a brabender mixer for 1 h at 180 °C. Subsequent ring-opening polymerization of the cyclic oligomers converted the matrix into linear polymer without disruption of the layer dispersion. Transmission electron microscopy revealed that a partially exfoliated structure was obtained, although no indication of layer correlation was observed in WAXD. If linear polycarbonate was similarly treated with B34 in a brabender mixer, only an intercalated hybrid was obtained. Furthermore, conventional melt or solution processing of the B34 with either linear polycarbonate or cyclic oligomers yielded intercalated nanocomposites with interlayer spacings of 3.27 and 3.6−3.8 nm, respectively. The...

Optical plastic refractive measurements in the visible and the near-infrared regions

Abstract: Some new refractometric results are obtained in the visible and the near-infrared spectral regions. The main optical plastics are analyzed: poly(methyl methacrylate), polystyrene, polycarbonate, and styrene acrylonitrile. New materials, such as methyl methacrylate styrene copolmer, CTE-Richardson, Zeonex, Optorez, and Bayer are examined. The refractive indices are measured for wavelengths from 435.8 to 1052 nm with a new device. Abbe constants and dispersion coefficients are calculated. The measured and computed data is intended for designers and technologists.

Polycarbonate resin composition

Abstract: The present invention relates to a thermoplastic resin comprising 100 parts by weight of a resin mixture comprising 30 to 95% by weight of a polycarbonate resin (a), 5 to 70% by weight of a polystyrene resin (b), 0.5 to 20 parts by weight of a specific block copolymer (c) and, if necessary, 0.1 to 20 parts by weight of a polyalkylene terephthalate (d), and/or 0.1 to 20 parts by weight of a polyphenylene ether resin (e), and a flame-retardant thermoplastic resin composition prepared by blending the above composition with 1 to 40 parts by weight of an organophosphorus compound (f) and, if necessary, 0.05 to 5 parts by weight of a fluoroethylene polymer (g).

Crystallization and Solid-State Polymerization of Poly(bisphenol A carbonate) Facilitated by Supercritical CO2

Abstract: Poly(bisphenol A carbonate) was synthesized by solid-state polymerization (SSP) using supercritical CO2 to induce crystallinity in low molecular weight polycarbonate beads. The CO2-induced crystallization was studied as a function of time, temperature, molecular weight, and pressure. There was an optimum temperature for crystallization which depended on the molecular weight of the polymer. The molecular weight and percent crystallinity of the polymer produced by SSP were determined as a function of time and radial position in the bead. The molecular weight and percent crystallinity were strong functions of the particle radius, probably because of the slow diffusion of phenol out of the polymer particles. Nitrogen and supercritical CO2 were used as sweep fluids for the SSP process. The polymerization rate was always higher in supercritical CO2 at otherwise comparable conditions. We hypothesize that supercritical CO2 plasticizes the amorphous regions of the polymer, thereby increasing chain mobility and the...

Metal/polymer interfaces with designed morphologies

Abstract: The morphology of a metal/polymer interface is important for many properties, e.g. its adhesional strength. Starting from the basic processes occurring in the initial stages of metal/polymer interface formation, it is possible to obtain different morphologies by variation of the preparation conditions. In this report we present selected examples from our own work of how metal/polymer interfaces with different morphologies can be prepared by evaporating noble metals (Au, Ag, Cu) onto chemically different polymers, i.e. bisphenol-trimethyl cyclohexane polycarbonate (TMC-PC), pyromellitic dianhydride-oxydianiline (PMDA-ODA) polyimide (PI), and on Teflon AF 1601. The interfaces were characterized using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The combination of these techniques allows one to determine morphological parameters such as the concentration and distribution of metal clusters at the surface and in the near-surface region. Usin...

Mixed macrodiol‐based siloxane polyurethanes: Effect of the comacrodiol structure on properties and morphology

Abstract: Two series of polyurethanes were prepared to investigate the effect of comacrodiol structure on properties and morphology of polyurethanes based on the siloxane macrodiol, α,ω-bis(6-hydroxyethoxypropyl) polydimethylsiloxane (PDMS). All polyurethanes contained a 40 wt % hard segment derived from 4,4′-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO), and were prepared by a two-step, uncatalyzed bulk polymerization. The soft segments were based on an 80/20 mixture of PDMS (MW 967) and a comacrodiol (MW 700), selected from a series of polyethers and polycarbonates. The polyether series included poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), poly(tetramethylene oxide) (PTMO), poly(hexamethylene oxide), and poly(decamethylene oxide) (PDMO), whereas the polycarbonate series included poly (hexamethylene carbonate) diol (PHCD), poly [bis(4-hydroxybutyl)-tetramethyldisiloxy carbonate] diol (PSCD), and poly [hexamethylene-co-bis(4-hydroxybutyl)-tetramethyldisiloxy carbonate] diol (COPD). Polyurethanes were characterized by size exclusion chromatography, tensile testing, differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA). The results clearly demonstrated that the structure of the comacrodiol influenced the properties and morphology of siloxane-based polyurethanes. All comacrodiols, except PEO, improved the UTS of the polyurethane; PHMO and PTMO were the best polyether comacrodiols, while PSCD was the best polycarbonate comacrodiol. Incorporation of the comacrodiol made polyurethanes more elastomeric with low modulus, but the effect was less significant with polycarbonate comacrodiols. DSC and DMTA results strongly supported that the major morphological change associated with incorporation of a comacrodiol was the significant increase in the interfacial regions, largely through the compatibilization with the hard segment. The extent of compatibilization varied with the comacrodiol structure; hydrophilic polyethers such as PEO were the most compatible, and consequently, had poor mechanical strength. Among the polyethers, PHMO was the best, having an appropriate level of compatibility with the hard segment for substantial improvement in mechanical properties. Siloxy carbonate comacrodiol PSCD was the best among the polycarbonates. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1071–1082, 2000

Carbon-reinforced thermoplastic resin composition and articles made from same

Abstract: Carbon fiber-filled, thermoplastic resin compositions having improved electrical properties at a given level of carbon fibers are formed from thermoplastic resin and carbon fibers associated into bundles with a binder. The thermoplastic resin and the binder are selected to be incompatible such that the adhesion of the fiber to the resin is poor. An exemplary composition is formed from a thermoplastic polymer selected from among polystyrene, high impact polystyrene, polycarbonate, polybutylene terephthalate, polyethylene terephthalate, polyphenylene ether, polyether imide and blends thereof; and carbon fibers associated into bundles with a polyamide terpolymer binder. The bundles are dispersed within the thermoplastic polymer. The compositions can be used for injection molding of articles for use as components in applications requiring static dissipation and/or EMI shielding. Such articles include electronic devices, dust handling equipment and notebook computer enclosures.

Electro-optic polymer modulators for 1.55 μm wavelength using phenyltetraene bridged chromophore in polycarbonate

Abstract: Electro-optic polymer modulators operating at 1550 nm are demonstrated based on a nonlinear optical polymer of a phenyltetraene bridged chromophore in polycarbonate. It has a large electro-optic coefficient (r33=55 pm/V at 1550 nm), good thermal stability (90 °C), and low loss (1.7 dB/cm). A thin protective layer was used in the fabrication of ridge waveguides on the nonlinear polymer. We measured Vπ of 2.4 and 3.7 V at 1300 and 1550 nm, respectively. The chip loss of the modulator at both wavelengths was 5 dB, not including fiber coupling losses.

Polycarbonate and molded polycarbonate articles

Abstract: The invention relates to a novel polycarbonate and its use as a material in the production of molded articles and semifinished products, especially for transparent articles such as data memories or audio compact discs, slabs, cellular sheets, films, lamp housings, panes, especially panes for motor vehicles, diffusion glasses, but also for electrical applications or for the construction of houses.

Deposition and characterization of metastable Cu3N layers for applications in optical data storage

Abstract: Cu3N films for optical data storage were deposited on Si(100) wafers and 0.6 mm thick polycarbonate DVD base material discs at a temperature of 50 °C by reactive magnetron sputtering. A copper target was sputtered in rf mode in a nitrogen plasma. For basic investigations concerning the composition and structure of Cu3N, Si wafers were used as substrate material. To study the suitability of Cu3N as an optical data storage medium under technical conditions, Cu3N/Al bilayers were deposited on polycarbonate discs. The composition and structure of the films were investigated by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD).

Flame-retardant resin composition

Abstract: PROBLEM TO BE SOLVED: To provide a flame-retardant resin composition that has excellent impact strength, mechanical strength and rigidity without adverse effect on the low gas-evolving properties in forming work, flame retardancy and heat resistance. SOLUTION: This flame-retardant resin composition comprises 100 pts.wt., in total, of a thermoplastic resin composition including 89.8-20 wt.% of an aromatic polycarbonate (A-component), 10-70 wt.% of at least one of thermoplastic resin (B-component) selected from among polystyrene, shock-resistant polystyrene, acrylonitrile-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, acrylonitrile-styrene-acrylic rubber copolymer, aromatic polyester resin and polyarylate resin, and 0.2-10 wt.% of red phosphorus (C-component); 5-55 pts.wt. of carbon fiber (D-component), 1-20 pts.wt. of a condensed phosphoric ester-based flame retardant (E-component) and 0.1-10 pts.wt. of at least one kind of resin selected from among aromatic epoxy resin and phenoxy resin (F-component).

Polycarbonate resin composition

Abstract: There is disclosed a polycarbonate resin composition which comprises an (A) polycarbonate-polyorganosiloxane copolymer, a (B) polycarbonate resin and a (C) polytetrafluoroethylene which has fibril forming capability and an average molecular weight of at least 500,000 wherein the amount of the polyorganosiloxane moiety contained in the component (A) is 0.1 to 2.0% by weight based on the total amount of the components (A) and (B). The resin composition is excellent in flame retardancy, thermal stability and fluidity while preventing melt dripping at the time of combustion. Accordingly, the resin composition is favorably used in the application field of office automation machinery and equipment, electric and/or electronic field, etc.

Flame-resistant polycarbonate blends

Abstract: The invention relates to flame-resistant polycarbonate blends which contain polyalkyl(alkyl)acrylate and halogen-free oligophosphates but substantially no polymers which are constituted of butadiene, styrene and acrylnitrile. The invention also relates to molded bodies that can be obtained on the basis of said compositions.

Light-diffusing aromatic polycarbonate resin composition

Abstract: PROBLEM TO BE SOLVED: To provide a light-diffusing aromatic polycarbonate resin composition which has a high light-diffusing property, is not discolored when melted and retained, holds an excellent color tone even when exposed to heat and moisture, and maintains the excellent color tone for a long period. SOLUTION: This light-diffusing aromatic polycarbonate resin composition comprising 100 pts. wt. of a polycarbonate resin composition comprising (A) 80 to 99.995 wt.% of an aromatic polycarbonate resin (component A) and (B) 0.005 to 20 wt.% of fine polymer particles (component B), (C) 0.0001 to 0.05 pt.wt. of a specific phosphorous stabilizer (component C), (D) 0.001 to 1.0 pt.wt. of trimethylphosphate (component D), (E) 0.001 to 1.0 pt.wt. of a hindered phenol- based compound (component E), and (F) 0 to 0.5 pt.wt. of a fluorescent brightening agent (component F).

Flame-resistant polycarbonate abs blends

Abstract: The invention relates to polycarbonate ABS moulding materials which are provided with phosphanatamine and which have an excellent flame resistance and very good processing properties such as improved flow behaviour, an improved elastic modulus and reduced deposit build-up on tools. The graft polymer is produced using mass, mass-solution or mass-suspension polymerisation methods.

Order and Mobility in Polycarbonate−Poly(ethylene oxide) Blends Studied by Solid-State NMR and Other Techniques

Abstract: Solid-state 1D and 2D 13C CP/MAS NMR and 1H CRAMPS (combined rotation and multipulse spectroscopy) and Raman spectroscopy, X-ray scattering, and DSC were used to investigate the structure, morphology, and dynamic behavior of blends of two semicrystalline polymers, polycarbonate (PC) and poly(ethylene oxide) (PEO). The splitting of aromatic carbon signals in the 13C CP/MAS NMR spectra and the absence of spinning sidebands in the 1H dipolar spectra (2D WISE) indicate restricted mobility and hindered cooperative motions of PC chains resulting from blending of PC with PEO and from fixed ordering due to partial crystallinity of PC itself. The observed multiple splittings of the signals of aromatic and carbonate carbons indicate comparable amounts of trans−trans and cis−trans conformational structures of the carbonate group. 2D WISE spectra prove large differences in molecular mobility of amorphous PEO and PC. High mobility of amorphous PEO is not imparted significantly to less mobile PC, despite intimate mixin...

Evidence for strong magnetoelastic effects in Ni nanowires embedded in polycarbonate membranes

Abstract: The uniaxial anisotropy energy of arrays of submicronic (30-500 hm) Ni wires synthesized by electrodeposition into cylindrical pores of track-etched polycarbonate membranes is studied as a function of temperature. At room temperature, the uniaxial anisotropy is equal to the shape anisotropy whereas an additional contribution, that reinforces the wire axis as an easy axis is evidenced at low temperature. This additional contribution is demonstrated to find its origin in magnetoelastic effects conjointly induced by the Ni and polycarbonate thermal-expansion coefficients mismatch and by the low volume fraction of Ni in Ni/polycarbonate samples.

Translucent polycarbonate composition, method for preparation thereof, and articles derived therefrom

Abstract: Translucent polycarbonate compositions include an aromatic polycarbonate, a cycloaliphatic polyester, and a polyolefin. The compositions have excellent optical characteristics and superior physical properties, particularly low-temperature impact strength, compared to translucent polycarbonate-polyester blends requiring inorganic fillers.

Synthesis of functional polycarbonates by copolymerization of carbon dioxide with allyl glycidyl ether

Abstract: Functional aliphatic polycarbonate was synthesized by copolymerization of carbon dioxide and allyl glycidyl ether in the presence of a catalyst system based on ZnEt 2 and pyrogallol at a molar ratio of 2:1. The polycarbonate obtained was oxidized with m-chloroperbenzoic acid to give poly(epoxycarbonate). These polymers were degraded in an aqueous buffer of pH 7.4 at 37°C. Hydrolytic degradation was monitored by determination of the weight loss.

Flame retardant polycarbonate-silsesquioxane compositions, method for making and articles made thereby

Abstract: A flame retardant polycarbonate composition includes (A) at least one polycarbonate and (B) a silsesquioxane flame retardant. The flame retardant polycarbonate composition can be made by providing a polycarbonate and incorporating a flame retardant amount of a silsesquioxane into the polycarbonate. An article can be molded from the composition.

Rheological behavior of (short) carbon fiber/thermoplastic composites. Part II: The influence of matrix type

Abstract: This study is the second of a series of two papers on the rheological properties of VGCF/thermoplastic composites, its aim being to compare the performance of different thermoplastic matrices when reinforced with sub-micron Vapor Grown Carbon Fibers (VGCF). For this purpose, two polymers (polypropylene, PP, and polycarbonate, PC) were used to produce composites with different levels of fiber incorporation. The highest content VGCF composites were produced, in pellet form, using a co-rotating twin-screw extruder. These were subsequently diluted during the injection molding stage to obtain composites with different levels of fiber content. The rheological characterization was performed, using the latter materials, by means of both capillary and rotational rheometries, results being presented and discussed in terms of reinforcing capability and its susceptibility to temperature, for the relevant functions in both shear (steady and oscillatory) and extensional flows. The results show that VGCF have a higher reinforcing capability, both rheological and mechanical, when incorporated in the PP matrix. This better performance can be due either to better adhesion between the fibers and PP in comparison to PC, or to a higher degree of melt penetration of non-wetted fiber rich areas and lower fiber length degradation, owing to the lower viscosity of PP in the extrusion shear rate range.

Studies on the synthesis and properties of thermotropic liquid crystalline polycarbonates. VII. Liquid crystalline polycarbonates and poly(ester‐carbonate)s derived from various mesogenic groups

Abstract: Three series of thermotropic liquid crystalline polycarbonates and poly(ester-carbonate)s were prepared by solution polycondensation of 4,4′-biphenyldiol (BP), 4′-hydroxybiphenyl-4-hydroxybenzoate (HHB), or 4-hydroxyphenyl-4″-hydroxybiphenyl-4′-carboxylate (HHBP), as mesogenic unit, with 1,10-bis(p-hydroxybiphenoxy)decane (N10), bisphenol A (BPA), 4,4′-dihydroxy-diphenyl ether (BPO), 4,4′-[phenylbis(oxy)]bisphenol (BPOO), methylhydroquinone (MeHQ), or phenylhydroquinone (PhHQ). One series of cholesteric poly(ester-carbonate)s were also prepared by using HHBP, the aromatic diols mentioned above and isosorbide as the chiral moiety. All polycondensations were implemented in pyridine by using triphosgene as the condensation agent. The synthesized polycarbonates were characterized by viscometer, FTIR, DSC, TGA measurements, polarizing microscopy equipped with a heating stage, and WAXD powder pattern. In this study, it was found that the liquid crystalline properties of polycarbonates strongly rely on the mesogenic unit applied. HHBP-series exhibits a wide temperature region of liquid crystalline (LC) phase even with 50% of bisphenol A (BPA), which is a V-shaped structure and usually destroys liquid crystalline properties. In addition, homopolycarbonate with HHBP structure possesses extraordinarily low phase-transition temperature and wide liquid crystalline phase range, due to its asymmetric structure. This asymmetric structure results in head-to-tail, head-to-head, and tail-to-tail random conformation of polymer chain. The isosorbide containing poly(ester-carbonate)s formed cholesteric phase, which showed homogeneous blue, green, or red Grandjean texture upon shearing in molten state and the Grandjean texture could be frozen easily while quenching the sample to the room temperature. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1852–1860, 2000

Thermoplastic resin composition and molded article

Abstract: PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition which has excellent electroconductivity, gas barrier property, strength, corrosion resistance, and moldability and is suitable for fuel cell separators SOLUTION: This thermoplastic resin composition containing milled pitch- based carbon fibers in an amount of 5 to 80 wt%, wherein the thermoplastic resin comprises one or more resins selected from polyacetal, amorphous polyesters, polyphenylene oxide, polycarbonate, polyphenylene sulfide, liquid crystal polyesters, polysulfones, polyether sulfones, and polyether imides COPYRIGHT: (C)2002,JPO

Adhesive Characteristics of Alder-Ene Adduct of Diallyl Bisphenol a Novolac and Bisphenol a Bismaleimide

Abstract: Diallyl bisphenol A–formaldehyde copolymer (ABPF) was addition cured with bisphenol A bismaleimide (BMIP) making use of the Alder-ene reaction at high temperatures. The lap shear strength (LSS) of the system was found to depend on the conditions of cure and the stoichiometry of the reactants. Moderate cross linking achieved at a 1:1 maleimide:allylphenol stoichiometry and a stepwise cure, up to a maximum of 250 °C for 2 h, was found to be the most effective in achieving the optimum LSS properties. The system exhibited greater than 100% retention of the LSS at temperatures up to 250 °C. Matrix modification using polysulfone (PS) and polycarbonate (PC) resulted in a remarkable improvement in the adhesive characteristics, although the high-temperature retention was marginally adversely affected. The performance advantage both at room temperature (RT) and at high temperature was greater in the case of PS modification, showing an optimum improvement at 20% loading as against PC modification, exhibiting maximum...