Showing papers on "Polycarbonate published in 1982"

Bisphenol‐A polycarbonate–poly(butylene terephthalate) transesterification. II. Structure analysis of the reaction products by IR and 1H and 13C NMR

Abstract: The structure of the four-component copolyester resulting from the exchange reaction between molten bisphenol-A polycarbonate and poly(butylene terephthalate) is analyzed as a function of the reaction time by infrared and nuclear magnetic resonance spectroscopy. By applying a statistical method developed earlier, the mean chain length of the various sequences as well as the degree of randomness is computed. The exchange reaction leads initially to the formation of a block copolyester with reduced solubility. As the reaction proceeds, a soluble random copolycondensate is progressively formed.

The Trans-esterification of Bisphenol-a Polycarbonate (pc) and Polybutylene Terephthalate (pbtp) - a New Route To Block Copolycondensates

Abstract: In this work, the exchange reaction taking place in molten blends of bisphenol-A polycarbonate and polybutylene terephthalate was studied. A direct transesterification mechanism catalyzed by titanium residues, present in commercial PBTP, was deduced. The transesterification reaction can be -stopped at various levels by additives capable of complexing the titanium catalyst. This work enhances the possibility of a new approach in macromolecular engineering by directly combining polycondensates in a processing machine such as an extruder.

A study of the pressure‐volume‐temperature relationships of four related amorphous polymers: Polycarbonate, polyarylate, phenoxy, and polysulfone

Abstract: The pressure-volume-temperature (PVT) relationships of bisphenol-A polycarbonate, polyarylate, and phenoxy were studied at pressures to 1800 kg/cm2 and in both the glassy and melt states. Earlier data on polysulfone are included in the analysis and discussion of the results. All four polymers contain the bisphenol-A residue in their repeat unit, together with a moiety of varying complexity, and are therefore somewhat related. At the glass transition, equations of the Ehrenfest type hold, provided the pressure dependence of the glass transition temperature is defined from the line obtained by intersecting the quasiequilibrium PVT relationship of the glass with the equilibrium PVT surface of the melt. The Prigogine-Defay ratio r = ΔκΔCp/TgVg(Δα)2 at P = O is unity within experimental error for all four polymers. The melt data were fitted successfully to the Simha-Somcynsky theory. Molecular parameters deduced from the reducing parameters vary in a reasonable manner among these four related polymers, lending support to the foundations of the theory.

Flame retardant polycarbonate compositions

Abstract: Flame retardant polycarbonate compositions are disclosed which are obtained from polymers derived from non-polycyclic, sulfur-free diphenols and polymers derived from sulfur-containing diphenols.

Effects of thermal history, crystallinity, and solvent on the transitions and relaxations in poly(bisphenol‐A carbonate)

Abstract: The following system of nomenclature for the transitions and relaxations in polycarbonate has been proposed: α = Tg = 150, β = 70, γ = −100, and δ = −220°C (frequency range of 10–50 Hz). The three component peaks of the γ relaxation are denoted by γ1, γ2, and γ3 relaxations correspond to phenylene, coupled phenylene-carbonate, and carbonate motions, respectively. Dynamic mechanical analysis of poly(bisphenol-A carbonate) using the DuPont 981–990 DMA system shows that the magnitude of the β relaxation depends upon the thermal history of the polycarbonate; annealing greatly reduces the intensity of the β relaxation. A relaxation map constructed for the β relaxation gives an activation energy of 46 kcal/mol. Exposure of polycarbonate to methylene chloride vapor for various times shows that after an induction period of about 5 min the intensity of the γ3 relaxation at −78°C decreases whereas the intensity of the γ1 relaxation of −30°C is unaffected and the ratio E″(γ1)/E″(γ3) increases linearly with the square root of time. This has been ascribed to the interaction of methylene chloride on the carbonate group in polycarbonate. Thermal crystallization of polycarbonate does not affect the positions of the γ relaxation and the glass transition peaks, but merely reduces their intensity. The glass transition peak intensity falls off sharply in comparison to the γ relaxation intensity. Both the γ3 and γ1 peaks in polycarbonate have been observed simultaneously for the first time by dynamic mechanical analysis. Impact strength measurements show that methylene chloride treatment of polycarbonate results in a change in mode of failure from ductile to brittle with a resultant 40-fold reduction in impact energy for fracture. Thermally crystallized polycarbonate exhibits brittle fracture with very low force and energy at break.

Coated and ultraviolet radiation stabilized polycarbonate article.

Abstract: A coated polycarbonate article having improved resistance to degradation by ultraviolet radiation, abrasion and attack by chemical solvents comprising a polycarbonate resin article with its surface layers impregnated with an ultraviolet radiation absorbing compound and having deposited on said impregnated surface a coating comprised of (i) a thermoplastic acrylic polymer containing primer layer; and (ii) a top coated disposed on said primer layer containing a colloidal silica filled thermoset organopolysiloxane.

Functional polycarbonate by copolymerization of carbon dioxide and epoxide: Synthesis and hydrolysis

Abstract: Polycarbonates with pendant carbonate groups were synthesized by copolymerization of carbon dioxide and epoxides containing a carbonate substituent using the diethylzinc/water system as catalyst. The polycarbonates underwent acidic and basic hydrolysis to release slowly the compound attached as the pendant group via the carbonate linkage. Other hydrolysis products were glycerol and CO2, but no oligomeric products were formed.

Residual stresses in plastics, rapidly cooled from the melt, and their relief by sectioning

Abstract: A theory for the residual stresses in tempered glass plates has been adapted for the cooling of plastics, which have temperature dependent thermal properties. The theory was checked against experimental residual stress distributions found in quenched polycarbonate sheet, and against the analytical solution for temperature independent properties. The heat transfer coefficient for quenching polycarbonate from 170° C into iced water was found to lie between 1000 and 4000 W m−2 K. It is known that the cutting of thin sections from a sheet relieves the residual stresses, and this is used for transparent plastics to distinguish between orientation and stress bi-refringence. An elastic stress analysis of the sectioning process showed that the section width must be less than 20% of the sheet thickness for the residual stresses to be reduced to 5% of their original values.

Coated surface stabilized polycarbonate article.

Abstract: A coated polycarbonate article having improved resistance to degradation by ultraviolet radiation, abrasion and attack by chemical solvents comprising a polycarbonate resin article with its surface layers impregnated with an ultraviolet radiation absorbing compound and having deposited on said impregnated surface a coating comprised of (i) a thermoplastic acrylic polymer containing functional groups primer layer; and (ii) a top coat disposed on said primer layer containing a colloidal silica filled thermoset organopolysiloxane.

Randomly branched aromatic polycarbonate from triphenol

Abstract: This invention relates to triphenolic compounds that may be used as branching agents for the manufacture of novel randomly branched polycarbonates. The polycarbonates are useful for the fabrication of blow molded articles.

Production of polycarbonate

Abstract: PURPOSE:To facilitate the production of a polycarbonate excellent in craking resistance, impact resistance, heat resistance, etc, by reacting a dihydroxydiaryl compound with an N,N'-carbonyl bond-containing compound by using, as a catalyst, at least one member selected from a basic organic compound and a basic organometallic complex CONSTITUTION:The purpose polycarbonate is synthesized by reacting a dihydroxydiaryl compound (eg, 4,4,'-dihydroxydiphenylbutane) with an N,N'-carbonyl bond-containing compound (eg, N, N'-carbonyldiimidazole) by using, as a catalyst, at least one member selected from a basic organic compound (eg, quinoline) and a basic organometallic complex (eg, sodium methylate) According to this process, it is possible to obtain a coloration-free, transparent polycarbonate having a uniform MW and excellent physical properties by using a relatively low temperature (160-190 degC) and a reaction time shorter than half of that of a conventional process

Melting and crystallization behavior of miscible copolyester–polycarbonate blends

Abstract: The melting and crystallization behavior of Kodar, a copolyester formed from 1,4-cyclohexanedimethanol and a mixture of terephthalic and isophthalic acids, and its miscible blends with polycarbonate was examined. The results of the melting behavior are discussed in terms of crystallization-induced chemical rearrangements and the copolymeric character of Kodar and interchange reactions between components when polycarbonate is present in the blend. For various reasons, the melting behavior cannot be extrapolated to infinite crystal size using the Hoffman–Weeks approach. Crystallization kinetics follows the Avrami equation, with rates being higher when the crystallization temperatuare is approached from the glass rather than from the melt. The kinetic data are discussed in terms of modern theories. An approximate melting point depression analysis is used to estimate the interaction parameter for the blend, and the result obtained is compared to a value from another technique.

Coated polycarbonate resin molding

Abstract: PURPOSE: To improve the abrasion resistance of a polycarbonate resin molding, by applying a priming coat containing a specified copolymer to the surface of the polycarbonate resin molding, and then applying thereto a composition comprising an organopolysiloxane containing colloidal silica. CONSTITUTION: A composition containing a copolymer comprising alkoxysilyl group-containing acrylic or/and vinyl monomers (e.g., vinyltrimethoxysilane) and another monomer copolymerizable therewith (e.g., methylacrylate), a curing catalyst (e.g., hydrochloric acid), and a crosslinking agent (e.g., ethylene glycol) is applied to a polycarbonate resin molding and cured to form a priming coat. A composition containing colloidal silica, a curing catalyst, and an organopolysiloxane (e.g., glycidoxymethyltrimethoxysilane) is applied to the priming coat and cured to form a top coat layer. In this way, the titled molding is obtained. COPYRIGHT: (C)1984,JPO&Japio

Composition of a polycarbonate resin and a selectively hydrogenated copolymer of a vinyl aromatic compound and an olefinic elastomer

Abstract: There are provided compositions having superior impact resistance and improved solvent resistance comprising (a) an aromatic polycarbonate resin and (b) a minor amount of a selectively hydrogenated elastomeric block copolymer. The use of component (b) also provides remarkable improvements in the melt flow characteristics, in resistance to brittle failure, and in the resistance to environmental stress crazing and cracking of the polycarbonate resin component (a).

Thermoplastic ternary molding composition of polyurethane polyphosphonates and polycarbonate resins

Abstract: The invention is directed to a molding composition comprising an intimate, well dispersed blend of thermoplastic polyurethane, thermoplastic polyphosphonate and thermoplastic polycarbonate which composition is characterized by an improved level of flame resistance. A process for the preparation of said composition is also disclosed.

Aromatic branched polycarbonate from tetraphenol

Abstract: This invention relates to tetraphenolic compounds that have utility as branching agents for the manufacture of novel randomly branched polycarbonates. The polycarbonates are useful in the fabrication of blow molded articles.

Synthesis of hydroxyl-terminated polycarbonates of controlled number-average molecular weight

Abstract: Hydroxyl-terminated polycarbonates are important starting materials for the synthesis of multiblock copolymers. Earlier papers from our laboratory and elsewhere have demonstrated their utility in siloxane, aryl ether, and ester systems. One synthesis problem that must be addressed is the control of the number-average molecular weight and hence block size of the polycarbonate oligomeric precursor. The facile phosgene-hydroxyl reaction is often difficult to monitor precisely. The present article describes a novel, simple, and convenient technique for the synthesis of hydroxyl-terminated polycarbonates of well-controlled number-average molecular weight. The approach involves an in situ blocking of some of the phenolic groups either prior to or during phosgenation. The protecting groups are easily removed after the polymerization is complete. In a practical laboratory experiment the technique does not require any additional step beyond that necessary for the preparation of nonfunctional polycarbonates of controlled molecular weight. The method is demonstrated in this article with the polycarbonate of bisphenol-A via the use of trimethylchlorosilane, trifluoroacetic anhydride, and trifluoroacetic acid as blocking groups. Ultraviolet, 19F-NMR, and 1H-NMR measurements as well as vapor-pressure osmometry were used to characterize the oligomers.

Boiling water aging of a miscible blend of polycarbonate and a copolyester

Abstract: Extruded films and injection molded bars of a copolyester based on 1,4-cyclohexanedimethanol condensed with a mixture of isophthalic and terephthalic acids, of a bisphenol-A based polycarbonate, PC, and of the miscible blends of these compounds were exposed to boiling water for up to 15 days. The ductility and strengths of film specimens rich in PC were found to degrade as a result of PC hydrolysis. These properties of specimens rich in copolyester were found to decline as a result of crystallization of the copolyester. Best overall performance was obtained for 50/50 blends of PC and copolyester. All amorphous materials showed a transition from ductile to brittle behavior at the same weight average molecular weight as previously observed for pure PC. This feature plus the observation that PC hydrolyzes in the blend at the same rate as it does in the pure state allows most of the superior performance of the 50/50 blends to be explained in terms of blend molecular weight.

Internal antistatic agents for polycarbonates and for polycarbonate films

Abstract: The present invention relates to polycarbonate articles and films characterized by their antistatic properties comprising polycarbonate resin and alkali, or alkali earth, salts of specific aromatic sulfonic acids, specific aromatic phosphonic acids or aromatic partial phosphoric acid esters.

Polycarbonate compositions having a high impact strength and melt flow rate

Abstract: The invention relates to thermoplastic aromatic polycarbonates which structural units are characterized by their end groups which are residues of ##STR1## and is predicated on the surprising and unexpected findings that high melt flow polycarbonates of this type are rendered improved impact performance by admixing therewith small amounts of an impact modifier.

Resinous composition comprising a polycarbonate resin, a linear low density polyolefin and an alkenyl aromatic copolymer

Abstract: Novel thermoplastic molding compositions are disclosed which comprise a polycarbonate resin, an alkenyl aromatic copolymer and a linear low density polyolefin.

A New Route to Carbonate Monomers for Synthesis of Polycarbonates

Abstract: A number of carbonates (RCH2)2CO3 (R=CH3, C2H5, CH2=CH, C3H7, C5H11, C6H5) have been synthesized by the reaction of alkali metal carbonates with corresponding halogen derivatives in the presence of activating agents such as crown ethers, polyglymes, polyamines, and triethylbenzylammonium chloride. The effects of various parameters (type of the halogen derivative, metal carbonate, activating agent, solvent and reaction time) on the reaction yield have been studied. The carbonates obtained were used as monomers in transesterification with diols and diphenols leading to the formation of polycarbonates. The polycarbonates obtained were characterized by means of IR spectroscopy and their intrinsic viscosity was determined.

Blends of aromatic polycarbonate resins, polyolefins and olefin copolymers, and acrylate interpolymer resins

Abstract: Thermoplastic molding compositions are described which comprise a miscible admixture of (a) an aromatic polycarbonate resin, (b) an olefinic polymer or copolymer and a minor amount of (c) a third component which is an acrylic polymer. The presence of the acrylic polymer permits the incorporation of amounts of component (b) in excess of 10 parts by weight per 100 parts by weight of (a) and (b) together to improve the stress cracking resistance without normally attendant loss in ductility.

Laminates having optically clear laminates having high molecular weight phenoxy-high crystallinity polyurethane adhesive

Abstract: An adhesive for bonding polyethylene terephthalate, polycarbonate and other transparent thermoplastic sheets to form optically clear laminants with improved bond strengths which remain intact over temperature exposures ranging from -40° C. to 70° C. and humidities ranging up to 90% at 40° C. is provided. The adhesive is a combination of approximately 20% molecular weight phenoxy resin and approximately 80% molecular weight polyurethane resin.

The weathering of engineering thermoplastics

Abstract: The photostability of four engineering thermoplastics, ARDEL, CYCOLOY, NORYL, and HOVEL, have been examined by mandrel bend tests on extruded channel as well as infrared and ultraviolet-visible spectroscopy on thin films. ARDEL D-100 and ROVEL 501 resins were found to have excellent stability to simulated sunlight, while CYCOLOY HHI and NORYL PX 1278 were found to have poor light stability. ARDEL is a polyarylate composed of bisphenol A. terephthalic acid, and isophthalic acid condensation units. CYCOLOY is an alloy of acrylonitrile-butadiene-styrene and polycarbonate. NORYL is a blend of poly(phenylene oxide) and polystyrene. ROVEL is an olefin-modified styrene-acrylonitrile.