Novel Polycarbonates via Phosgenation of Unsaturated Diols (original) (raw)
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Syntheses of cyclic polycarbonates by the direct phosgenation of bisphenol M
Journal of Polymer Science Part A: Polymer Chemistry, 2005
Bisphenol M was subjected to interfacial polycondensations in an NaOH/ CH 2 Cl 2 system with triethylamine as a catalyst. Regardless of the catalyst concentration, similar molecular weights were obtained, and matrix-assisted laser desorption/ ionization time-of-flight mass spectra exclusively displayed mass peaks of cycles (detectable up to 15,000 Da). With triethyl benzyl ammonium chloride as a catalyst, linear chains became the main products, but the contents of the cycles and the molecular weights strongly increased with higher catalyst/bisphenol ratios. When the pseudohigh-dilution method was applied, both diphosgene and triphosgene yielded cyclic polycarbonates of low or moderate molecular weights. Size exclusion chromatography measurements, evaluated with the triple-detection method, yielded bimodal mass distribution curves with polydispersities of 5-12. Furthermore, a Mark-Houwink equation was elaborated, and it indicated that the hydrodynamic volume of poly(bisphenol M carbonate) was quite similar to that of poly(bisphenol A carbonate)s with similar concentrations of cyclic species.
Journal of Applied Polymer Science, 2008
This article describes a new, nonphosgene method for the synthesis of poly(bisphenol A carbonate) (PC). The method involves three steps: the reaction of an aliphatic diol with phenyl chloroformate to form an alkylene diphenyl dicarbonate, the reaction of the alkylene diphenyl dicarbonate with bisphenol A to produce an aromatic-aliphatic polycarbonate, and the thermal treatment of the polycarbonate at 180-2108C under a stream of nitrogen with Ti(OBu) 4 to give PC and a cyclic alkylene carbonate. The method furnished low to moderate molecular masses of PC upon the complete elimination of the aliphatic moieties. The approach may be considered a new method, based on polycarbonate thermochemical degradation, for the synthesis of cyclic aliphatic carbonates. The obtained polymers were characterized by intrinsic viscosity and IR, 1 H-NMR, and 13 C-NMR spectroscopy. The thermal treatment step was conducted in a glass reaction tube at 180-2108C under a stream of nitrogen, and the reaction was completed by heating to 2508C. In the thermal treatment step, semisolid effluents composed of cyclic alkylene carbonates were formed and subsequently eliminated from the reaction mixture. Heating to 2508C under nitrogen or under a dynamic vacuum furnished the pure aromatic PC residue. This intrachange reaction provides a flexible method for the synthesis of polycarbonates with alkylene diols containing two or three methylene groups, from which the pure PC homopolymer can be prepared. The potential of this approach was demonstrated by the successful synthesis of PC homopolymer from five different polycarbonates with a bisphenol A unit linked to 1,2-propylene, 1,3-propylene, 2methyl-1,3-propylene, 2,2-dimethyl-1,3-propylene, and 1,3butylene as the alkane chains. V
Synthesis of hydroxyl-terminated polycarbonates of controlled number-average molecular weight
Journal of Polymer Science: Polymer Chemistry Edition, 1982
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 group are easily removed after the polymerization is complete. In a practical laboratoq 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, lgF-NMR, and 'H-NMR measurements as well as vapor-pressure osmometry were used to characterize the oligomers.
Molecules, 2010
This work presents a new synthetic approach to aromatic and aliphatic polycarbonates by melt polycondensation of bisphenol A diacetates with alkylene-and arylenediphenyl dicarbonates. The diphenyl dicarbonates were prepared from phenyl chloroformate and the corresponding dihydroxy compounds. The process involved a precondensation step under a slow stream of dry argon with the elimination of phenyl acetate, followed by melt polycondensation at high temperature and under vacuum. The potential of this reaction is demonstrated by the successful synthesis of a series of aromatic-aromatic and aromatic-aliphatic polycarbonates having inherent viscosities from 0.19 to 0.43 dL/g. Thus low to intermediate molecular mass polymers were obtained. The 13 C-NMR spectra of the carbon of the carbonate group showed that the formed polycarbonates contain partial random sequence distribution of monomer residues in their chains. The polycarbonates were characterized by inherent viscosity, FTIR, 1 H-NMR and 13 C-NMR spectroscopy. The glass transition temperatures, measured by DSC, of the polycarbonates were in the range 13-108 ºC. The thermogravimetric curves of showed that these polymers have good thermal stability up to 250 ºC. The present approach may open the door for novel polycarbonates containing other organic functional groups.
Journal of polymer science, 1984
The synthesis of bisphenol A poly(carbonate-ester) copolymers was studied by phase-transfer catalysis and modified interfacial polymerization. Only low molecular weight copolymers were prepared directly from dicarboxylic acids, phosgene, and bisphenol A by an interfacial process that involves the use of pyridine as catalyst, HCl acceptor, and weak base. To avoid the use of tertiary amines, which can be difficult to remove from the polymer products, and to produce higher molecular weight copolymers from the same dicarboxylic acid precursors another synthetic method was developed. This more effective method required careful pH control that was achieved by the selective use of the weak-base potassium carbonate in the first stage of the process. Moreover, elevated reaction temperatures (-65-7OOC) and phase-transfer catalysis were used. The carbonate-ester copolymers prepared by this technique had consistently high intrinsic viscosities, little or no anhydride microstructure, and higher degrees of ester unit incorporation than those produced by the pyridine-catalyzed method. These copolymers also had glass transition temperatures (T,) 20-30°C higher than bisphenol A polycarbonate homopolymer. An analytical method for determining quantitatively the amount of ester units in the bisphenol A poly(carbonate-esters) was developed by using Fourier transform infrared spectroscopy (FT-IR). Agreement between this FT-IR method and a quantitative nuclear magnetic resonance (NMR) method was found to be reasonable, especially for copolymers with ester unit percentages lower than 40%.
Macromolecules, 2019
Tetrabutylammonium carbonate (TBAC) which is obtained by treating CO 2 with tetrabutylammonium hydroxide is shown to perform as an ideal difunctional initiator for the copolymerization of carbon dioxide (CO 2) and propylene oxide (PO) in the presence of triethylborane (TEB). In this system, CO 2 thus serves as the initiating moiety of its own copolymerization with epoxides when used in the form of a carbonate salt. Based on this remarkable result, mono-, tri-, and tetrafunctional ammonium carboxylate initiators and also other difunctional carboxylate initiators were synthesized and used for the synthesis of well-defined ωhydroxyl-polycarbonates with linear and star structures. Well-defined telechelics, three-and four-armed star samples of molar mass varying from 1 kg/mol to 10 kg/mol, with around 95% carbonate content, were successfully synthesized. The structure of the obtained polycarbonate ω-polyols were characterized by 1 H NMR, MALDI-TOF, and GPC. The terminal hydroxyl functionality of polycarbonate diol was further used for polycondensation with diisocyanates to afford polyurethanes. Finally, taking TBAC as an example, the recyclability of this ammonium-based initiator is demonstrated for the preparation of polycarbonate diols. 65 polycarbonate diols and polyols eventually obtained under 66 these conditions are contaminated with monofunctional 67 chains, which is detrimental to the subsequent polycondensa-68 tion applications. As clearly demonstrated by Sugimoto et al., 69 polycarbonate tetrol and hexeol samples using
Journal of Polymer Science Part A: Polymer Chemistry, 1988
Glycerol, D-mannitol, and D-sorbitol were converted into their mono-and di-~1,3-dioxohe and 1,3-dioxane bromoethylidene derivatives through a transacetalation reaction with bromoacetaldehyde diethyl acetal under controlled conditions. These brominated dioxolane or dioxane derivativts were subsequently phosphonylated through the Arbwv reaction. The phosphonylated cyclic acetals were used as precursore for the synthesis of acrylated phosphonate monomers. All these compounds have been characterized by elemental analysis and spectroscopic (IR, 'H-, 13C-, 31P-NMR and-) methods. A mixture of 1,3-dioxane and 1,3-dioxohue derivatives was obtained with D-sorbitol, whereas the reaction products with glycerol and D-mannitol yielded primarily the 1,3-dioxohue derivatives. The acrylated phosphonates of glycerol and mannitol have been polymerized and studied on the basis of gel permeation chromatography and their spectral and thermal properties. The acrylated phosphonates, monomers, and polymers, were shown to have a large capacity to solvate and dissolve heavy metal salts. This results in a dramatic increase (> 100°C) of the glass trsnsition temperature of these polymers.
Synthesis and characterisation of some new photografted polycarbonates
Polymer Photochemistry, 1984
Several copolycarbonates of bisphenol-A (I) and 1,1,l-trichloro-2,2bis(4-hydroxyphenyl ethane) (II) containing different percentages of H have been prepared. Acrylonitrile monomer has been successfully grafted on these copolymers via the chlorinated group (-CCl3) by photochemical reaction using Mn2( CO )xo as a catalyst in the presence o[ UV light. The grafted copolymers were then purified by reprecipitation and extraction, and have been characterised by various techniques. The grafted copolymers show better thermal stability as measured thermogravimetrically ( TGA ). The solubility of the prepolymers decreases significantly after grafting, and the grafted copolymers also become more brittle.