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Sebacic Acid (sebacic + acid)
Selected AbstractsSynthesis, characterization, and degradation of poly(ester-anhydride) for particulate deliveryISRAEL JOURNAL OF CHEMISTRY, Issue 4 2005Sweta Modi A series of poly(ester-anhydride) from poly(lactic acid) and poly(sebacic acid) have been synthesized and characterized. Poly(lactic acid) of molecular weight 2,550 Da has been synthesized from pharmaceutical grade lactic acid. The copolymers are in the molecular weight range of 3,000-15,000 Da, with the higher molecular weights obtained for the polymers with higher sebacic acid content. With increase in sebacic acid content, the melting point is also found to increase. The polymers with 50% or more poly(sebacic acid) content melt between 80 and 84 °C. These polymers have been formulated into microspheres and their degradation studied. Due to their biodegradability and the flexibility to alter their degradation profile, they find a wide application in drug delivery. [source] Syntheses of aliphatic polyesters catalyzed by lanthanide triflatesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2009Mazen Garaleh Abstract Polycondensations of 1,6-hexane diol and sebacic acid were conducted in bulk with addition of a lanthanide triflate as acidic catalyst. With exception of promethium triflate all lanthanide triflates were studied. A particularly low molecular weight was obtained with neodym triflate and the best results with samarium triflate. With Sm(OTf)3 weight average (Mw) values up to 65 kDa (uncorrected SEC data) were achieved after optimization of the reaction conditions. Comparison of these results with those obtained from bismuth, magnesium, and zinc triflates, on the one hand, and comparison with the acidities of all catalysts, on the other, indicates that the esterification mechanism involves complexation of monomer by metal ions. Preparation of multiblock copoly(ether ester)s failed due to insufficient incorporation of poly(tetrahydrofuran) diols. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 170,177, 2009 [source] Main-chain, thermotropic, liquid-crystalline, hydrogen-bonded polymers of 4,4,-bipyridyl with aliphatic dicarboxylic acidsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2003Pradip K. Bhowmik Abstract A series of main-chain, thermotropic, liquid-crystalline (LC), hydrogen-bonded polymers or self-assembled structures based on 4,4,-bipyridyl as a hydrogen-bond acceptor and aliphatic dicarboxylic acids, such as adipic and sebacic acids, as hydrogen-bond donors were prepared by a slow evaporation technique from a pyridine solution and were characterized for their thermotropic, LC properties with a number of experimental techniques. The homopolymer of 4,4,-bipyridyl with adipic acid exhibited high-order and low-order smectic phases, and that with sebacic acid exhibited only a high-order smectic phase. Like the homopolymer with adipic acid, the two copolymers of 4,4,-bipyridyl with adipic and sebacic acids (75/25 and 25/75) also exhibited two types of smectic phases. In contrast, the copolymer of 4,4,-bipyridyl with adipic and sebacic acids (50/50), like the homopolymer with sebacic acid, exhibited only one high-order smectic phase. Each of them, including the copolymers, had a broad temperature range of LC phases (36,51 °C). The effect of copolymerization for these hydrogen-bonded polymers on the thermotropic properties was examined. Generally, copolymerization increased the temperature range of LC phases for these polymers, as expected, with a larger decrease in the crystal-to-LC transition than in the LC-to-isotropic transition. Additionally, it neither suppressed the formation of smectic phases nor promoted the formation of a nematic phase in these hydrogen-bonded polymers, as usually observed in many thermotropic LC polymers. The thermal transitions for all of them, measured by differential scanning calorimetry, were well below their decomposition temperatures, as measured by thermogravimetric analysis, which were in the temperature range of 193,210 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1282,1295, 2003 [source] Ion-Exchange Loading of Yttrium Acetate as a Sintering Aid on Aluminum Nitride Powder via Aqueous ProcessingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2000Yasuhiro Shimizu A novel fabrication process of AlN ceramics via aqueous colloidal processing and pressureless sintering has been presented. The chemical stability of AlN powder in water was improved by the surface chemical modification with sebacic acid, while maintaining a hydrophilic surface. The treatment of the sebacic acid-modified powder with yttrium acetate tetrahydrate resulted in strong immobilization of Y3+ ions, as a sintering aid, at a highly dispersive level on the AlN powder surface through ion exchange with the free carboxyl groups of the sebacic acid molecules attached to the AlN surface. By selecting slip compositions for a well-deflocculated condition and firing conditions to burn out organic components in the slip cast compacts, a thermal conductivity of about 250 W/(m·K) could be attained by the pressureless sintering at 1900°C for 5 h. [source] Biodegradable Poly(ester hydrazide)s via Enzymatic PolymerizationMACROMOLECULAR RAPID COMMUNICATIONS, Issue 16 2005Guillaume Métral Abstract Summary: The reaction of hydrazine with ethyl glycolate results in 1,2-bisglycoylhydrazine, a monomer that was used for the lipase-catalyzed synthesis of biodegradable poly(ester hydrazide)s. The polymers derived from the hydrazide-containing monomer and vinyl-activated adipic, suberic, and sebacic acid, respectively, showed low melting temperatures of 136 to 141,°C and are thermally stable up to 300,°C. The aliphatic poly(ester hydrazide)s (PEHs) are highly crystalline, as proven by polarization microscopy and atomic force microscopy. Further, the PEHs represent the first described biodegradable poly(hydrazide)s. They degrade in the presence of lipase at 37,°C within a few weeks. Synthetic route to poly(ester hydrazide)s. [source] Lithocholic-acid-containing poly(ester,anhydride)sPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11-12 2003Michal Y. Krasko Abstract New degradable poly(ester-anhydride)s were prepared by melt polycondensation of poly(sebacic acid) (PSA), transesterified by different amounts (30,90%) of lithocholic acid (LCA), a natural hydroxy bile acid. Transesterification of PSA is a one-pot reaction that starts with a high-molecular-weight polymer based on anhydride bonds and yields polymer based on random anhydride,ester bonds. A systematic study of the synthesis, characterization, degradation in vitro, drug release, and stability of these polymers was performed. Polymers with molecular weights (Mw) in the range of 12,000,115,000 and melting points in the range of 55,112,°C were obtained for 30,90% of lithocholic acid content. NMR and IR spectroscopic analyses indicate the formation of ester bonds in the polyanhydride backbone. The experimental results fit the calculated molecular weight, with the highest Mw obtained for a 4:6 PSA,LCA ratio. The study shows that some of these new degradable copolymers can be potentially used as carriers for the controlled release of drugs. Copyright © 2003 John Wiley & Sons, Ltd. [source] Main-chain, thermotropic, liquid-crystalline, hydrogen-bonded polymers of 4,4,-bipyridyl with aliphatic dicarboxylic acidsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2003Pradip K. Bhowmik Abstract A series of main-chain, thermotropic, liquid-crystalline (LC), hydrogen-bonded polymers or self-assembled structures based on 4,4,-bipyridyl as a hydrogen-bond acceptor and aliphatic dicarboxylic acids, such as adipic and sebacic acids, as hydrogen-bond donors were prepared by a slow evaporation technique from a pyridine solution and were characterized for their thermotropic, LC properties with a number of experimental techniques. The homopolymer of 4,4,-bipyridyl with adipic acid exhibited high-order and low-order smectic phases, and that with sebacic acid exhibited only a high-order smectic phase. Like the homopolymer with adipic acid, the two copolymers of 4,4,-bipyridyl with adipic and sebacic acids (75/25 and 25/75) also exhibited two types of smectic phases. In contrast, the copolymer of 4,4,-bipyridyl with adipic and sebacic acids (50/50), like the homopolymer with sebacic acid, exhibited only one high-order smectic phase. Each of them, including the copolymers, had a broad temperature range of LC phases (36,51 °C). The effect of copolymerization for these hydrogen-bonded polymers on the thermotropic properties was examined. Generally, copolymerization increased the temperature range of LC phases for these polymers, as expected, with a larger decrease in the crystal-to-LC transition than in the LC-to-isotropic transition. Additionally, it neither suppressed the formation of smectic phases nor promoted the formation of a nematic phase in these hydrogen-bonded polymers, as usually observed in many thermotropic LC polymers. The thermal transitions for all of them, measured by differential scanning calorimetry, were well below their decomposition temperatures, as measured by thermogravimetric analysis, which were in the temperature range of 193,210 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1282,1295, 2003 [source] | ||||||||||