نتایج جستجو برای: Aromatic polyesters
تعداد نتایج: 44691 فیلتر نتایج به سال:
In this paper, an efficient method for synthesis of aromatic polyesters containing schiff base units is described by preparation of two polyesters. These polyesters have been prepared by the reaction of terephthaloyl dichloride on Schiff bases derived from p-hydroxybenzyldehyde and 4,4-diamino diphenyl ether, 4,4-diamino diphenyl methane. The Polymers were characterized by IR, CHNS, thermal...
A microbial fermentation system was designed to convert glucose to 4-hydroxyphenyllactic acid (DHPA), which is an aromaticcontaining derivative of lactic acid. By methylation, DHPA was transformed to a diol monomer for synthesis of bio-based polyesters with benzene rings in their backbone. The polycondensation of the DHPA diol was performed with a series of aliphatic diacid chlorides to produce...
Thermal degradation of aromatic polyesters (see text for formula) (m = 2, 3, 4, 5, and 6) was studied by pyrolysis/gas chromatography using a Curie-point pyrolyzer directly attached to a gas chromatograph with a thermally stable polar separation column (Thermon-1000) to cover a wide range of the degradation products. The characteristic peaks appearing on the pyrograms were identified using a ma...
New carbohydrate-based polyesters were prepared from isoidide-2,5-dimethanol (extended isoidide, XII) through melt polymerization with dimethyl esters of terephthalic acid (TA) and furan-2,5-dicarboxylic acid (FDCA), yielding semi-crystalline prepolymers. Subsequent solid-state post-condensation (SSPC) gave high molecular weight (Mn =30 kg mol(-1) for FDCA) materials, the first examples of high...
Progress on biodegradable aromatic/aliphatic copolyesters based on aliphatic and aromatic diacids, diols and ester monomers was reviewed. The aromatic/aliphatic copolyesters combined excellent mechanical properties with biodegradability. Physical properties and biodegradability of copolyesters varied with chain length of the aliphatic polyester segment and atacticity of copolyesters. The proces...
2,5-Bis(hydroxymethyl)furan (BHMF) is a highly valuable biobased rigid diol resembling aromatic monomers in polyester synthesis. In this work, BHMF is enzymatically polymerized with various diacid ethyl esters by Candida antarctica lipase b (CALB) via a two-stage, three-step method. A series of novel biobased furan polyesters are successfully produced, with number average molecular weights ( ...
In this paper we use mono- and bi-metallic complexes, based on earth-abundant, cheap benign zinc, for the synthesis of sustainable aliphatic semi-aromatic polyesters. Tridentate hexadentate aldimine-thioetherphenolate ligands...
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