نتایج جستجو برای: aromatic polyesters
تعداد نتایج: 44691 فیلتر نتایج به سال:
A new series of blue photoluminescent aromatic polyesters (polyarylates) were synthesized from 1-[N,N-di(4-carboxyphenyl)amino]naphthalene with various bisphenols by the diphenylchlorophosphate (DPCP) activated direct polycondensation in a medium of pyridine and lithium chloride. The synthesis, basic characterizations, photoluminescence and electrochemical properties of this series of novel pol...
a new homologous series of linear aliphatic polyesters, such as poly (cis-2- butenylene carboxylate)s, pbms (m is the number of methylene groups in the acid component, m=2-8 have been synthesized by direct polyesterification reactions in anisole, as solvent. ft-ir, 400 mhz h- nmr, c-nmr and elemental analysis were used to establish the structure of polyesters. molecular weight distributions wer...
Four polyesters were prepared by stepwise condensation of isopbthalic acid, cblorendic acid and maleic anhydride with propylene glycol using p-toluenesulpbonic acid as catalyst and xylene as entrainer. The quantities of maleic anbydride and propylene glycol used were 1 and 2.2 moles respectively and tbe molar ratios of cblorendic acid to isopbtbalic acid were 0.2: 0.8. 0.4: 0.6, 0.6: 0.4 and 0....
The dimethyl ester of 2,3:4,5-di-O-methylene-galactaric acid (Galx) was made to react in the melt with 1,n-alkanediols HO(CH(2))(n)OH containing even numbers of methylenes (n from 6 to 12) to produce linear polycyclic polyesters. Two sets of poly(alkylene 2,3:4,5-di-O-methylene-galactarate) polyesters (PE-nGalx) with weight-average molecular weights in the ∼ 5000-10000 and ∼ 35000-45000 ranges ...
Due to our increasing concerns on environmental problems and limited fossil resources, biobased production of chemicals and materials through biorefinery has been attracting much attention. Optimization of the metabolic performance of microorganisms, the key biocatalysts for the efficient production of the desired target bioproducts, has been achieved by metabolic engineering. Metabolic enginee...
Four new polyesters based on 1,3-propanediol and different aliphatic dicarboxylic acids were used to prepare ropinirole HCl-loaded nanoparticles. The novelty of this study lies in the use of polyesters with similar melting points but different degrees of crystallinity, varying from 29.8% to 67.5%, as drug nanocarriers. Based on their toxicity to human umbilical vein endothelial cells, these ali...
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