نتایج جستجو برای: aromatic polyesters
تعداد نتایج: 44691 فیلتر نتایج به سال:
The synthesis of proteins, polyesters, polysaccharides and polynucleotides can be adapted to produce new macromolecular materials. Proteins of designed sequence, and with specific chemical functions, conferred by the incorporation of unnatural amino acids, have been prepared in genetically engineered bacteria. Polyesters, useful as biodegradable thermoplastics, have been made in bacterial hosts...
The light induced, catalyst-free ambient temperature preparation of macrocyclic aliphatic polyesters is pioneered. Based on the photo-induced Diels-Alder reaction of orthoquinodimethane and acrylate moieties, cyclic polyesters of high purity are readily synthesized. Considering the high tolerance to functional groups and the orthogonality of the ligation, the reported protocol can be easily tra...
Advanced drug delivery systems rely on the availability of biocompatible materials. Moreover, biodegradability is highly desirable in the design of those systems. Consequently, aliphatic polyesters appear as a class of promising materials since they combine both properties. Nevertheless, their use in practical biomedical systems relies on clinical approval which not only depends on the material...
Biodegradable aliphatic random copolyesters poly(butylene succinate-co-butylene adipate), PBSA and poly(butylene succinate-co-butylene azelate), PBSAz were synthesized from 1,4 butane diol, succinic acid and adipic acid/azelaic acid through direct melt polycondensation with Titanium Tetra isopropoxide (TTiPO) as a catalyst. These polyesters were characterized by Viscosity measurements, 1H NMR s...
Tissue engineering holds enormous challenges for materials science, wherein the ideal scaffold to be used is expected to be biocompatible, biodegradable and possess mechanical and physical properties that are suitable for target application. In this context, we have prepared degradable polyesters in different ratios by a simple polycondensation technique with citric acid and polycaprolactone tr...
One of the key requirements in semi-crystalline polyesters, synthetic or bio-based, is the control on crystallization rate and crystallinity. One of the limiting factors in the commercialization of the bio-based polyesters, for example polyhydroxyalkanoates synthesized by bacteria for energy storage purposes, is the slow crystallization rate. In this study, we show that by tailoring the molecul...
A novel approach to hyperbranched polymers is presented in this work. Hyperbranched polyesters with a large amount of terminal hydroxyl groups are prepared by a one-pot synthesis from commercially available AB-type and CD(n)-type monomers (n >/= 2). In this paper, Michael addition of diethanolamine (CD(2)) or N-methyl-d-glucamine (CD(5)) to methyl acrylate (AB) generates dominantly AD(n)-type i...
Properties of linear polyesters based on azoxybenzene and 2,2'-methylazoxybenzene moieties with linear, flexible spacers based on mixtures of dodecanedioic acid (DDA) and methyladipic acid (MAA), chiral or racemic, of various compositions (system MAA/DDA-8 and MAA/DDA-9, respectively) have been described. Substitution of methyl groups in the 2,2' or 3,3' positions of the mesogenic core Ieads to...
Biodegradable polyesters allow the development of acceptable bio-composites and bio-blends from agricultural-based raw materials without impairing their biodegradability and other useful properties. The tensile properties of binary blends of polystyrene (PS) with the biodegradable polyesters polycaprolactone (PCL), D,L-polylactic acid (PLA), and Eastar Bio Ultra (EBU) were investigated. Blend c...
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