نتایج جستجو برای: polyesters
تعداد نتایج: 2577 فیلتر نتایج به سال:
Polycaprolactone (PCL) is a biodegradable synthetic polymer that is currently widely used in many pharmaceutical and medical applications. In this paper we describe the coordination ring-opening polymerization of ε-caprolactone in the presence of two newly synthesized catalytic systems: diethylzinc/gallic acid and diethylzinc/propyl gallate. The chemical structures of the obtained PCLs were cha...
High molecular weight biodegradable polyesters were prepared from sebacic acid, ethylene glycol and butylene glycol through a simple non-solvent polycondensation with a low toxicity catalyst. The successful synthesis of the polyesters was confirmed by gel permeation chromatography, (1)H-nuclear magnetic resonance and Fourier transform-infrared spectroscopies and differential scanning calorimetr...
Polyhydroxyalkanoates (PHA) are a family of bio polyesters synthesized by many types of bacteria as carbon and energy reserve materials, Anderson AJ et al (1990). PHA can be divided into three classes depending on the number of carbon atoms in their monomer units; shortchain-length (SCL), medium-chain-length (MCL) and longchain-length polyhydroxyalkanoates (LCLPHAs), composed by hydroxyacids. P...
Exhaustive studies on the degradation of plastics have been carried out in order to overcome the environmental problems associated with synthetic plastic waste. Recent work has included studies of the distribution of synthetic polymer-degrading microorganisms in the environment, the isolation of new microorganisms for biodegradation, the discovery of new degradation enzymes, and the cloning of ...
Novel amphiphilic polyesters with both hydrophilic and hydrophobic functionalities being alternately distributed along polymer backbones have been synthesized and characterized. The polyesters are soluble in organic and aqueous media and reveal the formation of inverse architectures whose behavior could be correlated to their chemical structure. This work offers a new approach to building up se...
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