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A set of poly(L-lactide)-poly(ϵ-caprolactone) diblock copolymers (AB) and poly(L-lactide)-poly(ϵ-caprolactone)-poly(L-lactide) triblock copolymers (ABA) with predictable molecular weights and relatively narrow distributions were synthesized by ring-opening polymerization of successively added ϵ-caprolactone (ϵ-CL) andL-lactide (LLA) using 4-methyl benzo-12-crown-4 imidazol-2-ylidene as catalyst. The effects of polymerization conditions, such as reaction time, temperature, monomer/catalyst molar ratio and monomer concentration on the copolymerization have been discussed in detail. The resulting copolymers were characterized by1H-NMR,13C-NMR, IR, GPC and DSC methods which confirmed the successful synthesis of block copolymers of LLA and ϵ-CL. Hydrolytic degradation of the polymers showed that the PLLA-PCL-PLLA copolymer exhibited faster degradation as compared with the PCL homopolymer in alkaline medium at 37°C. [ABSTRACT FROM AUTHOR]

In this research, Ti/SnO 2 -RuO 2 stable anode was successfully prepared by thermal decomposition method, and low concentration cefotaxime sodium (CFX) was degraded by green and sustainable electrocatalytic oxidation technology. The electrocatalytic activity and stability of the Ti/SnO 2 -RuO 2 coating electrode were studied according to the polarization curve of oxygen and chlorine evolution. The effects of current density, initial concentration, pH, electrolyte concentration, and other technological parameters on the degradation efficiency were discussed. Orthogonal experiment results indicated that when the current density was 25 mA cm -2 , concentration of electrolyte was 5 mM and the pH value was 7, the best CFX removal rate of 86.33% could be obtained. The degradation efficiency of electrocatalytic oxidation was discussed through electrochemical analysis. Fourier transform infrared spectroscopy was used to analyze the different inlet and outlet stages before and after the degradation of CFX, and the possible degradation process was discussed. Therefore, the electrocatalytic oxidation of Ti/SnO 2 -RuO 2 electrode was a clean and efficient technology, which could be widely used in the treatment of CFX wastewater., (Copyright © 2022 Elsevier Ltd. All rights reserved.)