Papers by Keyword: Alternating Copolymerization

Abstract: A solvent-free cross-linked alternating copolymer electrolyte is synthesized through photo copolymerization of comb-like poly (ethylene glycol) ester maleate and styrene. Phase transitions, thermal properties, ionic conductivities and electrochemical stabilities are investigated to characterize the alternating copolymer electrolyte. The flexible solid polymer electrolyte (spe) with lithium salt content of 15 wt.% and MA/-OH = 1 has a good ionic conductivity of 1.45×10^-5 S cm^-1 at 35 °C and a superior electrochemical stability to 5.2 V. The maleic anhydride on the main chain increases the rigidity of the copolymer matrix and decreases the ionic conductivity.

Abstract: Radical copolymerization of styrene (St) and maleic anhydride (MA) were typically alternating copolymerization, which generated copolymer styrene-maleic anhydride (SMA). The copolymer was synthesized by solution polymerization method,with benzoyl peroxide (BPO) as initiator and xylene as solvent, and using the yield of copolymer as evaluation criteria, the reaction conditions were researched. The maleic anhydride of molar fraction was 45% in the copolymer measured by chemical titration, combined with the theoretical that the synthesis of styrene-maleic anhydride copolymer was confirmed to be the alternating copolymer. The structure and character of the copolymer was also confirmed by IR. The glass-transition temperature of the alternating copolymer was tested by DSC.

Abstract: Copolymerization of MAn and CHDDVE was conducted by using azobisisobutyronitrile (AIBN) or benzoyl peroxide (BPO) as the initiator, ethyl acetate (EA) or n-butyl acetate (BA) as the solvent, and n-hexane as the precipitator. Effects of several factors on monomer conversion were studied, such as reaction time, reaction temperature, composition of the monomer feed (MAn/CHDDVE) and initiator concentration. Molecular weight and its polydispersity and polymer material morphology were characterized by gel permeation chromatography (GPC) and transmission electron microscope (TEM) technologies, respectively. It was demonstrated that CTC was formed in MAn/CHDDVE system, based on ultraviolet-visible spectroscopy (UV-vis) analysis. The product was alternating copolymer with high crosslinking degree, so it could not be dissolved in common solvents, e.g. water, chloroform, N, N-dimethyl formamide (DMF), tetrahydrofuran (THF) and acetone (Ac).