| The copolymer of alkyl vinyl ether and maleic anhydride is a water-soluble polymerelectrolyte, which has good chemical stability, adhesion, water retention and is non-toxic tohumans. It is widely used in the field of chemical engineering, medicine, cosmetics industry,and so on. For example, the copolymer of alkyl vinyl ether and maleic anhydride can used asfixative of denture in medicine area and it’s an important component of insecticide, phytocidein agriculture. The synthetic technique of the copolymer of alkyl vinyl ether and maleicanhydride began in the1950s. Normally, the copolymerization of maleic anhydride and vinylethyl ether was in organic solvent, polymer and organic solvent could not be separatedthoroughly after the reaction and volatile solvent could cause air pollution. By contrast, if theorganic solvent could be replaced by supercritical carbon dioxide, the after-processing of thecopolymer was very easy and the copolymer could not be polluted with organic solvent.A copolymer of maleic anhydride（MA） and ethyl vinyl ether （EVE） was prepared usingsupercritical carbon dioxide（scCO2） as reaction medium. The influencing factors of thereaction such as reaction time and reaction pressure were researched. The copolymer wascharacterized by Fourier transforminfrared spectroscopy （FTIR）, gel permeationchromatography （GPC）, differential scanning calorimetry （DSC）, and thermogravimetricanalysis （TGA）. The result showed that the copolymer of MA and EVE has strict alternatestructure and the molecular weight of the copolymer synthesized in scCO2was higher than thecopolymer synthesized in organic solvent. Glass transition temperature of the copolymer wasabout150℃and the degradation temperature of the copolymer was about251℃.We also synthesized the copolymer of maleic anhydride, ethyl vinyl ether and styrene（St）in supercritical carbon dioxide. The influencing factors of the reaction such as reaction timeand reaction pressure were researched. The copolymer was characterized by Fouriertransforminfrared spectroscopy （FTIR）, gel permeation chromatography （GPC）, differentialscanning calorimetry （DSC）, and thermogravimetric analysis （TGA）. The result showed thatthe styrene has higher activity than ethyl vinyl ether in the systerm of maleic anhydride, ethylvinyl ether and styrene, styrene has priority to copolymerize with maleic anhydride. Thestructure of the copolymer has two kinds of structure, one structure was MA-St and the other structure was MA-EVE. Glass transition temperature of the copolymer was about154℃andthe degradation temperature of the copolymer was about270℃.We synthesized the coating thickener using the copolymer of MA and EVE as thickeningcomponents. The influencing factors of the reaction such as reaction time and reactiontemperature were researched and we screen out the best coating thickener. |
