Synthesis And Characterization Of PH-sensitive Rosin Polymers And Its Conformational Change Research

Three kinds of pH-sensitive rosin polymers were synthesized and their conformational transitions were investigated. The experiment of this article includes four parts.1. Dehydroabietic acid hydroxybutyl vinyl ether ester was prepared by Steglich Esterification method. And its composition and structure was characterized by IR and 1HNMR and so on. Then dehydroabietic acid(hydroxyl vinyl butyl ether) ester-acrylic acid copolymer was synthesized. The copolymer of structure was characterized by IR and 1HNMR. Its molecular weight and coefficient of dispersion was determined by GPC. Besides, its decomposition temperature was determined by Thermogravimetric Analysis.2. Dehydroabietic acid(hydroxyethyl methacrylate) ester was prepared by the way of chloride and esterification methods. Copolymer was prepared with dehydroabietic acid(hydroxyethyl methacrylate) ester and acrylic acid, The structure of ester and copolymer were characterized by Modern instrumental analysis methods, such as IR, 1HNMR, and etc. The molecular weight and the thermal decomposition temperature of the copolymer were measured.3. The Dehydroabietic alcohol obtained by Redox reaction was grafted on polyacrylic acid by Steglch Esterification. The graft polymer was characterized. The Molecular weight of polyacrylate was measured by base Titrimetric Analysis and its thermal decomposition temperature was determined by TG.4. The conformational transitions of above mentioned three pH-sensitive rosin polymers were performed at different pH and temperature. It was found that when pH is 6.32 or when the temperature reaches 1oC, dehydroabietic acid(hydroxyl vinyl butyl ether) ester-acrylic acid copolymer molecular chain begin to crimp. When the pH is 5.0 or a temperature of 17 oC, dehydroabietic acid hydroxyethyl methacrylate-acrylic acid copolymer molecular chains produce conformational transition. And when the pH is 7.96 or temperature reaches 5 oC, Dehydroabietic alcohol modified polyacrylic acid chains shrink, the polymer begins to gather.