Preparation And Properties Of Photoconductive Materials Of Poly(2-(carbazol-9-yl) Ethyl Methacrylate)

Polymer with carbazole group has widely been used in energy, national defense, information, medical, environmental protection, agriculture and other areas because of their excellent photoelectric properties and cavities conductive transmission properties. PVK with fine photoconductive characteristics is considered as the most adequately studied organic photoconductive materials. It has many shortcomings such as the high Tg, the poor film forming, great brittleness. So it greatly limits its research and application. In this article, the preparation method, technological conditions and photoconductivity property of poly[2-(cardazol-9-yl)ethyl methacrylate] were mainly studied. It will make a foundation for new polymer photoconductive materials research and application.In this paper, the 2-(cardazol-9-yl)ethyl methacrylate was synthesized by ester-exchange method and nucleophilic substitution method. Process feature of these two methods were mainly discussed. The ester-exchange method possesses the advantage of short time in making CEM. The nucleophilic substitution method has the simple aftertreatment procedure and the raw material of chlorine ethyl carbazole (by microwave) easy obtaining. The optimum process conditions of chlorine ethyl carbazole (by microwave) were that the reaction temperature of 45℃, reaction time of 40min, microwave power of 600W and under stirring conditions. Compared with conventional heating method, the microwave heating method in making chlorine ethyl carbazole has advantages of short reaction time, low temperature, high yield.The technological conditions of synthetizing poly[2-(cardazol-9-yl) ethyl methacrylate] were systematicly studied. The appropriate technological conditions were obtained as follows: CEM as the raw material, DMF as the reaction solvent , reaction temperature at 85℃, reaction time for 14h, dosage of initiator AIBN for 0.005g.Synthetic products were analyzed by UV-Vis, FT-IR, 1HNMR and GPC. The property of PCEM was studied by DSC and film forming. The results show that number-average molecular weight of PCEM is 2.9089×104g/mol. Tg of PCEM(145.2℃) is lower than that of PVK (185.4℃). The film forming of PCEM is better than PVK. By contrast with PVK, the photoconductive property of poly [2-(cardazol-9-yl)ethyl methacrylate] was studied by photoconductive testing. The analysis showed that the photoconductivity of PCEM is slightly stronger than PVK under the same conditions. The photoconductivity of PCEM was affected by reaction time and reaction temperature. The maximum photoconductivity of PCEM is 5.469×10-18 S·cm-1 when reaction time is 14h and reaction temperature is 85℃.