Research For Radical Polymerization Of Styrene/methyl Methacrylate Mediated By Xanthene-9-thione/Xanthene-9- Thioether

Controlled/living radical polymerization system methods rely on a dynamic equilibrium between the dormant chains and the propagating radicals via a reversible deactivation mechanism, and they show great potential for biological, optical and electronic applications thanks to a superior ability for the synthesis of structurally well-defined polymeric molecules.Our research group developed radical polymerization of styrene/methyl methacrylate mediated by xanthene-9-thione, found that its controllability was obviously better than Thioketone mediated polymerization ( TKMP )?So we inferred that the formation of addition free radicals with C=S of xanthene-9-thione to form stable tertiary carbon radicals play a major role in the regulation of polymerization.In the process of St/MMA polymerization mediated by Xanthene-9-Thione via two-step method, the best condition : toluene? St concentration 50% at 65 ? with I/TK/M =2:1:5, and the results show Mn increasing from 14 k to 22 k with PDI between 1.51 to 1.91; the best condition : THF?MMA concentration 50% at 65 ? with I/TK/M -2:1:5, and the results show Mn increasing from 23k to 35k with PDI between 1.61 to 1.65. The results show that St/MMA polymerization mediated by intermediates. The intermediates is deduced to small molecule thioether.From the oligomer structure formed by the polymerization process, the synthesis of small molecule thioether. The synthesis of small molecule sulfide system was used to mediate the polymerization of St / MMA in different solvents under the condition of separate use or ABVN.In the process of St/MMA polymerization mediated by small molecule thioether (PEPTX ),the best condition : toluene?MMA concentration 30 % at 65 ? with I/TK =0.5, and the results show Mn increasing from 38 k to 58 k with PDI at 1.71; the best condition : toluene? St concentration 30 % at 65 ? with I/TK =0.5, and the results show Mn increasing from 36 k to 63 k with PDI at 1.69. It show that St/MMA polymerization can be well mediated by PEPTX.In the process of St/MMA polymerization mediated small molecule thioether (EMOXM), the results show that St/MMA polymerization can be not mediated by EMOXM.