The Research On Copolymerization Of N-Substituted Maleimide With Active Side-group And Styrene Based On RAFT Process

In this article, several methods of living polymerization and the developing trends of the methods and N-substituted maleimide were summarized. Then,the copolymerization of styene and N-substituted maleimide with active side-group such as carboxyl and hydroxyl were investigated by the process of reversible addition fragmentation chain transfer(RAFT).The polymers of N-(4-carboxyphenyl) maleimide and styrene (P-CPMI-St), N-(4-hydroxyphenyl) maleimide and styrene (P-HPMI-St) with narrow polydispersities were synthesized successfully (Mw/Mn<1.5). The result was proved by the measure of infrared spectroscopy (IR), nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC).The connection of time with coversion and the value of Ln[M]0/[M]t was researched,the results showed that with the time increased, the conversion and the value of Ln[M]0/[M]t increased linearly. It proved that there was an invariable concentration of the free radical during the processing of the polymerization.So, the copolymerization is controlled.Furthemore, we found that the temperature was the influncing factor of the conversion, and the concentration of the RAFT agent is the influcing factor of the polydispersities. If the concentration of the RAFT agent was increased, the polydispersities woule be narrow, and the molecular weight would be minished, too.The thermodynamic properties of P-CPMI-St and P-HPMI-St were researched by different scanning calorimrtry (DSC) and thermogravimetry (TG). It showed that the polymers were well heat-resisitant and the T10% of P-CPMI-St and P-HPMI-St were 361℃and382℃. Compared with the product synthesized by conventional free-radiacal polymerization, the glass temperature of P-HPMI-St from RAFT process was higher than the former(ΔT=6K) because of the narrow polydispersities and the disciplinary structure.The polymerization of methyl acrylate(MA) were researched,from the result of their GPC, we knowed that P-CPMI-St and P-HPMI-St were active as the new RAFT agents in the copolymerization because of theirthiocarbonylthio group.Results show that P-CPMI-St and P-HPMI-St synthesized by RAFT process are not only well heat-resistant, but also very active in the next polymerization, which is very important for synthesizing the new functional marcromolecular materials.