Effects of RAFT Agent on the Chloromethylstyrene Polymerizations in a Simultaneous Radiation Grafting System.

Jinhua Chen,Noriaki Seko

doi:10.3390/polym9080307

Abstract

Reversible addition-fragmentation chain transfer (RAFT) agent was added into a simultaneous radiation grafting system and its effects on graft polymerization and homopolymerization were investigated. Chloromethylstyrene (CMS) was graft polymerized onto ethylene-tetrafluoroethylene copolymer (ETFE) films under γ-ray sources via simultaneous irradiation. The non-grafted poly(CMS) in the grafted films were extracted by xylene at 120 °C. The poly(CMS) was characterized by NMR and GPC instruments. Addition of the RAFT agent suppressed both graft polymerization and homopolymerization. However, under a high concentration of RAFT agent, the homopolymerization in the monomer solution could occur through a typical RAFT polymerization while polymerization in the ETFE films proceeded via RAFT and conventional radical polymerization, resulting in poly(CMS) in the ETFE films with molecular weight dispersity higher than 1.0 but lower than that without RAFT agent. Furthermore, it was found that the molecular weight of the poly(CMS) in the ETFE films was several times higher than that of the poly(CMS) in the monomer solution.

Highlights

Reversible addition fragmentation chain transfer (RAFT) polymerization is a reversible deactivation radical polymerization (RDRP) that can provide living characteristics for precise synthesis of polymers with well-defined constructs and designed molecular weights [1,2,3,4]
We found that a considerable amount of poly(CMS) could be extracted from the grafted ethylene-tetrafluoroethylene copolymer (ETFE) films by xylene at 120 ◦ C
Scheme 1 shows the process for the simultaneous radiation grafting of CMS monomer onto

Summary

Introduction

Reversible addition fragmentation chain transfer (RAFT) polymerization is a reversible deactivation radical polymerization (RDRP) that can provide living characteristics for precise synthesis of polymers with well-defined constructs and designed molecular weights [1,2,3,4]. Thiocarbonylthio compounds, having the general structure S=C(Z)SR, where the R and Z are leaving group and activating group, respectively, are usually used as RAFT agents. RAFT polymerization is a dynamic equilibrium between active radicals (propagating radicals) and dormant radicals via the reversible addition-fragmentation of the thiocarbonylthio groups. Radiation grafting can introduce new properties, such as proton-conductivity, ion-exchange, and catalytic ability, into existing polymer films while maintaining their inherent characteristics. Radiation grafting has been widely employed for the development of polymer electrolyte membranes for fuel cells and absorbents for recovery of metal ions [14,15]

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Conclusion