Reaction System, Initiation, Process and Application of Frontal Polymerization

Frontal polymerization (FP) is a synthesis process in which a localized reaction propagates directionally through the reactor. Compared with batch polymerization, FP is a simple, quick, energy-saving way to produce polymerization materials with distinctive properties. It is a new promising method for preparing functional materials and structural materials. In this paper, research progress on the reaction system, ignition, process, application and problems of FP are summarized. Some achievements of frontal polymerization in recent ten years are reviewed emphatically. Besides the free radical polymerization, there are more and more new frontal polymerization systems, such as binary-phase and multi-phase systems, ionic liquid monomer systems and deep eutectic solvents systems. More and more assistant agents, such as fillers, cross-linking agents, chain transfer agents, activators, thickening agents, surfactants and catalysts, are added to frontal polymerization and play an important role on the polymerization process and structure and property of polymers. New initiators, such as photo-initiators, ionic liquid initiators and other specially designed initiators, are described here. New initiation modes, such as UV, water, plasma and coupling ignition, are also discussed. Two new special processes of frontal polymerization are included. At last, the problems of frontal polymerization and the research area of commercializing the frontal polymerization are proposed.