Continuous fiber reinforced thermoplastic composite pultrusion with in situ polymerizable methyl methacrylate: A review

Compared to thermosetting resins, thermoplastic polymers offer many advantages as fiber reinforced composite matrices, such as excellent toughness, superior corrosion resistance, weldability, and recyclable, etc. However, the processibility of thermoplastic composites is commonly considered as a challenge because of the high viscosity of polymer melts (e.g., polypropylene, polyetheretherketone, etc.), which remarkably hinders their applications. Using low viscosity and in situ polymerizable thermoplastic resins to manufacture continuous fiber reinforced thermoplastic composites have been deemed as a cost-effective emerging approach to surpass the processibility challenges. Therefore, this paper presents an overview of advancement in the engineering, high-performance and room-temperature-processible liquid methyl methacrylate (MMA) resins and their composites up to date. First, the polymerization behavior and kinetic modeling of the MMA resins are reviewed, and the effects of initiators on the polymerization are summarized. In the second part, the pultrusion process and modeling including impregnation, temperature distribution and pulling force are discussed. Next, the mechanical properties and durability of the carbon fiber-, glass fiber-reinforced MMA-matrix composites are presented. Finally, the challenges of the preparation and application of the MMA-matrix composites are identified.