Monomer Selection for In Situ Polymerization Infusion Manufacture of Natural-Fiber Reinforced Thermoplastic-Matrix Marine Composites

Abstract

Awareness of environmental issues has led to increasing interest from composite researchers in using “greener” materials to replace synthetic fiber reinforcements and petrochemical polymer matrices. Natural fiber bio-based thermoplastic composites could be an appropriate choice with advantages including reducing environmental impacts, using renewable resources and being recyclable. The choice of polymer matrix will significantly affect the cost, manufacturing process, mechanical properties and durability of the composite system. The criteria for appropriate monomers are based on the processing temperature and viscosity, polymer mechanical properties, recyclability, etc. This review considers the selection of thermoplastic monomers suitable for in situ polymerization during resin, now monomer, infusion under flexible tooling (RIFT, now MIFT), with a primary focus on marine composite applications. Given the systems currently available, methyl methacrylate (MMA) may be the most suitable monomer, especially for marine composites. MMA has low process temperatures, a long open window for infusion, and low moisture absorption. However, end-of-life recovery may be limited to matrix depolymerization. Bio-based MMA is likely to become commercially available in a few years. Polylactide (PLA) is an alternative infusible monomer, but the relatively high processing temperature may require expensive consumable materials and could compromise natural fiber properties.

Reactive Processing of Acrylic-Based Thermoplastic Composites: A Mini-Review

“…A crucial disadvantage of such thermoplastic systems is the requirement of high processing temperature, for example above 150 °C for PA-6 and PA-12, 180 °C for PBT and 270 °C for TPU to achieve a viscosity of a few Pa.s (Figure 1). Qin et al made a review of the processing temperature and the corresponding viscosity of commercially available thermoplastic monomers for in-situ polymerization, including several bio-based monomers suitable for reactive processing of polymers such as PA-6 and polylactide (PLA), and reported a similar conclusion (Qin et al, 2020).…”

“…The only material for in situ polymerization at room temperature which is available in the market is Elium ® (Gardiner, 2015) (Qin et al, 2020) (Miranda Campos et al, 2022. Elium ® acrylic resin is a mixture of 2-Propenoic acid, 2-methyl-, methyl ester or methylmethacrylate monomer (MMA) and acrylic copolymers.…”

The 100 m Composite Ship?

“…Qin et al [78] have reviewed monomer selection for in situ polymerisation (ISP) during monomer infusion under flexible tooling (MIFT) manufacture of natural-fibre reinforced thermoplastic-matrix marine composites. Arhant and Davies [79] have reviewed the current status of materials, manufacturing methods, and durability of thermoplastic matrix composites for marine structures.…”

ED-ROP of macrocyclic oligomers: A synthetic tool for multicomponent polymer materials

“…Much less work has been devoted in the literature to composite materials prepared using macrocycles other than CBT. 54 More dated research regarded composites containing carbon fibers or nanofibers were obtained by starting from cyclic polycarbonate oligomers, 11,96,97 while more recent works reported the use of cyclic (arylene disulfide) oligomers 98 and aryl ether ketone macrocycles. 99 Song et al 98 prepared composites of poly(arylene disulfide) (PADS) reinforced with short CF by in-situ ED-ROP of cyclo(4,4'-oxybis(benzene)disulfide) (COBDS, see Chart 1) upon melt molding carried out in air at 200 °C for 30 min without catalyst.…”

“…Therefore, cyclic oligomers can be usefully added in minor amounts to intentionally lower the polymer melt viscosity during its processing without however affecting the final material properties, since, by raising the temperature, MCOs undergo spontaneous ring opening (the source of end groups being the admixed linear polymer chains) to give exactly the same macromolecules constituting the parent polymer. 49 Over the past dozen years, ED-ROP and related topics have been discussed in several review works, some of them being of a general purpose, 14,25 others focusing on the various polymerization techniques, 50 such as the "cousin" entropically-driven ring-opening metathesis polymerization (ED-ROMP) process, 51,52 others on applications of the resulting materials, 51,53,54 reactivity of the most developed cyclic oligomers, i.e., cyclic butylene terephthalate, 26,53,55 combination of CDP plus ED-ROP for polymer recycling, 56 and ring opening of macrocyclic oligo esters obtained from renewable resources. 27 In this review, the effectiveness of ED-ROP of MCOs as an efficient and versatile synthetic tool either to achieve multicomponent polymer materials (copolymers, blends, composites and nanocomposites) or facilitate their processing, compatibilization, properties modification or recycling is demonstrated through selected, representative examples, mostly taken from recent literature.…”