Implementation of a high-pressure resin transfer molding (HP-RTM) process to increase the production rate of structural composites and characterization of sustainable vitrimer-matrix high-performance composites

Builes Cárdenas, Cristian
Transport industry, especially automotive, is one of the most pollutant in the world. Current environmental concerns demand original equipment manufacturers (OEM’s) to reduce the amount of emissions released by their vehicles, requiring more green alternatives to mobility. By reducing the overall vehicle weight, it will be diminished the total amount of pollution for conventional combustion engine vehicles, or increase the autonomy of electric – hybrid vehicles, being the carbon fiber reinforced polymers (CFRP) the best option to reduce overall structural weight. Thermoset CFRP offer many advantages over traditional automotive materials as steel or aluminum due to their high mechanical strength, high chemical and thermal resistance, dimensional stability and high durability under harsh conditions. But production of high performance CFRP has been limited to time and energy consuming methods as autoclave. Out of autoclave (OoA) solutions as RTM have become interesting manufacturing processes, being cheaper and presenting energetical, economical and logistics savings in comparison. However, these OoA processes have limitations as long cycle times (specially filling and curing times), limiting the use of high-reactivity resins and making these processes unreliable to be considered for high-volume industries as the automotive, which needs very short cycle times (≈5 minutes). Other process steps as preforming or mold preparation also are time consuming, in which automation becomes a key factor to reduce overall processing time. Moreover, CFRP are very expensive compared with traditional materials, as the raw fibers alone represent almost half of the total component cost, requiring high-volume manufacturing alternatives to overcome this issue. Furthermore, the current demand of CFRP structures is creating concerns about the amount of waste that these materials would generate in the future, as thermoset polymers are very complex to recycle. Separating the fibers from the matrix implies damaging the reinforcement and reducing their mechanical properties. In addition to current disposal solutions also implying environmental and economic concerns. This thesis aims to explore the high-pressure resin transfer molding process (HP-RTM) as a feasible alternative to produce high performance CFRP in short cycle times. Additionally, it is complemented by using a new high-performance vitrimer polymer that presents thermoset-like performance while being reprocessable, reconformable and recyclable ​
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