Development of epoxy resin-bamboo composites through toughening modification of epoxy resin

The development of high-performance epoxy resin-bamboo composites is of great significance in the context of the "Replace Plastic with Bamboo". The integration of epoxy resin (EP) with bamboo yields composites exhibiting high strength and low shrinkage; however, these materials typically exhibit limitations such as excessive brittleness and inadequate weathering resistance, necessitating further optimization. Toughening modification of EP represents effective approaches to enhance the performance of bamboo-epoxy composites. Here, thermoplastic polyurethane (TPU) and polyether sulfone (PES) were selected as toughening agents, creating two types of toughened epoxy systems. These modified resins were then combined with bamboo to produce bamboo-epoxy composites (EP-TPU/BF or EP-PES/BF). Comparative results show that while both agents improve the composite properties to some extent, TPU induces much more pronounced enhancements in mechanical performance than PES. The EP-TPU/BF composite demonstrates exceptional mechanical properties, achieving flexural strength of 286.2 MPa, tensile strength of 258.93 MPa, elastic modulus of 9.7 GPa, and toughness of 37.91 MJ/m³. These values represent increases of 101.3 %, 30.7 %, 76 %, and 104 %, respectively, compared to the EP/BF. The toughening mechanism of TPU involves enhancing interfacial adhesion, reducing phase separation, and effectively absorbing energy associated with crack formation and propagation. These findings highlight TPU as a more effective toughening agent than PES for developing high-performance bamboo-epoxy composites. These improvements expand the applications of bamboo-based composites for construction, offering a promising strategy for eco-friendly material development and utilization of bamboos.