硼酸酯动态键强韧化酚醛树脂基竹塑复合材料研究OA

To address the brittleness of phenolic resin after curing and the stress concentration at the interface of bamboo-plastic composites,this study proposes a synergistic crosslinking modification strategy based on dynamic covalent bonds.Phenylboronic acid(PBA)and hexamethylenetetramine(HMTA)were used as curing agents to prepare modified phenolic resin-based bamboo-plastic composites,and their mechanical properties,wettability,thermal stability,and recyclability were investigated.The results showed that when the mass ratio of novolac resin(NR),PBA,HMTA,and bamboo powder(Phyllostachys edulis)was 100∶15∶5.5∶60,the modified phenolic resin-based bamboo-plastic composites exhibited the best overall performance.The flexural strength,tensile strength,impact strength and fracture energy reached 124.60 MPa,31.40 MPa,3.63 kJ/m2,and 1 433.7 kJ/m3,respectively.Compared with HMTA-modified composites,the flexural strength and fracture energy increased by 43.7%and 168.3%,respectively,indicating that modification with boronate ester dynamic covalent bonds significantly improved both the strength and toughness of the composites.The reason could be attributed to the introduction of boronate ester bonds into the composites,which constructed a synergistic cross-linked network,enabling effective energy dissipation and achieving matrix and interfacial bonding strength improvement,thereby enhancing both strength and toughness of composites.In addition,the modified composites also exhibits excellent thermal stability and water resistance(the water absorption rate after 72 h was only 2.5%),and demonstrates good recyclability potential.This research can provide new approach for the development and utilization of high-performance and sustainable bio-based composites.