The Study On Toughening Modification Of Resin Matrix Composites

In order to improve the toughness of epoxy resin, in this work, AlOOH, polystyrene nanospheres (PS), carbon nanotubes (CNTs) which is regarded as a toughening agent added to the resin matrix to improve the toughness of the resin. However, poor dispersion quality of CNTs in polymer matrix and weak interfacial force between them commonly lead to low reinforcing efficiency, amino modified CNTs is necessary to to improve the dispersion in the resin, the amination of CNTs was achieved via a wet chemical procedure using 1,6-diaminohexane(DAH) as amine source; polystyrene nanospheres can easily reunite in the resin matrix due to phase separation in the curing process, amination treatment were firstly done on them. The tensile strength, fracture toughness, fracture surface of modified resin and toughening mechanism were studied.The tensile test result of AlOOH/epoxy nanocomposites shows that when 4 wt% AlOOH was added to epoxy resin, the tensile strength of AlOOH/epoxy nanocomposites can increase from 62.92MPa to 78.17MPa, and the fracture toughness and bending strength of the modified resin increase by 28.7% and 22.2%, respectively. The fracture surfaces was measured by scanning electron microscope(SEM), a phase-separated morphology and plenty of cervices and river branches were observed in the fracture surfaces of composites. At the same time, with the increase of sheet AlOOH content, river-shaped cracks became more and more intensive.Fourier transform infrared spectroscopy, zeta potential test, and thermogravimetric analysis were employed to investigate the aminated CNTs and PS, the results show that amine groups have been successfully grafted to the surface of CNTs and PS, respectively. SEM observation suggests that aminated CNTs and PS are uniformly disperse in prepared epoxy blends, respectively. Mechanical properties tests suggest that the tensile strength and fracture toughness of the obtained CNT-NH2/epoxy composite are all enhanced compared with cured pure epoxy resin. The tensile strength and fracture toughness of the as-prepared CNT-NH2/epoxy composite with 0.8 wt% CNT-NH2 show 42% and 95% improvement, respectively. Similarly, The tensile strength and fracture toughness of the 15 wt% aminated PS spheres/epoxy polymer blends are 74.5 MPa and 2.23 MPa·m1/2, compared with cured pure epoxy polymer, they are increased by 25.6% and 84.3%, respectively. Excellent dispersion properties in epoxy matrix and increased interfacial force with epoxy matrix play a crucial role in the aminated PS spheres on toughening epoxy polymer.