STUDY ON IMPROVEMENT OF MECHANICAL PROPERTIES OF CFRP DUE TO RUBBER MODIFICATION OF EPOXY MATRIX USING SUBMICRON SPHERES

首先，为了获得亚微米CNBR（交联丙烯腈丁腈橡胶：直径70-100 nm）改性橡胶对环氧树脂与基体之间界面强度性能的改善信息，使用DCB样品测试了一种环氧树脂在静态和循环模式下的粘附强度。实验结果表明，CNBR体积分数为10%时，环氧树脂的粘接强度最大。在静载荷和循环载荷作用下，当疲劳裂纹扩展速率较高时，CNBR橡胶改性能显著提高界面强度。两种情况下，界面破坏均发生在低裂纹速度及接近阈值的情况下。在这种情况下，由于橡胶改性，阈值没有提高。以Crabon织物为材料，研究了环氧基橡胶改性对CFRP强度和性能的影响。研究中使用的层压板采用手工叠层法制备。测试了静载荷下的拉伸和抗压强度、不同温度下的疲劳强度以及模式I载荷下的层间强度。从实验中得出以下结论。CNBR改性后的I型层间强度（断裂韧性）在较宽的环境温度范围内得到了很大的提高。这比未修改的病例高出两倍多。冲击强度也得到了提高，同时在任何测试温度下的拉伸强度降低以及在压缩中发生。CNBR改性也没有降低Tg（玻璃化转变温度）。这是在拉伸和抗压强度性能没有退化的原因之一。环氧基CNBR改性对CFRP的疲劳寿命影响不大。由于含有亚微米CNBR球，发现任何寿命减少。少

Firstly, in order to obtain information on improvement of interfacial strength properties between rpoxy eesin and substrate due to rubber modification using submicron CNBR (Cross-linked acrylo Nitrile Butadiene Rubber : 70-100 nm in diameter) spheres, adhesive strenghts of an epoxy resin under Mode I loadings (both static and cyclic) were examined using DCB specimens. The experimental results revealed that The adhesive strength of the epoxy resin became maximum when the CNBR volume fraction was 10%. The interfacial strengths were greatly improved due to CNBR rubber modification under static loading as well as under cyclic loading when the fatigue crack growth rate was relatively high. In both cases, fracture occurred in a cohesive manner while interfacial failure occurred at low crack velocity including near threshold. In this case, the threshold was not improved due to rubber modification.Crabon fabric was used to evaluate the effect of rubber modification of epoxy matrix on strength … More properties of CFRP.The laminates used in the study were fabricated by the hand-lay-up method. Tensile and compressive strenghts under static loading and fatigue strength at several temperatures were measured as well as inter-laminar strength under Mode I loading. The following conclusions were drawn from the experiment. Mode I inter-laminar strength (fracture toughness) is greatly improved due to CNBR modification at a wide range of environmental temperature. It is more than two times higher than that for unmodified cases. Impact strength is also improved while on strength reduction in tension at any test temperature occurs as well as in compression. No reduction in Tg (glassy transition temperature) due to CNBR modification is found as well. That is one of reason for no degradaiton in both tensile and compressive strength properties. CNBR modification of epoxy matrix does not badly affects on the fatigue life of CFRP.Any life reduction was found due to inclusion of submicron spheres of CNBR. Less