Unidirectional carbon fiber-reinforced epoxy (UCFRE) is suffering from weak transverse mechanical properties and through-thickness properties. The effect of different amount (0.1, 0.3 and 0.5 phr which is proportional to 0.09, 0.27 and 0.46 wt%, respectively) of multiwall carbon nanotube (MWCNT), on transverse tensile properties, flexural strength, fracture toughness in transverse and longitudinal fiber directions, interlaminar shear strength and lap shear strength of UCFRE has been investigated. Dicyandiamide was used as a thermal curing agent of epoxy resin. MWCNT was dispersed in the epoxy resin by ultrasonic instrument and their dispersion state was investigated by scanning electron microscopy (SEM). The curing behavior of epoxy resin and its nanocomposites was assessed by differential scanning calorimetry. Results show that transverse tensile strength, modulus and strain-at-break were increased by 28.5%, 25% and 14%, respectively by adding 0.1 phr of MWCNT. Longitudinal flexural properties of UCFRE was not changed by adding different amount of MWCNT. Although longitudinal flexural strength was increased by 5% by adding 0.1 phr of MWCNT. Fracture toughness in transverse and longitudinal fiber directions was increased by 39% and 9%, respectively at 0.3 phr of MWCNT. Results also show that interlaminar shear strength and lap shear strength were increased at 0.3 phr of MWCNT by 8% and 5%, respectively. These increases in mechanical properties were due to the good adhesion of fibers to the matrix, interlocking and toughening action of MWCNT as revealed by SEM.

单向碳纤维增强环氧树脂（UCFRE）的横向机械性能和厚度均较弱。不同数量的多壁碳纳米管（MWCNT）的量（分别为0.1、0.3和0.5 phr，分别与0.09、0.27和0.46 wt％成比例）对横向拉伸性能，弯曲强度，横向和纵向纤维方向的断裂韧性的影响研究了UCFRE的层间剪切强度和搭接剪切强度。双氰胺用作环氧树脂的热固化剂。通过超声波仪器将MWCNT分散在环氧树脂中，并通过扫描电子显微镜（SEM）研究它们的分散状态。通过差示扫描量热法评估环氧树脂及其纳米复合材料的固化行为。结果表明，通过添加0.1 phr MWCNT，横向拉伸强度，模量和断裂应变分别提高了28.5％，25％和14％。通过添加不同数量的MWCNT，UCFRE的纵向挠曲特性没有改变。尽管通过添加0.1phr的MWCNT使纵向弯曲强度增加了5％。在MWCNT为0.3 phr时，纤维横向和纵向的断裂韧性分别提高了39％和9％。结果还表明，在0.3 phr MWCNT下，层间剪切强度和搭接剪切强度分别增加了8％和5％。这些机械性能的提高归因于纤维与基质的良好粘合性，SEM揭示的MWCNT的互锁和增韧作用。分别加入0.1 phr的MWCNT。通过添加不同数量的MWCNT，UCFRE的纵向挠曲特性没有改变。尽管通过添加0.1phr的MWCNT使纵向弯曲强度增加了5％。在MWCNT为0.3 phr时，纤维横向和纵向的断裂韧性分别提高了39％和9％。结果还表明，在0.3 phr MWCNT下，层间剪切强度和搭接剪切强度分别增加了8％和5％。这些机械性能的提高归因于纤维与基质的良好粘合性，SEM揭示的MWCNT的互锁和增韧作用。分别加入0.1 phr的MWCNT。通过添加不同数量的MWCNT，UCFRE的纵向挠曲特性没有改变。尽管通过添加0.1phr的MWCNT使纵向弯曲强度增加了5％。在MWCNT为0.3 phr时，纤维横向和纵向的断裂韧性分别提高了39％和9％。结果还表明，在0.3 phr MWCNT下，层间剪切强度和搭接剪切强度分别增加了8％和5％。这些机械性能的提高归因于纤维与基质的良好粘合性，SEM揭示的MWCNT的互锁和增韧作用。在MWCNT为0.3 phr时，纤维横向和纵向的断裂韧性分别提高了39％和9％。结果还表明，在0.3 phr MWCNT下，层间剪切强度和搭接剪切强度分别增加了8％和5％。这些机械性能的提高归因于纤维与基质的良好粘合性，SEM揭示的MWCNT的互锁和增韧作用。在MWCNT为0.3 phr时，纤维横向和纵向的断裂韧性分别提高了39％和9％。结果还表明，在0.3 phr MWCNT下，层间剪切强度和搭接剪切强度分别增加了8％和5％。这些机械性能的提高归因于纤维与基质的良好粘合性，SEM揭示的MWCNT的互锁和增韧作用。