Abstract:The homogenization method was used to prepare the fibrillated Lyocell fiber, and the effect of different initial fiber lengths on the fibrillation degree of Lyocell fiber was studied. On this basis, the fibrillated Lyocell/polylactic acid (PLA) composites were prepared by melt blending and injection molding, and the effect of initial fiber length on the structure and properties of fibrillated Lyocell/PLA composites were investigated. The results show that the longer the initial fiber length is, the lower the fibrillation degree of the fiber under the same treatment conditions is. The fibrillation of Lyocell fibers improves the interfacial bonding between fibers and matrix, thereby further increases the mechanical properties of composites. The initial fiber length has no significant effect on the tensile properties of fibrillated Lyocell/PLA composites, whereas the fibrillated Lyocell/PLA composite with the initial length of 4 mm shows the highest notch impact strength, which is 19.0% higher than that of the non-fibrillated composite. In addition, the Vicat softening temperature of the Lyocell/PLA composite can be further increased by the fibrillation of Lyocell fiber. The fibrillated Lyocell/PLA composite with the initial fiber length of 10 mm shows the highest Vicat softening temperature of 161.4 ℃.