Study on the effect of hybrid fiber length on tensile strength of sealing composites

The present paper aims at investigating the relationship between fiber length of hybrid fibers and the tensile strength of sealing composite materials. First, three kinds of fibers: cellulose fiber, aramid pulp fiber, and mineral wool fiber were sieved and their weight-average length was measured. Second, a uniform design method of U8 (4(3)) was adopted to prepare sealing composites by the beater-addition process, and the properties of the tensile strength of the composite were examined. In the end, the relation model was concluded and verified using multi-linear regression analyzation and was further analyzed using micro mechanic theory and interfacial bonding mechanism. The results show that the regression equation can be used to estimate the tensile strength of composites with different hybrid fiber lengths. The tensile strength increased corresponding to the increase of the length of the cellulose fiber but decreased with the increase of the length of aramid pulp and mineral wool fiber. Particularly the fiber length of aramid pulp fiber had the most significant effect on tensile properties. The cases were decided by the comprehensive effects of fibers dispersion, interfacial bonding, and micromechanics.