Application of Polymer Materials in Shear Thickening Gel-based Impact Protective Knee Pads for Martial Arts

Abstract

Martial arts exercise causes significant wear and tear on the knee joint. The existing anti-collision knee pads are insufficient to meet the requirements of wearing comfort and mechanical performance. Therefore, a composite material based on shear thickening gel (STG) is proposed. The preparation process of this material is doped with polyester short fibers and multi-walled carbon nanotubes (MWNT). The composite is filled into naturally structured Kevlar flat weave fabric (Kevlar) to enhance the mechanical properties of the pure fabric. The results indicated that the MWNT/STG/Kevlar composite material prepared by the proposed method effectively enhanced the dynamic properties of the shear thickening agent. The worst fracture strength and displacement were 600 N and 38 mm, respectively, both of which complied with national standards. The bending performance was 10.2 % and 14.2 % higher than the other two composite materials. The average air permeability was 190 mm/s, which was 60 % and 78 % higher than the other two materials, respectively. The impact resistance performance decreased by 42 %, 54 %, 57 %, and 68 % compared with the other three knee pads, respectively. Therefore, the MWNT/STG/Kevlar composite material prepared by the proposed method can be applied in the knee pad preparation process, effectively increasing the mechanical properties of the knee pad, preventing impact during martial arts exercise, and improving the wear comfort.