Three-dimensional orthogonal nonwoven single polymer composite

Abstract

This paper describes the production and bending properties of three-dimensional orthogonal single polymer composites made from axial–braider commingling yarns where the braider yarns are completely melted to produce the matrix phase. The research was demonstrated using poly(lactic acid) yarn as an example. The optimum linear density ratio of braider and axial yarn was prescreened. The effects of consolidation temperature, pressure, and preform thickness on the bending properties were investigated by Environment Scanning Electron Microscope (ESEM) observations and mechanical bending tests. The results showed that the best bending properties of single poly(lactic acid) composite were detected in the braider–axial yarns ratio of 5/6. At this ratio, the increase of the consolidation temperature was to improve the bending properties (from 145 to 160℃), while it markedly decreased at 165℃. As the processing pressure increased, a remarkable improvement in the interfacial bonding between fibers and matrix occurred at a pressure of around 8 MPa. The increase of preform thickness gave rise to higher fiber volume fraction in the single poly(lactic acid) composite, with the result that the peak values of maximum stress and modulus were obtained at the preform thickness of 9 mm.