Properties of glass fiber polypropylene composites produced from split-warp-knit textile preforms

Properties of uniaxial and biaxial glass fiber/polypropylene composites bas ed on split-warp-knit textile preforms and produced under various consolida tion conditions were investigated. Consolidation was carried out at T = 210 -260 degrees C, P = 1-3 MPa and t = 5-15 min, and the impact of each variab le was studied by 3(2) full factorial experimental design. The analysis of variance of the obtained results has shown the different influence of the a nalyzed process conditions on the longitudinal and transverse properties of uniaxial composites, with both temperature and pressure being of high sign ificance level. Higher longitudinal tensile properties were achieved after pressing at 240 degrees C and 3 MPa (15 min). However, for biaxial composit es, similar values for tensile properties were obtained For samples pressed at 210, 225 and 240 degrees C (under 1-3 MPa). The role of PET stitching y arns is demonstrated in anisotropy of tensile strength for biaxial composit es.