Improved tensile properties of laminates by hot-press tackifying using vacuum-assisted resin transfer molding and autoclave

Abstract

A hot-press tackifying process was used to improve the mechanical properties of cured laminates in vacuum-assisted resin transfer molding by placing a thermoplastic film into the preforms at various pressures and temperatures. Three modified preforms were prepared at 0.1, 0.3, and 0.6 MPa using an autoclave, and the laminates were then produced via vacuum-assisted resin transfer molding. The mechanical properties of the modified laminates were tested and compared to those of the unmodified ones. The fiber volume fractions of the modified laminates decreased with increasing pressure. The tensile strength of the modified laminates at the three pressures improved by 16.78%, 41.21%, and 29.47%, respectively, compared to the unmodified samples. Modified laminates at 0.3 MPa showed better results than those at 0.1 and 0.6 MPa, which were all better than the unmodified samples. The modulus of the modified laminates from vacuum-assisted resin transfer molding was improved by 2.48%, 19.01%, and 13.22%, respectively. The effect of the hot-press tackifying in improving the tensile strength and modulus of a laminate on a pre-impregnated laminate (prepreg) using the autoclave was studied and compared to that of the unmodified case. Here, the tensile strength increased by 32.5% and 12.3%, respectively.