Enhancing the Raveling Resistance of Polyurethane Mixture: From the Perspective of Polyurethane Adhesive

Polyurethane mixture, made of waste rubber particle, aggregate, and polyurethane adhesive, has low raveling resistance which affects the durability of the mixture. The objective of this study is to enhance the raveling resistance of polyurethane mixture. The content of polyol in the hydroxyl component was determined by Fourier transform infrared spectroscopy. The suitable curing conditions for polyurethane adhesive to enhance the raveling resistance were selected by the orthogonal experiment and mechanical tests. The relationship of the raveling resistance with crosslink density and elastic modulus was tested and calculated through the wear test. The results showed that when the ratios of the isocyanate component to the hydroxyl component were 1:3.2, 1:6.3, and 1:9.5, respectively, the isocyanate component was excessive. The ranking of the significance of the influence factors, from high to low, was first the curing temperature, then curing time, and finally the blending ratio; within the ranges of blending ratio, curing temperature, and curing time selected in this study, the appropriate blending ratio was 10:2, and the curing time was 6 h. For the polyurethane mixture involved in this study to obtain high raveling resistance, if a crosslinking agent or a new polyurethane adhesive is added, the tensile strength and tensile elastic modulus should be in the range of 3.02 to 3.27 MPa and 5.50 to 6.02 MPa, respectively; when using the FS2 polyurethane adhesive directly, the suitable curing conditions for the mixture are 90 °C and 6 h or 80 °C and 6 h. The results from this study could be beneficial for obtaining a high raveling resistance for the polyurethane mixture.