Abstract: To improve the surface wettability of extruded polystyrene foams （XPSF） and introduce functional groups that can strengthen the reactions with mortar， polyurethane acrylate （PUA） with a micron thickness was coated on the XPSF surface using a UV-curing technology. The effect of tripropylene glycol diacrylate （TPGDA） on the performance of PUA coating and the bonding performance between the modified XPSF and mortar were investigated by using viscometry， Fourier-transformation infrared spectroscopy， static contact angle meter， and universal testing machine. The results indicated that the viscosity of PUA coating decreased along with a change in the micromorphology of the coating with an increase in the TPGDA content. The static contact angle of XPSF decreased from 90.78 ° to 55.00 °， which facilitated the spreading and wetting of mortar. The tensile strength of the XPSF/mortar composites increased at first and then decreased with increasing the TPGDA content. The composites obtained tensile strength of 0.213 MPa at a TPGDA content of 60 wt%. This result is 4.26 times higher than that of the blank sample. Their water?resistant tensile strength was further increased to 0.230 MPa after immersion in water and then drying for 7 days.

Key words: extruded polystyrene, polyurethane acrylate, surface modification, ultraviolet curing, tensile strength