Interfacial properties of glass fiber/unsaturated polyester resin/poplar wood composites prepared with the prepreg/press process

Combining glass fiber-based composites to fast growing wood can remarkably enhance the mechanical properties of these wood materials, although it is really challenging to obtain an excellent adhesion between wood and commercial unsaturated polyester resin (UPR) composites even using structural adhesives. Herein, a Prepreg/Press process was investigated to prepare glass fiber/UPR/poplar wood composites by directly molding prepreg glass fiber onto the wood surface with the curing of the matrix. The effects of fabrication pressure and thickness gauge on the interfacial properties of composites were analyzed. To understand the formation of the wood/UPR interface, the wettability and penetrability between UPR and wood were evaluated, and the interface microstructure was observed with scanning electron microscopy. Results indicated that the Prepreg/Press process can achieve an interfacial adhesion between wood and glass fiber layer with the shear strength of up to 11.93 MPa. During a period of ten minutes, the contact angle of UPR onto wood significantly decreased from 103 ° to 33 °, and UPR had an absorptivity of 1.0×10−4 g/mm2 onto wood as high as water did. The favorable wettability and penetrability of UPR allowed it to penetrate into wood along the catheter and form a firm wood/UPR interface during the fabrication process.