Abstract: Due to the volatilization of inactive diluent during the curing of phenolic resin, the pultruded products are loose and have low strength. In order to improve this defect, the on-line prepreg pultrusion process of phenolic resin was developed by combining pultrusion process with prepreg technology. That was, the impregnated yarn was dried at 85 ℃ for 10 min, which can effectively remove the inactive diluent, most free aldehydes and some free phenols before entering the mold, which solved the problem to control the volatiles in the traditional phenolic pultrusion process, and the curing process of phenolic resin was not affected. By testing and analyzing the physical and mechanical properties of two products, it is found that porosity of the prepreg pultrusion products and the water absorption were significantly reduced. And the density, compressibility, interlaminar shear strength and impact toughness were improved greatly, proving the processing feasibility of the prepreg pultrusion.

Key words: phenolic resin, on-line prepreg process, inactive diluent, porosity, mechanical properties, composites