Toughened composites prepared from castor oil based polyurethane and soy dreg by a one‐step reactive extrusion process

Abstract

Abstract A series of water‐resistant composites were successfully prepared from a mixture of soy dreg (SD), castor oil, and 2,4‐toluene diisocyanate (TDI) by a one‐step reactive extrusion (REX) process. The structure and properties of the composites were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, dynamic mechanical analysis, tensile testing, and swelling experiments. The results indicated that the toughness of the composites prepared from castor oil based polyurethane and SD was significantly improved. In this case, TDI played an in situ compatibilization role through the crosslinking reaction of NCO groups with NH 2 , NH, and OH groups in SD and castor oil. With an increase in the molar ratio of NCO groups of TDI and OH groups of castor oil, the degree of crosslinking, tensile strength, glass‐transition temperature, water resistivity, and solvent resistivity of the composites increased. With an increase in the SD content of the composites, the tensile strength and solvent resistivity of the composites increased because of the reinforcement of the cellulose component in SD. This work provided a simple and effective way of preparing SD‐based composites by a REX process. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 953–960, 2006