Further investigation of polyaminoamide-epichlorchydrin/stearic anhydride compatibilizer system for wood-polyethylene composites

The combination of a polyaminoamide-epichlorohydrin (PAE) resin (a paper wet strength agent) and stearic anhydride was recently reported as an effective compatibilizer system for wood-polyethylene composites. Further investigation of this new compatibilizer system revealed that the pH value of a PAE solution, dosages of PAE and stearic anhydride, and the weight ratio of PAE to stearic anhydride had significant impacts on the compatibilization effects of the compatibilizer system. Adjusting the pH value of the PAE solution from 5.0 to 10.4 increased the strength of the resulting wood-polyethylene composites. The highest strength of the resulting wood-polyethylene composites was obtained at 3 wt % PAE and 3 wt % stearic anhydride. At 4 wt % or 6 wt % of a compatibilizer, this PAE-stearic anhydride system was superior to maleic anhydride-grafted polyethylene (MAPE), one of the most effective compatibilizers, in terms of enhancing the strength of the resulting wood-polyethylene composites. Fourier transform infrared spectroscopy (FTIR) analysis revealed that PAE and stearic anhydride formed covalent bonding with wood flour. The compatibilization mechanisms of this PAE-stearic anhydride compatibilizer system were investigated in detail. Water-resistance tests indicated that the PAE-stearic anhydride compatibilizer system increased the water-resistance of the resulting composites. (c) 2005 Wiley Periodicals, Inc.