X-ray photoelectron spectroscopy of lignocellulosic materials treated with maleated polypropylenes

The esterification reaction between lignocellulosic materials (ALCELL lignin and Bleached kraft cellulose) and maleated polypropylenes (graft copolymerization of maleic anhydride into polypropylene chains) was investigated. The reaction was conducted in a reactor in the presence of xylene used as a solvent and sodium hypophosphite as a catalyst. The reaction between lignocellulosic materials and pure maleic anhydride was also conducted to determine the effect of the long polypropylene chains on the formation of ester bonds. The XPS studies of maleated bleached kraft cellulose showed the emergence of C4 carbon type on high resolution spectra, which was related to ester carbonyl functionality formed by esterification reaction. No evidence of esterification was observed between ALCELL lignin and maleated polypropylenes. The XPS studies demonstrated that both ALCELL lignin and bleached kraft cellulose chemically react with maleic anhydride with the formation of ester bonds.