Graft copolymers of lignin from straw with 1-ethenylbenzene: Synthesis andcharacterization

The synthesis of copolymers between lignin from steam-exploded straw and 1- ethenylbenzene is described. Beforehand, lignin from steam-exploded straw w as fully characterized by using elemental analysis, ultraviolet spectroscop y, gel permeation chromatography (GPC), Fourier transform infrared (FTIR), and both H-1 and C-13 nuclear magnetic resonance (NMR) spectroscopy. Using a previously described procedure utilizing calcium chloride and hydrogen pe roxide as reagents the synthesis of the copolymers was performed. FTIR of t he copolymers showed the presence of both lignin and polystyrene. GPC analy sis showed the presence of a fraction with high molecular weights. These re sults were confirmed from both viscosity data and differential calorimetry. (C) 2000 John Wiley & Sons, Inc.