Synthesis and characterization of polymers from cashewnut shell liquid (CNSL), a renewable resource II. Synthesis of polyurethanes

Novel polyurethanes were prepared by solution polycondensation reaction of 1,6-diisocyanatohexane with 4-[(4-hydroxy-2-pentadecenylphenyl) diazenyl] phenol (HPPDP) and 1,4-butane diol. The monomer (HPPDP) was synthesized from cardanol, a renewable resource and the by-product of the cashew industry. It was characterized by CHN analysis, UV, IR and (HNMR)-H-1 spectroscopy techniques. Polyurethane characterization included elemental analysis. (HNMR)-H-1, IR, UV spectral analysis, dilute solution viscometry, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X-ray diffraction studies. The intrinsic viscosities were found to be in the range 1.68-1.84 dl g(-1). The wide-angle X-ray diffraction (WAXS) pattern of the polyurethanes indicated presence of crystallinity. DSC studies also supported the presence of crystallinity. TGA of the polyurethanes indicated a higher thermal stability of 245 degrees C in nitrogen atmosphere at 30% decomposition. (C) 1999 Elsevier Science Ltd. All rights reserved.