Synthesis and physicochemical study of bisphenol-C-formaldehyde-toluene diisocyanate polyurethane-jute and jute-rice Husk/Wheat husk composites

Bisphenol-C-formaldehyde-toluene-2,4-di isocyanate polyurethane (PU) has been synthesized at room temperature and used for the fabrication of jute and jute-rice husk/wheat husk hybrid composites. PU-jute and PU-jute-RH/WH composites were prepared under pressure of 30.4 MPa at room temperature for 8 h, while PU-jute-RH/WH composites were prepared under same pressure at 110 degrees C for 5 h. PU-jute composite has good tensile strength and flexural strength (50-53 MPa), while PU-jute-RH/WH hybrid composites have moderate tensile strength (9-11 MPa) and a fairly good flexural strength (15-31 MPa). Composites possess 1.1-2.2 kV electric strength and 0.94-1.26 X 1012 ohm cm volume resistivity. Water absorption in PU-jute composite is different in water (9.75%), 10% HCl (12.14%), and 10% NaCl (6.05%). Equilibrium water uptake time in salt environment is observed 96 h, while in pure water and acidic environments it is 192 h. In boiling water equilibrium water content and equilibrium time are found to be 21.7% and 3 h, respectively. Water absorption increased 2.2 times in boiling water, whereas equilibrium time reduced 64 times. Thus, PU-jute composite has excellent hydrolytic stability against boiling water, 10% HCl, and 10% NaCl solutions. Fairly good mechanical and electrical properties and excellent hydrolytic stability of composites signify their usefulness for low cost housing units and in electrical and marine industries. (c) 2006 Wiley Periodicals, Inc.