CHARACTERIZATION OF POLYURETHANE FORAMS FROM LIQUEFIED CASSAVA BAGASSE WITH POLYMERIC MDI

摘要

The feasibility of using polyethylene glycol to liquefy cassava bagasse for the production of bio-based polyols and polyurethane foam(PUF)was investigated in this study.The mild liquefaction condition(i.e 1.3～2％sulfur acid as catalyst at 130～140℃ for 90min)was demonstrated efficient for cassava bagasse.The PUF with the density of 0.027～0.062 g/cm3 was prepared from liquefied cassava bagasse(LCB)with ariable amount of polymeric MDI by one-shot method.In addition,the effects of partial replacement of petroleum-based polyether polyols by LCB on the mechanical,structural and thermal properties of PUF were characterized by means of universal stress tester,scanning electron microscope,and thermo-gravimetric analyzer.The compressive strength of LCB-PUF declined from 182kPa to 53kPa when the substitute ratio increased from 20％to 100％,compared with the increasing of yield stress from 0.04MPa to 0.13MPa.With respect to the compressive strength,the content of bio-based polyols had adverse effect on the thermal stability of LCB-PUF,and higher replacement resulted in heterogeneous surface and irregular pore shape.Nevertheless,the application properties of LCB-PUF have been improved by the adjustment of [NCO]/[OH] index and foaming additives.The results indicated that the cassava bagasse was feasible to be liquefied for PUF production instead of petroleum-based polyether polyol and the LCB-PUF had an obvious feature of semi-rigid polyurethane foam.1