Liquefaction Of Salix And Preparation Of Rigid Polyurethane Foams By The Liquefaction Products

In order to give light to the rich ShaSheng shrubs resource advantage of Inner Mongolia, the Salix was used as the major material which can be liquefied into liquid in normal temperature, atmospheric pressure and suitable solvent through biomass liquefaction technology. As the liquefied products retain the macromolecular structure of the plant fiber raw materials, they could be used as the matrix with isocyanate together to foamnew type of polyurethane rigid foam which has the property ofhigh strength, light weight, thermal insulation, flame retardanceand sound absorption.The experimental results showed that:1. The optimal process for liquefaction of Salx was the liquid-solid ratio of 4, time 140min, the temperature of 170℃, catalyst content of 5%, with the Salix flour liquefaction yield of 97.84%; The dynamic model was applied to show the relationship between the reaction time and the liquefied ratio of Salix at different temperatures. The results showed that the liquefaction of Salix in polyhydric alcohols was multilevel and the apparent reaction rate constants went up with the increase of temperatures. Liquefaction activation energy Ea was 7.15×1O4 J·mol-1 and pre-exponential factor A was 4.1371S-1. According to transition-state theory, the activation free enthalpy(△G), activation enthalpy(△H), and activation entropy(△S) of reaction changed with the increase of temperature. The whole liquefed reaction of Salix in polyhydric alcohols was endothermic, and the liquefaction system is easily to react when an external energy was input.2. The liquefied products of nuclear magnetic resonance spectra analysis showed that the degradationandpolycondensation reaction were in existence simultaneously, and the main liquefied products were furfural compounds, the guaiacyl group of lignin structure and aliphatic compound.The Hydroxyl value and acid value ofliquefied products increased with the increasing of the rate of liquefaction. At the beginning of the reaction, the viscosity of products were high, then the viscosity valuereduced first, then increased with the increasing of time.3. The influence of the conditions on foams follows the sequence:catalyst, foaming agent, stannous octoate and foaming agent. Under optimal conditions, the foaming material had about 0.094 g/cm3 density and 0.416MPa compression strength.4. Intercalated or exfoliated OMMT can be prepared by adding just the right amount, which significantly improved themechanical properties, thermal stability and flame retardance of materials.