Liquefaction Of Woodroom Waste And Preparation Of PUR

With polyethylene glycol (PEG) and Ethylene glycol (EG) as liquefier and sulphuric acid as catalyst, liquefaction of wood waste from the polar pulping was investigated. The results are obtained as below: according to the relationship between the viscosity and waste usage, proper viscosity could be got for PU preparation as the waste usage changes in the range of 20% to 25%, and the optimum amount is fixed at 20%. Orthogonal experiment was carried out to evaluate the influence of the principle parameters (temperature, usage, reaction time and the ratio of liquefiers) to liquefaction. The influence factor is as following sequence: temperature> the ratio of liquefiers> reaction time> usage. The optimum conditions are: usage of catalyst is 5%, the ratio of PEG/EG is 3/1, temperature is 160oC, and reaction time is 80min.The liquefied product is characterized by liquefied yield 93.36%, hydroxyl value 370mgKOH/g, acid value 53mgKOH/g and viscosity 420mPa·s, which could be used for Polyurethane foams preparation. The molecular weight of the liquefied products (LP) was 11593-12637. The molecular structure of LP consists of polyhydroxy, ether and sugar chains, according with FT-IR results. By thermogravimetric analysis (TGA), the results are obtained: the raw material decomposes in the temperature ranges of 255℃to 368℃and 355℃to 400oC.Polyurethane foam was successfully prepared with water as vesicant. The effect of usage of LP, isocyanate index, water amount, catalyst and foam stabilizer contents on the LP-PUR(The foam added LP) are studied. Apparent density of the LP-PUR is in the range of 22.13kg·m^-3 to 33.73kg·m^-3 and compressive strength is from 52.3 kPa·s to 205.5kPa·s. By SEM, the cell diameter of the LP-PUR accounts for about 1/4 of the PUR (polyurethane foam). Comparison between regular foam and polyurethane foam is investigated, PUR is decomposed under the scope from 225℃to 380℃and LP-PUR degraded in the range of 245℃to 380oC, displayed that polyethylene glycol with nature fiber as liquefaction material could improve the thermal stability of Polyurethane. The Thermal Conductivityof the LP-PUR was 30.1 mW/m.k,which is satisgied for insulation.