Liquefaction Of Poplar Sawdust And Preparation Of Polyur Ethane Foam

Biomass is the only renewable carbon resources, which can be converted into liquid fuel and chemical materials. Moreover, liquefaction technology is one of the most effective ways of extensive use of lignocelluloses. However, both high temperature and high pressure (including super-critical method) method or atmospheric pressure liquefaction using solvent have the secondary pollution problem. In addition, the liquefaction temperature and pressure are too high or corrosive chemical reagents using too more. Therefore, in this paper,a higher conversion rate and more economical liquefied process of poplar sawdust were explored by using polyol. Furthermore, the amount of catalyst can be reduced by using this new process, keeping the reaction temperature and pressure down. The property and composition of liquefied Oil was analyzed. At the same time, the liquefied oil and Polyether polyol were utilized in polyurethane foam preparation. The light and heavy components of the liquefied oil have been separated by a fractional process. Moreover, the property and composition of light components were analyzed. The main contents are studied as follows.1,In this study, poplar sawdust was used as raw materials which contains cellulose 42.82%, hemi cellulose 25.61% and lignin 16.45%, moisture content 8.29%, ash 1.34%. Based on the results of FT-TR, it contains Hydroxyl, methyl, carbonyl and benzene structure.2,The best reaction conditions were using 0.05g concentrated sulfuric acid as a catalyst, 5g ethylene glycol and 15g ethanol as liquid agent under the reaction temperature at 200℃for 6 hours in the hydrothermal synthesis reactor. Sawdust liquefaction rate was up to 96%. Liquefied oil were measured that the hydroxyl value was 682.5mg/g, acid value was 1.5mg/g and viscosity (20℃) was 37.84mm~2/s. Liquefied oil contained esters, alcohols, ethers and ketones and polyester/polyether polyols were detected. Molecular weight of the liquefied oil continuously distributed between 35593 to 18.3,In the autoclave, the optimum reaction conditions was 0.05g concentrated sulfuric acid as a catalyst, 5g ethylene glycol and 10g ethanol as liquid agent under the reaction temperature at 250℃for 1 hours. Sawdust liquefaction rate was up to 98%. Liquefied oil were measured that the hydroxyl value was 715.3 mg/g, acid value was 1.43 mg/g and viscosity (20℃) was 45.36mm~2/s.Liquefied oil contained esters, alcohols, ethers and ketones and polyester/polyether polyols were detected. Molecular weight of the liquefied oil continuously distributed between 21673 to 18.4,In the autoclave, the optimum process was used 0.05g concentrated sulfuric acid as a catalyst, 5g glycerin and 10g ethanol as liquid agent under the reaction temperature at 250℃for 1 hours. Sawdust liquefaction rate was up to 98.3%.Based on orthogonal test, the factors affected the liquefied rate were glycerol content, temperature, reaction time and the amount of concentrated sulfuric acid. Those four factors has less and less influence on liquefied rate. Liquefied oil were measured that the hydroxyl value was 846mg/g, acid value was 2.1mg/g, moisture content 3.04% and viscosity was 1000mPa·s. Liquefied oil contained lots of polyester/polyether polyols with the ring or chain structure. Its average molecular weight was 810.7.5,In the best condition, the cellulose and the lignin were liquefied by using glycerin. The result showed that the liquefied rate of lignin higher than liquefied rate of cellulose. Both of two liquefied oil have a large number of hydroxy compounds. Liquefied oil of lignin has more aromatic acids/ esters and less aliphatic alcohol/ester than liquefied oil of cellulose.6,Polyurethane foam(PUF) was made in liquefied oil of poplar sawdust and Polyether4110. It was possessed of better mechanical Properties with higher density. Polyether with 10%-20% liquefied oil has little effect on structure of PUF and has better thermal stability.7,The components of liquefied oil that has been separated by a fractional process in five temperature range. The fraction of liquefied oil contain components such as 2-ethyl-4- methyl-1,3-dioxa cyclopentane, 3-ethoxy-1,2-propanediol,1,3-diethoxy-2-propanol, 4-carbonyl ethyl ether and Glycerin triethyl. The average molecular weight of the heavy components is 749.6.