Heterogeneous Liquefaction Of Banana Pseudo-stem And Preparation Of Polymer Material Based On Liquefied Products

As the energy shortage and environmental problem is becoming more and more serious, biomass has become a powerful resource and gotten more and more attentions. Biomass liquefaction is considered to be an efficacious method.Banana pseudo-stem was selected as raw material to study the heterogeneous liquefaction mechanism. Liquefaction of banana pseudo-stem and banana pseudo-stem holocellulose were carried out in the presence of PEG400and glycerin (4:1, w/w) as a liquefying reagent, with sulphuric acid as catalysts. Effects of reaction temperature, liquid/solid ratio and reaction time on residue content were investigated. A series of novel polymer materials were prepared by blending liquefied banana pseudo-stem (LBP) with various proportions of polyvinyl acetate emulsion. Analytic methods including FT-IR, TGA, DSC, SEM and etc. were selected to analyze the liquefied residues and products, cellulose and polymer materials, respectively.The main results are as following:Liquefaction process undergoes coexistence of liquefying-degradation and coexistence of liquefying-degradation-condensation. In the liquefaction process, catalyst content, liquid-solid ratio, reaction temperature all have significant effect on the reduction of residue content. The effect of liquid-solid ratio on residue content is also relied on liquefaction temperature. The residue content significantly decrease with the increase of liquid-solid ratio under170℃. The liquefaction is hard to start when the liquid/solid ratio is5:1, and when the liquid/solid ratio increase from5:1to20:1, the residue content decrease49.44%in15min, and even63.82%in75min. While the residue content has no obvious decline with the increase of liquid-solid ratio under130℃, when the liquid/solid ratio increase from5:1to20:1the residue content decrease11.47%in60min, and when the liquid/solid ratio is20:1, the residue content will increase after60min.The cellulose can be effectively separated by adjusting the liquefaction conditions, and the optimum liquefaction conditions:liquid/solid ratio5:1, catalyst content lmmol/g, reaction temperature150℃and reaction time75min, and the content and crystallinity of cellulose is85.02%and81.26%, respectively. Furthermore, the crystal structure of the cellulose remains cellulose I. The hemicellulose is removed effectively, which leads to increase the surface area and improve the thermal properties of the cellulose fiber, making them suitable as reinforcing elements in bio-composite material preparation and paper makingThe liquefied products are rich in carbonyl and hydroxyl groups which are conducive for the preparation of resin material. The performance of PVAC at humid conditions can be improved by the formation of the hydrogen bonds and/or ether bonds between LBP and PVAC. And, when charge ratio of LBP (pH1.14)/PVAC=1:20,60℃curing2h, the shear strength of adhesive is3.88Mpa. Furthermore, a series of novel membrane materials were prepared by blending LBP and PVAc with different proportions. The elongation, flexibility and water resistant property of PVAC are improved. When the charge ratio of LBP/PVAC>10, the prepared membranes can be kept for64days without destroying in water. And the membrane material may be a potential material applied in preparing high elongation leathers, cushioning material and packing material.