Study On The Mechanism Of Bamboo Biomass In Dry Process

Bamboo is one of the world famous fast growing plants,which have advantage with short growth cycle,short selective cutting interval,sustainable utilization without destroying the its forest and so on,Bamboo resources are widely used in artificial board,furniture,pulp and paper and so on.However,it exist physical anisotropy of mechanical properties,hydrophilicity and hollow structure defects,leading to the low utilization rate and serious waste of resources.So this study take bamboo as the research object,using the GPC,2D-HSQC modern analysis methods to analyze change rule of bamboo in dry process and proven bamboo/lignin composite mechanism.The main research contents and results of this paper are as follows:(1)The bamboo/lignin composite processing.The results showed that lignin/bamboo ratio was main factors that influence the bamboo composite wood physical and mechanical properties,it had a significant influence on the performance of the static bending strength,the inner strength of the plate and the swelling ratio of the water absorption thickness;Composite temperature was the main factor that affected its performance,which has a significant effect on the internal bond strength and water absorption thickness swelling ratio.The optimum process parameters were as follows:compound temperature 180 degrees C,lignin/bamboo is 40:100,compound pressure 5MPa,and compound time is 15min.(2)The mechanism of bamboo/lignin composite.the lignin samples were isolated from the corresponding boards and characterized by high-performance anion-exchange chromatography(HPAEC),gel permeation chromatography(GPC),quantitative 31P-NMR,and 2D-HSQC NMR,respectively.The best bonding strength of the Bamboo composite board was obtained under the conditions of temperature 1800C,pressure 5 MPa and lignin/bamboo mass ratio 0.4.GPC analysis showed that the weight average molecular weight and the multi dispersion of lignin were decreased.The NMR results presented the content of ?-O-4' and ?-?' linkages reduced and the?-5' linkages boost with the hot pressing temperature rose.Simultaneously,the percentage of the G-type and H-type lignins as well as the content of phenolic OH were increased,This was beneficial to the composite of bamboo and lignin..(3)FT-IR,XRD,TG,TD-GC-MS and other modern means use to characterize the bamboo composite board.The chemical structure of bamboo was found to change dramatically during preparation of its bio-composites.XRD suggested that high temperatures more seriously destroyed the crystalline cellulose in the bio-composites than the amorphous cellulose,and the crystallinity of the sample MOLH-2 was the largest,reaching 58,85%.FT-IR spectra showed that composite increased the amounts of functional groups in the samples.The TGA/DTG showed that the DTGmax value of the sample MOLH-2 was 351,which was higher than other Bamboo wood composite and indicated that the thermal stability of the samples was better.TD-GC-MS showed that the contents of phenol,benzene and its derivatives in sample MOLH-2 were the least.(4)The semicellulose was characterized by FT-IR,XRD,TG and other modern means.The results show that the optimal semicellulose polymer can be obtained at 230? and 20min,FT-IR,and,TGA and DTG analysis support the above results.Adding lignin can reduce the thermal degradation of hemicellulose in the composite.