The Research On Microanatomical Structure And Pore Distribution Characteristic Of C.Oleifera Abel.

In this paper,the shell of Camellia oleifera was used as the raw material,and the biological structure was analyzed by macroscopic,microscopic and ultra micro scale observation.The results show that the shell of Camellia oleifera is mainly composed of three parts,that is,exocarp,mesocarp and endocarp.The pericarp is the main part of the shell.The exocarp is dark brown,hard and dense,and the color of the mesocarp and endocarp is shallow,and the texture is loose.The main cell types of the shell are fiber cells,stone cells and parenchyma cells.The cell tissue proportions were 65.75%,14.62%and 19.63%respectively.Fibrous cell is the most important cell type in the shell.The morphological characteristics of the fiber cells exist differences in different parts of the pericarp.The fiber cell of Camellia oleifera shell is short and coarse with poor flexibility,which is not suitable for the pulp and paper industry.The outer surface of Camellia oleifera shell has protuberance,stratum corneum,waxy layer,microfracture and epidermis.There are tumor like processes on the inner surface,including stratum corneum and waxy layer,with irregular pore distribution.The cells of the shell are arranged in no direction and disorderly.There are a large amount of pores distributed on the wall of the stone cells and fiber cells.The microfibril angles of the different parts of the shell are different.The mean value of the exocarp,mesocarp and endocarp were 31.41,32.83 and 20.22 degrees respectively.The microfibril angle of the shell is similar to that of Cunninghamia lanceolata,which is higher than that of poplar,eucalyptus and bamboo.In this study,the characteristics of pore distribution were studied by nitrogen adsorption-desorption method.The results showed that the nitrogen adsorption-desorption isotherm of Camellia oleifera shell belonged to the IV type isotherm.The hysteresis loop type belonged to H3 type.The nitrogen adsorption capacity was 17.43cm3/g,and the BET specific surface area was 75.82g/m2.The pores of the shell are mainly mesopores,and a certain number of macropores and small amout of micropores.The structures of the pores are flat slits or wedge-shaped structures,funnel-shaped.The pores were mainly derived from cellulose microfibrils and non crystalline regions in the cell wall.The mean pore diameter is 3?15nm,,and the pore volume of 3?4nm is about 57.35%of the total pore volume.The pore volume of 4?15nm is about 32.43%of the total pore volume,and the pore volume greater than 15nm accounts for 10.22%of the total pore volume.Calculated by the t-diagram method,the pore volume of the Camellia oleifera shell is 12cm3/g,the total surface area is 75.87m2/g and the external surface area is 75.29m2/g.According to pore diameter analysis,the penetration efficiency of fluid in Camellia oleifera shell is superior to that of broad-leaved poplar,but its penetration efficiency is not satisfactory compared with that of Pinus sylvestris L.lumber and non wood Moso.In this paper,the fractal characteristics of pore structure are analyzed on the basis of fractal theory.The results show that the pore of the shell of Camellia oleifera has a certain fractal structure.The specific surface area of the pore has obvious fractal characteristics.The linear fitting equation of Ln(V/Vm)and Ln[In(p0/p)]is y=0.3293x+0.8676,and the fractal dimension is 2.67,and the correlation coefficient is 0.9451,which is high in fitting degree.The pore volume corresponding to the different aperture levels also presents a certain fractal feature.The linear fitting equation of lnV and Ln[ln(p0/p)]of the pore whose pore diameter ranged from 3?4nm was y=-0.3752x-0.6326.The fractal dimension of pore volume is 2.62 and the correlation coefficient is 0.9968.The linear fitting equation of InV and Ln[ln(p0/p)]of the pore whose pore diameter ranged from 4?15nm was y=-0.5349x-1.3194.The fractal dimension of pore volume is 2.47 and the correlation coefficient is 0.9974.The linear fitting equation of InV and Ln[In(p0/p)]of the pore whose pore diameter greater than 15nm was y=-0.2551x-0.8717.The fractal dimension of pore volume is 2.74 and the correlation coefficient is 0.9788.The linear fitting degree of three kinds of pore level was high.The comprehensive fractal dimension of the pore of Camellia oleifera shell was 2.55.There was a positive correlation between the pore volume and the comprehensive fractal dimension.The linear fitting equation was y=0.0035x-0.0048,and the correlation coefficient was 0.67,with amount of scattered data.There was a linear relationship between the pore ratio of the Camellia oleifera and the comprehensive fractal dimension,and the linear fitting equation was y=52.36x-111.96,and the correlation coefficient was 0.81.Based on the fractal model theory,the porosity of the Camellia oleifera shell was predicted to be 0.425?0.441,and the permeability coefficient was predicted to be 0.016m/d,which meant that the shell was a weak pervious material.