Exploration Of Manufacturing Technique And Mechanical Performance Prediction Of Reconsolidated Square Materials Of Cotton Stalk

Since the forestry resource is deficient in China，the wooden material supplying shortageshould be a serious problem．The cotton stalk resource is very plentiful in China．As thestructure of cotton stalks are similar to wood, it is suitable as materials instead of wood.Thispaper reports on the manufacturing process of reconsolidated square materials of cotton stalkbased on the phenolic resin adhesive glue. The effect of process parameters, namely timberdensity, glue consumption, hot-pressing temperature and hot pressing time,on therestructuring timber’s mechanical performance were discussed and the best processparameters were confirmed in this paper. It compare the mechanical properties ofreconsolidated square materials of Straw.It’ also presents to build the relationship betweenmechanical performance of cotton stalk reconsolidated square materials and main technologyparameters through Artificial Neural Network.(1)Using scanning electron microscopy and X-ray energy dispersive spectroscopy(SEM-EDAX) test cotton stalks, we found cotton stalks skin surface are covered with lumpsand rods,looks more smooth and dense,which is not conducive to glue penetration;Cotton’skin are mainly composed by the elements of C, O, Si, whose average weight ratioswere48.34%,31.26%and4.7%.Cotton stalk roots skin contents elements of Si up to8.4%,and the elements of Si exist by Si or SiO2, which greatly hindered the glue liquid wetting andagglutination and made an adverse effect on the restructuring of cotton stalk.Different withcotton stalks skin,we can see grooves and pits there in the surface of cotton stalk xylem，which are benefit for attachment and penetration of adhesive. Cotton stalk’xylem surface areconsist by element of C and O, reached more than90%of the total,whose weight ratios were58.1%and34.57%, and mostly exist by the form of holocellulose, but the element of Si onlyaccount for0.43%, so we main use the xylem of cotton to prepare reconsolidated squarematerials. Cotton’pitch are consists of hollow thin-walled cells, and the three most abundantelement are C, O, and Al, whose weight ratio respectively of54.63%,34.49%and6.47%.(2)According to the production mechanism of reconsolidated square materials,wetransform the hot pressand and achieve all round press at one-time.We use phenolic resin adhesive produce reconsolidated square materials of cotton stalk under the existing condition,and found that within the scope of this test, the better parameter are: density of0.65g/cm3glue consumption10%, hot-pressing temperature180℃, hot pressing time40min.(3)Different with particle board and fibreboard, the grain of reconsolidated squarematerials of cotton stalk are similar with the wood,its grain in top and bottom side are straightjust like wood’ radial section,but it also has some flaw,such as dark-colored glue joints,carbonized black in surface, barbs and holes and so on.(4)We found that cotton stalk are better material for prepare reconsolidated squarematerials after compare with the other kind of crop straw,which are bean stalk, tobacco stemsand sorghum stalk.,its bending elasticity modulus can reach8756MPa, bending strength are80.37MPa, and compression strength parallel to grain is50.32MPa.(5)Based on the orthogonal experiment data to establish the BP artificial neural networkmodel, this model can reflect the cotton restructuring lumber process parameters and therelationship between the mechanical performance index. The predicted values favorablyaccorded with experimental results under the given technology conditions(glueconsumption10%，hot-pressing temperature180℃，hot-pressing time40min, density0.6g/cm3，0.65g/cm3，0.7g/cm3). Under the above conditions, the average error of modulus ofelasticity，bending strength and compression strength parallel to grain are2.4%，1.93%and7.4%，respectively.The study on preparation of reconsolidated square materials of cotton stalk, providing atheoretical basis and technical parameters for the reconsolidated square materials of cottonstalk,and provides a new way for the cotton stalks of high value-added applications. Usingneural network model to predict the performance of reconsolidated square materials of cottonstalk shorten the number of preliminary experiments, and reduce production costs, lay thefoundation for the industrialization of reconsolidated square materials of cotton stalkproduction.