Study On The Preparation And Drying Characteristics Of Hexacyclite Modified Poplar Wood

With the continuous development of China’s economy and society,the demand for wood is increasing.Artificial fast-growing forests are abundant in resources and can meet people’s daily needs.However,fast-growing forests have drawbacks such as low density,low strength,and easy shrinkage and deformation,which limit their application.Through modification technology,artificial fast-growing forests are endowed with multifunctionality,but there are drying problems in the multifunctional utilization of modified materials.The introduction of modified substances changed the pore structure of wood.Therefore,the research on the drying characteristics of modified materials is of great significance.This study takes poplar wood as the research object,uses hexacyclic stone powder as a modifier,and uses vacuum pressure impregnation technology to impregnate hexacyclic stone powder into the interior of the wood to prepare a health functional wood with the effect of releasing negative oxygen ions.The drying characteristics of the modified wood are explored,with a focus on revealing the influence of hexacyclic stone on water movement and heat inside the wood.The main content and conclusions are as follows:1.Preparation of Six Ring Stone Modified Poplar Wood.(1)Using sodium hexametaphosphate as a dispersant,a 1wt%hexacyclite dispersion was prepared using a composite process.The XRD,SEM,and FT-IR of the dispersed powder indicate that the original crystal structure and chemical properties have not been changed,and the powder has been effectively dispersed Hexacyclic stone modified poplar wood was prepared by vacuum pressure impregnation.The optimal preparation process is to first vacuum to-0.08MPa,then pressurize it at a pressure of 1MPa,with a pressure impregnation time of 2h,and finally maintain a normal pressure of 5min for one cycle,with 6 cycles being the optimal impregnation number.The weight gain rate and liquid absorption rate of the modified material are 18.47%and 155.25%,respectively.The total dry density and air dry density of hexacyclic stone modified materials increased by30.55%and 26.47%,respectively.The average release of negative oxygen ions from the modified material reached 1506.95/cm~3.After 7 and 49 days,the average release reached 1604.88 and 1739.4 pieces/cm~3.2.Study on the Drying Standards of Modified Poplar Wood with Hexacyclic Stone.The drying characteristics of modified materials were studied using the Baidu test method,and the results showed that the initial cracking level of the modified material was level 3,the internal cracking level was level 1,the cross-sectional deformation level was level 2,and the twisting level was level 2.The drying conditions for the modified material are determined as follows:initial dry bulb temperature of 60℃,initial dry wet bulb temperature difference of 3-25℃,and maximum temperature at the end of drying period of 90℃.After optimizing its drying benchmark,the final moisture content is 8.73%,the average deviation of moisture content in thickness is 1.34%,the drying speed is level 2,and the initial cracking is level 2.The comprehensive drying quality meets the level 2standard.3.Study on moisture and heat during the drying process of modified poplar wood with hexacyclic stones.The modified materials were dried using conventional chamber drying,and the transfer laws of moisture and heat during the drying process were studied.The results show that the average drying rate of the modified material in the first stage is 7.13%/h,the average drying rate in the second stage is 1.26%/h,and the average drying rate throughout the entire process is 3.97%/h.The total drying speed of modified materials increased by1.05%/h compared to untreated materials,increased by 2.04%/h above the fiber saturation point,and increased by 0.25%/h below the fiber saturation point When the moisture content of the modified material is 40%,the deviation of moisture content in thickness is 3.59%;6.01%at a moisture content of 30%;1.1%at a moisture content of 20%;0.21%at a moisture content of 10%.(3)The nuclear magnetic resonance signal indicates that w hen the moisture content of the modified material is 40%,30%,and 20%,the internal moisture state is mainly composed of bound water.Compared with untreated wood,modified wood has weaker binding with water and is prone to water movement Far infrared radiation of modified materials 9-15μThe emissivity of m is 0.25%-0.5%.The surface temperature of the modified material increased by 0.5℃/h faster;The temperature of the subsurface layer increased by 0.53℃/h faster;The temperature of the core layer increased by 0.53℃/h.