Study On The Properties Of Poplar Wood Modified With Litsea Cubeba Oil

The wood of fast-growing plantation forest has the defects of low density,soft wood,poor physical and mechanical strength,and easy shrinkage and deformation,which greatly limits its scope of use.Modification of plantation wood can increase its use value.Natural plant extracts have a wide range of raw materials,low cost,environmental protection,no pollution and multiple functions.Using them as modifiers can achieve high value-added and functional applications for plantation wood.In this study,the plant extract Litsea Cubeba oil was used as a modifier,which was combined with the widely cultivated plantation of Poplar in China.The impregnation modification method was used to optimize and improve the wood properties of the plantation Beijing Poplar and to give it antibacterial activity.And the low-cost,simple process of the standing tree modification method to modify the plantation of poplar wood reflects the energy-saving and environmental protection research ideas.The main conclusions of the paper are as follows:1.The weight gain rate of sapwood impregnated with Litsea Cubeba oil solution after drying by different methods in plantation Beijing Poplar is similar to each other,and the weight gain rate of sapwood is much higher than that of heartwood.The weight gain rate of sapwood was up to 138%.The weight gain rate of the heartwood is microwave drying>high temperature drying>conventional drying>vacuum drying.The maximum weight gain rate of the heartwood is 110.7%,the minimum volumetric swelling rate of the impregnated modified Poplar is only 2.6%,and the minimum volumetric hygroscopic expansion rate is only 0.02%.The anti-hygroscopic expansion rate is up to 99.56%,showing good dimensional stability.After the high temperature drying,the color change of the modified Poplar that is impregnated is the most obvious,and the color difference value?E*reaches 16.80 at most.In addition to the slight increase in the bending strength of the impregnated modified Poplar under conventional drying slightly by 0.61%,the rest have slightly decreased,but the modified Poplar have increased bending modulus of elasticity to varying degrees.2.When the volume ratio of the modifier is 5:100 or more,the impregnated modified Poplar has obvious inhibitory effect on Staphylococcus aureus,the maximum width of the antibacterial zone along the longitudinal grain of the wood is 4.80mm,and the maximum is 2.23mm in the horizontal direction;When the volume ratio of the modifier is above 10:100,the impregnated modified Poplar has obvious inhibitory effect on Escherichia coli,the maximum width of the antibacterial zone along the longitudinal grain of the wood is 2.49mm,and the maximum is 0.93mm in the horizontal direction;and under the same modifier concentration The impregnated modified Poplar has stronger inhibitory effect on Staphylococcus aureus.3.The modifier is input into the standing timber through the tree hanging needle method,and it is found that the absorption is positively correlated with the atmospheric temperature and weather level,negatively correlated with the air humidity,and has no obvious correlation with the wind level;The modifier will gradually hinder the water transmission during the upward transportation in the live standing wood.After 35 days,the standing wood stops absorbing the modifier and dies.4.The water absorption rate of the live standing wood modified Poplar is reduced from 172.3%to 125.6%,the volume wet expansion rate of the live standing wood modified Poplar is reduced to 5.9%,the volume hygroscopic expansion rate is only-0.12%,and the dimensional stability is extremely greatly improved;The width of the live standing wood modified Poplar against Staphylococcus aureus in the longitudinal grain direction is 2.09mm and the transverse direction is 0.95mm,but the inhibitory effect on Escherichia coli is not obvious.5.Through SEM,XRD and FTIR characterization analysis of modified Poplar and untreated Poplar,it was found that the modifier mainly transmits and penetrates longitudinally through the vessel in the wood,and finally adheres to the vessel in the form of film or agglomerate on the wall,the modifier can uniformly cover the pits in a thin film shape,and can achieve radial penetration through the pits.This hydrophobic film-like distribution can play a role in isolating moisture;When the modifier enters the interior of the wood tissue,it will interact with The hydroxyl groups in cellulose form hydrogen bonding,and there is no obvious chemical reaction with wood.They mainly exist in wood through physical adsorption and physical filling;The crystallinity value of the untreated wood and the modified wood are close to each other.The modified treatment of standing wood has no obvious effect on the crystallization area of wood,indicating that the modifier Litsea cubeba oil does not react with the main components of wood after entering the wood.