Preparation And Performance Study Of Outdoor Weather-resistant Hydrophobic Wood

As one of the earliest materials used by human beings,wood has been favored by the public for thousands of years.In recent years,global wood resources have gradually decreased,and there has been a serious shortage.How to realize the"great utilization of little modification"and"excellent use of inferior wood",to maximize the use of wood with high quality and high efficiency,has become one of the urgent problems to be solved at present.Based on the above background,this thesis took Populus L as the research object,through functional improvement,made wood obtain excellent performance,prolonged its service time in outdoor environment.Considering the variability of the outdoor environment.This thesis selected nano-Ti O₂with low-price,non-toxic,UV absorbent,nano-Si O₂with good mechanical properties,PDMS and silane coupling agent KH550 for wood treatment.Nano-Ti O₂and nano-Si O₂modified by silane coupling agent KH550 were tightly combined with wood by PDMS to construct micro-nano rough structure on the surface of wood,which not only had good hydrophobicity,but also had excellent mechanical stability,chemical stability,freeze-thaw cycle,self-cleaning and ultraviolet aging resistance,the results show that the hydrophobic wood has good weather resistance.The preparation technology of hydrophobic wood was studied by FT-IR,XPS or XRD.Through the changes of static contact angles of wood sections under different technological conditions,the drying time（7 h,9 h,11 h）,drying temperature（80℃,100℃,120℃）,nanoparticle amount（1.5 g,2.0 g,2.5 g）and impregnation times（5 times,7 times,9 times）were determined and selected as independent variables.The static contact angles of each section were used as the response value,and the optimum experimental design was carried out for the preparation process of hydrophobic wood by Design-Expert V8.0.6.1software,and then the optimum preparation process of hydrophobic wood was obtained.It was figured out that drying temperature had the most significant effect on wettability of wood sections（P<0.0001）,and other factors had different effects.The effects of various factors on static contact angles of different sections of wood conform to the quadratic polynomial model,and the interaction between various factors presents different elliptic and 3D diagrams.Finally,the optimum technological conditions for the preparation of hydrophobic wood were as follows:drying time 9 h,drying temperature 100℃,nano-particle content 2.0 g,impregnation times 7 times.Compared with the static contact angles predicted by the model,the experimental results show that the relative errors of cross,radial and tangential static contact angles are 1.51%,0.97%and 1.35%.