Study On The Mildew Germination Mechanism Of Heat-treated Masson Pine Wood And Its Anti-mildew With Nano-copper

Heat-treated wood is a kind of environmental friendly material without chemical additives and it has good dimensional stability,decay resistance performance and vision quality,widely used in interior decoration materials and decorating side fascia of outdoor garden architecture and so on,very popular.However,in the process of application,its shortcomings of being easy to mould in the southern climate of relatively higher humidity are also exposed,which further affects its usability and use value and limits its application scope.At present,in the research on the mildew of heat-treated wood,there exists the problem of poor mildew controlling efficiency.In term of the problem of the mildew of heat-treated wood,this paper starts from the surface wettability,sugar,pH and dynamic water absorption properties of heat-treated wood,carries out research on the occurrence mechanism of the mildew,puts forward that adopting high-heat treatment after the drug-based wood pretreatment,and further obtains better wood anti-mildew treatment process.The main research results are as follows:1)The reducing sugar and pH value of the growing environment of high-heat treatment wood mildew.Heat-treated wood is 7.1%-86.0%higher than the source material in the reducing sugar content while heat-treated copper-containing material is 11.1%-33.8%lower than the source material in the reducing sugar content.The pH value of heat-treated wood is between 4.38 and 5.1 while that of heat-treated copper-containing material between 6.63 and7.12.It can effectively reduce the likelihood of an occurrence of mildew by reducing the reducing sugar content and increasing the pH value.2)Heat-treated wood’s moisture absorption properties are studied.The specific surface area of unheat-treated wood is up to 12.09 m²/g,and that of high-heat treated wood respectively reduces to be 8.73 m²/g;After heat treatment,the polar distilled water is larger than the source material in the angle of contact with the wood surface,and the higher the temperature for heat treatment is,the larger the angle of contact with the wood surface is,up to90.078°.The Masson pine wood through heat treatment of 220℃is shorter than the untreated wood in total equilibrium time.W is used to represent the water absorbing capacity of wood,and then the water absorbing capacity of the control wood is far larger than that of the Masson pine wood through heat treatment and the copper-containing Masson pine wood through heat treatment.With the increasing of the heat treatment temperature,the Masson pine wood through heat treatment is reduced in water absorbing capacity,and the wood which has lowest water absorbing capacity is the Masson pine wood after 220℃treatment of five hours,W being 20303.0.When the copper-containing Masson pine wood undergoes 220℃treatment of three hours,the water absorbing capacity is the lowest,W being 15155.39.3)The system studies the influences of different pre-treatment methods on heat treated wood anti-mildew efficiency.The Masson pine wood after 220℃heat treatment of two hours with the extracted 10g·kg^-1 HCl is 33.25%in mildew controlling efficiency,the Masson pine wood after 200℃heat treatment of two hours with the extracted hot water is 33.25%in mildew controlling efficiency,the Masson pine wood after 180℃heat treatment of two hours with the extracted ethanol:benzene is 33.25%in mildew controlling efficiency,the Masson pine wood after 180℃heat treatment of three hours with the extracted hot water is 33.25%in mildew controlling efficiency,the Masson pine wood after 200℃heat treatment of one hour with the extracted hot water is 16.75%in mildew controlling efficiency,after the pre-treatment of the Masson pine wood with SGB for soaking,carrying out 180²20℃treatment of one to five hours respectively of the Masson pine wood,the top mildew controlling efficiency obtained is 41.7%under 200℃/1h heat treatment and the lowest mildew controlling efficiency obtained is 20.8%under 220℃/5h heat treatment;after the pre-treatment of the Masson pine wood with 5%borax for soaking,carrying out 180²20℃heat treatment of one to five hours of the Masson pine wood respectively,the top mildew controlling efficiency obtained is 25.0%under 180℃/1h heat treatment and the lowest mildew controlling efficiency obtained is 0 under 220℃/5h heat treatment.4)After heat treatment at high temperature of 220℃and more than 3 hours,the result of XPS and XRD analysis shows that the nano-copper produced in the wood can achieve mildew control efficacy is more than 90%.Therefore,it can be considered that the nano-copper material produced by heat treatment of copper containing can significantly improve the mildew control efficacy of wood.Combining with traditional wood heat treatment methods,it is an economical method to obtain nano-copper in situ in wood.This method can avoid human body damage caused by direct contact with nano-materials.5)The heat treated copper-containing wood’s controlling efficiency of different mildews is studied and analyzed.The heat treated wood of 6.35 copper content has the best mildew controlling efficiency of blue-stain fungi,Aspergillus niger and Penicillium citrinum,and it is up to 100%in mildew controlling efficiency of blue-stain fungi and Aspergillus niger and 75%of Penicillium citrinum,but invalid in controlling the Trichoderma viride.6)The mildew controlling efficiency of the different positions of the copper-containing heat treatment based Masson pine wood is studied comparatively.The 0mm-5mm Masson pine sawn timber’s mildew controlling efficiency of blue-stain fungi and Penicillium citrinum are respectively 8.25%and 12.55%,and that of Aspergillus niger and Trichoderma viride are both0;the 5mm-15mm Masson pine sawn timber’s mildew controlling efficiency of these four types of mould are respectively 0.The 0mm-5mm heat-treated copper-containing Masson pine sawn timber has the lowest mildew controlling efficiency of Trichoderma viride which is66.75%,higher in the mildew controlling efficiency of the other three types of mould,up to100%in the mildew controlling efficiency of blue-stain fungi;the 5mm-10mm Masson pine sawn timber’s mildew controlling efficiency of these four types of mould can be up to 100%while the 10mm-15mm Masson pine sawn timber’s mildew controlling efficiency is lower than the 5mm-10mm Masson pine sawn timber’s,but slightly higher than the 0mm-5mm Masson pine sawn timber’s;the heat-treated copper-containing Masson pine wood below the 5mm surface layer has the best mildew controlling efficiency of the four types of mould,up to 100%.The surface polishing measure of the heat-treated copper-containing Masson pine wood can effectively improve the mildew controlling efficiency.