| Wood is widely used as indoor wood products such as floors and furniture,because of its natural advantages.However,wood is rich in nutrients,such as hemicellulose,starch,and monosaccharides.Besides,wood has a porous structure,moisture absorption characteristics and weak acidic environment,which is favorable for the growth of mold.And thus affects the wood quality and potentially harms human health.Therefore,anti-mold treatment of wood is indispensable in production and application.Previous studies have shown that the use of antibacterial materials to sterilize wood microorganism and change the wood moisture absorption properties can inhibit the mold growth on wood to a certain extent.The degree of improvement depends on the type of material used and the treatment method.But on the whole,the various methods that have been reported have certain drawbacks,such as high toxicity of organic antibacterial materials to human and environment,poor resistance of inorganic antibacterial materials to leaching,complex treatment methods,and unsatisfied treatment effects.This study was based on the above shortcomings.useing poplar wood,which was the most important fast-growing artificial plant wood in Shandong,as raw materials.Besides,the study used "nanometer-sized silver-based materials with good leaching resistance to directly kill molds" and "environmental moisture barrier agents to reduce the environmental humidity for inhibiting molds growth" as the two treatments to evaluate the anti-mould effect of wood and explored green solutions for high-efficiency anti-mould treatments of wood.In the method of sterilization,the study selected nanometer-sized silver materials and nanometer-sized silver-copper materials with a particle size of 10～20 nm.At first,the study screened the concentration ranges of the two nanomaterials,which were relatively effective in inhibiting Aspergillus niger,Penicillium citrinum and Trichoderma viride,through the culture medium test.Based on the result,the study discussed the impact of the types and additions of these two nanomaterials on the anti-fungal performance of wood,besides,the study evaluated the antibacterial effect of this method on the wood surface.At last,the study screened and determined the toxicity limit concentration of each nanometer-sized antibacterial agents.In the method of preventing moisture,at first,the study selected two moisture barriers:solvent-based resin and water-based resin.Then,the study explored the impact of their types and impregnation methods on the moisture barrier effect of wood samples.At last,the study evaluated the inhibitory effect of this method preliminarily on wood surface mildew.All of the research conclusions are as follows:(1)When the mass ratio of nano-silver added was below 0.013%(the concentration of antibacterial material was below 700 ppm),the relative effective concentration ranges for Aspergillus niger,Penicillium citrinum and Trichoderma viride were ≥ 500 ppm,≥ 500 ppm and 700 ppm,respectively;When the mass ratio of nanometer-sized silver-copper added was less than 0.018%(the concentration of antibacterial material was less than 1000 ppm),the relative effective concentration ranges for Aspergillus niger,Penicillium citrinum and Trichoderma viride were ≥700 ppm,≥300 ppm and ≥700 ppm,respectively.At similar addition levels,the order of the inhibition efficiency of the two nanomaterials for Aspergillus niger was: nanometer-sized silver>nanometer-sized silver-copper;the order of inhibition efficiency for Penicillium citrinum was: nanometer-sized silver-copper>nanometer-sized silver;the order of inhibition efficiency for Trichoderma viride was: nanometer-sized silver>nanometer-sized silver-copper.(2)For Aspergillus niger,Penicillium citrinum and Trichoderma viride,the toxicity limit concentration of nanometer-sized silver anti-mold agent and nanometer-sized silver-copper anti-mold agent were both 1000 ppm.At the same concentration,the order of the effectiveness of the two nanomaterials against Aspergillus niger was: nanometer-sized silver>nanometer-sized silver-copper;the order of the effectiveness against Penicillium citrinum was: nanometer-sized silver-copper>nanometer-sized silver;the order of the effectiveness against Trichoderma viride was: nanometer-sized silver>nanometer-sized silver-copper.In addition,through SEM,XPS,FTIR test analysis,it was found that the surface structure of the wood sample did not chang significantly after adding the anti-mold agent.(3)After using solvent-based moisture barrier agents and water-based moisture barrier agents to perform moisture barrier treatment on wood samples,the moisture absorption rate of the samples decreased;In addition,the moisture barrier effect of the water-based moisture barrier was slightly better than that of the solvent-based moisture barrier.Among them,for Aspergillus niger,the control efficiencies obtained by treating with a solvent-based moisture barrier for 3 min and 1 h were 20% and 25%,respectively;the control efficiencies obtained by treating with a water-based moisture barrier for 3 min and 1 h were 30% and 35%,respectively.For Penicillium citrinum,the control efficiencies obtained by treating with a solvent-based moisture barrier for 3 min and 1 h were 5% and 10%,respectively;the control efficiencies obtained by treating with a water-based moisture barrier for 3 min and 1 h were20% and 25%,respectively.For Trichoderma viride,the control efficacies obtained by treating with a solvent-based moisture barrier for 3 min and 1 h were 5% and 10%,respectively;the control efficiencies obtained by treating with a water-based moisture barrier for 3 min and 1 h were 10% and 15% respectively.After comprehensive comparison,the control effects of solvent-based moisture barrier agents on the three molds were ranked from high to low: Aspergillus niger>Penicillium citrinum≈Trichoderma viridis.The ranking of the mildew-resistant effects of water-based moisture barrier agents on the three molds was:Aspergillus niger>Penicillium citrinum>Trichoderma viride.When the treatment time remained the same,the anti-mold effect of the water-based moisture barrier was better than that of the solvent-based moisture barrier,whether it was for Aspergillus niger,Penicillium citrinum or Trichoderma viride.When the bacteria remained the same,for the same moisture barrier material,the longer the processing time of the sample,the better the anti-mold effect.The treatment with a lower moisture absorption rate of the sample corresponds to a better anti-mold effect,indicating that the method of reducing the moisture absorption rate of the wood can inhibit the growth of mold on the surface of the wood to a certain extent. |
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