Study On The Application Of Water-borne Organic Preservatives In Thermally Modified Wood

Thermal modification is a green and environmental-friendly wood modification method.However the thermally modified wood does not have anti-mildew and anti-termite properties,which severely limits the application range of thermally modified wood.Therefore this study introduced several organic preservative microemulsions,such as isothiazolinone(DCOIT)microemulsions,propiconazoletebuconazole(PT)microemulsions,DCOIT/PT/imidacloprid(IMI)microemulsions,into thermally modified wood through a post-impregnation process.The combined modification was carried out,and the physical,mechanical and biological properties of the combined modified wood were determined.The organic microemulsion/thermal treatment combined modified wood with excellent resistance to biological degradation and a wide range of applications is prepared,which provides a new idea for the development of environmentally friendly wood preservation,anti-mildew and anti-termite technologies.The primary conclusions are shown as follows:(1)After the wood thermal modification,the dimensional stability is significantly improved,and it has a certain degree of decay resistance,but it does not have the resistance to termites,and even promotes the growth of mold.The MOR of the thermally modified wood has been reduced,and the MOE is positively correlated with the processing temperature.(2)After introducing PT microemulsion and DCOIT microemulsion into thermally modified wood,the dimensional stability of the combined modified wood has been improved,and the MOE of the combined modified wood has a certain increase.With the increasing heat treatment temperature,the negative effect of the agent microemulsion on the thermally modified MOR has been improved.Waterborne preservatives have better permeability to thermally modified wood,but their anti-leaching in thermally modified wood is reduced to a certain extent.(3)Compared with PT microemulsion,DCOIT microemulsion significantly improves the mold resistance of thermally modified wood.At the high concentration(0.10%),the combined modified wood showed a lower mass loss after decay tests,and the decay resistance of PT is better than DCOIT.In addition,PT and DCOIT can improve the anti-termite performance of thermal modified wood to a certain extent.However,PT and DCOIT have not shown obvious killing effect on termites.(4)The average particle size of DCOIT/IPBC/IMI microemulsion is about 20 nm,the particle size distribution is relatively uniform,and it has excellent storage stability and dilution stability.After the thermally modified wood is treated with DCOIT/IPBC/IMI microemulsion,the termite resistance is significantly improved,the quality loss rate is significantly reduced,and the mildew resistance performance is further enhanced.The anti-termite test results showed that the quality loss rate of the compound treatment group was below 3%,the termite survival rate was below 18%,and the termite decay rating increased from 4-5 to 9.5.The anti-mold test results show that the inhibition rate of the composite modified material to mold reached 100%.