| Wood is widely used in interior furniture,flooring and decoration,while the volatile organic compounds and peculiar smell from wood are one of the important causes of indoor air pollution.To solve the urgent problem in the development of wood science and engineering,at the same time expand the database of odor substances from wood,and help people establish a clearer understanding of the source of wood indoor odor,this study was carried out from the perspective of odor.The technology of Gas Chromatography-Massspectroscopy-Olfactometry(GC-MS-O)was used to identify the odor active compounds from wood of different tree species,while 11 species from Guangxi China,which always used in wood-based panels,furniture raw material,and 5 species from northeast China,which used in furniture raw material.The odor characteristic map and key odor active compounds from different wood were gotten,the impact of moisture content,different finishing treatments and environmental conditions on wood odor release were analyzed at the same time.The advantages and disadvantages of Thermal Desorption/Gas Chromatography-Massspectroscopy-Olfactometry(TD/GC-MS-O)technology and wood extract odor extraction dilution technology were compared and analyzed.On the basis of VVOC/VOC and odor release characteristics of wood,referring to the relevant standards at home and abroad,a comprehensive evaluation model for health level of multi-component compound release materials was established by using mathematical modeling.To realize the rapid evaluation and comparison of wood health level under different application,the artificial intelligence software for comprehensive evaluation of material health grade was developed by using QT computer technology.The research results not only fill in the gaps in the field of wood odor research,help people establish a clear understanding of the sources of wooden materials used in daily life,but also help to solve the problems of "odor" of wood and decoration products and the issues on health.It is of great significance to ensure the physical and mental health of residents,promote the healthy development of wood furniture and woodwork,it also provide new ideas and reference for the follow-up development of wood odor.(1)The analytic hierarchy process(AHP)was used to build the hierarchical structure model based on the odor intensity index.Through comparative matrix analysis,single ranking weight vector calculation,matrix total ranking weight calculation and consistency test,the main odor source compounds of 16 species of wood were analyzed qualitatively and quantitatively,and the key odor source compounds were obtained.According to the relevant research results of neuroscientists,different types of odor profiles were sorted out.It was found that the odor profiles of different tree species had their own characteristics.The main odor profile of wood used in the experiment is food-like,followed by flowery and citrus-like.Wood-like,green leaf-like,chemicals-like,lichen glycosides-like,fruity and pungent constitute the basic odor profile of different wood.The compounds with high odor intensity were mainly distributed in C.mollissima B1.,Pinus massoniana Lamb.,Choerospondias axillaris(Roxb.)Burtt et Hill,Cinnamomum camphor a(L.)Presl,T.sinensis(A.Juss.)Roem.,and Xylosma racemosum(Sieb.et Zucc.)Miq.The results showed that the odor intensity of odorant active compounds released from the wood of 16 species mainly concentrated in 1.0-2.0.(2)The volatile organic compounds and odor release characteristics of wood,such as Choerospondias axillaris(Roxb.)Burtt et Hill,Pinus massoniana Lamb.and Cinnamomum camphora(L.)Presl were analyzed by single factor method.The effects of moisture content on VOC,VVOC and odor components from three kinds of wood were explored,and the key odor active compounds,dominant odor components and odor profiles were obtained.It was found that the VVOC/VOC release of wood composition and odor was directly related to the movement of water in wood.With the decrease of water content,VOC and VOC in wood released with the evaporation and migration of water,which led to the decrease of total wood component concentration of three different tree species.The change was most significant when the water content decreased from 60%to 30%.The decrease of moisture content has a great influence on the profile intensity of flowery,green leaf and delicious food of Choerospondias axillaris(Roxb.)Burtt et Hill,and has a great influence on the profile intensity of delicious food and woody of Pinus massoniana Lamb.and P.neurantha(Hemsl.)Gamble.(3)The technology of GC-MS-O was used to explore the effects of polyurethane coating(PU),UV curing coating(UV)and water-based coating on odor components and odor intensity of wood of Choerospondias axillaris(Roxb.)Burtt et Hill,Xylosma racemosum(Sieb.et Zucc.)Miq.and Fraxinus mandshurica Rupr.VOC is the main releasing component of PU coating and waterborne coating,and VVOC is the main odor component of UV coating.The release concentration and odor characteristics of paint veneer are greatly affected by the characteristics of the board itself.PU,UV and water-based coatings have a certain sealing effect on some odor active compounds released from three kinds of wood,and also increase the release of some odor active compounds.Among the wood of three species,the main odor profile characteristics of PU coating and UV coating are flowery,delicious food and fruity.The main odor profile characteristics of water-based coating veneer are woody,chemical,delicious food and flowery.(4)To explore the effects of environmental conditions on the release components of volatile organic compounds and odor-active compounds,the odor active compounds of Fraxinus mandshurica Rupr.were studied by TD/GC-MS-O and microcell thermal extractor.It found that the increase of temperature and humidity in a certain range can significantly promote the release of some key odor active compounds,and enhance some odor characteristics.The higher the relative humidity can inhibit the release of butane,acetone and heptyl in Fraxinus mandshurica Rupr.With the increase of air exchange rate and load factor,the odor intensity of six key characteristics of fraxine decreased.The ratio of air exchange rate to load factor was found to have bigger impact to Fraxinus mandshurica Rupr.In order to accelerate the components emission of Fraxinus mandshurica Rupr.,it is suggested that it should be placed in the environment of high temperature,high humidity and high air exchange rate to load factor ratio.(5)The most suitable odor analysis method should be selected according to different purposes and application.TD/GC-MS-O has a good application in exploring the daily release of odor components from wood materials.It can analyze and study the odor release of wood under different states and environmental conditions,and is suitable for exploring the "odor source" of indoor environment from wood.The technology of wood extract extraction dilution is suitable for the basic study of wood odor compounds characterization,which can identify the odor components in wood comprehensively.The odorant active substances in Betula pendula Roth were studied by extraction and dilution technology of odor components in wood extracts.The hedonic rating of European birch was rated as neutral,and a little pleasant.Based on the data evaluation of Shapiro-Wilk combined with Kolmogorov-Smirnov test,it was found that there was no significant difference in the aspect of overall distribution of odor intensity/hedonic rating between six birch samples.The 10 odor attributes were earth-like,pencil-like,cork-like/moldy,grass-like,fatty,fruity,green tea-like,herbal-like,vanilla-like and vinegar-like.Most of the odor properties can well match the identified odor active compounds.It found that most of the odorant compounds were fatty acid degradation products,including saturated and unsaturated aldehydes,ketones,and acids.The odorant active compounds also come from a series of phenyl compounds produced in the process of lignin degradation of Betula pendula Roth.and some terpenes.(6)A comprehensive evaluation model for the health level of multi-component compounds release materials was established based on the fuzzy comprehensive evaluation(FCE)method and relevant standards.The membership judgment matrix was established,on the basis of grey relational analysis matrix(GRA).The final judgment of material health level was gotten according to the normalized comprehensive evaluation vector,based on the maximum membership principle and combined with the relevant standards and health evaluation program.To realize the rapid evaluation and comparison of health level of lacquer wood in different application,Qt technology and back-end development was used to build GRA-FCE materials health level comprehensive evaluation artificial intelligence software,which runs on Windows 10. |
PDF Full Text Request