Study On Odor Release Characteristics Of MDF And Its Veneer

People living in indoor polluted environment for a long time will affect their health and mood.As a major source of indoor air pollution,wood-based panels release volatile organic compounds(VOCs)and odors,which are harmful to human beings.However,in terms of odor,the research of MDF,which is widely used in furniture and construction industry,is very limited,which is not conducive to the systematic study of the odor of wood-based panels.In order to supplement the blank of this research field and improve the quality of human settlements,gas chromatography-mass spectrometry olfactometry(GC-MS-O)was used to analyze the MDF board,different veneers(PVC,melamine)and coating finishes(water-based paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane paint,polyurethane The odor release characteristics of MDF were analyzed,the key odor compounds were identified,and their sources and hazards were explored.The influence of the thickness of MDF board on the odor release of MDF board and MDF board with different finishes was analyzed,and the performance of odor release characteristics of MDF board under different environmental conditions was explored.Based on the particularity and uncertainty of the odor itself,the fuzzy comprehensive evaluation method was used to evaluate the odor level of three kinds of boards,and the odor evaluation level of different boards was determined.The research results of this paper are helpful to find out the composition,source,harm and odor release law of different kinds of MDF,and provide theoretical support for manufacturing environment-friendly MDF and wood products,which has a positive effect on improving indoor air quality.The details are as follows:(1)Aromatic hydrocarbon components(aroma)are the main odor sources of MDF,PVC veneered MDF and melamine veneered MDF.The odor intensity is the strongest in the initial release and equilibrium state,which has a great impact on the odor of MDF.The odor components of MDF were aromatic hydrocarbons,aldehydes and esters.The odor components detected by PVC MDF and melamine MDF were aromatic hydrocarbons,aldehydes,ketones,esters and alcohols.From the initial stage of release to the equilibrium state,the odor intensity of each odor compound decreased,and the odor characteristics also decreased,but the main odor characteristics of the board did not change much,and still showed a mixed odor dominated by aromatic odor.The odor characteristics of MDF with PVC veneer were mainly aromatic and fruity,while that of MDF with melamine veneer was mainly aromatic.(2)Alcohols have the greatest influence on the odor of MDF,aldehydes have the greatest influence on the odor of MDF,and aromatic hydrocarbons have the greatest influence on the odor of MDF.Water based paint MDF,polyurethane paint MDF and nitro paint MDF have the characteristics of fresh and fruity aroma,mainly mixed aroma and strong pungent aroma respectively.The order of odor release intensity of MDF with the same thickness was nitro paint MDF>polyurethane paint MDF>waterborne paint MDF.(3)Environmental conditions and thickness are important factors affecting odor release of MDF.With the increase of temperature and relative humidity,the total mass concentration and total odor intensity of three kinds of MDF(MDF board,MDF veneer,MDF coating)odor compounds increased,but the odor intensity of individual odor compounds had no obvious effect with the increase of temperature and relative humidity.With the increase of the ratio of air exchange rate to load factor,the total mass concentration and odor intensity of the three MDF odor compounds decreased.Under different temperature,relative humidity and the ratio of air exchange rate to load factor,the odor components in the initial stage and equilibrium state were different,and the odor characteristics of some odor compounds changed with the change of odor intensity.It was found that the total mass concentration and total odor intensity of odor compounds increased with the increase of MDF thickness,but not doubled.Under the same environmental conditions,the MDF release rate of the same substrate with different thickness is faster than that of the thinner one.After veneering and finishing,the influence of thickness on the odor of veneering MDF and finishing MDF decreased.(4)In order to manufacture environment-friendly wood-based panels,it is suggested that wood materials with less odor should be used as far as possible for fiber preparation,and thinner substrate should be used as far as possible on the basis of meeting the performance of the panels.It can also reduce the odor of the substrate and the release of harmful components in volatile organic compounds by modifying the adhesive used in MDF manufacturing or reducing the amount of sizing.The use of environment-friendly veneering materials,veneering treatment under appropriate hot pressing process conditions and finishing treatment with environment-friendly coatings are also conducive to improving the environmental protection level of the plate,but special attention should be paid to the types of coatings and the green quality of solvents and diluents.(5)A fuzzy comprehensive evaluation method based on multi odor characteristics(odor intensity,mass concentration and toxicity)was established to quantitatively evaluate the odor level of MDF boards.According to the fuzzy comprehensive evaluation,the odor evaluation grade of MDF plain board is grade III,the odor evaluation grade of PVC veneer MDF and melamine veneer MDF is grade ?,and the odor evaluation grade of water-based paint MDF,polyurethane paint MDF and nitro paint MDF is grade ?.Fuzzy comprehensive evaluation of three types of MDF board,the overall odor hazard is not high,reaching the qualified level.