Experimental Study On Releasing Characteristics Of Volatile Organic Compounds From Polyurethane Plastic Runway

As one of the common sports venues,the PU plastic runway consists of multiple organic hydrocarbons and their derivatives.It is easy to release many kinds of VOCs under specific conditions such as high temperature and high humidity.The VOCs released by PU plastic runway can be absorbed by the human body through various ways such as breathing,skin contact and other channels,and can cause different degrees of irritation to the skin,eyes,and respiratory tract of the human body.It is carcinogenicity to liver,kidney and other organs,and it also has some teratogenicity to the nervous system.Although the National Standards and provincial and municipal standards have stipulated the limit values of VOCs released from plastic runway,but the test conditions can't meet the actual release laws of VOCs from PU plastic runway,and the limit values also can't fully reflect the VOCs value.At present,the releasing mechanism of VOCs in PU plastic runway is still unclear.In view of this,it's urgent to strengthen the research on the releasing characteristics of VOCs released from PU plastic runway,and provide a data basis for the improvement of release and detection methods of VOCs released from PU plastic runway and the revision of national standards.Aiming to clarify the releasing characteristics of VOCs released from PU plastic runways,taking the PU plastic runway as research object,this paper carries out the analysis of VOCS by using TVOC tester for TVOC detection,GC-MS for qualitative and quantitative analysis of VOCs based on controlling the actual working conditions such as temperature,relative humidity,and air exchange rate of the 0.1m~3environmental chamber,clear-cuts the change characteristics over time of the mass concentration of TVOC and the impact of the mass concentration of all kinds of VOCs and major VOCs monomers releases from PU plastic runway under different temperature,relative humidity and air exchange rate,discusses the main sources of VOCs releases from PU plastic runway,and also compares and analyses the TVOC and VOCs monomers released from different types of PU plastic runways.The study shows that:(1)Using environmental chamber release and TVOC detector to detect the TVOC releases from PU plastic runway has high precision and good repeatability.At the same time,the environmental Cabin-GC-MS technology also has good linear correlation,low detection limit,excellent precision and good repeatability in the qualitative and quantitative analysis of PU plastic runway VOCs.(2)Temperature,relative humidity and air exchange rate will accelerate mass concentration of TVOC releases from PU plastic runway;and the temperature,which will be promoted,is significantly higher than other two factors;and the air exchange rate will change the trend of TVOC mass concentration.The increase of temperature will lead to a significant shortening of the rapid release period of TVOC release of PU plastic runway and a prolonged slow release period,and the increase of air exchange rate will shorten both the rapid release period and the slow release period,while the relative humidity has no effect on it.The maximum and 24h value(equilibrium value)of TVOC mass concentration releases from PU plastic runway are proportional to the temperature and relative humidity;The maximum value is inversely proportional to the air exchange rate in normal temperature segment and proportional to high temperature segment;and the 24h value is inversely proportional to air exchange rate.The results show that the maximum mass concentration of TVOC can be determined more quickly and accurately by confined cabin.And when the temperature,humidity or air exchange rate is high,exercise time on the PU plastic runway can be reduced appropriately,especially when the two or three are acting together.(3)During the stable release period,VOCs releases from PU plastic runway include seven categories such as alkanes,alkenes,alkynes,aromatic hydrocarbons,halogenated hydrocarbons,oxygen-containing organics,and nitrogenous organics,also including 102 species VOCs monomers.The temperature and relative humidity have no effect on the detection rate of VOCs monomers,and the increase of the air exchange rate will lead to a decrease of it.The changes in temperature,relative humidity,and air exchange rate will not change the composition of VOCs and major VOCs monomers releases from PU plastic runway,and the mass concentration of VOCs are dominated by alkanes,oxygen-containing organics and halogenated hydrocarbons,supplemented by aromatic hydrocarbons,alkenes and nitrogenous organics.The influence of temperature on the mass concentration of kinds of VOCs and VOCs monomers in PU plastic runway was not consistent,and increase of relative humidity causes it to increase gradually,and increase of air exchange rate causes it to decrease gradually.In general,the influence of temperature on the mass concentration of all kinds of VOCs and major VOCs monomers in PU plastic runways is greater than air exchange rate,and relative humidity is minimal.It is found that when discussing the effects of VOCs on the human body releases from PU plastic runway,it is necessary to focus on the influence of temperature on the release of VOCs from plastic runway and the analysis of the hazards of alkanes,oxygen-containing organics,halogenated hydrocarbons and aromatic hydrocarbons to the human body.(4)The PU bottom layer,PU surface layer,diluent and rubber particles together provide the main source of VOCs releases from PU plastic runway,including the raw materials themselves released and generated by the chemical reaction.In general,diluents contribute the most to the mass concentration of TVOC releases from PU plastic runways,and PU bottom layer and PU surface layer contribute less.The results show that in the process of PU plastic runway laying,it is necessary to strictly control the addition of organic solvents such as diluents.(5)The detection rate of 102 kinds of VOCs monomers in four types of PU plastic runways is basically the same.And the increase rate,maximum value,and 24h value(balance value)of TVOC mass concentration are all mixed type>complex type>breathable type>full-plastic type.There were significant differences in mass concentrations of kinds of VOCs and major VOCs monomers in different types of PU plastic runways.The results show that comprehensive considerations the effects of TVOC,benzene,toluene,ethylbenzene,xylene and other substances on the human body,the use of full-plastic type PU plastic runways is less harmful to the human body.The research results of this paper can provide a data basis for the revision of national standards and the formulation of local standards for plastic runways,can provide a foundation for the production,use,and supervision of plastic runways,and can also be applied to the practice of effectively preventing"toxic runway"events.