Effect Of Loading Rates On VOCs Released From Veneered Plywood

In order to explore the VOCs emission characteristic of plywood in standard and closed environment and the impact on air quality,and to provide scientific guidance and suggestions for decoration and material selection in real life,loading rate as the main factor to carry out the test in this paper.8mm thick and 18 mm thick PVC veneered plywood(PVC-PW),melamine impregnated paper veneered plywood(MF-PW),water-based paint veneered plywood(WV-PW)and undecorated plywood(PW)were test with four loading rates of 1 m2/m3?1.5 m2/m3?2 m2/m3 and 2.5 m2/m3.VOCs were collected in the standard environment with 1/h air exchange rate and the closed environment with 0/h.The concentration of VOCs and the release characteristics of the main components were analyzed by GC-MS,and the theoretical guide value of loading rate was calculated by the comprehensive index evaluation method.And comparing with particleboard and MDF.The main conclusions were as follows:1.In the standard environment,the VOCs concentration change of plywood and the fitting calculation of the theoretical guidance value of loading rate were analyzed.Results shows:The VOCs released from 8 mm/18 mm thick plywood showed a consistent trend of concentration decline with time and divided into three release stages.The decrease rate of VOCs in veneered plywood is higher than that in undecorated plywood.At the release equilibrium stage,the VOCs concentration of PW was the highest and followed by WV-PW,MF-PW,PVC-PW.The VOCs concentration of plywood increased with the loading rate,and the growth rate of loading rates will vary with the different facing materials.Thickness has little effect on VOCs concentration,but it has a significant impact on WV-PW.The theoretical guide values of loading rate of 8mm thick plywood are PVC-PW:9.71 m2/m3,MF-PW:9.98 m2/m3,WV-PW:7.90 m2/m3,PW:4.08 m2/m3 according to the fitting calculation;while the 18mm thick are PVC-PW:4.26 m2/m3,MF-PW:6.84 m2/m3,WV-PW:5.99 m2/m3,PW:3.28 m2/m3.Compared with the decay rate of the three main components on the day1/day28 of the experiment,the increase of the decay rate of aromatic hydrocarbon concentration was caused by the increase of loading rate,and also effected by thickness.2.Analysis of VOCs concentration and components in closed environment,and fitting calculation of theoretical guidance value of loading rate.Results shows:The concentration of VOCs released from plywood in the closed environment was much higher than that in the standard environment.The VOCs concentration increased rapidly in the closed time of 2h-8h.The VOCs concentration gradually increased and tended to saturation in the closed time of 8h-30h.The VOCs concentration of three kinds of veneered plywood was gradually stable after being sealed for 12h,while PW needs 18h.The increase of loading rate would lead to the increase of VOCs released from plywood in closed environment,but the effect was small.When the composite index is 1,the theoretical guide values of loading rate of 8mm thick plywood are PVC-PW:1.32 m2/m3,MF-PW:1.24 m2/m3,WV-PW:0.7 m2/m3,PW:0.94 m2/m3;18mm thick PVC-PW:0.62 m2/m3,MF-PW:0.86 m2/m3,WV-PW:0.43 m2/m3,PW:0.43 m2/m3.In the closed environment test,the concentration of aromatic hydrocarbon in the main components of VOCs is the largest,and its concentration was obviously affected by the loading rates.Esters were next highest concentration in the components of VOCs.The concentrations of esters were WV-PW,MF-PW,PVC-PW and PW in turn.The decorative materials have obvious blocking effect on alkenes and aldehydes and ketones,but they also release alkanes,alcohols and esters.3.The theoretical guidance values of loading rate and VOCs concentration from plywood compared with particleboard and MDF.Results shows:The concentration of VOCs released from plywood was the lowest in both standard and closed environment,followed by particleboard and MDF.The VOCs concentration of three kinds of wood-based panels increased with the increase of loading rates,and MDF was least affected.MDF was the most affected by thickness,particleboard was the second,plywood was the least affected.Plywood was most affected by loading rate,particleboard and MDF were less affected and had little difference.The environmental protection performance of plywood was the best,which was manifested in the lower VOCs and harmful monomer concentration,and the higher guidance value of loading rate.When the composite index is 1 in standard environment,the guidance value of loading rate of MF-PW was the largest;but in closed environment,the guidance value of loading rate of PVC is the largest.