Volatile organic compound (VOC) emissions from no-added-formaldehyde lignosulphonate/pMDI particleboards and their effect on indoor air quality

Wood-based panels, for example particleboards, are responsible for releasing formaldehyde and volatile organic compounds (VOCs), consequently polluting indoor air. Thus, the demand for eco-friendly wood adhesives, such as lignosulphonates (LS), has increased in detriment of the traditionally used ureaformaldehyde resins. However, combination with polymeric 4,4′-diphenylmethane diisocyanate (pMDI) is commonly proposed to minimize pressing times. In this study, particleboards were manufactured using a low lab-scale press factor of 7.5 s/mm. The adhesive contents were: 1.3% pMDI with 2.2% propylene carbonate (PC) solvent in the core layer and 15% LS in the surface layers. The VOC emissions of these boards were evaluated against those of commercial urea-formaldehyde boards. Headspace gas chromatography-mass spectrometry analysis indicated that the total VOC emissions were 66% higher for the LS/pMDI boards, comprising mainly of PC and furfural. After 14-days in a 25 L chamber, VOC emissions were examined according to ISO 16000-9:2006. LS/pMDI particleboards emitted four times more VOCs than standard boards, with 80% corresponding to PC and furfural, a suspected carcinogen. Consequently, the need for VOC quantification, even for bio-based boards is highlighted. An extension of EN 16516:2017 + A1:2020 to furniture products is also advised.