Formaldehyde and VOCs emissions from bio-particleboards

Formaldehyde and other volatile organic compounds (VOCs) emissions were determined from particleboards manufactured with natural adhesives. Thus, mimosa tannin with hexamine solution (T) and a blending of glyoxalated wheat straw lignin solution mixing with mimosa tannin and hexamine (TL) in 50/50 proportion were used as resins. These ones were compared with a traditional synthetic urea formaldehyde (UF) adhesive. Formaldehyde and other VOCs were determined and quantified with high performance liquid chromatography (HPLC) and gas chromatography–mass spectrometry (GC–MS) methods. Formaldehyde, acetaldehyde, acetone/acroleine and hexanaldehyde were the main compounds detected by HPLC. Toluene, ethylbenzene, xylene and following terpenes: α-pinene, β-pinene, 3-carene and limonene were determined by GC–MS. Results were obtained according to the EN-16000. After three days, emission results were the following: (a) formaldehyde UF: 240 > T:66 > TL:34 μg/m2 h; (b) acetaldehyde TL:46 > T:40 > UF:29 μg/m2 h; (c) acetone/acroleine TL:53.9 > UF:39.5 > 29.3 μg/m2 h; (d) hexanaldehyde T:14.6 > TL:13.7 > UF:11.7 μg/m2 h; (e) toluene UF:19.4 > TL and T: 9.4 μg/m2 h; (f) ethylbenzene UF:17.4 > TL and T: 7.6 μg/m2 h; (g) m-xylene UF 69.11 > TL and T 26.6 μg/m2 h; (h) o-xylene UF:16.0 > TL and T: 5.6 μg/m2 h; and (i) terpenes were emitted with lower rate than all the other compounds. In general, higher emissions have been noticed in natural adhesives than in the UF. Thus, the main terpenes found were α-pinene: UF:8.5 < TL:14.8 < T:19.7; β-pinene: UF:1.8 < TL:2.6 < T:3.6 and 3-carene UF:3.6 < TL and T: 4.9. Concerning limonene, no difference was observed whether the used adhesive was natural or not.