In order to explore the emission characteristics of volatile organic compounds (VOCs) and different VOC components in airtight environments, polyvinyl chloride laminated plywood (PVC-P), melamine-impregnated paper laminated plywood (MI-P), water-based paint laminated plywood (WP-P) and unfinished plywood (UF-P) were tested as materials in 15 L small environment cabins. VOCs were collected after being sealed for 2 h, 4 h, 6 h, 8 h, 12 h, 18 h, 24 h and 30 h under different loading ratios (1 m²/m³, 1.5 m²/m³, 2 m²/m³, 2.5 m²/m³) and analyzed using a gas chromatography–mass spectrometer. The results show that VOCs gradually increased and tended to be saturated with the increase of time in an airtight environment. The saturation of veneered plywood was faster than unfinished plywood and the pollution degree of three kinds of veneered plywood from lowest to highest was in order of PVC-P, MI-P, WP-P. Aromatic hydrocarbons account for more than half of VOC concentration, and was most obviously affected by the loading ratios. Surfaced laminated plywood can reduce the emission of aromatic hydrocarbons, but also increases the amount of other compounds released. The concentration of VOC-components shows different characteristic curves at different loading ratios due to the influence of decorative materials.

Modification of poplar (Populus adenopoda Maxim) wood by using maltodextrin (MA) combined with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DM) resin was investigated in this study. The weight percent gain, dimensional stability, mechanical strength, and microscopic chemical change were determined before and after impregnation. Results indicated that the composite modifier was impregnated into the wood cell lumen, as verified by scanning electron microscopy and a change in weight percent gain. Anti-swelling efficiency was significantly improved compared with the untreated sample; however, the sample treated with MA obtained an anti-swelling efficiency that was slightly lower than that of the sample treated with sucrose. The flexural strength, flexural modulus, and compressive strength perpendicular to the grain increased with an increase in MA concentration, but the compressive modulus and impact strength were reduced. Fourier-transform infrared spectroscopy demonstrated that MA delayed the cross-linking of the DM resin cell wall, and X-ray diffraction analysis showed that the crystallinity of the cellulose crystalline region was reduced to a certain extent. In general, the poplar wood treated with combined MA and DM resin exhibited enhanced properties relative to those of the poplar wood treated with sucrose.

The drying characteristics of poplar wood (Populus adenopoda Maxim) under three treatments were investigated with the aim of improving the drying quality of the impregnated wood. Untreated materials, impregnated materials with 10% initial moisture content (MC), and impregnated materials with 20% initial MC—denoted as T1, T2, and T3, respectively—were examined during conventional drying. Relative to that of T1, the average drying rate of T2 was reduced by 46%, and that of T3 was reduced by 37%. The anti-swelling efficiency of T2 sharply increased, whereas that of T3 only slightly increased in width and thickness. The drying defects of T2 were markedly less than those of T1 and T3, attributed to the reduced residual stress and fixation of the modifier. Scanning electron microscopy indicated that large amounts of modifiers were deposited inside the cell cavity of T2, whereas small amounts of modifiers were deposited in the cell cavity of T3. The impregnation treatment generally reduced the average drying rate and MC uniformity and delayed the decrease in residual stress; however, it reduced the number of defects in the wood and considerably improved the dimensional stability of the wood. Meanwhile, impregnation treatment with increased initial MC could potentially lead to more drying defects and increase production cost.