RESUMEN
In this study, a phenol-formaldehyde resin-montmorillonite intercalation composite solution was used as a modifier to treat Chinese fir via impregnation and compression. The basic characteristics and wettability of the PF (phenol-formaldehyde)-montmorillonite impregnation solution were analyzed. The effects of the solid content of PF, the quantity of montmorillonite, and the impregnation time on the impregnation weight gain of Chinese fir were studied through orthogonal experiments. The results showed that when the amount of montmorillonite was 1%, the wettability of the PF-montmorillonite impregnation solution performed the best, the curing time was short, and the curing strength was high. The optimal impregnation process consists of a PF solid content of 25%, an impregnation time of 120 min, and a montmorillonite ratio of 1%. Under these conditions, the modified Chinese fir was prepared via hot pressing. The effects of the addition of montmorillonite and different levels of compressibility on the physical and mechanical properties of modified wood were studied. The physical and mechanical properties were found to be better when the compression ratio was 33%: the density increased from 0.33 g/cm3 to 0.58 g/cm3; the surface hardness increased from 33.6 HD to 70.9 HD; the static bending strength increased from 60.4 MPa to 98.7 MPa; and the elastic modulus increased from 6 390 MPa to 11 498 MPa. After 30 days of release, the compression rebound rate was 3.97%. Meanwhile, the micromorphology and heat resistance of the impregnated compressed Chinese fir showed that the PF-montmorillonite impregnation solution entered into the cell cavity and intercellular space of the Chinese fir and formed a good composite, thus improving the water resistance, heat resistance, and physical and mechanical properties.
RESUMEN
Impregnated decorative paper was an important wood-based panel finishing material. However, traditional impregnated decorative paper was impregnated with melamine-formaldehyde resin, which will release formaldehyde and harm the human health. To solve this problem, small molecule polyacrylate-polyethylene glycol (PEG) adhesive was used to achieve the non-formaldehyde addition of the impregnation system. The dialdehyde modified CNF (D-CNF), modified by sodium periodate (NaIO4), and triethylenediamine were introduced to enhance the surface properties of the impregnated decorative paper. The results showed that the incorporation of D-CNF and triethylenediamine imparted excellent physical strength and surface properties to impregnated decorative paper. When the dosage of 0.3 wt% D-CNF and 3 mL/100 g triethylenediamine in the compound emulsion, the hardness, abrasion resistant value and surface bonding strength of impregnated decorative paper adhered fiberboard reached 3H, 330 r of damage and 1.13 MPa, respectively. Thus, it could be effectively used for making high-performance formaldehyde-free impregnated decorative paper.
RESUMEN
A fast water-based ultraviolet light (UV) curing polyurethane-acrylate (PUA) wood coating was prepared in the laboratory, and applied on oak (Quercus alba L.) at different coating amounts. The PUA wood coating can be fast cured within 22 min, which highly improved the drying speed compared to normal water-based wood coatings (often higher than 35 min). The coating amounts affected the coating properties after curing on oak. With the increase of coating amount, the adhesion, hardness and gloss value of surface increased to different extents. Meanwhile, the surface of sample became smooth gradually because the voids of the oak were filled. Thus, higher coating amount resulted in better coating properties. However, no significant increase of penetration depth was found. During curing, the hydroxyl groups of the wood reacted with the coating. The optimal parameter in this study was the coating amount of 120 g/m2, where the adhesion reached 1 (with 0-5% cross-cut area of flaking along the edges), with the hardness of 2H and the gloss of 92.56°, which met the requirement of Chinese standard GB/T 18103-2013, and could be used for engineered wood flooring.
RESUMEN
In order to clarify the chemical color change of teak (Tectona grandis L.F.), the difference of chemical composition between the heartwood and sapwood of teak was investigated by gas chromatography-mass spectrometry (GC-MS) based on the acetone extractive compounds. The results showed that the difference in content of the main components between heartwood and sapwood was not obvious. However, the amount of extractives in heartwood was higher than that in sapwood, especially for phenols, quinones, and ketones. The most obvious different substances in the acetone extractive between heartwood and sapwood were 4-tert-butyl-2-phenyl-phenol,2-methyl-anthraquinone, and 2,3-dimethyl-1,4,4a,9a-tetrahydro-9,10-anthracenedione, which might be the main composition for the chromatic aberration of teak. This paper focuses on a preliminary study and further work such as high-performance liquid chromatography (HPLC) with ultraviolet photometric detector (UV)/mass spectrometry (MS) will be carried out.
