WOOD RESEARCH Volume 69, Number 3, 2024
SHUYU ZHAO, FU HU, LIFEN LI, YAN CAO, HUA GAO, XIAOHUI YANG, and HAILONG XU

EVALUATION OF PROPERTIES OF WOOD PLASTIC COMPOSITES MADE FROM SEVEN TYPES OF LIGNOCELLULOSIC FIBERS

This article aims to investigate the characteristics of wood plastic composites (WPC) prepared from polyethylene (PE) reinforced with lignocellulosic fibers derived from the xylem and bark of Masson pine, fir, cypress, as well as from Moso bamboo. The surface polarity and elemental composition of fibers were determined through contact angle measurements and X-ray photoelectron spectroscopy (XPS). The lignocellulosic fiber/PE composites were manufactured through hot-pressing technique, and their water absorption, mechanical properties, and mildew resistance were evaluated. The results revealed that the surface free energy of xylem fibers was higher than that of bark fibers among the three conifer species. XPS analysis showed that the O/C ratio of bark was consistently lower than that of xylem fiber. Among the three conifers, the Masson pine bark had the lowest O/C ratio (22.25%), while its xylem fibers had the highest ratio of 41.64%. WPC made with bark fibers had better water resistance. Additionally, the composites reinforced with xylem fibers showed superior static bending strength, impact strength, and mildew-resistant properties as compared to the composites reinforced with bark fibers. WPC made from bamboo fibers exhibited the best water resistance, with a water absorption rate and thickness swelling rate of 1.83% and 1.42%, respectively. They also had the highest static bending strength, elastic modulus, and impact strength, at 41.31 MPa, 3.82 GPa, and 10.24 kJ/m2, respectively. The WPC made from fir xylem fibers showed the most effective mildew resistance, with the smallest damage (0.50)

WOOD RESEARCH Volume 67, Number 5, 2022
Renyuan Liu, Zhuliang Zeng, Quan Li, and Cenlong Hu

The effects of ACQ and water glass on the color change and decay resistance of carbonized bamboo

In this study, samples of bamboo and carbonized bamboo were impregnated with alkaline copper quaternary (ACQ) and water glass, the resulting differences in color and resistance to decay by Gloeophyllum trabeum were evaluated. The results showed that the impregnated bamboo and carbonized bamboo greatly reduced their lightness (L*). The red-green color index (a*) first decreased and then increased, while the yellow-blue color index (b*) first increased and then decreased. The total chromatic aberration (ΔE) was largest for bamboo and carbonized bamboo impregnated with ACQ and allowed to decay. Carbonized bamboo impregnated with ACQ and water glass and bamboo impregnated with ACQ reached level I (strong decay resistance). The decay resistance of bamboo and carbonized bamboo was as follows: ACQ impregnated > water glass impregnated > CK. Scanning electron microscopy further confirmed that the bamboo and carbonized bamboo were impregnated with ACQ had fewer hyphae, the maintained intact structure, and good decay resistance.

WOOD RESEARCH Volume 65, Number 6, 2020
Quan Li, Renyuan Liu, Xiaoqian Chen, and Hui Lin

Box-Behnken design for process parameters optimalization of bamboo-based composite panel manufacturing

High performance bamboo-based composite panel taking bamboo mats, bamboo curtains and poplar veneers are used as raw material, is manufactured from the each layers slab was crisscrossed, impregnated with phenolic resin, compressed and cured. The product was optimized by Box-Behnken model design and data analysis. The results show that the best parameter conditions were hot pressing temperature of 140°C, hot pressing time of 94 s.mm-1, and hot pressing pressure of 2.5 MPa. The model was validated according to the optimal process parameters and the static bending strength (MOR), elastic modulus (MOE), thickness expansion rate of water absorbing, adhesive strength and density are 98.95 MPa, 8.81 GPa, 4.7%, 1.25 MPa, 0.89 g.cm-3, respectively. The actual value is close to the predicted value, confirming that the obtained model can accurately predict the MOR of the product using the three factors of hot pressing as variables under different conditions.