WOOD RESEARCH Volume 69, Number 4, 2024
RUI JIANG, YUANFEI XU, XUEJIAN YANG, LEI ZHANG, ZHENYU FAN, XIAOYAN GUO, FENG XIAO, LIZHI ZHU, and BINGQIN SUN

THE EFFECT OF COLORANTS ON THE DEGRADATION PERFORMANCE OF WOOD PLASTIC COMPOSITES

The degradation performance of the colorful wood flour/poly (β-hydroxybutyrate valerate) composites (CWPHBVs) in natural outdoor landfill was investigated by some physical, analytical, and microscopic tests. The mass loss rate of the CWPHBVs within 80 days of degradation shows a growth trend and the mass loss rate decreases by more than 20%. With the increase of degradation time, the bending strength of the CWPHBVs continues to decline, the elastic modulus of the CWPHBVs shows a logarithmic decline trend. After 30 days, the bending strength of the CWPHBVs decreases over 50% and tend to be stable. The colorant has a certain inhibitory effect on the degradation. However, with the shedding of the colorant, the effect of the colorant on the degradation is gradually weakened. The addition of colorants reduces the decomposition rate of PHBV and improves the thermal stability of poplar fibers. However, after 20 days, this effect almost disappears

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)