WOOD RESEARCH Volume 64, Number 4, 2019
Shaoxiang Cai, Shouheng Hu, Yanjun Li, Xinzhou Wang, Lican Chen, and Jun Li

Nanomechanical behavior of wood cell walls observed by different indentation loading prerequisites

The variations of nanomechanical behavior of wood cell walls under different peak loads, loading times, and holding times were studied. Samples were separately loaded to preset peak loads of 100, 150, 200, 250 and 300 μN. Changes in the micromechanical properties were tracked in the longitudinal direction to determine change values of the elastic modulus and hardness. Moreover, the creep behavior was also analyzed under different holding times. It was found that the longer the holding time, the larger the creep ratio of all of the samples, and the creep rate decreased slowly with longer loading times. Finally, when the peak load was larger, the displacement rate and strain rate increased, but the strain rate in each test exhibited a tendency to become constant after 10 s.

WOOD RESEARCH Volume 64, Number 3, 2019
Shaoxiang Cai, Naihua Zhang, Kang Li, Yanjun Li, and Xinzhou Wang

Effect of pressurized hot water treatment on the mechanical properties, surface color, chemical composition and crystallinity of pine wood

The effect of a pressurized hot water treatment (PHWT) on the mechanical properties, chemical composition, surface color, and cellulose crystalline structure of Pine wood were examined in this study. The effects of PHWT of pine wood at 140, 160, 180, and 200°C for 1, 3 and 5 h were investigated in terms of changes in mechanical properties, chemical composition, surface color and cellulose crystallinity of pine wood by means of a GB/T standard, NREL LAP, Color Difference Meter, and X-ray diffraction (XRD). Both the temperature and treatment time showed significant effects. The results showed that the bending strength and elastic modulus decreased with an increasing temperature and duration. Changes in the chemical components and surface color occurred because of the degradation of the cellulose, hemicelluloses and lignin in the wood during the PHWT. Additionally, the relative degree of relative crystallinity of the samples increased. These findings demonstrated the potential of PHWT for the wood modification.