Hung Ke-Chang, Wu Tung-Lin, Wu Jyh-Horng
Department of Forestry, National Chung Hsing University, Taichung 402, Taiwan.
College of Technology and Master of Science in Computer Science, University of North America, Fairfax, VA 22033, USA.
Polymers (Basel). 2019 Jul 20;11(7):1215. doi: 10.3390/polym11071215.
In this study, methyltrimethoxysilane (MTMOS), methyltriethoxysilane (MTEOS), tetraethoxysilane (TEOS), and titanium(IV) isopropoxide (TTIP) were used as precursor sols to prepare wood-inorganic composites (WICs) by a sol-gel process, and subsequently, the long-term creep behavior of these composites was estimated by application of the stepped isostress method (SSM). The results revealed that the flexural modulus of wood and WICs were in the range of 9.8-10.5 GPa, and there were no significant differences among them. However, the flexural strength of the WICs (93-103 MPa) was stronger than that of wood (86 MPa). Additionally, based on the SSM processes, smooth master curves were obtained from different SSM testing parameters, and they fit well with the experimental data. These results demonstrated that the SSM was a useful approach to evaluate the long-term creep behavior of wood and WICs. According to the Eyring equation, the activation volume of the WICs prepared from MTMOS (0.825 nm) and TEOS (0.657 nm) was less than that of the untreated wood (0.832 nm). Furthermore, the WICs exhibited better performance on the creep resistance than that of wood, except for the WIC. The reduction of time-dependent modulus for the WIC prepared from MTMOS was 26% at 50 years, which is the least among all WICs tested. These findings clearly indicate that treatment with suitable metal alkoxides could improve the creep resistance of wood.
在本研究中，甲基三甲氧基硅烷（MTMOS）、甲基三乙氧基硅烷（MTEOS）、四乙氧基硅烷（TEOS）和异丙醇钛（IV）（TTIP）被用作前驱体溶胶，通过溶胶 - 凝胶法制备木材 - 无机复合材料（WICs），随后，采用阶梯等应力法（SSM）评估这些复合材料的长期蠕变行为。结果表明，木材和WICs的弯曲模量在9.8 - 10.5 GPa范围内，它们之间没有显著差异。然而，WICs的弯曲强度（93 - 103 MPa）比木材（86 MPa）更强。此外，基于SSM过程，从不同的SSM测试参数获得了光滑的主曲线，并且它们与实验数据拟合良好。这些结果表明，SSM是评估木材和WICs长期蠕变行为的一种有用方法。根据艾林方程，由MTMOS（0.825 nm）和TEOS（0.657 nm）制备的WICs的活化体积小于未处理木材的活化体积（0.832 nm）。此外，除了由MTMOS制备的WIC外，WICs在抗蠕变性能方面表现优于木材。由MTMOS制备的WIC在50年时随时间变化的模量降低了26%，这是所有测试的WICs中最低的。这些发现清楚地表明，用合适的金属醇盐处理可以提高木材的抗蠕变性能。
