Hung Ke-Chang, Wu Jyh-Horng
Department of Forestry, National Chung Hsing University, Taichung 402, Taiwan.
Polymers (Basel). 2018 Apr 6;10(4):409. doi: 10.3390/polym10040409.
In this study, methyltrimethoxysilane (MTMOS) was used as a reagent to prepare SiO₂-based wood-inorganic composites (WIC) via the sol-gel process, and subsequently, the extended creep behaviors of WIC with weight percent gains (WPGs) of 10%, 20%, and 30% were estimated using the stepped isostress method (SSM). The results revealed that the density of all samples ranged from 426 to 513 kg/m³, and no significant difference in the modulus of elasticity (MOE) was noted among all of the samples (10.5⁻10.7 GPa). However, the MOR of WIC with a WPG of 20% (102 MPa) was significantly greater than that of untreated wood (87 MPa). In addition, according to the result using the SSM, the SSM-predicted creep master curve fitted well with the experimental data for the untreated wood and WIC. This result demonstrated that the SSM could be a useful method to evaluate long-term creep behaviors of wood and WIC. Furthermore, the activation volume (*) of the specimens was calculated from the linear slope of Eyring plots, and the resulting * of all of the WIC (0.754⁻0.842 nm³) was lower than that of untreated wood (0.856 nm³). On the other hand, the modulus reduction of untreated wood showed 39%, 45%, 48%, and 51% at 5, 15, 30, and 50 years, respectively. In contrast, the modulus reduction of the WIC with a WPG of 10% decreased to 25%, 31%, 35%, and 38% at 5, 15, 30, and 50 years, respectively. Similar trends were also observed for other WIC with different WPGs. Of these, the WIC with a WPG of 20% exhibited the lowest reduction in time-dependent modulus (31%) over a 50-year period. Accordingly, the creep resistance of the wood could be effectively enhanced under the MTMOS treatment.
在本研究中，使用甲基三甲氧基硅烷（MTMOS）作为试剂，通过溶胶 - 凝胶法制备了基于SiO₂的木材 - 无机复合材料（WIC），随后，使用阶梯等应力法（SSM）评估了增重率（WPG）分别为10%、20%和30%的WIC的长期蠕变行为。结果表明，所有样品的密度范围为426至513 kg/m³，所有样品的弹性模量（MOE）没有显著差异（10.5⁻10.7 GPa）。然而，WPG为20%的WIC的抗弯强度（MOR）（102 MPa）显著高于未处理木材（87 MPa）。此外，根据使用SSM的结果，SSM预测的蠕变主曲线与未处理木材和WIC的实验数据拟合良好。该结果表明，SSM可能是评估木材和WIC长期蠕变行为的有用方法。此外，根据艾林曲线的线性斜率计算了试样的激活体积（），所有WIC的所得（0.754⁻0.842 nm³）低于未处理木材（0.856 nm³）。另一方面，未处理木材的模量降低在5年、15年、30年和50年时分别为39%、45%、48%和51%。相比之下，WPG为10%的WIC的模量降低在5年、15年、30年和50年时分别降至25%、31%、35%和38%。对于其他不同WPG的WIC也观察到类似趋势。其中，WPG为20%的WIC在50年期间表现出最低的随时间变化的模量降低（31%）。因此，在MTMOS处理下，木材的抗蠕变性能可以得到有效提高。
