强化复合木材细胞壁的纳米压痕测试分析

Nanoindentation test and analysis of cell wall of strengthened composite wood

通过纳米压痕测试技术,测定和分析了未处理材和经硅溶胶强化处理的复合木材细胞壁层面的力学性能和弹塑性,以及硅溶胶的存在位置对强化复合木材细胞壁微观力学性能的影响。结果表明:1)浸渍强化处理工艺可以使硅溶胶进入木材细胞壁,使得强化复合木材细胞壁的弹性模量和硬度达到18.64和0.64GPa,分别比未处理材提高59%和31%;2)控制改性处理工艺,可以得到改性细胞壁和既有改性细胞壁又有填充细胞腔2种改性形式的强化复合木材,并且2种改性形式下细胞壁层面上的弹性模量和硬度没有显著差异,证实了细胞腔填充对细胞壁层面的力学性能没有影响;3)复合木材细胞壁形貌表征和力学测试曲线表明,硅溶胶强化处理后的复合木材细胞壁保持了较好的弹塑性特性,相对弹性回复率与未处理材基本相同。

The mechanical properties and elastic-plastic of samples untreated and strengthened by silica sol using nanoindentation method were tested and analyzed. And the impacts of silica sol location on micro- mechanical properties of wood cell wall were also analyzed in this paper. The testing results indicated that： 1 ） the silica sol can be introduced into wood cell wall through impregnating process,and the modulus and hardness of cell wall of composite wood were 18. 64 and 0. 64 GPa,increased by 59% and 31% than untreated wood,respectively. 2） Two kinds of composite wood,the modified cell wall and the bulked cell wall,can be prepared through different vacuum-pressure processes,and the modulus and hardness of the two kinds of composite wood had no significant differences. It was indicated clearly that the filled lumina had no effects on the nano-mechanical properties of wood cell wall. 3 ） The cell wall morphology of the composite wood and testing curve analysis of nanoindentation showed that the wood cell wall after silica sol treated had the same relative elastic recovery rate with that of untreated wood,and still maintained the good elastic properties.