Broda Magdalena, Spear Morwenna J, Curling Simon F, Ormondroyd Graham A
Department of Wood Science and Thermal Techniques, Faculty of Forestry and Wood Technology, Poznań University of Life Sciences, Wojska Polskiego 38/42, 60-637 Poznań, Poland.
BioComposites Centre, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK.
Materials (Basel). 2021 Sep 8;14(18):5150. doi: 10.3390/ma14185150.
Waterlogged wood treatment with methyltrimethoxysilane (MTMS) proved effective in stabilising wood dimensions upon drying (anti-shrink efficiency of 76-93%). Before the method can be proposed as a reliable conservation treatment, further research is required that includes the evaluation of the mechanical properties of treated wood. The aim of the study was to characterise the effect of the treatment on the viscoelastic behaviour of archaeological waterlogged elm and oak wood differing in the degree of degradation. Dynamic mechanical analysis in the temperature range from -150 to +150 °C was used for the study. To better understand the viscoelastic behaviour of the treated wood, pore structure and moisture properties were also investigated using Scanning Electron Microscopy, nitrogen sorption, and Dynamic Vapour Sorption. The results clearly show that methyltrimethoxysilane not only prevents collapse and distortions of the degraded cell walls and decreases wood hygroscopicity (by more than half for highly degraded wood), but also reinforces the mechanical strength by increasing stiffness and resistance to deformation for heavily degraded wood (with an increase in storage modulus). However, the MTMS also has a plasticising effect on treated wood, as observed in the increased value of loss modulus and introduction of a new tan δ peak). On the one hand, methyltrimethoxysilane reduces wood hygroscopicity that reflects in lower wood moisture content, thus limiting the plasticising effect of water on wood polymers, but on the other hand, as a polymer itself, it contributes to the viscous behaviour of the treated wood. Interestingly, the effect of silane differs with both the wood species and the degree of wood degradation.
用甲基三甲氧基硅烷（MTMS）处理水浸木材被证明在干燥时能有效稳定木材尺寸（抗收缩效率为76 - 93%）。在该方法被提议作为一种可靠的保护处理方法之前，还需要进一步的研究，包括对处理后木材力学性能的评估。本研究的目的是表征该处理对不同降解程度的考古水浸榆木和橡木粘弹性行为的影响。研究采用了在-150至+150°C温度范围内的动态力学分析。为了更好地理解处理后木材的粘弹性行为，还使用扫描电子显微镜、氮吸附和动态蒸汽吸附研究了孔隙结构和水分特性。结果清楚地表明，甲基三甲氧基硅烷不仅能防止降解细胞壁的坍塌和变形，并降低木材的吸湿性（对于高度降解的木材降低超过一半），而且还通过提高重度降解木材的刚度和抗变形能力（储能模量增加）来增强机械强度。然而，MTMS对处理后的木材也有增塑作用，如损耗模量值增加和出现新的tan δ峰所示。一方面，甲基三甲氧基硅烷降低了木材的吸湿性，这反映在较低的木材含水量上，从而限制了水对木材聚合物的增塑作用，但另一方面，作为一种聚合物本身，它促成了处理后木材的粘性行为。有趣的是，硅烷的效果因木材种类和木材降解程度而异。
