Institute of Wood Sciences and Furniture, Warsaw University of Life Sciences - SGGW, 159 Nowoursynowska Str., 02-787, Warsaw, Poland.
Natural Fibers Advanced Technologies, 42A Blekitna Str., 93-322, Lodz, Poland.
Sci Rep. 2020 Nov 17;10(1):19998. doi: 10.1038/s41598-020-77101-2.
Paper degradation on a macroscopic scale is characterised primarily by yellowing, an increase in brittleness, and other destructive changes caused by the hydrolysis of glycoside bonds and oxidation reactions. Until now, lignin has been believed to cause these changes. However, contemporary analysis has not confirmed this assumption and has attributed low paper resistance to ageing with acidification owing to the production in acid environments that involve aluminium sulfate. In view of the common belief this manuscript presents studies on the accelerated ageing of papers with different lignin contents that are produced in neutral environments. To achieve the objective, artificially aged papers under conditions of increased humidity and temperature were investigated using chromatographic (SEC) and spectroscopic (FTIR and UV-Vis spectroscopy) techniques. Mechanical tests were used to determine the decrease in tensile properties of the samples. We observed no effects of the lignin content on the ageing rate of paper produced at neutral pH. This work also reveals the extent to which spectroscopic methods are useful for studying the papers containing lignin.
纸张在宏观尺度上的降解主要表现为变黄、脆性增加以及糖苷键水解和氧化反应引起的其他破坏性变化。到目前为止，人们一直认为木质素是造成这些变化的原因。然而，现代分析并没有证实这一假设，并将纸张的低耐老化性归因于酸化，这是由于在涉及硫酸铝的酸性环境中产生的。考虑到这种普遍的观点，本文介绍了在中性环境中生产的具有不同木质素含量的纸张的加速老化研究。为了实现这一目标，使用色谱（SEC）和光谱（FTIR 和 UV-Vis 光谱）技术研究了在高湿度和高温条件下人工老化的纸张。机械测试用于确定样品拉伸性能的下降。我们没有观察到木质素含量对在中性 pH 值下生产的纸张老化速率的影响。这项工作还揭示了光谱方法在研究含木质素纸张方面的有效性。
