Department of Organic Technology, Catalysis and Petroleum Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava I, 81237 Bratislava, Slovakia.
Department of Wood, Pulp and Paper at the Institute of Natural and Synthetic Polymers, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, 81107 Bratislava, Slovakia.
Molecules. 2022 Apr 30;27(9):2855. doi: 10.3390/molecules27092855.
Samples of papers artificially (2 to 60 days) and naturally (10, 45, and 56 years) aged were studied by the Py-GC/MS method to identify decomposition products. Possible reaction scenarios for cellulose degradation were developed. One of the degradation products is acetic acid, which can (auto)catalyze the cleavage of cellulose β(1→4)-glycosidic bonds of cellulose polymer chains. However, during 20 s of Py-GC/MS analysis, temperatures of up to 300 °C did not significantly increase or modify the formation of decomposition products of paper components. At 300 °C, the amount of several cellulose decomposition products increased regularly depending on the number of days of artificial aging and natural aging, demonstrated mainly by the generation of 2-furancarboxaldehyde, 5-hydroxymethylfurfural, and levoglucosan and its consecutive dehydration products. No correlation between the amount of lignin decomposition products and the time of aging was found when the pyrolysis was performed at 300 °C and 500 °C. Compounds present in the products of decomposition at 500 °C bear the imprint of the chemical composition of the sampled paper. Pyrograms taken at 300 °C using the Py-GC/MS method can give additional information on the changes in the chemical structure of paper during natural or artificial aging, mainly about the cleavage of β(1→4)-glycosidic bonds during aging.
对人工（2 至 60 天）和自然（10、45 和 56 年）老化的纸张样本进行了 Py-GC/MS 方法研究，以鉴定分解产物。开发了纤维素降解的可能反应方案。一种降解产物是乙酸，它可以（自动）催化纤维素聚合物链中纤维素β(1→4)-糖苷键的断裂。然而，在 20 秒的 Py-GC/MS 分析中，高达 300°C 的温度并没有显著增加或改变纸张成分分解产物的形成。在 300°C 时，几种纤维素分解产物的数量根据人工老化和自然老化的天数而有规律地增加，这主要是通过生成 2-糠醛、5-羟甲基糠醛和左旋葡聚糖及其连续脱水产物来证明的。当在 300°C 和 500°C 下进行热解时，未发现木质素分解产物的量与老化时间之间存在相关性。在 500°C 下分解产物中存在的化合物带有所采样纸张化学成分的印记。在 300°C 下使用 Py-GC/MS 方法获得的热谱图可以提供有关纸张在自然或人工老化过程中化学结构变化的额外信息，主要是关于老化过程中β(1→4)-糖苷键的断裂。
