Cichosz Stefan, Masek Anna
Institute of Polymer and Dye Technology, Faculty of Chemistry, Lodz University of Technology, Stefanowskiego 12/16, 90-924 Lodz, Poland.
Polymers (Basel). 2020 Feb 21;12(2):484. doi: 10.3390/polym12020484.
When considering cellulose (UFC100) modification, most of the processes employ various solvents in the role of the reaction environment. The following article addresses a solvent-free method, thermal drying, which causes a moisture content decrease in cellulose fibers. Herein, the moisture content in UFC100 was analyzed with spectroscopic methods, thermogravimetric analysis, and differential scanning calorimetry. During water desorption, a moisture content drop from approximately 6% to 1% was evidenced. Moreover, drying may bring about a specific variation in cellulose's chemical structure. These changes affected the cellulose-filled polymer composite's properties, e.g., an increase in tensile strength from 17 MPa for the not-dried UFC100 to approximately 30 MPa (dried cellulose; 24 h, 100 °C) was observed. Furthermore, the obtained tensile test results were in good correspondence with Payne effect values, which changed from 0.82 MPa (not-dried UFC100) to 1.21 MPa (dried fibers). This raise proves the reinforcing nature of dried UFC100, as the Payne effect is dependent on the filler structure's development within a polymer matrix. This finding paves new opportunities for natural fiber applications in polymer composites by enabling a solvent-free and efficient cellulose modification approach that fulfils the sustainable development rules.
在考虑纤维素（UFC100）改性时，大多数工艺都采用各种溶剂作为反应环境。以下文章介绍了一种无溶剂方法——热干燥，它能降低纤维素纤维中的水分含量。在此，采用光谱法、热重分析和差示扫描量热法对UFC100中的水分含量进行了分析。在水分解吸过程中，证明水分含量从约6%降至1%。此外，干燥可能会使纤维素的化学结构发生特定变化。这些变化影响了纤维素填充聚合物复合材料的性能，例如，观察到拉伸强度从不干燥的UFC100的17 MPa增加到约30 MPa（干燥纤维素；24小时，100℃）。此外，获得的拉伸试验结果与佩恩效应值非常吻合，佩恩效应值从不干燥的UFC100的0.82 MPa变为1.21 MPa（干燥纤维）。这种提高证明了干燥的UFC100的增强性质，因为佩恩效应取决于聚合物基体中填料结构的发展。这一发现为天然纤维在聚合物复合材料中的应用开辟了新机遇，通过实现一种符合可持续发展规则的无溶剂且高效的纤维素改性方法。
