Sehn Timo, Meier Michael A R
Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.
Institute of Organic Chemistry (IOC), Materialwissenschaftliches Zentrum (MZE), Karlsruhe Institute of Technology (KIT), Straße am Forum 7, 76131 Karlsruhe, Germany.
Biomacromolecules. 2023 Nov 13;24(11):5255-5264. doi: 10.1021/acs.biomac.3c00762. Epub 2023 Oct 15.
Increasing environmental pollution and petroleum resource depletion are important indicators for the necessary and inevitable replacement of fossil-based polymeric materials with more sustainable counterparts. Hence, the development of bio-based materials from renewable resources, such as cellulose, is of great importance. Herein, we introduce a rapid and homogeneous microwave assisted synthesis of high molecular weight (59 kDa ≤ ≤ 116 kDa) short chain (mixed) cellulose esters (CEs) with variable acyl side chain length (2 ≤ ≤ 8) by using a DMSO/TMG/CO switchable solvent system. Accordingly, (mixed) CEs were synthesized by implementing tetramethylguanidine (TMG) into a switchable solvent system (DMSO/TMG/CO), followed by in-depth structural characterization via IR, H NMR, C NMR, and SEC. Examination of the structure-property relationships revealed a decrease in the glass transition temperature (177 °C ≤ ≤ 204 °C), an increase in surface hydrophobicity, i.e., water contact angle (WCA) (65° ≤ WCA ≤ 98°), and a decrease of Young's modulus (7.51 MPa ≤ ≤ 13.6 MPa), with longer alkyl side chains.
日益严重的环境污染和石油资源枯竭是用更具可持续性的材料替代化石基聚合物材料的必要性和必然性的重要指标。因此，从可再生资源（如纤维素）开发生物基材料具有重要意义。在此，我们介绍了一种快速且均匀的微波辅助合成方法，通过使用二甲基亚砜/四甲基胍/一氧化碳可切换溶剂体系，合成具有可变酰基侧链长度（2≤≤8）的高分子量（59 kDa≤≤116 kDa）短链（混合）纤维素酯（CEs）。相应地，通过将四甲基胍（TMG）引入可切换溶剂体系（二甲基亚砜/TMG/一氧化碳）中来合成（混合）CEs，随后通过红外光谱、氢核磁共振、碳核磁共振和尺寸排阻色谱进行深入的结构表征。对结构-性能关系的研究表明，随着烷基侧链变长，玻璃化转变温度降低（177°C≤≤204°C），表面疏水性增加，即水接触角（WCA）增大（65°≤WCA≤98°），杨氏模量降低（7.51 MPa≤≤13.6 MPa）。
