Chen Pei, Xie Fengwei, Tang Fengzai, McNally Tony
College of Food Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.
International Institute for Nanocomposites Manufacturing (IINM), WMG, University of Warwick, Coventry CV4 7AL, United Kingdom.
ACS Omega. 2020 Jul 22;5(30):19070-19081. doi: 10.1021/acsomega.0c02418. eCollection 2020 Aug 4.
The structure and properties of different biopolymer composites based on chitosan and chitosan/carboxymethyl cellulose (CMC) are governed by multiple structure-property relationships associated with different phase interactions. Plasticization of these matrices with ionic liquid 1-ethyl-3-methylimidazolium acetate ([Cmim][OAc]) played a dominant role, increasing the mobility of biopolymer chains as well as ions and associated dipoles but reducing biopolymer chain interactions, crystallinity, and thermal stability. These structural changes led to higher matrix ionic conductivity, shorter electrical relaxation time, and greater matrix ductility. The inclusion of graphene oxide (GO) and reduced GO (rGO) also influenced the structure and properties of these bionanocomposites by disrupting the biopolymer hydrogen bonding and/or polyelectrolyte complexation (PEC) and interacting with [Cmim][OAc]. The impact of GO/rGO was more evident for 20 wt % [Cmim][OAc], such as increased crystallinity and thermal stability of chitosan. PEC was hindered with excess (40 wt %) [Cmim][OAc] added and further hindered again when rGO was included. This study shows that the structure and properties of bionanocomposites are not just determined by the surface chemistry of GO/rGO but can also be influenced by multiple interactions involving plasticizers such as ILs and additional biopolymers.
基于壳聚糖以及壳聚糖/羧甲基纤维素（CMC）的不同生物聚合物复合材料的结构与性能，受与不同相相互作用相关的多种结构-性能关系的支配。用离子液体1-乙基-3-甲基咪唑鎓乙酸盐（[Cmim][OAc]）对这些基体进行增塑起了主导作用，它增加了生物聚合物链以及离子和相关偶极子的流动性，但减少了生物聚合物链间的相互作用、结晶度和热稳定性。这些结构变化导致了更高的基体离子电导率、更短的电弛豫时间以及更大的基体延展性。氧化石墨烯（GO）和还原氧化石墨烯（rGO）的加入，也通过破坏生物聚合物的氢键和/或聚电解质络合（PEC）以及与[Cmim][OAc]相互作用，影响了这些生物纳米复合材料的结构与性能。对于20 wt%的[Cmim][OAc]，GO/rGO的影响更为明显，比如壳聚糖的结晶度和热稳定性增加。加入过量（40 wt%）的[Cmim][OAc]会阻碍PEC，而加入rGO时会进一步阻碍PEC。这项研究表明，生物纳米复合材料的结构与性能不仅由GO/rGO的表面化学决定，还会受到涉及增塑剂（如离子液体）和其他生物聚合物的多种相互作用的影响。
