Jin Longming, Gan Jianyun, Hu Gang, Cai Long, Li Zaiquan, Zhang Lihua, Zheng Qiang, Xie Haibo
Department of Polymer Materials & Engineering, College of Materials & Metallurgy, Guizhou University, West Campus, Huaxi District, Guiyang 550025, China.
Polymers (Basel). 2019 Jun 4;11(6):994. doi: 10.3390/polym11060994.
Cellulose films are regarded as sustainable materials having wide applications in food packaging, separation, etc. Their preparation substantially relies on sufficient dissolution. Herein, various celluloses adequately dissolved in a new solvent system of carbon dioxide,1, 8-diazabicyclo [5.4.0] undec-7-ene and dimethyl sulfoxide (CO/DBU/DMSO) were made in to films using different regeneration reagents. The films regenerated from ethanol and methanol presented homogeneous and smooth surfaces, while those from 5 wt % NaOH (aq.) and 5 wt % HSO (aq.) showed rough surfaces, as analyzed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The films regenerated from 5 wt % NaOH (aq.) and 5 wt % HSO (aq.) rendered cellulose II structures, while those regenerated from alcohols had amorphous structures as evidenced using fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) results. The films made of microcrystalline cellulose had a good light transmittance of about 90% at 800 nm with a tensile strength of 55 MPa and an elongation break of 6.5%, while those from wood pulp cellulose demonstrated satisfactory flexibility with a tensile strength of 91 MPa and an elongation break of 9.0%. This research reports a simple, environmental, and sustainable method to prepare cellulose films of good mechanical properties.
纤维素膜被视为具有广泛应用于食品包装、分离等领域的可持续材料。它们的制备很大程度上依赖于充分溶解。在此，将各种纤维素充分溶解在二氧化碳、1,8 - 二氮杂双环[5.4.0]十一碳 - 7 - 烯和二甲基亚砜（CO/DBU/DMSO）的新溶剂体系中，使用不同的再生试剂制成薄膜。通过扫描电子显微镜（SEM）和原子力显微镜（AFM）分析可知，从乙醇和甲醇再生的薄膜呈现出均匀光滑的表面，而从5 wt%氢氧化钠水溶液和5 wt%硫酸水溶液再生的薄膜表面粗糙。从5 wt%氢氧化钠水溶液和5 wt%硫酸水溶液再生的薄膜呈现纤维素II结构，而从醇类再生的薄膜具有无定形结构，这由傅里叶变换红外光谱（FT - IR）和X射线衍射（XRD）结果证明。由微晶纤维素制成的薄膜在800 nm处具有约90%的良好透光率，拉伸强度为55 MPa，断裂伸长率为6.5%，而由木浆纤维素制成的薄膜具有令人满意的柔韧性，拉伸强度为91 MPa，断裂伸长率为9.0%。本研究报道了一种制备具有良好机械性能的纤维素膜的简单、环保且可持续的方法。
