Choo Kaiwen, Ching Yern Chee, Chuah Cheng Hock, Julai Sabariah, Liou Nai-Shang
Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia.
Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia.
Materials (Basel). 2016 Jul 29;9(8):644. doi: 10.3390/ma9080644.
In this study microcrystalline cellulose (MCC) was oxidized by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation. The treated cellulose slurry was mechanically homogenized to form a transparent dispersion which consisted of individual cellulose nanofibers with uniform widths of 3-4 nm. Bio-nanocomposite films were then prepared from a polyvinyl alcohol (PVA)-chitosan (CS) polymeric blend with different TEMPO-oxidized cellulose nanofiber (TOCN) contents (0, 0.5, 1.0 and 1.5 wt %) via the solution casting method. The characterizations of pure PVA/CS and PVA/CS/TOCN films were performed in terms of field emission scanning electron microscopy (FESEM), tensile tests, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The results from FESEM analysis justified that low loading levels of TOCNs were dispersed uniformly and homogeneously in the PVA-CS blend matrix. The tensile strength and thermal stability of the films were increased with the increased loading levels of TOCNs to a maximum level. The thermal study indicated a slight improvement of the thermal stability upon the reinforcement of TOCNs. As evidenced by the FTIR and XRD, PVA and CS were considered miscible and compatible owing to hydrogen bonding interaction. These analyses also revealed the good dispersion of TOCNs within the PVA/CS polymer matrix. The improved properties due to the reinforcement of TOCNs can be highly beneficial in numerous applications.
在本研究中，微晶纤维素（MCC）通过2,2,6,6-四甲基哌啶-1-氧基自由基（TEMPO）介导的氧化反应进行氧化处理。将处理后的纤维素浆液进行机械均质化，以形成一种透明分散体，该分散体由宽度均匀为3-4纳米的单个纤维素纳米纤维组成。然后，通过溶液浇铸法，由具有不同TEMPO氧化纤维素纳米纤维（TOCN）含量（0、0.5、1.0和1.5重量％）的聚乙烯醇（PVA）-壳聚糖（CS）聚合物共混物制备生物纳米复合薄膜。通过场发射扫描电子显微镜（FESEM）、拉伸试验、热重分析（TGA）、傅里叶变换红外光谱（FTIR）和X射线衍射（XRD）对纯PVA/CS和PVA/CS/TOCN薄膜进行表征。FESEM分析结果表明，低含量的TOCNs均匀且均质地分散在PVA-CS共混基质中。随着TOCNs含量的增加，薄膜的拉伸强度和热稳定性提高到最大值。热学研究表明，添加TOCNs后热稳定性略有提高。FTIR和XRD证明，由于氢键相互作用，PVA和CS被认为是可混溶且相容的。这些分析还揭示了TOCNs在PVA/CS聚合物基质中的良好分散性。由于添加TOCNs而改善的性能在众多应用中可能非常有益。
