Sivaranjana P, Nagarajan E R, Rajini N, Jawaid M, Rajulu A Varada
Department of Chemistry, Kalasalingam University, Krishnankoil 626126, Tamil Nadu, India.
Centre for Composite Materials, Department of Mechanical Engineering, Kalasalingam University, Krishnankoil 626126, Tamil Nadu, India; Biocomposite Technology Laboratory, Institute of Tropical Forestry and Forest Products (INTROP), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
Int J Biol Macromol. 2017 Jun;99:223-232. doi: 10.1016/j.ijbiomac.2017.02.070. Epub 2017 Feb 23.
Cotton linters were dissolved in aq. (8% LiOH+15% urea) that was pre-cooled to -12.5°C. Using this solution cellulose gel films were prepared by regeneration method with ethyl alcohol as a coagulant. These wet films were diffused with 10wt% Cassia alata leaf extract that acted as a reducing agent. The leaf extract diffused cellulose wet films were used as the matrix. The wet matrix films were dipped individually in lower concentrated 1-5mM aq.AgNO source solutions in the presence of sunlight and allowed the solutions to react with the diffused leaf extract reducing agent which in situ generated the silver nanoparticles (AgNPs) inside the films as well as in the source solution. The AgNPs formed in the source solution were observed by transmission electron microscope (TEM) and scanning electron microscope (SEM) while those formed in situ the films were observed by SEM and the particle size distribution was determined. The cellulose/AgNP composite films showed good antibacterial activity against Escherichia coli bacteria. These nanocomposite films were also characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and tensile tests. At temperatures below 300°C, the thermal stability of the nanocomposite films was lower than that of the matrix due to the catalytic effect of AgNPs. The nanocomposite films also possessed good tensile properties. The ecofriendly cellulose/AgNP composite films with good antibacterial activity and tensile properties can be considered for medical applications like dressing materials.
棉短绒溶解于预先冷却至-12.5°C的水相（8%氢氧化锂+15%尿素）中。使用该溶液，以乙醇作为凝固剂，通过再生方法制备纤维素凝胶膜。这些湿膜用10wt%的铁刀木叶提取物进行扩散处理，该提取物作为还原剂。经叶提取物扩散处理的纤维素湿膜用作基质。将湿的基质膜在阳光照射下分别浸入较低浓度的1-5mM水相硝酸银源溶液中，使溶液与扩散的叶提取物还原剂反应，从而在膜内以及源溶液中原位生成银纳米颗粒（AgNPs）。通过透射电子显微镜（TEM）和扫描电子显微镜（SEM）观察源溶液中形成的AgNPs，而通过SEM观察膜内原位形成的AgNPs，并测定粒径分布。纤维素/AgNP复合膜对大肠杆菌显示出良好的抗菌活性。这些纳米复合膜还通过傅里叶变换红外（FTIR）光谱、X射线衍射（XRD）、热重分析（TGA）和拉伸试验进行了表征。在低于300°C的温度下，由于AgNPs的催化作用，纳米复合膜的热稳定性低于基质。纳米复合膜还具有良好的拉伸性能。具有良好抗菌活性和拉伸性能的环保型纤维素/AgNP复合膜可考虑用于诸如敷料材料等医疗应用。
