Tsou Chi-Hui, Shui Yu-Jie, Du Juan, Yao Wei-Hua, Wu Chin-San, Suen Maw-Cherng, Chen Shuang
School of Materials Science and Engineering, Sichuan University of Science and Engineering, Zigong 643000, China.
Material Corrosion and Protection Key Laboratory of Sichuan Province, Sichuan University of Science and Engineering, Zigong 643000, China.
Polymers (Basel). 2023 May 31;15(11):2535. doi: 10.3390/polym15112535.
In this investigation, purified attapulgite (ATT) and polyvinyl alcohol (PVA) were utilized to fabricate nanocomposite hydrogels and a xerogel, with a focus on studying the impact of minor additions of ATT on the properties of the PVA nanocomposite hydrogels and xerogel. The findings demonstrated that at a concentration of 0.75% ATT, the water content and gel fraction of the PVA nanocomposite hydrogel reached their peak. Conversely, the nanocomposite xerogel with 0.75% ATT reduced its swelling and porosity to the minimum. SEM and EDS analyses revealed that when the ATT concentration was at or below 0.5%, nano-sized ATT could be evenly distributed in the PVA nanocomposite xerogel. However, when the concentration of ATT rose to 0.75% or higher, the ATT began to aggregate, resulting in a decrease in porous structure and the disruption of certain 3D porous continuous structures. The XRD analysis further affirmed that at an ATT concentration of 0.75% or higher, a distinct ATT peak emerged in the PVA nanocomposite xerogel. It was observed that as the content of ATT increased, the concavity and convexity of the xerogel surface, as well as the surface roughness, decreased. The results also confirmed that the ATT was evenly distributed in the PVA, and a combination of hydrogen bonds and ether bonds resulted in a more stable gel structure. The tensile properties exhibited that when compared with pure PVA hydrogel, the maximum tensile strength and elongation at break were achieved at an ATT concentration of 0.5%, indicating increases of 23.0% and 11.8%, respectively. The FTIR analysis results showed that the ATT and PVA could generate an ether bond, further confirming that ATT could enhance the PVA properties. The TGA analysis showed that the thermal degradation temperature peaked when the ATT concentration was at 0.5%, providing further evidence that the compactness of the nanocomposite hydrogel and the dispersion of the nanofiller was superior, contributing to a substantial increase in the mechanical properties of the nanocomposite hydrogel. Finally, the dye adsorption results displayed a significant rise in dye removal efficiency for methylene blue with the increase in the ATT concentration. At an ATT concentration of 1%, the removal efficiency rose by 103% compared with that of the pure PVA xerogel.
在本研究中，使用纯化的凹凸棒土（ATT）和聚乙烯醇（PVA）制备了纳米复合水凝胶和干凝胶，重点研究了少量添加ATT对PVA纳米复合水凝胶和干凝胶性能的影响。研究结果表明，在ATT浓度为0.75%时，PVA纳米复合水凝胶的含水量和凝胶分数达到峰值。相反，含有0.75%ATT的纳米复合干凝胶的溶胀率和孔隙率降至最低。扫描电子显微镜（SEM）和能谱分析（EDS）表明，当ATT浓度在0.5%及以下时，纳米级的ATT能够均匀分布在PVA纳米复合干凝胶中。然而，当ATT浓度升至0.75%或更高时，ATT开始聚集，导致多孔结构减少，并破坏了某些三维多孔连续结构。X射线衍射（XRD）分析进一步证实，当ATT浓度为0.75%或更高时，PVA纳米复合干凝胶中出现了明显的ATT峰。观察到随着ATT含量的增加，干凝胶表面的凹凸度和表面粗糙度降低。结果还证实，ATT均匀分布在PVA中，氢键和醚键的结合导致凝胶结构更加稳定。拉伸性能表明，与纯PVA水凝胶相比，在ATT浓度为0.5%时达到最大拉伸强度和断裂伸长率，分别提高了23.0%和11.8%。傅里叶变换红外光谱（FTIR）分析结果表明，ATT和PVA可以生成醚键，进一步证实ATT可以增强PVA的性能。热重分析（TGA）表明，当ATT浓度为0.5%时，热降解温度达到峰值，进一步证明纳米复合水凝胶的致密性和纳米填料的分散性更佳，有助于大幅提高纳米复合水凝胶的力学性能。最后，染料吸附结果显示，随着ATT浓度的增加，亚甲基蓝的染料去除效率显著提高。在ATT浓度为1%时，与纯PVA干凝胶相比，去除效率提高了103%。
