Bhattacharya Sayantani, Shunmugam Raja
Polymer Research Centre, Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India.
ACS Omega. 2020 Feb 5;5(6):2800-2810. doi: 10.1021/acsomega.9b03554. eCollection 2020 Feb 18.
With the aim to develop chemical adsorbents that are inherently nontoxic to living beings and the environment, a gel system based on thiol-norbornene photoclick chemistry was developed. Norbornene was strategically functionalized with different poly(ethylene glycol) (PEG) chains to produce PEG-functionalized macromonomers. The influence of incorporating PEG in the cross-linked network was evaluated on the basis of its physical properties and dye-removing efficiency from aqueous solutions. The excellent swelling ability of the gels in organic solvents was found to improve with the PEG chain length. The rheological measurements of the as-synthesized materials also exhibited the presence of elasticity in the network, and a decrease in storage and loss moduli was observed with an increase in PEG molecular weight. The materials possess excellent thermal stability, which enhanced with an increase in PEG chain length, as revealed from thermogravimetric analysis (TGA). Differential scanning calorimetry (DSC) studies revealed the tendency of higher-molecular-weight PEG to form a crystalline phase in the network. Kinetic studies of dye removal from aqueous solutions by the as-prepared cross-linked networks indicate that the dye removal proceeds via pseudo-second-order kinetics. The study of adsorption isotherm of the removal process indicates that the adsorption follows the Langmuir isotherm model. In this present work, we have thoroughly evaluated the influence of PEG chain length on several physical properties and toxic cationic dye removal efficiencies of thiol-norbornene photo-cross-linked networks.
为了开发对生物和环境本质无毒的化学吸附剂，基于硫醇-降冰片烯光点击化学开发了一种凝胶体系。通过不同的聚乙二醇（PEG）链对降冰片烯进行策略性功能化，以制备PEG功能化的大分子单体。基于其物理性质和从水溶液中去除染料的效率，评估了PEG在交联网络中的掺入影响。发现凝胶在有机溶剂中的优异溶胀能力随PEG链长的增加而提高。合成材料的流变学测量也表明网络中存在弹性，并且随着PEG分子量的增加，储能模量和损耗模量降低。热重分析（TGA）表明，材料具有优异的热稳定性，且随着PEG链长的增加而增强。差示扫描量热法（DSC）研究表明，高分子量PEG在网络中有形成结晶相的趋势。对所制备的交联网络从水溶液中去除染料的动力学研究表明，染料去除遵循准二级动力学。去除过程的吸附等温线研究表明，吸附遵循朗缪尔等温线模型。在本工作中，我们全面评估了PEG链长对硫醇-降冰片烯光交联网络的几种物理性质和有毒阳离子染料去除效率的影响。
