R&D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan University , Chung Li 32023, Taiwan.
Department of Chemical Engineering, University of Arkansas , Fayetteville, Arkansas 72701, United States.
Environ Sci Technol. 2016 Nov 1;50(21):11935-11942. doi: 10.1021/acs.est.6b02102. Epub 2016 Oct 11.
A thermoresponsive chitosan derivative was synthesized by reacting chitosan (CS) with butyl glycidyl ether (BGE) to break the inter- and intramolecular hydrogen bonds of the polymer. An aqueous solution of the thermoresponsive CS derivative exhibits a lower critical solution temperature (LCST) than CS, and it undergoes a phase transition separation when the temperature changes. Successful incorporation of BGE into the CS was confirmed by FTIR and XPS analyses. Varying the BGE content and the concentration of the aqueous solution produced different LCST ranges, as shown by transmittance vs temperature curves. The particle size was observed by scanning electron microscopy, which revealed that the particles were smaller and well dispersed at 15 °C, whereas the particles became larger and tended to aggregate at 60 °C. A similar trend was observed with the mean particle size measured using dynamic light scattering. Positron annihilation lifetime spectroscopy data also revealed the reversibility of the particle properties as a function of temperature. Microstructure analysis showed that the particles had larger free-volume sizes at 15 °C than at 60 °C. The particles were also found to be nontoxic with 92% cell survival. A simple forward osmosis (FO) test for dye dehydration revealed the potential use of the thermoresponsive chitosan derivative as a draw solute with a flux of 8.6 L/m h and rejection of 99.8%.
一种温敏性壳聚糖衍生物通过壳聚糖（CS）与丁基缩水甘油醚（BGE）反应合成，以打破聚合物的分子间和分子内氢键。温敏性 CS 衍生物的水溶液具有比 CS 更低的临界溶解温度（LCST），并且当温度变化时会发生相分离。FTIR 和 XPS 分析证实了 BGE 成功掺入 CS 中。通过透射率随温度曲线，改变 BGE 含量和水溶液的浓度可以产生不同的 LCST 范围。通过扫描电子显微镜观察到粒径，结果表明在 15°C 时颗粒较小且分散良好，而在 60°C 时颗粒较大且趋于聚集。使用动态光散射测量的平均粒径也表现出相似的趋势。正电子湮没寿命光谱数据还揭示了粒子特性随温度的可逆性。微观结构分析表明，在 15°C 时颗粒的自由体积尺寸大于 60°C 时的尺寸。还发现这些颗粒具有 92%的细胞存活率，无毒性。简单的正向渗透（FO）脱水染料测试表明，温敏性壳聚糖衍生物作为一种具有 8.6 L/m h 的通量和 99.8%的截留率的汲取剂具有潜在的用途。
