【作者】 陈继伟； 施冬健； 肖鑫； 董开杰； 陈明清；

【Author】 Jiwei Chen;Dongjian Shi;Xin Xiao;Kaijie Dong;Mingqing Chen;The Key Laboratory of synthetic and Biological Colloids,Ministry of Education,School of Chemical and Material Engineering,Jiangnan University;

【机构】 合成与生物胶体教育部重点实验室江南大学化学与材料工程学院；

【摘要】 自然生物体统具有复杂的结构以应对复杂的环境条件。而水凝胶作为亲水性聚合物交联网络链,具有与生物体组织相似的结构和性质,因此成为水凝胶是模拟生物系统功能的理想选择之一。但是水凝胶的性质阻碍了其在低温(0℃)和干燥环境下的应用。而最近常见的耐低温和干燥水凝胶通常采用有机试剂置换水凝胶中的水,存在一定的危害。本文依次通过冷冻-解冻法和高温退火(100℃)制备了聚乙烯醇-海藻酸钙双交联网络结构水凝胶,提高水凝胶力学性能的同时降低了水凝胶的自由水含量,赋予水凝胶一定的抗冻性能。未经退火的水凝胶在-20℃环境下冷冻20h后成为硬而脆的白色固体,很容易折断,而经过退火后的水凝胶在-20℃环境下冷冻20 h后反复折叠仍保持原状。通过X射线衍射(XRD)、热重分析(TGA)和差示扫描量热分析(DSC)等对样品进行分析,结果表明退火降低了水凝胶中自由水的含量,促进水凝胶中聚乙烯醇结晶的同时减少了寒冷条件下凝胶中水的结晶。更多还原

【Abstract】 Natural living systems display complex structures to survive in complicated environmental conditions. Hydrogels as a hydrophilic polymer cross-linked network chain, have similar structures and properties with biological tissues, so they become one of the ideal candidates to mimic the functions of biological systems. However, the properties of hydrogels make them lack anti-freezing and non-drying properties, which hinders the application of hydrogels at sub-zero temperatures in long term. Recently prepared anti-freezing and non-drying hydrogels usually used organic reagents to replace the water in hydrogels, which has certain harm. In this paper, frozen-thawed and annealing(100 ℃) was used to prepared polyvinyl alcohol-calcium alginate double cross-linked hydrogel, it endows hydrogels with anti-freezing properties while the mechanical properties of hydrogels enhanced. Unannealed hydrogels become hard and brittle after being frozen for 20 h at-20 ℃, which is easy to break, while annealed hydrogels remain intact after being repeatedly folded after being frozen for 20 h at-20 ℃.Through X-ray diffraction(XRD), thermogravimetric analysis(TGA) and differential scanning calorimetry analysis(DSC) analysis of samples, the results showed that, annealing reduced the free water content in the hydrogel, promoted the crystallization of poly(vinyl alcohol) hydrogel, and calcium ions and annealing synergy significantly decreased the crystallization of the water in the hydrogel.更多还原