纤维素羧酸钠基半互穿高吸水凝胶的温控溶胀效果

Thermo-tunable Swelling Effect of Cellouronic Acid Sodium-based Superabsorbent Hydrogels

具有温控溶胀性的高吸水凝胶由于其独特的性能,如随环境温度微小变化,材料体积发生多种改变,在学术研究及工业应用领域都属于一种多用途、有前途的功能材料。纤维素羧酸钠(CAS)是一类通过纤维素选择性氧化反应得到的水溶性衍生物,但对其功能凝胶改性的研究鲜有报道。本工作以蔗髓为原料改性得到的CAS为线性聚合物,丙烯酰胺(AM)和二烯丙基二甲基氯化铵(DAC)为共聚单体,N,N'-亚甲基双丙烯酰胺(MBAM)为交联剂,采用序列合成法制得半互穿网络结构的CAS/聚合(AM-co-DAC)凝胶。利用红外光谱、X射线光电子能谱仪及扫描电镜对凝胶化学组成及表面形态进行表征,研究CAS、引发剂用量及介质性质对凝胶在不同温度作用下溶胀能力的影响。结果表明:制备的CAS基凝胶的溶胀度高且受温度控制;随着温度升高,溶胀度提升;溶胀能力及其温控灵敏性取决于凝胶的化学构成及溶液性质。

The high water-absorbent hydrogels with thermo-tunable swelling property represent a versatile and promising class of functional materials in both academic and industrial fields due to their unique characteristics,such as multifold change of volume in response to minute change in the ambient temperature.Cellouronic acid sodium(CAS)is a water-soluble cellulose derivative produced by a selective oxidation of cellulose,but its modification of functional hydrogels was less documented.Based on a sequential synthesis method,the copolymer network was firstly synthesized with acrylamide(AM)and diallyldimethylammonium chloride(DAC)as comonomers,N,N′-methylenebisacrylamide(MABM)as crosslin-ker.Then,linear polymer CAS obtained from bagasse pith,has been introduced into cross-linked poly(AM-co-DAC)to form thermo-sensitive semi-interpenetrating polymer networks(semi-IPNs).The chemical composition and morphology of hydrogel were characterized by FT-IR,XPS and SEM.The effects of CAS dosage,initiator charge and medium property on gel s swelling ability at various temperatures were also investigated.The results showed that the prepared CAS-based gels exhibited a high water-absorbency and temperature-tunable swelling property.The swelling degree enhanced with increasing ambient temperature.Both swelling ability and its thermo-sensitivity largely depended on the chemical structure of the semi-IPNs and the solvent property.