纤维素纳米纤维接枝聚丙烯酸pH响应水凝胶的制备及性能

Synthesis and Properties of pH-responsive Cellulose-g-PAA Nanofiber Hydrogels

以硝酸铈铵为引发剂,将具有pH响应的聚丙烯酸(PAA)接枝到电纺纤维素(Cell)纳米纤维膜上,制备了pH响应纤维素接枝聚丙烯酸(Cell-g-PAA)纳米纤维水凝胶。研究了接枝单体丙烯酸(N)与纤维素(c)质量比对Cell-g-PAA形貌、接枝率和溶胀性的影响。结果表明:m(N)∶m(c)值从5增加到10,接枝率从11%急剧增加到28%,然后趋于平稳;而m(N)∶m(c)值从5增加到15,溶胀率从(15.2±1.6)g/g增加到(46.1±4.9)g/g,然后下降。同时,研究了pH值和离子强度对水凝胶溶胀率的影响,pH值从2.2增加到7.8时,水凝胶的溶胀率从(31.3±2.5)g/g增加到(42.7±3.2)g/g,pH值进一步增大,溶胀率降低;溶液中离子强度从0mol/L增加到0.15mol/L,水凝胶溶胀率从(36.2±2.6)g/g降低到(21.4±1.4)g/g。本研究为制备快速响应pH水凝胶提供了一种新方法。

Cellulose-g-PAA nanofiber hydrogels with pH-responsive were synthesized by graft copolymerization of pH-responsive polyacrylic acid（PAA）on to electrospun cellulose nanofibrous membranes with ammonium ceric nitrate as initiator.The effect of m（N）/m（c）on the morphology,grafting rate and swelling rate of cell-g-PAA nanofiber hydrogels were investigated.The results showed that the grafting rate of cell-g-PAA nanofiber hydrogels rapidly increased from 11% to 28% with increasing m（N）/m（c）from 5 to 10,and then leveled off.The swelling rate of cell-g-PAA nanofiber hydrogels increased from（15.2±1.6）g/g to（46.1±4.9）g/g with increasing m（N）/m（c）from 5 to 15,and then decreased.The effect of pH and ionic strength on the swelling rate of hydrogels were investigated.When the pH value changed from 2.2 to 7.8,the swelling rate increased from（31.3±2.5）g/g to（42.7±3.2）g/g,and then decreased.Moreover,the swelling rate decreased from（36.2±2.6）g/g to（21.4±1.4）g/g when ionic strength increased from 0 mol/L to 0.15 mol/L.This research provides a new approach to fabricate hydrogels with great sensitivity to pH value.