通过正离子聚合原位制备壳聚糖-g-聚四氢呋喃接枝共聚物/银纳米复合材料  

In situ Synthesis and Characterization of Chitosan-g-polytetrahydrofuran Graft Copolymer/Ag Nanocomposite via Living Cationic Polymerization

作　　者：常添笑 张航天[1] 卢聪杰 吴一弦[1] Tian-xiao Chang;Hang-tian Zhang;Cong-jie Lu;Yi-xian Wu(State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing Laboratory of Biomedical Materials, Beijing 100029)

机构地区：[1]北京化工大学化工资源有效利用国家重点实验室生物医用材料北京实验室,北京100029

出　　处：《高分子学报》2018年第6期700-711,共12页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号51521062;21574007)资助项目

摘　　要：采用活性正离子开环聚合方法合成聚四氢呋喃(PTHF)活性链,再通过"grafting onto"方式接枝到壳聚糖(CS)刚性主链上,原位制备壳聚糖-g-聚四氢呋喃接枝共聚物/银纳米复合材料.采用FTIR、1H-NMR和XPS分别表征该接枝共聚物化学结构,采用AFM、TEM、HR-TEM、POM、SEM、TGA和UV研究复合材料的Ag含量、微观结构与形态,并研究该复合材料的载药/释药性和抗菌性能.结果表明:通过上述方法可以原位制备出壳聚糖-g-聚四氢呋喃接枝共聚物/银(CS-g-PTHF/Ag)纳米复合材料,PTHF支链的平均分子量为1400~2600,以1000个氨基葡萄糖环为整体计算接枝链PTHF的平均支链数目为4~21,纳米Ag的质量含量为2.2%~5.7%.所制备的CS-g-PTHF接枝共聚物形成明显的微观相分离结构,主链CS的结晶性随着侧链PTHF接枝数目增大而受到限制,结晶形态发生变化;CS-gPTHF接枝共聚物可作为药物载体,载药率在53%~80%之间,载药微球的尺寸随侧链PTHF接枝数目增大而减小;CS-g-PTHF接枝共聚物载药微球具有一定的p H敏感性,CS-g6-PTHF1.4k在p H=6.0的弱酸性环境中释放速率快,25 h时药物释放完全.CS-g7-PTHF2.6k/Ag-5.7纳米复合材料表现出良好的抗菌性,对于抗大肠杆菌,抑菌圈直径为13.0 mm,对于抗黑曲霉,抑菌圈直径为10.5 mm.所制备的CS-gPTHF/Ag纳米复合材料结合了壳聚糖良好的生物相容性、聚四氢呋喃优异的抗湿强度与柔韧性以及纳米银优良的抗菌性,在生物医学领域具有潜在应用前景.A novel nanocomposite material of chitosan-g-polytetrahydrofuran（PTHF） graft copolymers with silver（Ag） nanoparticles, CS-g-PTHF/Ag, was successfully in situ prepared via combination of living cationic opening polymerization of tetrahydrofuran（THF） with controlled termination of living PTHF chains ＂grafting onto ＂ chitosan macromolecular backbone. Chemical structure of CS-g-PTHF/Ag was confirmed by Fourier transform infrared spectroscopy（FTIR）, nuclear magnetic resonance（~1H-NMR）, and X-ray photoelectron spectroscopy（XPS）. The total content of Ag, drug releasing rate and micromorphology of CS-g-PTHF/Ag composites were characterized by ultraviolet spectroscopy（UV）, polarizing microscopy（POM）, atomic force microscopy（AFM）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and highresolution TEM（HR-TEM）, respectively. The results show that the acylation degree of average functional groups in single glucosamine was 20%. The number-average molecular weight（Mn） and average grafting number could be designed by changing the dosage of allyl Br/AgClO_4 initiating system and the molar ratio of living PTHF chains to thefunctional groups in chitosan backbone.Theranged from 1400 to 2600 and average grafting number increased from 4 to 21 on the basis of every 1000 glucosamine units along the macromolecular backbone.The PTHF branches influenced the crystallinity of the acylated chitosan backbone.The microphase separation of CS-g-PTHF/Ag nanocomposite was observed,and the micromorphology was related to grafting density in the CS-g-PTHF graft copolymers.The crystallization activity of the backbone was limited with an increase in the grafting number of PTHF branches.Meanwhile,the CS-g-PTHF graft copolymer was found to behave p H-sensitive drug delivery.The size of the drug-loaded microspheres decreased with the increasing average grafting number in CS-g-PTHF graft copolymers.Drug-loading percentage of different CS-g-PTHF drug deliveries varied from 53%to

关 键 词：壳聚糖 聚四氢呋喃 接枝共聚物 正离子聚合 纳米复合材料 

分 类 号：TB333[一般工业技术—材料科学与工程] TQ317[化学工程—高聚物工业]