基于酰腙可逆共价键制备溶胶-凝胶转变的可自愈合水凝胶

Synthesis of Sol-Gel Transition and Self-Healable Hydrogel by Acylhydrazone Covalent Bonds

通过自由基聚合合成了系列丙烯酰胺（AM）和双丙酮丙烯酰胺（DAAM）的共聚物PAM-co-PDAAM。用核磁共振（~1H-NMR）和凝胶渗透色谱（GPC）对其结构和组成进行了表征。将PAM-co-PDAAM和己二酰肼（ADH）混合,利用酮羰基和酰肼键之间形成酰腙可逆共价键构建具有溶胶（sol）-凝胶（gel）可逆转变特性的pH响应型凝胶。利用流变仪、扫描电镜（SEM）以及红外光谱（FT-IR）对sol-gel的转变过程进行了研究。考察了共聚物的组成对形成凝胶最低质量分数的影响。结果表明,随着DAAM含量的增加,形成凝胶的最低质量分数逐渐减小。制备得到的凝胶具有可自愈合性能。

A serial of poly（acrylamide-co-diacetone acrylamide）（PAM-co-PDAAM）copolymers were synthesized by radical polymerization from acrylamide（AM）and diacetone acrylamide（DAAM）.The structure of PAM-co-PDAAM was characterized by Nuclear Magnetic Resonance spectroscopy（~1H-NMR）and Gel Permeation Chromatography（GPC）.Resorting to the acylhydrazone dynamic covalent bonds between hydrazides and carbonyl group of ketone,the hydrogel with pH-responsive sol-gel transition was formed by mixing PAM-co-PDAAM and adipic dihydrazide（ADH）.The sol-gel transition was studied by rheological measurement,Scanning Electron Microscope（SEM）and Fourier Transform Infrared spectroscopy（FT-IR）.Effect of the compositions of copolymers on the lowest mass fraction for hydrogel formation was studied.Results demonstrated that the higher composition of DAAM,the lower mass fraction for hydrogel formation.Besides,the hydrogel exhibited self-healing property.