含金刚烷基的N-异丙基丙烯酰胺共聚物水凝胶的制备和性能研究

合成了含金刚烷基的甲基丙烯酸金刚烷酯(AdMA)疏水单体,并通过与N-异丙基丙烯酰胺(NIPAM)共聚,制备了温敏性的(P(NIPAM-co-AdMA))共聚物水凝胶.用傅里叶变换红外光谱仪(FTIR)表征了凝胶的化学结构,用环境扫描电镜(ESEM)对凝胶断层结构的形貌进行了观察,用DSC测试了凝胶的体积相转变温度(LCST),并研究了共聚水凝胶的溶胀性能.结果表明,共聚物水凝胶的LCST能够高效地通过改变疏水单体的含量来调节,在实验所考察的范围内,LCST随AdMA含量的增加而线性降低;疏水单体的含量对凝胶的孔洞结构和溶胀性能存在一最优值,在最优的单体配比下,水凝胶具有均匀规整的大孔结构和超快的响应速率.如疏水单体含量为3%(AdMA∶NIPAM=3%)的共聚物水凝胶具有如渔网般均匀的多孔结构,当发生去溶胀时,在5min内就可以失去92%的水,不到10min的时间就可以完全达到去溶胀平衡,水保留率在4%以下.

PREPARATION AND PROPERTIES OF TEMPERATURE-SENSITIVE N-ISOPROPYLACRYLAMIDE COPOLYMER HYDROGELS CONTAINING ADAMANTYL GROUPS

To study the effect of adamantyl groups on the properties of temperature-sensitive hydrogels,hydrophobic monomer adamantyl methacrylate ( AdMA ) was synthesized and copolymerized with N- isopropylacrylamide ( NIPAM ).A series of temperature-sensitive P ( NIPAM-co-AdMA ) hydrogels with different content of AdMA were prepared.Fourier transform infrared (FTIR) spectroscopy was used to confirm the chemical structure of the resultant hydrogels.The peak of C O around 1714 cm -1 in FTIR spectra demonstrated that the AdMA units were successfully incorporated into the hydrogel network.The inner morphology of copolymer hydrogels was observed using an enviromental scanning electron microscope (ESEM).It is found that the morphology strongly depends on AdMA content.In a proper range( AdMA∶ NIPAM≤3% ),with the increase of AdMA content,the copolymer hydrogels can form perfect porous structure,but when the AdMA content increases further,the porosity decreases,even the hydrogel surface becomes compact.The volume phase transition temperature ( LCST ) was characterized by differential scanning calorimetry (DSC).The results indicate that the LCSTs of the copolymer hydrogels decrease linearly with the increase of AdMA component,so it can be designed easily to obtain hydrogels with needed LCST.The equilibrium swelling ratios ( SR ) and the deswelling kinetics of the hydrogels were also measured gravimetrically.It is noteworthy that the swelling properties of the copolymer hydrogels can be optimized by the proportion of AdMA,with optimum AdMA content,the SR of the copolymer hydrogel can exhibt fast change with temperature,and the deswelling rate increase significantly.The hydrogel with 3% AdMA (AdMA∶ NIPAM = 3% ) can lose 92% of water within 5 min and reach deswelling equilibrium within 10 min with a water retention below 4% .