不同交联剂对甲基丙烯酸-β-羟乙酯/E-51双甲基丙烯酸酯聚合物水凝胶性能的影响

以水溶性单体甲基丙烯酸-β-羟乙酯(HEMA)与大分子交联剂E-51双甲基丙烯酸酯(E-51-DMA)(质量比HEMA/E-51-DMA=90/10)为主要原料,分别引入了5种小分子交联剂:N,N′-亚甲基双丙烯酰胺(MBA)、二乙烯基苯(DVB)、双甲基丙烯酸乙二醇酯(EDMA)、1,1,1-三(丙烯酰氧甲基)丙烷(TAP)和2,2,2-三(丙烯酰氧甲基)乙醇(TAE),采用本体聚合方法合成了5个系列的聚合物水凝胶.研究了小分子交联剂的类型及用量对水凝胶溶胀性能、杨氏模量以及有效交联密度ve和聚合物-水相互作用参数χ的影响,并比较了不同交联剂的交联效率.结果表明,随着小分子交联剂用量的增大,水凝胶平衡含水量EWC逐渐降低,聚合物体积分数2逐渐增大,反映聚合物网络结构的有效交联密度ve以及热力学参数聚合物-水相互作用参数χ值也随之增大.通过理论交联密度和有效交联密度的线性拟合,得到所选用的5种小分子交联剂在E-51-DMA10/HEMA90水凝胶体系中的交联效率,其顺序为DVB>EDMA>TAE>MBA≈TAP.

EFFECT OF VARIOUS CROSSLINKERS ON PROPERTIES OF 2-HYDROXYETHYL METHACRYLATE/E-51-DIMETHACRYLATE POLYMERIC HYDROGELS

Five series of polymeric hydrogels based on 2-hydroxyethyl methacrylate(HEMA) of 90 wt% and a macromolecular crosslinker — E-51 dimethacrylate(E-51-DMA) of 10 wt% were prepared by bulk copolymerization,crosslinked with N,N′-methylene-bisacrylamide(MBA),divinyl benzene(DVB),ethylene dimethacrylate(EDMA),1,1,1-triacryloxymethyl propane(TAP) and 2,2,2-triacryloxymethyl ethanol(TAE),respectively.The effect of the species and content of crosslinkers on swelling properties,(Young's) modulus,effective crosslinking density(v_e) and polymer-water interaction parameter(χ) were studied,and crosslinking efficiencies of various crosslinkers were also compared.As the amounts of crosslinkers increased,a large number of crosslinks will be generated wihtin hydrogels,so the equilibrium water content(EWC) decreased,in contrast,the volume fraction of polymer in hydrogels(_2) increased.As a result,the enhancement of effective crosslink density(v_e) concerning network structures and interaction parameter(χ) that represents thermodynamic interaction between water and polymers could be observed.The crosslinking efficiencies of five adoptive crosslinkers in E-51-DMA10/HEMA90 hydrogel systems were fitted from the relationships between effective crosslink density and theoretical crosslink density,and their order was as follows DVB>EDMA>TAE>MBA≈TAP.The changing magnitudes for these above-mentioned parameters may be attributed to the nature of crosslinkers and their crosslinking efficiencies.