蓝光诱导聚乙二醇二丙烯酸酯水凝胶的聚合交联动力学

Blue Light Induced Polymerization Kinetics of Polyethylene Glycol Diacrylate Hydrogel

为探明蓝光诱导聚乙二醇二丙烯酸酯(PEGDA)水凝胶聚合交联的动力学,系统地研究了光引发剂用量、单体用量及光照强度等因素对水凝胶聚合前驱液的蓝光聚合性能和凝胶化行为的影响。以樟脑醌(CQ)/N,N-二甲氨基苯甲酸乙酯(EDB)/二苯基碘金翁六氟磷酸盐(DPI)为三组分光引发剂,配制了PEGDA光聚合前驱液。以400~500 nm蓝光为辐照光源,采用光差示扫描量热法(Photo-DSC)和光流变系统(Photo-rheology)对PEGDA光聚合前驱液的聚合反应进行了监测。结果表明,水凝胶聚合前驱液的聚合速率(Rp)与CQ/EDB,DPI的用量和光照强度(I)的平方根,及PEGDA用量均呈线性增长关系。过高的引发剂和单体用量、光强均会影响这种线性关系。光流变行为表明,PEGDA水凝胶的凝胶转变反映了其黏弹性变化趋势,凝胶转变时间(tgel)与光引发剂用量、单体用量及光照强度均呈现指数降低关系。PEGDA水凝胶弹性模量与光照时间呈指数增长关系。不同条件下PEGDA水凝胶的理论终点弹性模量(G′∞)较为稳定,均位于1.1×10^(5)~1.5×10^(5) Pa的范围之内。

To investigate the blue light induced polymerization and crosslinking kinetics of polyethylene glycol diacrylate(PEGDA)hydrogel,the effects of the photoinitiator dosage,monomer dosage and light intensity on the photopolymerization performance and the gel behavior of hydrogel precursor solutions were studied.By using camphorquinone(CQ)/ethyl 4-(dimethylamino)benzoate(EDB)/diphenyliodine hexafluorophosphate(DPI)as photoinitiator system,PEGDA photopolymerization precursors were prepared.A 450 nm blue light LED was used as irradiation source,and the polymerization process of the hydrogel precursor solutions was monitored by the photo-differential scanning calorimetry(Photo-DSC)and photorheology system.The results show that the polymerization rate(Rp)of hydrogel precursor solutions has a linear relationship with the PEGDA dosage and square root of the amount of CQ/EDB,DPI and light intensity.An excessive dosage of initiator and monomer,light intensity will destruct this linear relationship.The rheological behavior shows that the gel transition of PEGDA hydrogels reflects the change trend of viscoelasticity.The gel transition time(tgel)decreases exponentially with the amount of initiator,monomer dosage and light intensity.The elastic modulus of PEGDA hydrogels is increased exponentially with illumination time.The theoretical plateau modulus(G′infinity)of PEGDA hydrogels under different conditions is relatively stable,which is located in the range of 1.1×10^(5)~1.5×10^(5) Pa.