Konuray Osman, Fernández-Francos Xavier, Ramis Xavier, Serra Àngels
Thermodynamics Laboratory, ETSEIB, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona, Spain.
Department of Analytical and Organic Chemistry, Universitat Rovira i Virgili, C/Marcel lí Domingo s/n, 43007 Tarragona, Spain.
Polymers (Basel). 2019 Aug 27;11(9):1408. doi: 10.3390/polym11091408.
A novel set of dual-curable multiacetoacetate-multiacrylate-divinyl sulfone ternary materials with versatile and manipulable properties are presented. In contrast to common dual-curing systems, the first stage polymer herein consists of a densely crosslinked, high network as a result of base-catalyzed multiacetoacetate-divinyl sulfone Michael addition. A more flexible secondary network forms after base-catalyzed Michael addition of remaining multiacetoacetate to multiacrylate. Curing is truly sequential as the rates of the two Michael additions are significantly different. Curing kinetics were analyzed using differential scanning calorimetry (DSC) and Fourier-transform infrared (FTIR). The materials at each curing stage were characterized using dynamic mechanical analysis (DMA) and SEM. Although some phase separation was observed in certain formulations, the incompatibilities were minimized when the molar percentage of the acetoacetate-divinyl sulfone polymer network was above 75%. Furthermore, the environmental scanning electron microscopy (ESEM) images of these materials show that the more flexible acetoacetate-acrylate phase is dispersed in the form of polymeric spheres within the rigid acetoacetate-divinyl sulfone matrix. This unique dual microstructure can potentially render these materials highly resilient in applications requiring densely crosslinked polymer architectures with enhanced toughness.
本文介绍了一组新型的具有多功能且可调控性能的双固化多乙酰乙酸酯-多丙烯酸酯-二乙烯基砜三元材料。与常见的双固化体系不同，此处的第一阶段聚合物是由碱催化的多乙酰乙酸酯-二乙烯基砜迈克尔加成反应形成的高度交联的高密度网络。在碱催化剩余的多乙酰乙酸酯与多丙烯酸酯进行迈克尔加成反应后，形成了一个更具柔韧性的二级网络。由于两种迈克尔加成反应的速率显著不同，固化过程是真正的分步进行。使用差示扫描量热法（DSC）和傅里叶变换红外光谱（FTIR）分析固化动力学。使用动态力学分析（DMA）和扫描电子显微镜（SEM）对每个固化阶段的材料进行表征。尽管在某些配方中观察到了一些相分离现象，但当乙酰乙酸酯-二乙烯基砜聚合物网络的摩尔百分比高于75%时，不相容性被降至最低。此外，这些材料的环境扫描电子显微镜（ESEM）图像显示，更具柔韧性的乙酰乙酸酯-丙烯酸酯相以聚合物球的形式分散在刚性的乙酰乙酸酯-二乙烯基砜基质中。这种独特的双微观结构可能使这些材料在需要具有增强韧性的高密度交联聚合物结构的应用中具有高度弹性。
