Phase-Separated Thiol-Epoxy-Acrylate Hybrid Polymer Networks with Controlled Cross-Link Density Synthesized by Simultaneous Thiol-Acrylate and Thiol-Epoxy Click Reactions
Phase-Separated Thiol-Epoxy-Acrylate Hybrid Polymer Networks with Controlled Cross-Link Density Synthesized by Simultaneous Thiol-Acrylate and Thiol-Epoxy Click Reactions
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DOI：
10.1021/acs.macromol.6b00141
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发表时间：
2016-06-14
期刊：
影响因子：
5.5
通讯作者：
Torkelson, John M.
中科院分区：
文献类型：
--
作者：
Jin, Kailong;Wilmot, Nathan;Torkelson, John M.
硫醇环氧-丙烯酸酯杂化聚合物网络（HPN）是由亲核硫醇丙烯酸酯迈克尔加成和由1,8=cliazabicyclo[5.4.0]undec-7-ene（DBU）催化的硫醇环氧偶联反应在一锅法合成中形成的。硫醇基团（硫醇官能度大于两个的多官能硫醇）与环氧化物（双官能环氧）和丙烯酸酯基团（双官能丙烯酸酯）的加成之间的化学计量平衡应用于反应物混合物中。基于傅里叶变换红外光谱中硫醇吸收峰的消失实现了完全转化，证明了硫醇点击反应的高效率。利用相对较高分子量（MW = 2000 g mol(-1)）丙烯酸酯，可以获得新型相分离的硫醇基杂化材料，差示扫描量热法和动态力学分析以及扫描电子显微镜形态表征表明存在两个玻璃化转变温度。通过用不同量的双官能硫醇取代多官能硫醇，同时保持反应基团之间的化学计量平衡，系统地控制杂化网络的交联密度。通过改变 HPN 中的交联密度，可以获得广泛的热性能和机械性能；例如，杨氏模量的范围为 1.5 至 75.7 MPa。还讨论了交联密度对这些材料中相形态的影响。
Thiol epoxy-acrylate hybrid polymer networks (HPNs) are formed by the combination of nucleophilic thiol acrylate Michael addition and thiol epoxy coupling reactions catalyzed by 1,8=cliazabicyclo[5.4.0]undec-7-ene (DBU) in a one -pot synthesis. A stoichiometric balance between thiol groups (multifunctional thiols with a thiol functionality greater than two) and the addition of epoxide (difunctional epoxy) and acrylate groups (difunctional acrylate) :is applied in the reactant mixture. Full conversion is achieved based on the disappearance of the thiol absorbance peak from Fourier transform infrared spectroscopy, demonstrating the high efficiency of thiol click reactions. With relatively high molecular weight (MW = 2000 g mol(-1)) acrylates, novel phase-separated, thiol-based hybrid materials are obtained, as evidenced by the presence of two glass transition temperatures from both differential scanning calorimetry and dynamic mechanical analysis as well' as morphology characterization by scanning electron microscopy. Cross-link density of the hybrid networks is systematically controlled by substituting the multifunctional thiols with different amounts of difunctional thiols while maintaining a stoichiometric balance between reacting groups. By changing cross-link density in the HPNs, a wide range of thermal and mechanical properties can be obtained; e.g., Young's modulus can range from 1.5 to 75.7 MPa. The effect of cross-link density on the phase morphology in these materials is also discussed.