Ternary thiol-ene/acrylate photopolymers: Effect of acrylate structure on mechanical properties
Ternary thiol-ene/acrylate photopolymers: Effect of acrylate structure on mechanical properties
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DOI：
10.1021/ma062534b
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发表时间：
2007-07-10
期刊：
影响因子：
5.5
通讯作者：
Gould, Trenton E.
中科院分区：
文献类型：
--
作者：
Senyurt, Askim F.;Wei, Huanyu;Gould, Trenton E.
用实时FTIR对硫醇-烯/丙烯酸酯三元光聚合反应进行了监测，包括丙烯酸酯均聚反应和硫醇-烯单体与硫醇-丙烯酸酯单体的共聚反应。在所有三元混合物中，包括用不同丙烯酸酯浓度制备的那些，丙烯酸酯转化率为100%。然而，硫醇-烯转化率被发现是由它们的初始浓度控制。采用DMA、DSC和冲击吸收法研究了丙烯酸酯单体的化学结构对硫醇-烯/丙烯酸酯三元体系热物理性能的影响。向硫醇-烯体系中添加丙烯酸酯增加了橡胶态模量，同时tan δ（max）向更高的温度移动。在高丙烯酸酯浓度下，随着tan δ峰的加宽，观察到密集交联的非均匀基质形成。这些三元热固性光聚合物的高冲击吸收与网络的动态机械阻尼能力相关。具有较高官能度和每个双键低分子量的丙烯酸酯在提高硫醇-烯聚合物网络的玻璃化转变温度方面更有效。冲击下的三元硫醇-烯/丙烯酸酯网络的断裂行为显示出依赖于丙烯酸酯的化学结构，组分浓度和低温松弛过程。用基于双酚A的双官能丙烯酸酯单体形成的三元基体在室温下表现出改善的冲击能量吸收。最后，拉伸性能的聚合物网络形成的硫醇烯/丙烯酸酯和硫醇-丙烯酸酯的混合物进行了比较。
Model ternary thiol-ene/acrylate photopolymerization involving acrylate homopolymerization and copolymerization of thiol-ene and thiol-acrylate monomers were monitored by real-time FTIR. In all ternary mixtures, including those prepared with different acrylate concentrations, acrylate conversion was 100%. However, thiol-ene conversions were found to be controlled by their initial concentrations. The influence of acrylate monomer chemical structure on the thermophysical properties of ternary thiol-ene/acrylate systems was studied with DMA, DSC, and the absorbance of a nondestructive impact energy. The addition of acrylate to the thiol-ene system increased the rubbery modulus while the tan delta(max) shifted to higher temperatures. Densely cross-linked, heterogeneous matrix formation was observed with the broadening of tan delta peaks at high acrylate concentrations. The high impact absorption of these ternary thermoset photopolymers was correlated with the dynamic mechanical damping ability of the networks. Acrylates with higher functionality and low molecular weight per double bond are more effective at increasing the glass transition temperature of the thiol-ene polymer network. Fracture behavior of ternary thiol-ene/acrylate networks under impact shows a dependence on the chemical structure of the acrylate, component concentrations, and low-temperature relaxation processes. The ternary matrix formed with a bisphenol A based difunctional acrylate monomer exhibited improved impact energy absorption at room temperature. Finally, tensile properties of polymer networks formed with thiol-ene/acrylate and thiol-acrylate mixtures are given for comparison purposes.