Li Hai, Xiao Rui
College of Mechanics and Materials, Hohai University, Nanjing 210098, China.
Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China.
Materials (Basel). 2021 Feb 4;14(4):730. doi: 10.3390/ma14040730.
We have performed a systematical investigation on the glass transition behavior of amorphous polymers with different solvent concentrations. Acrylate-based amorphous polymers are synthesized and treated by isopropyl alcohol to obtain specimens with a homogenous solvent distribution. The small strain dynamic mechanical tests are then performed to obtain the glass transition behaviors. The results show that the wet polymers even with a solvent concentration of more than 60 wt.% still exhibit a glass transition behavior, with the glass transition region shifting to lower temperatures with increasing solvent concentrations. A master curve of modulus as a function of frequency can be constructed for all the polymer-solvent systems via the time-temperature superposition principle. The relaxation time and the breadth of the relaxation spectrum are then obtained through fitting the master curve using a fractional Zener model. The results indicate that the breadth of the relaxation spectrum has been greatly expanded in the presence of solvents, which has been rarely reported in the literature. Thus, this work can potentially advance the fundamental understanding of the effects of solvent on the glass transition behaviors of amorphous polymers.
我们对不同溶剂浓度的非晶态聚合物的玻璃化转变行为进行了系统研究。合成了丙烯酸酯基非晶态聚合物并用异丙醇处理，以获得具有均匀溶剂分布的样品。然后进行小应变动态力学测试以获得玻璃化转变行为。结果表明，即使溶剂浓度超过60 wt.% 的湿聚合物仍表现出玻璃化转变行为，玻璃化转变区域随着溶剂浓度的增加向低温移动。通过时间-温度叠加原理，可以为所有聚合物-溶剂体系构建模量随频率变化的主曲线。然后使用分数齐纳模型拟合主曲线来获得弛豫时间和弛豫谱宽度。结果表明，在溶剂存在下弛豫谱宽度大大扩展，这在文献中鲜有报道。因此，这项工作可能会推进对溶剂对非晶态聚合物玻璃化转变行为影响的基本理解。
