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    光、热可控双重动态聚合物的设计及性能

    Design and Performance of Dual Dynamic Crosslinked Polymer with Light and Thermal Tunable Properties

    • 摘要: 将动态亚胺键和蒽基团引入到聚合物体系,构建了双重动态交联网络,系统研究了其光响应行为、流变动力学特性及力学性能。利用傅里叶变换红外光谱(FT-IR)和核磁共振氢谱(1H-NMR)对样品进行表征,表明成功合成了具有动态亚胺键与光响应基团的双重动态键聚合物。通过紫外-可见光谱表征,可直观观察到光照过程中化学结构的变化,揭示光交联反应的成功进行。随着光照时间的延长,样品的杨氏模量逐渐增大(从10.33 MPa升高至17.52 MPa);断裂伸长率整体呈现下降趋势(从167%降至105%);拉伸强度先增大后减小,表明光照时间的延长会导致材料脆性增强。光交联后样品在温度扫描中出现2个拐点(95 ℃和142 ℃),揭示了其内部动态亚胺键交换与光交联结构解聚的不同温度响应性,表明了双重动态键聚合物网络的多重响应能力。光交联样品在高温下仍保持较高的模量,但在更高温度(如160 ℃)下,光交联结构逐渐解聚,材料也同样进入黏流状态。

       

      Abstract: By incorporating dynamic imine bonds and anthracene moieties into a polymer matrix, we constructed a dual-dynamic cross-linked network and systematically investigated its photo-responsive behavior, rheological dynamics, and mechanical properties. Fourier-transform infrared spectroscopy (FT-IR) and 1H nuclear magnetic resonance (1H-NMR) confirmed that the target polymer bearing both dynamic imine linkages and photo-responsive groups was successfully synthesized. UV–vis spectroscopy revealed four characteristic absorption peaks in the range of 300 nm to 400 nm, allowing the evolution of the chemical structure under irradiation to be directly monitored and verifying the occurrence of the photocrosslinking reaction. To elucidate the effect of irradiation time on mechanical performance, tensile tests were conducted after precisely controlled exposure periods. As irradiation time increased, the Young’s modulus rose steadily from 10.33 MPa to 17.52 MPa, while the elongation at break decreased from 167 % to 105 %. The tensile strength first increased and then declined, indicating that excessive irradiation leads to greater brittleness. Rheological measurements further showed two inflection points at 95  ℃ and 142  ℃ in the temperature sweep of the photocross-linked sample, directly evidencing distinct temperature responses associated with internal dynamic-imine bond exchange and depolymerization of the photocross-linked network, respectively. Stress-relaxation experiments revealed that, although the photocross-linked material retained a high modulus at elevated temperatures, the network gradually depolymerized at high temperatures (e.g., 160  ℃), transitioning the material into a viscous-flow state. These results demonstrate the multi-responsive capability of the dual-dynamic polymer network.

       

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