Zhang Zekun, Tian Rui, Zhang Pudun, Lu Chao, Duan Xue
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
ACS Cent Sci. 2020 May 27;6(5):771-778. doi: 10.1021/acscentsci.0c00133. Epub 2020 May 6.
Monitoring the evolution of polymer aging, especially early-stage aging, over both time and dimensionality can provide in-depth insight into aging-induced material invalidation and even disastrous accidents. However, it remains a great challenge because currently available methods for polymer aging only provide statistic results at a macroscopic scale. Herein, we report the first three-dimensional early-stage visualization (ESV) technique of polymer aging by using the fluorophore-bonded boronic acid to specifically target aging-induced hydroxyl groups through the B-O click reaction. This method can identify the initial aging of polypropylene (PP) as early as 20.0 min. In contrast, no signals can be detected by conventional infrared spectroscopy even after 21 days of thermal treatment. More importantly, the three-dimensional evolution for early-stage polymer aging was demonstrated: faster aggression in the horizontal plane (4.1 × 10 s) than in the vertical direction (2.6 × 10 m s) for PP films. The approach could undoubtedly provide valuable information in elucidating mechanistic details of polymer aging in three-dimensional scale and assessing the utility of advanced antiaging materials.
监测聚合物老化的演变，尤其是早期老化，从时间和维度两方面进行监测，能够深入洞察老化导致的材料失效甚至灾难性事故。然而，这仍然是一个巨大的挑战，因为目前可用的聚合物老化方法仅能在宏观尺度上提供统计结果。在此，我们报告了首个通过使用与荧光团结合的硼酸，通过B - O点击反应特异性靶向老化诱导产生的羟基，实现聚合物老化的三维早期可视化（ESV）技术。该方法能够早在20.0分钟时就识别出聚丙烯（PP）的初始老化。相比之下，即使经过21天的热处理，传统红外光谱也检测不到信号。更重要的是，展示了早期聚合物老化的三维演变：对于PP薄膜，在水平面上老化侵蚀速度（4.1×10 s）比在垂直方向（2.6×10 m s）更快。该方法无疑能够为阐明三维尺度下聚合物老化的机理细节以及评估先进抗老化材料的效用提供有价值的信息。
