Imato Keiichi, Kanehara Takeshi, Ohishi Tomoyuki, Nishihara Masamichi, Yajima Hirofumi, Ito Masayoshi, Takahara Atsushi, Otsuka Hideyuki
Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
‡Graduate School of Engineering and §Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
ACS Macro Lett. 2015 Nov 17;4(11):1307-1311. doi: 10.1021/acsmacrolett.5b00717. Epub 2015 Nov 9.
Stress evaluation in polymeric materials is important in order to not only spot danger in them before serious failure, but also precisely interpret the destructive mechanism, which can improve the lifetime and durability of polymeric materials. Here, we are able to visualize stress by color changes, as well as quantitatively estimate the stress in situ, in segmented polyurethane elastomers with diarylbibenzofuranone-based dynamic covalent mechanophores. We prepared films of the segmented polyurethanes, in which the mechanophores were incorporated in the soft segments, and efficiently activated them by mechanical force. Cleavage of the mechanophores during uniaxial elongation and their recovery after the removal of the stress were quantitatively evaluated by in situ electron paramagnetic resonance measurements, accompanied by drastic color changes.
对聚合物材料进行应力评估很重要，这不仅是为了在严重失效前发现其中的危险，还能精确解释破坏机制，从而提高聚合物材料的使用寿命和耐久性。在此，我们能够通过颜色变化可视化应力，并在含有基于二芳基联苯并呋喃酮的动态共价机械响应基团的嵌段聚氨酯弹性体中原位定量估算应力。我们制备了嵌段聚氨酯薄膜，其中机械响应基团被引入软段，并通过机械力有效激活它们。通过原位电子顺磁共振测量定量评估了单轴拉伸过程中机械响应基团的断裂及其在去除应力后的恢复情况，同时伴有剧烈的颜色变化。
