Sutyak Keith B, Iezzi Erick B, Daniels Grant C, Camerino Eugene
ASEE Post-Doctoral Fellow, U.S. Naval Research Laboratory, Chemistry Division, Washington, DC 20375, United States.
U.S. Naval Research Laboratory, Chemistry Division, Washington, DC 20375, United States.
ACS Appl Mater Interfaces. 2022 May 18;14(19):22407-22417. doi: 10.1021/acsami.2c00485. Epub 2022 May 3.
Cross-linked polymeric networks that possess tunable properties and degrade on-demand have broad applications in today's society. Herein, we report on silyl-containing poly(urethane) (silyl-PU) thermoset networks, which are highly cross-linked stimuli-responsive materials with hydrolytic stability at 37.7 °C and 95% relative humidity, thermal stability of 280-311.2 °C, tensile properties of 0.38-51.7 MPa strength and 73.7-256.4% elongation, including storage modulus of 2268-3499 MPa (in the glassy state). However, unlike traditional (i.e., nondegradable) PU thermosets, these silyl-PUs selectively activate with fluoride ion under mild and static conditions to completely degrade, via cascading bond cleavages, and generate recoverable and reusable molecules. Silyl-PUs, as thin films, also demonstrated complete removal (within 30 min) from a strongly adhered epoxy thermoset network without altering the structure of the latter. Silyl-PU thermosets have potential applications in composite parts, vehicle and industrial coatings, and rigid plastics for personal devices, and may reduce environmental waste compared to nondegradable, single-use materials.
具有可调谐性能且能按需降解的交联聚合物网络在当今社会有着广泛应用。在此，我们报道了含硅烷基的聚（聚氨酯）（硅烷基 - 聚氨酯）热固性网络，它们是高度交联的刺激响应材料，在37.7°C和95%相对湿度下具有水解稳定性，热稳定性为280 - 311.2°C，拉伸性能为强度0.38 - 51.7 MPa和伸长率73.7 - 256.4%，包括玻璃态下的储能模量为2268 - 3499 MPa。然而，与传统的（即不可降解的）聚氨酯热固性材料不同，这些硅烷基 - 聚氨酯在温和静态条件下能被氟离子选择性激活，通过级联键断裂完全降解，并生成可回收和可重复使用的分子。作为薄膜的硅烷基 - 聚氨酯，在不改变强粘附的环氧热固性网络结构的情况下，也能在30分钟内从后者中完全去除。硅烷基 - 聚氨酯热固性材料在复合部件、车辆和工业涂料以及个人设备的刚性塑料方面有潜在应用，并且与不可降解的一次性材料相比，可能减少环境废弃物。
