Construction from destruction using a photo-triggered self-propagating degradable polyurethane as a one-pot epoxy
Construction from destruction using a photo-triggered self-propagating degradable polyurethane as a one-pot epoxy
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DOI：
10.1039/d0py00779j
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发表时间：
2020-10
影响因子：
4.6
通讯作者：
Yanhua Xu;Ephraim G. Morado;S. Zimmerman
中科院分区：
文献类型：
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作者：
Yanhua Xu;Ephraim G. Morado;S. Zimmerman
我们报道了一种光引发、碱生成、碱传播的可降解聚氨酯，其由365 nm紫外光照射引发。该聚氨酯材料的小区域可以暴露于365 nm UV光照射以产生碱性物质，该碱性物质可以在本体材料内引发碱传播降解过程，导致整体降解，而不需要连续的UV照射。该聚合物是由少量邻硝基苯二醇2、大量Fmoc基二醇3和己基亚甲基二异氰酸酯缩聚而成。将光敏性和碱敏感性氨基甲酸酯部分整合到聚合物1主链中提供了UV光触发的碱传播可降解聚氨酯材料。使用1H NMR和凝胶渗透色谱法（GPC）对聚合物1进行的降解研究表明，初始UV辐照引发光敏邻硝基苯氨基甲酸酯键的降解，释放出伯氨基，通过进一步降解剩余的Fmoc氨基甲酸酯基团，导致胺级联形成。使用Fmoc基三醇4作为单体制备本体聚氨酯膜。紫外线照射的一个小的局部区域的膜启动整个传播，导致有效的整体降解的整个材料。胺降解产物可用于制备一锅法环氧胶粘剂，显示了这种自蔓延可降解聚氨酯体系的潜在升级循环应用。
We report a photo-triggered, base generating, base propagating degradable polyurethane that is triggered by 365 nm UV light irradiation. A small area of this polyurethane material can be exposed to 365 nm UV light irradiation to generate basic species that can initiate a base propagated degradation process within the bulk material leading to global degradation without the need for continous UV irradiation. The polymer was synthesized by a polycondensation polymerization of a small amount of o-nitrobenzene diol 2, a large amount of Fmoc-based diol 3, and hexylmethylene diisocyanate. Integrating both photosensitive and base-sensitive carbamate moieties into the polymer 1 backbone provides the UV light-triggered base propagating degradable polyurethane material. Degradation studies of polymer 1 using 1H NMR and gel permeation chromatography (GPC) suggest that initial UV irradiation triggers the degradation of the photosensitive o-nitrobenzene carbamate linkages, releasing a primary amino group that causes a cascade of amines to form by further degrading the remaining Fmoc carbamate groups. A bulk polyurethane film was prepared using Fmoc-based triol 4 as a monomer. UV-irradiation of a small localized area of the film initiates the propagation throughout, leading to efficient bulk degradation of the entire material. The amine degradation products could be utilized to make a one-pot epoxy adhesive, showing a potential upcycling application of this self-propagating degradable polyurethane system.