Controllable Degradation of Polyurethane Thermosets with Silaketal Linkages in Response to Weak Acid

ABSTRACT: Polyurethane (PU) thermosets offer great favors to our daily life on account of their excellent mechanical, physical, and chemical properties as well as appreciable biocompatibility. Nevertheless, PU waste is increasingly causing environmental and healthrelated problems as it is mostly resistant to chemical degradation under mild conditions. Herein, we report a kind of PU thermoset with silaketal leakages in its main chains to enable polymer degradation in response to weak acids, even in edible vinegar. The degradation rate is significantly influenced by the alkyl substituents on the silicon atoms, with entire degradation in hours, days, weeks, or months. Besides controllable degradation, investigations are also provided into the recycling of PU thermosets by means of thermal reprocessing based on carbamate bond exchange or repolymerization of degradation residuals. Because of the controllable degradation and easy recycling, this particular kind of PU thermoset exhibits great potential in manufacturing green polymer products that can be decomposed by nature or reutilized after disposal.