Preparation and properties of self-healing cross-linked polyurethanes based on blocking and deblocking reaction

Publication date: Available online 26 August 2019Source: Reactive and Functional PolymersAuthor(s): Feilong Han, Sayyed Asim Ali Shah, Xin Liu, Fugui Zhao, Bowen Xu, Junying Zhang, Jue ChengAbstractSelf-healing polyurethane via incorporating reversible bonds obtains great recognition. However, a reasonable design of polyurethane containing reversible bonds with high self-healing efficiency, facile preparing and low costs is still a challenge. Here, we report a novel self-healing polyurethane (Sh-C-PU) containing reversible urethane bonds (NHCOO), which was conducted by the reaction of diphenol (tetrabromobisphenol A, TBBPA) and 4, 4′-diphenylmethane diisocyanate (MDI). TBBPA can block the NCO groups in MDI at 60 °C, and NCO groups can be deblocked at the temperature higher than 90 °C, which gave Sh-C-PU self-healing property. FTIR analysis demonstrated thermal reversibility of Sh-C-PU by monitoring the deblocking and reblocking reaction in thermal cycles. In addition, qualitative self-healing phenomenon of cracks was observed under polarizing optical microscopy, and quantitative evaluation of self-healing Sh-C-PU via mechanical properties confirmed the great healing property of Sh-C-PU with healing efficiency by 97.82%, 86.38% and 55.04% for three times self-healing cycles, respectively.

Source: Reactive and Functional Polymers - August 27, 2019 Category: Chemistry Source Type: research