No abstract

Polymer materials containing oxime-carbamate bonds show superior self-healing ability under certain conditions. In this study, a series of dynamic oxime-carbamate based PU-D-x (Polyurethane-Dimethylglyoxime-x) with different crosslinking degrees (x indicates the content of crosslinker based on the weight of solid content) were prepared, and the self-healing together with the reprocessing characteristic was investigated. In situ variable temperature FTIR spectroscopy shows that the dissociation of oxime-carbamate bonds occurred at 80 C and can be accelerated by the increasing temperature. With relatively lower cross-linking degrees, these types of PU can be healed at low temperature and in a short time, for example, PU-D-0.3 can be completely healed at 80 C in 6 h, and PU-D-0.45 can be almost completely healed at 80 C in 9 h. With the increase of cross-linking degree, the self-repair of this kind of PU needs to be carried out at higher temperature and needs an extension of time.However, when the temperature increased to 100 C, the self-healing time is greatly reduced to 3-5 h. Most interestingly, these types of crosslinked PUs showed expected reusing and reprocessing characteristics, even the PU-D-1.2 sample with the highest crosslinking degree can be completely reshaped and reprocessed under 120 C and 10 MPa pressure.

No abstract