Evaluation of 5-ethylidene-2-norbornene with an adhesion promoter for self-healing applications

Abstract

5-Ethylidene-2-norbornene (ENB) has a potential application as part of a new generation of healing agents, owing to its rapid polymerization rate and wide liquid temperature range. In this study, we developed a new self-healing system using ENB as the healing agent and methyl 5-norbornene-2-carboxylate (MNC) as the adhesion promoter. Dynamic differential scanning calorimetry (DSC) was used to monitor cure behaviors of ENB with different MNC loadings, through which a series of cure temperatures were designed. The MNC loading and cure temperature had significant effects on the adhesion strength. The adhesion strength increased remarkably with MNC loadings of up to 10 wt % compared with ENB alone. The ENB monomer and the ENB/MNC mixture were successfully microencapsulated, and the resultant microcapsules were embedded into an epoxy resin along with Grubbs' catalyst for self-healing efficiency measurements. Peak fracture loads for both healing agents showed maximal values at a low catalyst loading (0.3 wt %). In comparison with neat ENB, a significant improvement in healing efficiency was observed for the ENB/ MNC mixture.

Optimization of synthesis parameters of PUF/ENB microcapsules for self‐healing applications using factorial design methodology

“…ENB has a higher reaction speed with a smaller amount of catalyst and greater thermal stability when compared to DCPD, so it is necessary to investigate this curing agent in urea-formaldehyde (U/F) microcapsules and its behavior when embedded into a polymeric matrix. 9,10 Understanding synthesis variables and how they affect the properties of polymeric microcapsules obtained via in situ polymerization is of utmost importance. [11][12][13][14][15] Thus, the present work is part of a strategy using factorial designs based on previous work, 16 which evaluated the influence of various synthesis parameters on the final characteristics of polymeric microcapsules.…”