|
|||||
|
|
Thermal Activation of Mendable Epoxy through Inclusion of Microcapsules and Imidazole Complexes |
|
| Authors: | Manorama Tripathi Raman Dwivedi Devendra Kumar |
| Affiliation: | 1. Center for Fire, Explosive and Environment Safety, DRDO, Delhi, India;2. Department of Applied Chemistry and Polymer Technology, Delhi Technological University, Delhi, India;3. Department of Applied Chemistry and Polymer Technology, Delhi Technological University, Delhi, India |
| Abstract: | Epoxy resin was encapsulated in poly(urea–formaldehyde) microcapsules using an in situ dispersion polymerization technique. The efficiency of Ni and Cu–imidazole complexes as latent hardeners was compared to that of 2-methylimidazole. Calorimetric studies revealed higher reactivity of the nickel complex toward oxirane functionalities. Both the complexes could effectively cure the epoxy released from within the microcapsules in the event of damage followed by thermal treatment. The curing could be effected at lower temperature (Tonset = 145°C) using Ni(2-Me-ImidH)4Cl]Cl as compared to Cu(2-Me-ImidH)4Cl]Cl (Tonset = 152°C). A healing efficiency of 100 ± 2% could be achieved at 30% microcapsule loading, irrespective of the type of metal complex used. |
| Keywords: | Epoxy latent hardener microcapsule microencapsulation selfhealing |