Epoxy resin microcapsules

Baek et ah [79] used the phase-inversion emulsification technique in order to obtain epoxy resin microcapsules containing the flame retardant triphenyl phosphate... 

Bisphenol A type epoxy resin (Epikote 828 Shell) cured with modified amine (Epomate B002 Shell) was used as the matrix of the dismantlable adhesive (re-sin/matrix=2 1 w/w). Fig. 34.3 shows their chemical structures. The bulk adhesive was cured at room temperature for 24 h before the experiments. Cured bulk resin mixed with the microcapsules was used for the specimens to measure the volume change. 

Li, Y Guozheng, L. Jianqiang, X. Lan, L. ling, G. Preparation and characterization of polyfureaformaldehyde) microcapsules filled with epoxy resins. Polymer A1(15), 5338-5349, 2006. 

Hosokawa, T. Matsushita, T. Hata, M. Encapsulated cross-linking agents or accelerators, epoxy resins containing the microcapsules, curing process of the resins, and cured products. JP 08337633, 1996. 

Liao, L. P Zhang, W. Xin, Y. Wang, H. M. Zhao, Y Li, W. J. Preparation and characterization of microcapsule containing epoxy resin and its self-healing performance of anticorrosion covering material. Chinese Science Bulletin (2011), 56(4-5), 439-443. 

Cosco, S. Ambrogi, V. Musto, P Carfagna, C. Urea-formaldehyde microcapsules containing an epoxy resin Influence of reaction parameters on the encapsulation yield. Macromolecular Symposia (2006), 234 (Trends and Perspectives in Polymer Science and Technology), 184-192. 

Pascu, O. Garcia-Valls, R. Giamberini, M. Interfacial polymerization of an epoxy resin and carboxylic acids for the synthesis of microcapsules. Poly Int 57 (2008) 995-1006. 

Epoxy adhesives are also targets for separation using TEMs, although these adhesives are very strong. For instance, a type of TEMs, shown in O Fig. 58.7, is mixed into an epoxy resin to be used as a strong dismantlable adhesive (Nishiyama et al. 2003). The microcapsules have... 

Fig. 1. Original microencapsulation-based self-healing system. Microencapsulated dicy-clopentadiene is embedded in an epoxy resin containing Grubbs catalyst which is capable of polymerizing the dicyclopentadiene. A propagating crack ruptures the microcapsules causing DCPD to be released into the crack plane where it comes in contact with and reacts with catalyst to form a polymer that bonds the crack hices and restores structural continuity.

Microcapsule Induced Toughening. Brown and co-workers have demonstrated that the incorporation of microcapsules into an epoxy matrix do not adversely affect the mechanical properties of the matrix. On the contrary, the fracture toughness measurements of samples cast from an EPON 828 epoxy resin system were observed to increase with concentration up to an optimal concentration that is dependent on the average diameter of the microcapsules. Overall, the incorporation of microcapsules containing DCPD into epoxy samples yielded up to a 127% increase in fracture toughness, outperforming samples containing similar concentrations of silica microspheres, or solid urea-formaldehyde particles (31). 

Fig. 10. Solvent induced healing system. A propagating crack ruptures the microcapsules releeising a hlend of epoxy resin and solvent into the crack plane where the epoxy penetrates the matrix network to elute out and react with residual unreacted amine groups.

Figure 11.18 Microcapsule-based self-reporting material amine cured epoxy coating mixed with microcapsules that contained 2, 7 -dichlorofluorescein (DCF), (a) Schematic of the release of DCF solution from broken microcapsules into a crack or scratch where the dye encounters the amine groups of the resin, resulting in colour change, (h) Colour change of a DCF solution in the presence of an amine, (c) Self-reporting properties of the described material.

---