Microcapsulated epoxy resin with nanosilica‐urea formaldehyde composite shell

Abstract

In this study, the epoxy microcapsules with the nanosilica (0, 1, 2, and 3 wt %)-urea formaldehyde composite shell were synthesized and then characterized by optical microscope (OM), field emission scanning electron microscope (FESEM), Fouriertransform infrared spectroscopy (FT-IR), and thermogravimetric analysis. According to the OM analysis, the without nanosilica microcapsules had the semitransparent structures and equal size distributions. Also, the formation of the microcapsule clusters and rupturing microcapsules in the sample containing 3 wt % nanosilica were observed by OM method. The FESEM analysis showed that without nanosilica, microcapsules had a smooth surface, whereas by increasing the percentage of nanosilica up to 2 wt %, the surface roughness was enhanced. It was also observed that on the surface of the microcapsules without nanosilica, two size ranges of the submicrocapsules with the average diameters of 1.12 μm and 208 nm were formed. By adding 1 wt % nanosilica, three size ranges of submicrocapsules were formed, with the average size of 2.63 μm, 824 and 179 nm. The interesting phenomena in the microcapsules containing 2 and 3 wt % nanosilica were the packing submicrocapsules with the polymeric shell and the formation of the microcapsule clusters, respectively.

Experimental investigation of flexural properties of glass fiber–epoxy self-healable composite structures containing capsulated epoxy healing agent and NiCl2(imidazole)4 catalyst

“…Figure 5(a) represents the FESEM image of fabricated microcapsules by promoted Tang's method [16], which has been published in our previous work [15]. The encapsulation efficiency was about 90-95%.…”

“…In this method, the epoxy and ureaformaldehyde were core and shell, respectively. It should be noted that the encapsulation of epoxy was performed based on the one stage in situ polymerization method [15]. Figure 1 represents the schematic flowchart of encapsulation process in this research.…”

“…(C 3 N 2 H 4 ) 4 as healing agents into the glass fiber-epoxy composite structure. It is worth noting that the epoxy was encapsulated by promoted one-stage method, which has been previously published by us in other journal [15]. The second novelty is using the quasi-static penetration method for creating the different damages into the composite structures.…”

Development of a dual capsule self‐healing silicone composite using silicone chemistry and poly(melamine‐urea‐formaldehyde) shells

“…11,12 The versatility of microencapsulation technologies offers an unlimited combination of core and shell materials for the selfhealing of surfaces. 13 Encapsulation of dicyclopentadiene, 3,14,15 epoxies, [16][17][18][19][20] polydimethylsiloxanes, [21][22][23][24] and isocyanates, 25 inside various polymeric shells such as ureaformaldehyde, 17,20,[26][27][28] melamine-formaldehyde, 10,29 melamine-urea-formaldehyde, [29][30][31] polymethylmethacrylate, [32][33][34] silica, 35 and so on, are investigated for self-healing purposes. The fabrication of microcapsules can be divided into physical or chemical methods.…”

Effect of MF-Coated Epoxy Resin Microcapsules on Properties of Waterborne Wood Coating on Basswood

“…The heat resistance and water resistance are better than those of urea formaldehyde resin [13]. The epoxy resin has the advantages of compactness [14], good water resistance [15], good leakage resistance [16] and high resistance to impact [17]. Basswood is a kind of common wood, which has the characteristics of oil resistance, wear resistance, corrosion resistance and non cracking.…”