Polyamidoamine (PAMAM) dendrimer of zero generation was synthesized and characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopic techniques. A novel chemistry has been developed to synthesize polyurea microcapsules containing solvent and linseed oil as the active healing agent by interfacial polymerization of commercial methylene diphenyl diisocyanate (MDI) and dendritic 0.0 G PAMAM capable of cross-linking to form a shell material. Spherical with some irregular shape microcapsules were observed with average diameter from 20 to 270 μm at different agitation rates (3000–8000 rpm). Interfacial interaction between polyurea microcapsules and polyurethane (PU) coating were studied by FTIR, and this showed that chemical bonds were formed by the reaction between isocyanates and the amine groups present on the wall of microcapsules. The thermal stability of the microcapsules showed that prepared microcapsules experienced excellent stability up to 380 °C. The anticorrosive performance of PU coatingd loaded with different percentages of microcapsules was carried out in 5% NaCl aqueous solution. The results showed that the composite provides satisfactory anticorrosive properties at 5% capsule loading under an accelerated corrosion process. The idea and approach presented in this work have the potential to fabricate microcapsules which could provide better anticorrosive and mechanical properties to coating composites.

Polymeric researchers desire strongly to reduce dependency on fossil or petroleum feed stock by utilizing renewable source based polymeric resins in coating. The present research represents the attempt made to develop neem oil (a renewable source) two-pack self-healing anticorrosive polyurethane (PU) coatings cured at room temperature. The oil-based polyesteramide was prepared in two steps; viz., in the first step, oil fatty amide was synthesized, and in the second, it was directly converted to polyesteramide by condensing amide with phthalic anhydride. A spectral study of prepared resin was carried by FT-IR and NMR techniques. Polyesteramide further was utilized for preparation of self-healing PU coatings with incorporation of polyamidoamine based polyurea microcapsules containing natural self-healing agent. The obtained coatings were tested for thermal, physicochemical, and corrosion resistance tests. The coating properties, like gloss, impact resistance, adhesion, and flexibility, were also studied and found to be superior for anticorrosive self-healing industrial coatings.

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New sequence of microcapsules with dendritic PAMAM-based novel polyurea as shell wall material containing herbicide as a core moiety has been prepared by interfacial polymerization technique. Dendrimer-based polymeric microcapsules were fabricated with aim to study the effect of different reaction parameters such as surfactant dose, core loading, agitation speed, and amount of solvent on particle size, particle size distribution, and appearance of microcapsules. Prepared microcapsules were characterized by FTIR, thermo gravimetric analysis, particle size analysis, scanning electron microscope, and other microscopic technique. In present investigation, surfactant dose of 2.5% with 5 mL of solvent at 400 rpm was found to be optimum for fabrication of stable new polyurea microcapsules containing 1 g of core. The synthesized microcapsules with optimized parameters were evaluated quantitatively for controlled release study by gas chromatography in different environmental conditions. The highest percent release of core was found in acidic conditions compared to that of basic and least in neutral medium.