Novel Polyurea Microcapsules Using Dendritic Functional Monomer: Synthesis, Characterization, and Its Use in Self-healing and Anticorrosive Polyurethane Coatings

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

Novel Polyurea Microcapsules Using Dendritic Functional Monomer: Synthesis, Characterization, and Its Use in Self-healing and Anticorrosive Polyurethane Coatings

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

Fabrication of Core–Shell Novel Polyurea Microcapsules Using Isophorone Diisocyanate (IPDI) Trimer for Release System

<div><p>Isophorone diisocyanate (IPDI) trimer based novel polyurea core shell structures were developed by interfacial polymerization. Different operating conditions have been used to fabricate shell to encapsulate core. Characterizations of prepared microcapsules were done by Fourier transform infrared spectroscopy, thermogravimetric analysis, and particle size analyzer. The surface morphology of microcapsules was examined by optical microscopy, scanning electron microscopy, and transmission electron microscopy. The release rate of core from microcapsules was estimated by UV and gas chromatography. The results revealed that tailor made release can be adjusted by varying operational protocol for shell and fabricated shell can be extended to other applications such as self-healing coatings and drug delivery.</p> </div

Enhancement of Anticorrosive Performance of Cardanol Based Polyurethane Coatings by Incorporating Magnetic Hydroxyapatite Nanoparticles

The present investigation demonstrates renewable cardanol-based polyol for the formulation of nanocomposite polyurethane (PU) coatings. The functional and structural features of cardanol polyol and nanoparticles were studied using FT-IR and 1H NMR spectroscopic techniques. The magnetic hydroxyapatite nanoparticles (MHAPs) were dispersed 1&ndash;5% in PU formulations to develop nanocomposite anticorrosive coatings. An increase in the strength of MHAP increased the anticorrosive performance as examined by immersion and electrochemical methods. The nanocomposite PU coatings showed good coating properties, viz., gloss, pencil hardness, flexibility, cross-cut adhesion, and chemical resistance. Additionally, the coatings were also studied for surface morphology, wetting, and thermal properties by scanning electron microscope (SEM), contact angle, and thermogravimetric analysis (TGA), respectively. The hydrophobic nature of PU coatings increased by the addition of MHAP, and an optimum result (105&deg;) was observed in 3% loading. The developed coatings revealed its hydrophobic nature with excellent anticorrosive performance