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A novel method for the fabrication of robust polyurea microcapsules containing tung oil as a core material was developed for self-healing anticorrosive coating application. Well-distinct microcapsules with polyurea as a shell were prepared by reacting hexamethylene diisocyanate trimer with 0.0 G polyamidoamine (PAMAM) via interfacial polymerization technique. Fourier transform infrared spectroscopic analysis was performed to elucidate the chemical structure of microcapsules as well as to confirm successful encapsulation of core by the polyurea shell. Surface morphology, particle size, distribution of particle size, thermal, and mechanical properties of the prepared PAMAM-based polyurea microcapsules were compared with microcapsules that were prepared using diethylenetriamine (DETA) and triethylenetetramine (TETA). The prepared microcapsules were embedded with acrylic polyol-based polyurethane (PU) coatings to ensure anticorrosive performance. The immersion study of self-healing PU coatings loaded with 5% PAMAM-based polyurea microcapsules possesses satisfactory anticorrosive property under an accelerated corrosion process in 5% NaCl salt solution.

This work focused on two difficulties associated with preparation of polypropylene/wood flour (PP/WF) composites, viz. the compatibility of PP with WF and processing of the composites with high melt viscosity. Maleic anhydride-grafted polypropylene (MAPP) was used in the preparation of PP composites to provide the compatibility between polymer and filler. Hyperbranched polyester (HBPE) was incorporated to check feasibility of it as a processing aid in the same. The PP/WF composites were formulated by melt compounding on a Brabender Plastograph EC. Blending effect of compatibilizer and processing aid HBPE on PP/WF biocomposites have been carried out on the basis of torque analysis, mechanical properties, morphology, and thermal stability. The investigation showed that HBPE improves the processibility of PP/WF composites than MAPP with respective to torque value. The mechanical and thermal properties slightly vary with change in relative proportion of MAPP and HBPE. J. VINYL ADDIT. TECHNOL., 2016. © 2016 Society of Plastics Engineers

In this article, we represent preparation of renewable source based smart polyurethane coatings reacting polyols prepared by acetylation of neem oil with different diisocyanates in presence of encapsulated corrosion inhibitor. The structures of polyols were confirmed by Fourier transfer infra-red and nuclear magnetic resonance spectroscopic techniques. The prepared polyols were used to form polyurethane coatings by treating with diisocyanates such as methylene phenyl, dicyclohexylmethane, and isophorone diisocyanates. Further, conversion of polyurethane to smart coatings was carried by incorporation of encapsulated form of quinoline as a corrosion inhibitor. Coatings were characterized for their thermal stability and physico-chemical properties by suitable sophisticated techniques. Anticorrosive properties of the smart coatings were studied by exposing them to corrosive medias like 0.5 M HCl and 3.5% NaCl solutions. Incorporation of encapsulated corrosion inhibitor into the neem oil based smart PU coatings shown enhanced anticorrosive property. Finding of this study also shown encapsulated form of commercial corrosion inhibitor can be extended for other PU coatings.

The use of reservoirs containing corrosion inhibitors as active substances for corrosion protection is an issue of great interest in the scientific literature. The aim of the present study is to encapsulate quinoline, a corrosion inhibitor, into a micro-reservoir to overcome disadvantages caused by its direct addition into a coating layer. Quinoline incorporated microcapsules with different core solvents were synthesized at room temperature by an interfacial polymerization method. The morphologies, wall structures, particle size and thermal properties of the synthesized microcapsules were investigated. The release study of core material was carried out by loss on drying and UV spectrophotometric methods. The prepared quinoline based microcapsules were incorporated in polyurethane (PU) coatings to study their effect on corrosion of substrate. The anticorrosive performance of coatings loaded with different weight % of microcapsules containing quinoline was tested by immersion of the PU coated mild steel specimens in 5 wt% HCl solution by visual observation and weight loss measurements.

In the present investigation, nanocomposites of polypropylene (PP)-montmorillonite (MMT) clay were prepared by a single-step compounding method to study the influence of hyperbranched polyester (HBPE) on rheological and mechanical properties of PP composites in the presence of a compatibilizer. In service of this objective, polyvinylchloride-grafted-maleic anhydride (PP-g-MA) was used as a compatibilizer for hydrophobic PP and hydrophilic clay. Rheological property in terms of melt viscosity was examined by a Brabender torque rheometer. The composite's morphology was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), whereas the dispersion state of nanoparticles in the PP matrix was studied by X-ray diffraction (XRD). The thermal behavior of nanocomposites was examined by differential scanning calorimetry (DSC). The analysis of results confirmed that the interactions among both additives significantly influenced the morphology, rheology, and thermomechanical properties of the nanocomposites. J. VINYL ADDIT. TECHNOL., 22:72–79, 2016. © 2014 Society of Plastics Engineers

The present work accounts new approach for processing of PP nanocomposites containing 5 phr pristine Na+ montmorillonite clay with better clay dispersion by a single-step process along with improved processability using hyperbranched polyester (HBPE). A series of PP/MMT nanocomposites with different HBPE contents were fabricated by direct melt compounding on a Brabender torque rheometer where all components of the blends were fed simultaneously for mixing. The efficiency of this approach was evaluated against PP/MMT nanocomposites prepared with polypropylene graft-maleic anhydride (PP-g-MA) compatibilizer. The overall results revealed that systems with HBPE showed better balance of rheology and mechanical properties than nanocomposites with PP-g-MA.

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...

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...

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 anticorros...