Sharathkumar K. Mendon

Formaldehyde-Free Wood Composites from Soybean Protein Adhesive

Commercial particleboards are currently synthesized by blending wood furnish with formaldehyde-based resins and curing them under a combination of heat and pressure. Particleboards manufactured with urea-formaldehyde resin are known to liberate formaldehyde during their service lives. Formaldehyde’s carcinogenicity has prompted the search for environmentally-friendly resins for wood composite manufacture. Soybean protein-based adhesives have been developed as a renewable and formaldehyde-free replacement for urea-formaldehyde resins. Particleboards processed using the soybean protein adhesive matched or exceeded performance criteria of M-2-grade commercial particleboards when evaluated as per American National Standards Institute (ANSI) specifications.

Treatment of Mg powder with carbonic acid and the effect of treatment variables and treated Mg ratios on coating performance in salt spray tests

Magnesium-rich primers (MgRPs) are known to exhibit excellent corrosion resistance during natural weathering due to the formation of a controlled and complex cathodic protective layer which includes but is not limited to changing combinations of magnesium metal, magnesium hydroxide, and magnesium carbonate each during film formation, cure, and environmental exposure. Pretreating Mg powder with carbonic acid before incorporation into coatings has been shown to enhance the corrosion resistance of MgRPs. In an earlier study, the conditions for treating Mg powder and the effects of variables such as time and the order of addition were evaluated to determine optimized treatment conditions. In this study, the treatment process was analyzed further to better understand the nature of the carbonation process and the effect of treatment variables on the overall corrosion protection process. Coatings prepared with different ratios of treated and untreated Mg were evaluated via ASTM B117 salt fog exposure to determine the optimized ratio of treated and untreated pigments for maximum corrosion protection.

A rapid quantitative protocol for measuring carbon nanotube degree of dispersion in a waterborne epoxy–amine matrix material

The available literature makes it very clear that accurate measurements of carbon nanotube dispersion quality are very complicated and the typical characterization is neither simple nor reliable. Most methods to quantify carbon nanotube dispersion reported in the literature require investigator-chosen assumptions or software interpretations that are impractical at best and misleading at worst for facile application. Herein, we report on the use of visible light absorption-based method(s) and validate that these were quantitative for discerning dispersibility differences for MWCNTs with three distinct surface chemistry modifications and concentration levels blended with polymeric materials. Ultimately, the dispersion quality was quantified via the trendline slope of the thickness-normalized absorbance values as a function of MWCNT concentration. Extremely poor dispersions were represented by statistically insignificant slope trendlines. Our data revealed that hydroxyl surface modification increased MWCNT dispersibility by a factor of ~2.8 and ~2.6 compared to the as-received MWCNT formulations via the absorption and the blackness methods, respectively. These results support and quantifiably validate that simple optical blackness values directly measured the degree of dispersion for MWCNTs in coatings applied to substrates, and our data support that this is a simple and effective quality control metric.

Investigation of ouzo effect colloid formation via organosilica nanoparticles

The ouzo effect is a rapid route to nanoparticle formation through nanoprecipitation via the addition of a poor solvent to supersaturate a polymer solution. Currently, there are differing opinions on the mechanism of particle formation: nucleation and growth, nucleation and aggregation, or spinodal decomposition. To elucidate the mechanism, various concentrations of organosilica were added as artificial nucleation embryos to poly(methyl methacrylate)-tetrahydrofuran solutions prior to nanoprecipitation. Particle size distribution was monitored via dynamic light scattering, while the morphology and organic content of select samples were further characterized via transmission electron microscopy and thermal gravimetric analysis, respectively. The data establishes that spinodal decomposition was the mechanism of particle formation and that silica can be used as an additive for particle size distribution control during ouzo effect particle formation.

CHAPTER 12:Utilization of Green Materials for Coating Applications

The continued use of fossil (petroleum-based) materials has raised environmental concerns due to their lack of bio-degradability and bio-sustainability. The coatings industry has been proactive by incorporating natural materials into its products. The recent thrust in favor of bio-based materials for coatings has led to even greater interest in using technologies to integrate green materials into coating formulations without performance property losses. This chapter highlights some examples of how bio-based materials are being modified for use in resins and coatings.