Jan W. Gooch

Emulsion and miniemulsion copolymerization of acrylic monomers in the presence of alkyd resin

Emulsion and miniemulsion copolymerizations were carried out with acrylic monomers (methyl methacrylate, butyl acrylate, and acrylic acid) in the presence of an alkyd resin. Poly(methyl methacrylate) was used as a hydrophobe or cosurfactant in the miniemulsion reactions. The results demonstrate that miniemulsion polymerization is the preferred process, probably because of mass transport limitations of the alkyd in the conventional emulsion polymerization reactions. The monomer emulsions prepared for the miniemulsion reactions were much more stable and the polymerizations were free of coagulum. Reaction rates, particle size characteristics, grafting efficiencies, and some film properties were measured.

Waterborne oil-modified polyurethane coatings via hybrid miniemulsion polymerization

As part of a wider effort to develop a new class of waterborne coatings, hybrid miniemulsion polymerization was carried out with acrylic monomers (methyl methacrylate, butyl acrylate, and acrylic acid) in the presence of oil-modified polyurethane resin. Latexes with different ratios of resin to acrylic monomers were synthesized. The monomer emulsions prepared for hybrid miniemulsion polymerization showed excellent shelf-life stability (>5 months) and the polymerization was run free of coagulation. Solvent extraction indicated that the grafting efficiency of polyacrylics was greater than 29% for all the samples produced. A 13C solution NMR spectrum showed that a substantial fraction of the original carbon double bonds (>61%) in oil-modified polyurethane remained after polymerization for film curing. Films obtained from the latexes presented good adhesion properties and fair hardness properties.

Water-based crosslinkable coatings via miniemulsion polymerization of acrylic monomers in the presence of unsaturated polyester resin

Hybrid miniemulsion polymerization was performed with a three-component acrylic system of methyl methacrylate, butyl acrylate, and acrylic acid in the presence of a Bayer® Roskydal TPLS2190 unsaturated polyester resin. Latexes were obtained in which the polyester resin was grafted to the acrylic polymer, forming a water-based crosslinkable coating. Grafting between the resinous component and the acrylic polymer is a feature different from the work of others who have attempted to combine the properties of both systems in water-based blends. Both emulsions and latexes were shelf-stable for over 6 months, shear-stable, and resistant to at least one freeze/thaw cycle. Resin-to-monomer ratios were studied as high as 1 : 1 (wt : wt), and total emulsion solids, as high as 45%. Monomer droplet and latex particle sizes were similar, suggesting evidence of the preponderance of droplet nucleation. A high level of crosslinking (>70%) during polymerization was observed in this particular hybrid system in contrast to those involving alkyd or polyurethane resins (<5%). Films, both homogeneous and hard, were achieved with exceptional adhesion. Electron microscopy showed the hybrid particle morphology to have internal domains of polyester resin in an acrylic matrix.

Electromagnetic shielding and corrosion protection for aerospace vehicles

Electromagnetic Shielding Effectiveness and Corrosion Prevention.- Fundamentals of Corrosion.- Fundamentals of Electromagnetic Shielding.- Investigation of the Relationship Between DC Resistance and Shielding Effectiveness.- Identification and Evaluation of Optimum Conductive Sealant Materials.- Field Test Evaluations on E-3A Aircraft.- Assessment of the Validity of the MIL-B-50878 Class R Bonding Requirements.- EMI Gaskets.

Rheological Characterization Of High Solids Magnetic Dispersions

Advancements in magnetic media technology for audio and video tapes have been made possible by investigating the fundamental mechanisms and properties of magnetic dispersions and coatings. In this study, development of magnetic dispersions required novel and quick methods for determining the degree of dispersion during milling in the liquid state since magnetic dispersions degenerate by agglomeration within minutes. Improved formulations were developed by observing compatibility of resins and solvents with acicular magnetic iron oxide powders and results were interpreted in rheological terms for the liquid dispersions since rapid feedback of information was possible. Coatings were characterized by surface gloss, x-ray radiography, optical and electron microscopy together with magnetic measurements. Results show that viscometric trends, degree of dispersion and magnetic properties are interrelated, and that capillary viscometry flow data provide the most consistent method of monitoring the “goodness” of the liquid dispersion before the coating is applied to uniaxially oriented polyester tape.

Scope, Objectives, and Summary of Investigations

This series of research efforts were designed to effectively support the individual warfighter wounded forward of hospitals and possible field aid stations. The scope of this investigation spans: Barrier dressings (liquid and particulate) for soft tissue wounds Sutureless tissue adhesives Antibacterial nanoemulsions One-hand operated and automatic tourniquets for the battlefield

Barrier Dressings for Wounds

The skin is the largest human organ and is the essential interface between the host and its environment. Among the major functions of this organ are mechanisms that provide heat loss or heat retention; water loss or water retention; elimination of waste via exfoliation; protection against penetration of ultraviolet light; touch location of physical objects; and, perhaps most obviously, protection of underlying tissues from microbial pathogens contacted in the environment. Methods to establish an artificial barrier function over damaged skin by use of bandages, compresses, poultices, and other devices have been recorded during all phases of medical history. Today, there are adequate methods and devices for skin closure and/or bandaging at medical institutions capable of providing definitive surgical care, for example, hospital emergency and operating suites. The general availability of such facilities and emergency medical transportation systems are basic infrastructure components of modern societies. The wide variety of sizes, shapes, materials, and mechanical devices necessary to accomplish this level of wound care, however, is dependent upon an extensive logistic and storage base.

Antibacterial Aqueous Emulsions

Researchers at the Center for Biologic Nanotechnology, University of Michigan, Ann Arbor Michigan published and patented results of project MDA 972-1-007 of the Unconventional Pathogen Countermeasures Program, Defense Advanced Research Project Agency. The introduction of biological agents to our working and living environment has forced an examination of preventative and decontamination methods (Mobley 1995). The project involved antibacterial aqueous nanoemulsions to treat bacteria-infected people and disinfect contaminated surfaces such as vehicles and medical equipment exposed to anthrax spores. Literature and patents were reviewed, materials and equipment were procured, and emulsions were prepared and evaluated for antibacterial activity. The antibacterial emulsion technology could possibly be useful if it is reproducible. Regarding emulsion technology, the term “emulsion” is the industry standard, and “nanoemulsion” pertains to emulsified particle less than a micron in diameter (e.g., typical of paint latex particle size), but greater than a nanometer. Actually, particle diameters for industrial emulsions are usually in the nanometer range.

One-Hand Operated and Automatic Tourniquet

On the battlefield, a properly applied tourniquet can be an extremely effective means of controlling severe extremity wound hemorrhage. However, a great deal of confusion exists among soldiers, medics, and military medical officers on a number of tourniquet-related issues. What is an appropriate combat tourniquet? When is it appropriate to use a tourniquet? When and by whom should a tourniquet be removed? Under what conditions should a tourniquet not be released or removed? What are the most effective ways to increase limb salvage while using a tourniquet?

Fundamentals of Electromagnetic Shielding

The shielding effectiveness (SE) is typically defined as the ratio of the magnitude of the incident electric field, E i , to the magnitude of the transmitted electric field, E t :