The Role Of Water Repellents And Chemicals In Controlling Mildew On Wood Exposed Outdoors

The natural look of wood siding, and the retention of that look, has become increasingly popular over the past several years. Many new commercial formulations are being offered for use as clear natural wood finishes. A successful finish will retain color, control mold and mildew, and minimize weathering. Some of these formulations contain a chemical as a mildewcide (fungicide, preservative) and/or a water repellent, and some do not. To evaluate several chemicals (alone or in combination with water repellents) as components of natural finish formulations, we dip-treated ponderosa pine sapwood specimens in various formulations and exposed them on test fences in Mississippi, Wisconsin and Washington. Several chemicals were very effective at controlling mildew and maintaining the natural appearance of the exposed wood. Aqueous formulations of chromium salts were the most effective for up to 22 months exposure outdoors. Many chemical formulations in mineral spirits (including water repellents and wood sealers) were effective for 5 to 9 months of exposure, but their effectiveness was reduced with longer exposure. Of all the chemicals evaluated in mineral spirits formulations, only pentachlorophenol and copper naphthenate were found to be effective mildewcides after exposures of greater than 9 months. Their mildewcidal effectiveness was improved with the addition of a simple water repellent (paraffin wax), especially with exposures greater than 9 months. Mildew growth was markedly worse in the warm, humid climate of Mississippi than in Washington or Wisconsin. This means that natural wood finishes for climates similar to Mississippi must contain high concentrations of effective mildewcides for good performance. This paper should be useful to homeowners, architects, builders, and wood finish formulators.

Handbook of Modern Coating Technologies: Application and Development reviews recent applications and developments of modern coating technologies. The topics in this volume consist of role of antibacterial coatings in the development of biomaterials, insights of technologies for self-healing organic coatings, sensor applications, application of carbon nanotubes–based coating in the field of art conservation, oxide-based self-cleaning and corrosion-protective coatings, protective coatings for wood, applications of optical coatings on spectral selective structures, application of natural antimicrobial coating for controlling foodborne pathogens on meat and fresh produce, efficacy of antimicrobial coating in reducing pathogens on meat, composite membrane: fabrication, characterization, and applications, development of nanostructured HVOF coatings on high strength steel components for turbine blades, nanoscale multilayered composite coating, applications of sol–gel coatings, application of graphene in protective coating industry, application of coatings in outdoor high-voltage installations, defects and doping effects in thin films of transparent and conductive oxides, and functional coatings for lab-on-a-chip systems based on phospholipid polymers.

This book is primarily a general text covering the whole sweep of the forest industries. The over-riding emphasis is on a clear, simple interpretation of the underlying science, demonstrating how such principles apply to processing operations. The book considers the broad question "what is wood?" by looking at the biology, chemistry and physics of wood structure. Wood quality is examined, and explanations are offered on how and why wood quality varies and the implications for processing. Finally, various "industrial processes" are reviewed and interpreted. All chapters have been written by specialists, but the presentation targets a generalist audience.