Roger M. Rowell

University of Wisconsin–Madison | UW · Biological Systems Engineering

Wood was designed, after millions of years of evolution, to perform in a wet environment. Nature is programmed to recycle it, in a timely way, back to the basic building blocks of carbon dioxide and water. All recycling chemistries start with an invasion of the wood surface. The surface of wood is porous, hygroscopic, viscoelastic, and anisotropic...

The first research on acetylation of wood started in 1928, and the first research done on acetylation of wood at the USDA Forest Service Forest Products Laboratory (FPL) started in 1945. This is a review of the research done between 1945 and 1966 at the FPL. This research was the first to show that acetylated wood was both decay-resistant and dimen...

The wood preservation industry has depended on toxicity as a mechanism of effectiveness against decay fungi to extend the life of wood used in adverse conditions. An alternative to toxicity, however, is to study and understand the mechanism of fungal attack and stop it before it can start. Knowing that fungi need moisture for colonization, a new ap...

Stable and durable wood products can be produced by chemical modification at the molecular level. One modification that is effective in achieving these properties is by reacting both hardwoods and softwoods with acetic anhydride. The reaction takes place in the most accessible hydroxyl groups in the cell wall polymers. Lignin reacts the fastest fol...

Coated wood exposed to an outdoor environment is susceptible to weathering due to a series of chemical, biological, and physical processes. Acetylation of wood is known to improve weathering resistance and coating performance by increasing UV resistance, dimensional stability, and durability against fungal decay. Understanding improved coating perf...

Most wood coating tests are done either in a short term artificial weathering chamber or long term on an outdoor rack/fence. In both cases, the coatings are exposed to both ultraviolet radiation and water. This study is focused on the influence of moisture alone on wood opaque film forming coating failures. As moisture is sorbed into the wood struc...

We have used natural fibers for many applications since the beginning of the human race. The earliest humans used biomass to make shelters, cook food, construct tools, and make boats and weapons. The use of natural fibers dates back in history to about 8000 BC. Linen and hemp fabrics are known to have existed at that time and linen textiles are kno...

The reaction of wood to acetic anhydride greatly reduces moisture sorption and improves the dimensional stability of the wood due to the esterification of the accessible hydroxyl groups in the cell wall, reducing hydrogen bonding with water and bulking the cell wall back to its green volume. The sorption of both primary and secondary water are redu...

Wood exposed to the outdoor environment is susceptible to weathering due to a series of chemical, biological and physical processes. Acetylation of wood is known to reduce cell wall moisture content, improve dimensional stability and durability against fungal decay. As a result of these improvements, less stress is created between the coating and t...

Wood is a porous three dimensional, hydroscopic, viscoelastic, anisotropic bio-polymer composite composed of an interconnecting matrix of cellulose, hemicelluloses and lignin with minor amounts of inorganic elements and organic extractives. Some, but not all, of the cell wall polymer hydroxyl groups are accessible to moisture and these accessible h...

There are many different types of natural fibers coming from a wide variety of plant sources. These fibers have been used by humans since the beginning of human existence for clothing, heating, shelter, weapons, tools, packaging and writing materials. This chapter will deal with the use of biomass in biocomposites. These will include waferboard, fl...

Furan monomers are produced when wood is heated at high temperatures. To understand the process conditions for production of furfural (FF) and hydroxymethylfurfural (HMF) from wood, samples of milled aspen wood were subjected to autohydrolyzis by microwave heating in a sealed Teflon reactor. The experiments were designed to simulate temperature and...

Wood is best de‹ned as a three-dimensional biopolymer composite composed of an interconnected network of cellulose, hemicelluloses and lignin with minor amounts of extractives, and inorganics. The major chemical component of a living tree is water, but on a dry weight basis, all wood cell walls consist mainly of sugar-based polymers (carbohydrates,...

One of the greatest assets of cellulosic resources is their compatibility with nature, including their combustibility and degradability which allow for constant turnover and regeneration of these natural resources. A fundamental understanding of these properties and possible methods for controlling them is essential for protection and better utiliz...

Wood has played a major role throughout human history. Strong and versatile, the earliest humans used wood to make shelters, cook food, construct tools, build boats, and make weapons. Recently, scientists, politicians, and economists have renewed their interest in wood because of its unique properties, aesthetics, availability, abundance, and perha...

To understand what has happened to a historic wooden object, it is important to understand the wood structure and the chemistry of the original wood as well as the structure and chemistry of the historic wood. With this information, it is possible to understand the degradation that has occurred over time. With this knowledge, it is also possible to...

Dimensionally stable solid wood and wood composites can be achieved by several methods, including cell wall bulking, cell wall polymer crosslinking and removal of hygroscopic components in the cell wall. Bulking the cell wall with bonded chemicals produces dimensionally stable products that can withstand wet and dry cycles. Crosslinking with a shor...

Natural fibers can be modified to increase durability and stability. Two technologies are presently commercial to improve both of these properties: reaction of the fiber with acetic anhydride (acetylation) and heat treatments. Both increase durability and stability. Mechanical properties are slightly improved with acetylation, especially wet streng...

Tray samples of starch foam reinforced with aspen wood fiber were produced using a lab model-baking machine. Surfaces of the trays were treated with CF4 and SF6 plasma to get hydrophobic properties on surfaces. Fluorine compounds were found in XPS analysis of plasma treated samples. Due to the hydrophobic fluorine-rich surface, the contact angle wa...

We depend on our forests and agricultural lands to supply most of our biofiber needs. For pulp and paper, we depend on a sustainable wood resource while turning to nonwood agricultural biomass for alternative supply. For building materials, such as biofiber boards, we also depend on wood however many countries are running out of wood and are beginn...

Wood and other lignocellulosics have been used as "engineering materials" because they are economical, low in processing energy, renewable, and strong. In some schools of thought, however, lignocellulosics are not considered "materials" in that they do not have consistent, predictable, reproducible, continuous, and uniform properties. This is true...

Reductions in hygroscopicity, increased dimensional stability and decay resistance of heat treated wood depends on decomposition of a large portion of the hemicelluloses in the wood cell wall. In theory, these hemicelluloses are converted to water and volatile furan-type intermediates that can polymerize in the cell wall. Reductions in hygroscopici...

Polylactide (PLA)-recycled wood fiber (RWF) composites with a small amount of silane were compounded using a kinetic-mixer and molded using an injection molding machine. The molded PLA-RWF composites were characterized using gel permeation chromatography, scanning electron microscope, X-ray diffraction, differential scanning calorimeter, tensile te...

Dry-process hardboard represents a favorable option for recycling old newspaper fibers. However, dry-process boards tend to be less dimensionally stable than boards processed by other methods. The objective was to determine the mechanical and physical properties of 3-mm and 11-mm dry-process hard-boards made from various ratios of wood fiber to old...

Starch foam trays were produced using a laboratory model-baking machine. Surfaces of the trays were treated with SF6 plasma to create fluorine-rich layers on the surfaces. RF power, gas pressure and reaction time were varied to evaluate the effects of each parameter on fluorination of surfaces. The fluorine concentrations of treated sample surfaces...

Utilizing proprietary acetylation technology, Titan Wood operates the first large-scale commercial wood acetylation plant. Prior to the introduction and commercialization of Accoya ® wood, a considerable amount of testing on the material properties of this "new wood species" was performed. Furthermore, testing procedures to assure the quality of th...

Wood, having the lowest embodied energy of any mainstream building material, is carbon neutral. As such, wood, our only naturally renewable construction resource, helps combat global warming by absorbing carbon from the atmosphere and storing it away for the life of the wood product. Not only is wood renewable, but it is also biodegradable and sust...

Aspen fibers were plasma activated to enhance bonding between the particles and the adhesive for wood composites. The activation of materials was carried out by environmental-friendly dry plasma processing. After argon, oxygen or ammonia plasma treatments, the aspen fibers were analyzed by ESCA and FTIR. The fibers were used for designing fiberboar...

Wood block specimens pre-steamed at 120-220°C for 5-20 min were compressed in the radial direction. The recovery of set decreased with increasing presteaming temperature and time. The reduction of set recovery correlated with the amount of weight loss in steaming irrespective of pre-steaming temperature and time. The weight loss for the highest lev...

Three different mechanisms to explain the partial fixation of the compressive deformation of wood are postulated: non-softening, cross-linking and stress relaxation. This study attempted to fix the compressive deformation of wood by the non-softening mechanism of the cell-wall matrix using acetylation of the cell wall making it more hydrophobic. In...

The purpose of this study was to evaluate the dimensional stability and strength properties of compressed laminated veneer lumber (LVL) produced using a closed hot pressing system. LVL specimens were produced with varying number of veneers using either diphenylmethane diisocyanate (MDI) or a water-soluble phenol formaldehyde (PF) resin at varying t...

Imidazo[1,5-a]pyridines are a novel class of ligands that have gained recognition for its biological and medicinal applications. Recently, these ligands have been covalently incorporated into organic-inorganic hybrids as a means to remove heavy metal ions from water. Traditionally, the synthesis of imidazo[1,5-a]pyridines was limited to low yieldin...

NEAPP plasma-enhanced process is used to convert high molecular weight, liquid phase polymeric materials that were previously deposited on wood surfaces as thin layers, into hydrophobic, solid state networks. The entrapment of polymeric structures in the surface layers of wood samples and controlled plasma-processing performed in the next step allo...

Animal agriculture is under increasing pressure to produce more and more meat, milk and eggs giving rise to an increasing amount of manures. In the past, manures have been viewed as a waste byproduct used mainly as a fertilizer that has a value of 2 to 4 cents per dry pound. We need to change our view of manures from waste to asset. Destroying manu...

There is a great incentive and motivation in the building and wood research communities as well as in the industry to develop more eco-efficient and durable wood-based products with better performances. In this context, eco-efficient products refer to “green” sustainable products where both economical and ecological aspects have to be balanced. Thi...

Heat treatment of wood fibers in a closed press for 4 and 8 minutes and pressed into fiberboards greatly reduces moisture regain and increases dimensional stability of the boards. Part of the hemicellulose sugars are lost during the steam treatment and furan intermediates were detected. Mannose, galactose, xylose, arabinose and rhamnose were partia...

The focus of this study was on aspen wood and other lignocellulosic materials for removing organic and inorganic contaminants typically present in stormwater runoff. The study demonstrated that aspen wood fibers remove PAHs from the aqueous solution. Removal increased with increasing molecular weight of the PAH, but did not seem to be related to th...

This paper presents a thin polymer surface coating approach to facilitate dispersion of poly(styrene-maleic anhydride) (SMA) copolymer-coated alumina (Al2O3) nanoparticles in polycarbonate (PC) using a high intensity thermokinetic mixer (K-mixer) and the optical properties of the resultant nanocomposites. Electron spectroscopy for chemical analyses...

Biobased and biodegradable polylactide (PLA)-pine wood flour (PWF) composites were investigated as a means to reduce the overall material cost and tailor the material properties. The composites were prepared using a kinetic-mixer and an injection molding machine. The tensile modulus of the PLA-PWF composites increased with the PWF content whereas t...

A new procedure has been developed to treat wood with aqueous solutions, microemulsions or other fluids using a roller-press. Green lumber is used which eliminates the need for predrying before treatment. Compressing the green wood to 50–60% of its thickness in a roller-press submerged in a phenol formaldehyde solution resulted in weight gains of 4...

Milled southern pine wood was modified with sequential treatments of sodium periodate and sodium hypobromite for the purpose of improving copper ion (Cu2+) sorption capacity of the wood when tested in 24-h equilibrium batch tests. The modified wood provided additional carboxyl groups to those in the native wood and substantially increased Cu2+ upta...

Filter paper (100% cellulose) was treated with either a 25% solution of polyacrylic acid (PAA) or poly (4-vinyl) pyridine powder (PVP). The dried paper was held under vacuum, treated with a 5% solution of PAA, heated and washed. The treated paper was then exposed to Ar-plasma to crosslink the PAA on the surface of the paper. The paper was dried, wa...

Wood and other biomass resources have been blended with thermoplastic such as polyethylene, polypropylene, polylactic acid and polyvinyl chloride to form wood plastic composites (WPC). WPCs have seen a large growth in the United States in recent years mainly in the residential decking market with the removal of CCA treated wood decking from residen...

This article presents the development and characterization of transparent poly(styrene-r-maleic anhydride) (SMA)/alumina nanocomposites for potential use in optical applications. Chemically treated spherical alumina nanoparticles were dispersed in an SMA matrix polymer via the solution and melt-compounding methods to produce 2 wt % nanocomposites....

For most markets for wood, it is used without any treatments or modifications. When wood is used in adverse environments, it may be treated with chemicals to help prevent decay, improve water resistance, reduce the effects of ultraviolet radiation or increase fire retardancy. Many of these treatments involve the use of toxic or corrosive chemicals...

Renewable and sustainable composite materials can be produced using forest biomass if we maintain healthy forests. Small diameter trees and other forest biomass can be processed in the forest into small solid wood pieces, sliced veneers, strands, flakes, chips, particles and fiber that can be used to make construction composite products such as glu...

The mechanical properties of newly developed aspen fiber-polypropylene composites (APC) were experimentally explored and numerically predicted at the temperatures and humidity that are typical for domestic housing applications. The mechanical properties of APCs with five different fiber-loadings were evaluated at the room temperature, 4 °C, and 40...

Southern pine solid wood and wood fiber were reacted with acetic anhydride to various acetyl weight gains. The equilibrium moisture content (EMC) was determined on these specimens at 30%, 65% and 90% relative humidity (RH) and 27 °C. A standard soil block decay test using the brown-rot fungus Gloeophyllum trabeum was performed and weight loss calcu...

The aim of the publication is to present coherent and up-to-date views of the modern concepts which dominate the new techniques in the plasma chemistry. Scope will also be given for presentation of new and challenging ideas in functionalization of natural polymers. The book’s content provides a broad topical survey of this branch of cold plasma tre...

The properties and performance of wood, which is resulted from the chemistry of its cell wall components are discussed. It performs efficiently in a wet environment, and is naturally recyclable in a timely way, degrading it to the basic compounds such as carbon dioxide and water through biological, thermal, aqueous, photochemical, chemical, and mec...

Milled aspen wood was thermochemically modified with citric acid for the purpose of improving the copper (Cu 2+) ion sorption capacity of the wood when tested in 24-hour equilibrium batch tests. The wood-citric acid adducts provided additional carboxyl groups to those in the native wood and substantially increased Cu 2+ ion uptake of the mod-ified...

When untreated wood is exposed to adverse outdoor conditions, nature has a series of chemistries to degrade it to its original building blocks of carbon dioxide and wa­ ter. Fungi, termites, heat, moisture, ultraviolet (UV) en­ ergy, and chemicals take their toll on the performance properties of wood. We tend to study each of these degra­ dation ch...

SUMMARY Wood can be chemically modified to reduce the moisture content of the cell wall and increases decay resistance. As the level of bonded chemical increases, the cell wall equilibrium moisture content decreases and the resistance to attack by white- and brown- rot fungi increases. There is a direct relationship between the decrease in cell wal...

As the world population grows, there is a growing awareness that our environment is getting more polluted. Clean water is becoming a critical issue for many parts of the world for human, animal and agricultural use. Filtration systems to clean our air and water are a growing industry. There are many approaches to removing contaminates from our wate...

Juniper (Juniperus monosperma), a small-diameter underutilized material, has been studied as a lignocellulosic biosorbent for removing heavy metals from water. In this study, juniper wood was modified by sulfonation to enhance sorption capacity for cadmium in water. The origin of the enhancement was investigated by observing the sorption behaviors...

The degradable nature of high-performance, wood-based materials is an attractive advantage when considering environmental factors such as sustainability, recycling, and energy/resource conservation. The Handbook of Wood Chemistry and Wood Composites provides an excellent guide to the latest concepts and technologies in wood chemistry and bio-based...

High moisture content, flat sawn Japanese cedar (Cryptomeria japonica D. Don) veneer was compressed using a roller press to mechanically remove water. The amount of water removed depended on the amount of compression applied. At 60% compression, 400kg/m3 of water was removed. The process was not dependent on the size of the wood, the degree of comp...

Spruce, coconut coir, sugarcane bagasse, kenaf bast, kenaf core, and cotton were tested for their ability to remove copper, nickel and zinc ions from aqueous solutions as a function of their lignin content. The fibers were analyzed for sugar and lignin content and extracted with diethyl ether, ethyl alcohol, hot water, or 1% sodium hydroxide. The o...

The chemical composition of a variety of agricultural biomass samples was analyzed with near infrared spectroscopy and pyrolysis molecular beam mass spectroscopy. These samples were selected from a wide array of agricultural residue samples and included residues that had been subjected to a variety of different treatments including solvent extracti...

Phosphorus from excess fertilizers and detergents ends up washing into lakes, creeks, and rivers. This overabundance of phosphorus causes excessive aquatic plant and algae growth and depletes the dissolved oxygen supply in the water. In this study, aluminum-impregnated mesoporous adsorbents were tested for their ability to remove phosphate from wat...

The objective of this research was to improve the fire-retardant properties of wood in one treatment using a phosphorus pentoxide–amine system. Phosphorus pentoxide and 16 amines including alkyl, halophenyl, and phenyl amines were compounded in N,N-dimethylformamide and the resulting solutions containing phosphoramides were reacted with wood. The c...

Resistance of wood reacted in situ with phosphorus pentoxide-amine to the brown-rot fungus Gloeophyllum trabeum and white-rot fungus Trametes versicolor was examined. Wood reacted with either octyl, tribromo, or nitro derivatives were more resistant to both fungi. Threshold retention values of phosphoramide-reacted wood to white-rot fungus T. versi...

A new procedure has been developed for the rapid continuous acetylation of lignocellulosic fiber. A limited amount of acetic anhydride is applied to the fiber before the fiber goes through a reactor at high temperature. The acetylated fiber is then stripped in a first step with superheated vapor of anhydride/acetic acid and, optionally, in a second...

The acetylation of natural fibers to improve its performance was studied. The acetylation is on method of chemically modifying natural lignocellulosic fibers to improve propetties of dimensional stability, resistance to biological attack and degradation due to ultraviolet energy. Many chemicals have been used to chemically modify natural fibers to...

Sisal fibers and finely powdered high-density polyethylene were surface functionalized using dichlorosilane (DS) under R-F plasma conditions to improve interfacial adhesion between the two dissimilar substrates. The functionalized polyethylene (70%) and sisal (30%) were compounded on four different ways using thermokinetic mixer and injected molded...

Sisal fibers and finely powdered high-density polyethylene were surface functionalized with dichlorosilane on a RF(radio frequency)-plasma reactor. Composites made from sisal and high-density polyethylene were compounded using a thermokinetic mixer. The discharged mass was cooled, granulated, and injected molded into composite specimens for testing...

Woodfiber-thermoplastic composites (WPC) have received considerable attentions from the forest product industry for civil engineering appli- cations due to its superior properties over wood and plastics alone. Particularly WPCs can be easily fabricated using traditional plastic processing techniques. The major limitation in the applica- tions of WP...

Moisture sorption in fiber-thermoplastic composites leads to dimensional instability and biological attack. To determine the pick up of moisture this type of composite, aspen fiber/polypropylene composites were made using several different levels of aspen fiber (30 to 60% by weight) with and without the addition of a compatibilizer (maleic anhydrid...

High temperature steam treatment of wood fiber in a closed press during fiberboard pressing and then cooling the fiberboard while still under pressure to below the glass transition temperature of lignin, greatly increased the dimensional stability and decreased the hemicellulose content of the fiberboards produced. For example, after pressing aspen...

The effect of acetic, maleic or succinic anhydride modifications of wood fiber on the mechanical properties and dimensional stability of differently bonded fiber boards was studied. The binders for the fiber boards used in this work were: powdered phenol formaldehyde resin of the novolak type (PF), polypropylene (PP) and a combination of the two. I...

The leaves of the agave plant are left in the field after harvesting the heads for tequila production. Different types of agave leaves were isolated, classified, and their content in the total plant determined. The usable fractions were collected and their properties determined. Of the total wet weight of the agave plant, 54% corresponds to the aga...