Treesearch

Acetylation of wood imparts moisture durability, decay resistance, and dimensional stability to wood; however, making durable adhesive bonds with acetylated wood can be more difficult than with unmodified wood. The usual explanation is that the acetylated surface has fewer hydroxyl groups, resulting in a harder-to-wet surface and in fewer hydrogen bonds between wood and adhesive. This concept was evaluated using four different adhesives (resorcinol–formaldehyde, emulsion polymer isocyanate, epoxy, and melamine–formaldehyde) with unmodified wood, acetylated wood, and acetylated wood that...

The fungal decay hazard map used by the American Wood Protection Association (AWPA) currently describes regional decay hazards in ground contact for North America and is based on condition assessments of utility poles from the 1970’s. Current work at the USDA Forest Service, Forest Products Laboratory is underway to analyze soil and wood samples from several National Forests in the different AWPA hazard zones and evaluate fungal biodiversity using next-generation sequencing (NGS) of fungal DNA. The results of these analyses will provide fungal biodiversity data to contribute to the...

Processing strategies were developed to manufacture poly(lactic acid) (PLA) blown films without melt strength enhancers (MSEs). The effects of processing temperature on PLA’s melt properties (shear and elongational viscosities), PLA grades, and other processing conditions [ratio of take-up roller to extruder’s rotational screw speeds or processing speed ratio (PSR) and internal air pressures] on film’s blow-up ratio were examined. Experimental results indicate that extrusion-blown amorphous and semicrystalline PLA films can be successfully manufactured without MSEs by controlling melt...

Cellulose nanomaterials have attracted much attention in a broad range of fields such as flexible electronics, tissue engineering, and 3D printing for their excellent mechanical strength and intriguing optical properties. Economic, sustainable, and eco-friendly production of cellulose nanomaterials with high thermal stability, however, remains a tremendous challenge. Here versatile cellulose nanocrystals (DM-OA-CNCs) are prepared through fully recyclable oxalic acid (OA) hydrolysis along with disk-milling (DM) pretreatment of bleached kraft eucalyptus pulp. Compared with the commonly used...

This paper is the first stage of a study that attempts to improve the process of manufacturing treated lumber through the use of statistical process control (SPC). Analysis of industrial and auditing agency data sets revealed there are differences between the industry and agency probability density functions (pdf) for normalized retention data. Resampling of batches of treated wood without replacement appears to affect the pdf of the industrial data. The best-fitting pdf for the agency data is the Largest Extreme Value (LEV) pdf. Assumptions of a normal or a Gaussian pdf may not be valid....

Stake tests are a critical part of evaluating durability of wood in ground-contact, but there is a lack of criteria for interpreting stake test results. This paper discusses criteria that might be used to determine if short term ratings indicate satisfactory longterm performance. Ratings of 19 by 19 mm stakes from multiple plots in the Harrison Experimental Forest, Mississippi, were analyzed to determine how well performance criteria at years three, four, or five predicted durability over the longer term (nine years). Results revealed that with only three years of data, false prediction of...

This report summarizes a state-of-the-art review conducted on the topic of field measurement of the quality of wood in trees. The foundation science of micro-resistance drilling and acoustic-based techniques for use with woody materials is presented, and use of these techniques for the detection of biodeterioration in wood is discussed. Quantification of the physical and mechanical properties of wood, in standing timber, is reviewed. Studies designed to examine the use of these techniques with trees are summarized, and a list of commercially available technologies that use these techniques...

Thirteen bonded engineered wood products representing those commonly used in building construction were evaluated for volatile organic chemicals using methods developed for interior bonded wood products. Although formaldehyde and acetaldehyde were emitted from all samples, they were not the dominant volatiles, which greatly depended on wood species and bonding processes.

Limited long-term field data exist evaluating the benefit of chemical wood preservatives on refractory wood species with abundant heartwood. The objective of this study was to determine the effectiveness of preservative-treated refractory solid heartwood comprised of southern pine, Douglas-fir, or Engelmann spruce. Non-incised and incised solid lumber of these species were treated to three different retentions of either chromated copper arsenate (CCA) or ammoniacal copper arsenate (ACA) and placed in ground contact (AWPA E7) at a Mississippi field test site in 1975. Field stakes were rated...

Surfaces of novel foam core sandwich panels were adhered with intumescent fire‐retardant paper underneath the veneers (FRV) to improve their flammability properties. The panels were evaluated by means of cone calorimeter test (ASTM E 1354). Variables tested were different surface layer treatments, adhesives used for veneering, surface layer thicknesses, and processing conditions, having the objective of obtaining similar or better flammability as that of solid particle boards. Previous research showed that sandwich panels without FRV compared to panels with FRV generally had much higher...