Todd F. Shupe

Antioxidant activity of extracts from the wood and bark of Port Orford cedar

Heartwood, sapwood, and inner and outer bark of Port Orford cedar were extracted with methanol, and the extracts evaluated for antioxidant activity. The total phenol content (TPC) of the extracts was determined by the Folin-Ciocalteu method and expressed as gallic acid equivalent (GAE). Butylated hydroxytoluene was used as a positive control in the free-radical-scavenging activity tests and ethylenediaminetetraacetic acid dihydrate disodium salt served as a positive control in the metal-chelating activity assay. All wood extracts showed significant freeradical-scavenging activity. In the radical-scavenging assay of 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (the ABTS assay), the inner bark extracts exhibited the strongest free-radical-scavenging activity. The 50% inhibitory concentrations (IC50) in the radical-scavenging assay against 1,1-diphenyl-2-picrylhydrazyl hydrate radical (DPPH) of the heartwood, sapwood, and inner and outer bark extracts were 64.77, 29.03, 10.31, 19.87 μg·ml−1, respectively. In the metal-chelating activity system, the sapwood extract demonstrated significant activity. The greatest TPC, 537.5 mg GAE/g dry extract, was detected in the inner bark. The lowest TPC of 136.9 mg GAE/g dry extract was observed in the heartwood dry extract. The results indicate that the antioxidant activities of the extracts are in accordance with the amounts of phenolics present; the inner and outer barks of Port Orford cedar are rich in phenolics and may provide good sources of antioxidants.

Tracheid length prediction in Pinus palustris by means of near infrared spectroscopy: the influence of age

The prediction of tracheid length using near infrared (NIR) wavelengths can provide either useful or misleading calibrations depending on the context. This can happen since tracheid length is not directly related to the absorbance at any wavelength but is instead the result of a secondary correlation with some unknown chemical constituent. In this work, the effect of tree age and height on NIR predictability was investigated since tracheid length and chemistry may vary as a function of location within the tree. It was found that tracheid length predictability did not change with height but decreased with age. As a result, predicting tracheid length regardless of age was good (R2 = 0.72) while predictability holding age and height constant was mostly low to moderate with the exception of rings 1 and 4 which was quite strong.ZusammenfassungDas Abschätzen der Tracheidenlänge mittels NIR-Spektroskopie kann je nach Sachlage zu brauchbaren oder auch irreführenden Kalibrierungen führen. Das kommt daher, dass die Tracheidenlänge nicht unmittelbar mit der Extinktion bei irgendeiner Wellenlänge in Beziehung steht, sondern über eine indirekte Korrelation mit unbekannten Inhaltsstoffen. In dieser Arbeit wird der Einfluss des Baumalters und der Höhe auf die Verlässlichkeit der NIR-Messung untersucht, da sowohl die Tracheidenlänge als auch die chemischen Bestandteile je nach Position im Baum varieren können. Es zeigte sich, dass die Vorhersagbarkeit der Tracheidenlänge sich nicht mit der Baumhöhe ändert, jedoch mit dem Alter abnimmt. Insgesamt war die Vorhersagbarkeit der Tracheidenlänge unabhängig vom Alter recht gut (R2=0,72); bei konstantem Baumalter und -höhe war sie jedoch mäßig bis niedrig außer für die Jahrringe 1 und 4, wo die Korrelation sehr streng war.

Characterization of novolac type liquefied wood/phenol/formaldehyde (LWPF) resin.

AbstractNovolac type liquefied wood/phenol/formaldehyde (LWPF) resins were synthesized from liquefied woodn and formaldehyde. The average molecular weight of the LWPF resin made from the liquefied wood reacted inn an atmospheric three neck flask increased with increasing P/W ratio. However, it decreased with increasingn phenol/wood ratio when using axa0sealed Parr reactor. On average, the LWPF resin made from the liquefiedn wood reacted in the Parr reactor had lower molecular weight than those from the atmospheric three neck flask.n The infrared spectra of the LWPF resins were similar to that of the conventional novolac resin but showedn axa0major difference at the 1800–1600xa0cm-1 region. These resultsn indicate that liquefied wood could partially substitute phenol in the novolac resin synthesis. The compositesn with the liquefied wood resin from the sealed Parr reactor yielded higher thickness swelling than thosen with the liquefied wood resin from the three neck flask likely due to the hydrophilic wood components incorporatedn in it and the lower cross-link density than the liquefied wood resin from the three neck flask during then resin cure process.n ZusammenfassungNovolakartige LWPF-Harze wurden aus verflüssigtem Holz und Formaldehyd synthetisch hergestellt.n Das mittlere Molekülgewicht des LWPF-Harzes, das aus verflüssigtem Holz in einem atmosphärischenn Dreihals-Kolben hergestellt worden war, nahm mit steigendem Phenol/Holz-Verhältnis (P/W) zu, wohingegenn es bei der Herstellung in einem versiegelten Parr Reaktor mit steigendem P/W-Verhältnis abnahm. LWPF-Harz,n das aus verflüssigtem Holz in einem Parr Reaktor hergestellt worden war, hatte durchschnittlich einn niedrigeres Molekülgewicht als LWPF-Harz, das in einem atmosphärischen Dreihals-Kolben hergestelltn worden war. Die Infrarot-Spektren der LWPF-Harze ähnelten denjenigen von konventionellem Novolak Harz,n unterschieden sich jedoch im 1800–1600xa0cm-1 Bereich deutlich. Diesen Ergebnisse zeigen, dass das Phenol bei der Synthese von Novolak-Harz teilweise durch verflüssigtesn Holz ersetzt werden kann. Verbundwerkstoffe mit LWPF-Harz, das aus verflüssigtem Holz im versiegeltenn Parr Reaktor hergestellt worden war, wiesen eine höhere Dickenquellung auf als diejenigen mit LWPF-Harz,n das im Dreihals-Kolben hergestellt worden war. Der Grund besteht wahrscheinlich in den im Vergleich zun LWPF-Harz aus dem Dreihals-Kolben eingebundenen hydrophilen Holzbestandteilen und der niedrigeren Vernetzungsdichten während der Aushärtung.n

Antioxidant activity of extracts from the bark of Chamaecyparis lawsoniana (A. Murray) Parl

Abstract The bark of Chamaecyparis lawsoniana (A. Murray) Parl. was extracted with methanol and sequentially partitioned with n-hexane, ethyl acetate, n-butanol and deionized water. The antioxidant activities of the four extracts were evaluated using the DPPH• and ABTS+• methods. The total phenolic content of the extracts was determined using the Folin-Ciocalteu method and expressed as gallic acid equivalents (GAE). Butylated hydroxytoluene was used as a positive control in the radical-scavenging activity tests. All the bark extracts showed significant radical-scavenging activity. In the ABTS+• assay, n-butanol extracts exhibited the strongest radical-scavenging activity, followed by ethyl acetate, water, and n-hexane extracts. The greatest total phenolic content was 428.54 mg GAE per gram of dry extract and was detected in the n-butanol extract, followed by the ethyl acetate and n-hexane extracts. The antioxidant activities correlate with the amount of phenolics present in these extracts. The ethyl acetate and n-butanol extracts were rich in phenolics and may represent a good source of antioxidants.

The termiticidal properties of superhydrophobic wood surfaces treated with ZnO nanorods

ZnO is a cost-effective and more environmentally friendly wood preservative than other metallic-based formulations. ZnO-stearate treatment imparts superhydrophobicity to wood surfaces, thereby providing triple protection to wood products, i.e., superhydrophobicity, inhibition to insects and microorganisms, and UV radiation protection. The objective of this study was to evaluate ZnO-stearate hydrophobic treatments of southern pine sapwood for resistance to Formosan subterranean termites. The data indicated that ZnO-stearate superhydrophobic treatment of southern pine wood samples received excellent mean visual ratings and mean weight loss values. The mean termite mortality was moderate. Unidentified fibril-like substances were found on the wood surfaces that were damaged by the termites.ZusammenfassungZnO ist ein kostengünstiges und umweltfreundlicheres Holzschutzmittel als viele andere Rezepturen auf Metallbasis. Eine Imprägnierung mit ZnO-Stearat verleiht der Holzoberfläche Superhydrophobizität mit Dreifachschutz, d.h. Superhydrophobizität, Wirkung gegen Insekten und Mikroorganismen sowie Schutz vor UV-Strahlung. Ziel dieser Studie war es, die Resistenz von mit ZnO-Stearat behandeltem Southern Pine Splintholz gegen die Formosan Bodentermiten zu untersuchen. Die Ergebnisse zeigten, dass der mittlere visuell festgestellte Zerstörungsgrad und der mittlere Masseverlust der mit ZnO-Stearat superhydrophobisch behandelten Southern Pine Splintholzproben sehr gering waren. Die mittlere Termitensterblichkeitsrate war mäßig. Auf den durch Termiten befallenen Holzoberflächen wurden unbekannte fibrillenartige Substanzen gefunden.

Characteristics of regenerated nanocellulosic fibers from cellulose dissolution in aqueous solutions for wood fiber/polypropylene composites

The effects of aqueous solutions were evaluated on the properties of regenerated cellulosic nanofibers prepared from pure cellulose fibers in various formulations of aqueous solutions. Thermoplastic composites were prepared with reinforcement of the regenerated cellulosic nanofibers. The regenerated cellulosic fibers from cellulosic woody biomass were obtained from dissolved cellulose solutions by coagulating with sulfuric acid and water for phase separation. The properties of the regenerated cellulosic fibers were characterized using Fourier-transform infrared spectroscopy (FTIR), wide angle X-ray diffraction (WAXRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy, and tensile testing. The TGA, WAXRD, and FTIR spectra indicated that the regenerated nanofibers possessed cellulosic crystal type II. The micrographs of regenerated cellulosic fibers showed a dense composite structure and lower crystallinity than controlled fibers. The tensile strength of regenerated cellulosic fiber-reinforced polymer composites reached 30 MPa, which was 70% higher than the control fiber-reinforced composites. The composites prepared from regenerated fibers with sodium hydroxide (NaOH)/urea and NaOH/urea/thiourea aqueous solutions provided the best results. This work also provides a potential promising method to efficiently obtain nanocellulosic fibers as reinforcement materials in bio-based nanocomposites.

Laminated crossarms made from decommissioned chromated copper arsenate-treated utility pole wood. Part II: Preservative retention, glue-line shear, and delamination.

Laminated utility pole crossarms constitute one of the potential industrial products that can be produced from decommissioned wood utility poles. A previous report evaluated the mechanical properties of laminated utility pole crossarms made from decommissioned chromated copper arsenate (CCA)―treated southern pine (Pinus spp.) utility pole wood, untreated virgin wood, and a mixture of virgin wood and decommissioned utility pole wood. In particular, the bending strength, stiffness, and acoustic properties were assessed after pentachlorophenol (penta) retreatment. This study evaluated CCA and penta retention, glue-line shear, and glue-line delamination of the laminated crossarms. The results of this study show that, after penta retreatment, penta retention increased in correlation to the presence of increasing numbers of treated wood plies in the beams. All the laminated crossarms met the minimum shear strength requirement of 8.60 MPa, which is specified in American Society for Testing and Materials (ASTM) Standard D2559. Most of the laminated crossarms (22 of 24) showed a delamination average of less than 5 percent. However, none of the beams met the individual glue-line delamination requirement (1%) of ASTM Standard D2559. More glue-line delamination was found between two utility pole wood plies and between a utility pole wood ply and a virgin wood ply than between two virgin wood plies. Delamination could be a concern for utility pole wood laminated crossarms to be used in an adverse environment. A better gluing system is needed to improve the delamination performance of utility pole wood laminated beams for exterior applications.