M.C. Lagel¹, A. Pizzi^1,2, S. Giovando³, A. Celzard⁴

Journal of Renewable Materials, Vol.2, No.3, pp. 220-229, 2014, DOI:10.7569/JRM.2014.634113

Abstract With the depletion of fossil resources, tannin extracts can be a natural alternative to some synthetic products. Hydrolysable chestnut tannin extracts have been used to partially replace phenol in PF resins for phenolic rigid foams. Phenol-formaldehyde-chestnut tannin (PFT) phenolic foams were initially made from copolymerized PFT resins of different molar ratio. The PFT foams so prepared were tested for thermal conductivity, these being slightly worse than that of pure PF foams; and for mechanical and water absorption, these two properties being better than those of pure PF foams. Indeed, PF resins represent an important part of synthetic resins. They are… More >

V. K. Srivastava¹, A. Pizzi^2,3,*

Journal of Renewable Materials, Vol.2, No.3, pp. 201-206, 2014, DOI:10.7569/JRM.2014.634107

Abstract Fine wood powder/furanic foams were prepared with a strong predominance of the wood component. Low weight and density are important properties of foamed composites. Focusing on preparing light materials, wood foam composites were made using a chemical foaming method and expanded using diethyl ether as the foaming agent. The additives were added to note their effect on the density and mechanical properties, like impact strength and Young’s moduli, of the expanded composites. Various tests and scanning electron microscopy analysis were also performed. The foaming agent resulted in closed cells with varied sizes and more or less regular shapes, and with… More >

Richard C. Ferguson, Sharathkumar K. Mendon, James W. Rawlins^*, Shelby F. Thames

Journal of Renewable Materials, Vol.2, No.3, pp. 166-172, 2014, DOI:10.7569/JRM.2013.634133

Abstract Commercial particleboards are currently synthesized by blending wood furnish with formaldehyde-based resins and curing them under a combination of heat and pressure. Particleboards manufactured with urea-formaldehyde resin are known to liberate formaldehyde during their service lives. Formaldehyde’s carcinogenicity has prompted the search for environmentally-friendly resins for wood composite manufacture. Soybean protein-based adhesives have been developed as a renewable and formaldehyde-free replacement for urea-formaldehyde resins. Particleboards processed using the soybean protein adhesive matched or exceeded performance criteria of M-2-grade commercial particleboards when evaluated as per American National Standards Institute (ANSI) specifi cations. More >

Marion Noël^1,*, Warren Grigsby², Thomas Volkmer¹

Journal of Renewable Materials, Vol.2, No.4, pp. 291-305, 2014, DOI:10.7569/JRM.2014.634118

Abstract Oligomer systems based on poly(lactic acid) (PLA), poly(glycolic acid) (PGA), poly(butylene succinate) (PBS) and poly(butylene adipate) (PBA) were impregnated in wood and polymerized in situ to improve the dimensional stability of the treated wood. Dynamic mechanical thermal analysis (DMTA) was used to characterize the impact on the treated wood properties. Cell wall bulking treatments (PLA and PGA oligomers: OLA and OGA) induced softening and plasticization of wood components. Lumen fi lling treatments (PBS and PBA oligomers: OBS and OBA) led to minor decreases in treated wood stiffness with any softening dependent on the polymer melt temperature. Overall, no oligomer treatment… More >

Antti Ojala^1,*, Lisa Wikström¹, Kalle Nättinen², Jani Lehmonen³, Karita Kinnunen-Raudaskoski⁴

Journal of Renewable Materials, Vol.2, No.4, pp. 278-284, 2014, DOI:10.7569/JRM.2014.634126

Abstract This article presents a new method of producing thermomoldable nonwoven materials based on kraft lignin (KL) and softwood kraft pulp (KP). A mixture of starch acetate (SA) and triethyl citrate (TEC) was used as a water insoluble plasticizer for KL. The thermoplastic lignin (TPL) material with the optimized ratio of KL, SA and TEC was prepared in a twin-screw extruder. The TPL compound was ground and mixed with KP fi bers to produce thermoformable sheets using foam-laid technology. The formed webs were compression molded (CM) into plates and mechanically tested. The foam-laid composites had tensile strengths and modulus of 67… More >

M. Tazi¹, F. Erchiqui^1,*, F.Godard¹, H. Kaddami²

Journal of Renewable Materials, Vol.2, No.4, pp. 258-263, 2014, DOI:10.7569/JRM.2014.634120

Abstract This article evaluates the mechanical properties and biodegradability of wood-plastic composite materials made from sawdust and thermoplastic polymer (HDPE). For the preparation of the composites, sawdust in different proportions with Maleic Anhydride grafted Polyethylene (MAPE) as the coupling agent was used. The mechanical properties and biodegradability of the biocomposites were successively characterized. The results indicate that adding sawdust particles to a polymer matrix improves the mechanical strength and stiffness of composites. The tensile strength of a composite with 3% coupling agent was improved by 13%, 34% and 54% respectively when 20%, 30% and 40% wood fi llers were added to… More >

Houda Saad^1,2,*, Antonio Pizzi^3,4, Bertrand Charrier², Naceur Ayed¹, Karsten Rode⁵, Fatima Charrier - El Bouhtoury²

Journal of Renewable Materials, Vol.3, No.1, pp. 34-43, 2015, DOI:10.7569/JRM.2014.634130

Abstract The possible use of Tunisian pomegranate tannins in wood adhesive formulation was studied for the fi rst time. Colorimetric tests, Fourier transformed infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and matrix-assisted laser desorption/ionization time-of-fl ight (MALDI-TOF) mass spectrometry were used to examine pomegranate tannins. Analysis showed that pomegranate peels are rich in hydrolyzable tannins. The Stiasny number tests showed the low reactivity of pomegranate tannin extract to formaldehyde and thus the diffi culty of using it in wood adhesive formulation. Thermomechanical analysis (TMA) and strength analysis of pomegranate tannin/hexamine-based resin showed weak bonding properties. More >

Xiaoqing Zhang^*, Simon Schmidt^φ, Nick Rigopoulos, Januar Gotama, Eustathios Petinakis

Journal of Renewable Materials, Vol.3, No.2, pp. 91-100, 2015, DOI:10.7569/JRM.2014.634135

Abstract The behavior of a biodegradable CO₂ -based polymer polypropylene carbonate (PPC) as polymer matrix of wood fi ber (WF) composites was examined and compared with that of using poly(lactic acid) (PLA) as the matrix. The PPC/WF composites displayed poor mechanical properties as compared to PLA/WF composites because PPC is an amorphous polymer with low T_g and poor thermal stability. However, when PPC was used in conjunction with PLA in WF composites, the mechanical strength and modulus of the composites could match or even exceed the level of PLA/WF composites. The strong intermolecular interactions between PPC and WF and those between… More >

Christopher Voth¹, Nathan White², Vikram Yadama^3,*, William Cofer³

Journal of Renewable Materials, Vol.3, No.3, pp. 234-243, 2015, DOI:10.7569/JRM.2015.634109

Abstract Part of a long-term goal of developing a sustainable composite panel that meets both structural and energy performance requirements in building construction applications, this study discusses the development of a thinwalled wood-strand 3D core element that shows promise for a variety of panelized construction applications, such as in a building envelope. Sandwich panels take advantage of the lightweight corrugated core sandwiched between stress skin faces acting similar to an I-beam. Specific bending stiffness of sandwich panels fabricated with ponderosa pine strands was significantly higher than average values of commercially produced composite panels of equivalent thickness (141–156% and 120–133% stiffer than… More >

Vikram Yadama^*, Michael P. Wolcott

Journal of Renewable Materials, Vol.3, No.3, pp. 216-223, 2015, DOI:10.7569/JRM.2015.634103

Abstract The effects of strand undulation angles in wood-strand composites have often been ignored due to the virtual impossibility of experimental determination of their effects on composite material properties, and the diffi culty in modeling localized deviations in angle along the path of a strand. The fi ber undulation model (FUM), that has been previously verifi ed, was applied in this study to predict the elastic constants of laboratory-manufactured oriented strand panels. A stochastic approach was incorporated where a series rule of mixtures with probability density functions of angle distributions was utilized in the model to transform the elastic constants in… More >