Jiang Min, Lu Tingting, Zhang Qiang, Chen Ying, Zhou Guangyuan^*

Journal of Renewable Materials, Vol.3, No.2, pp. 120-141, 2015, DOI:10.7569/JRM.2014.634139

Abstract Novel copolyesters were successfully synthesized from terephthalic acid (TPA), 2,5-furandicarboxylic acid (FDCA) and ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol and 1,8-octanediol via direct esterifi cation method by using tetrabutyl titanate (TBT) as catalyst. The copolyesters were characterized by nuclear magnetic resonance spectroscopy (¹ H-NMR), gel permeation chromatography (GPC), X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and tensile tests. The results of GPC showed that all of the copolyesters had high molecular weight, with an average molecular weight (Mw) more than 1×10⁴ g/mol. The results of ¹ H-NMR showed that the copolyesters were random copolymers which… 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 More >

Nassibeh Hosseini¹, Samad Javid¹, Ali Amiri¹, Chad Ulven^1,*, Dean C. Webster², Ghodrat Karami¹

Journal of Renewable Materials, Vol.3, No.3, pp. 205-215, 2015, DOI:10.7569/JRM.2015.634112

Abstract In this study, a novel, bio-based polyol was used in the formulation of a polyurethane (PU) matrix for a composite material where fl ax fi ber was used as the reinforcement. The viscoelastic properties of the matrix and fl ax fi ber were determined by a linear viscoelastic model through experimentation and the results were used as input for the material properties in the computational model. A fi nite element micromechanical model of a representative volume element (RVE) in terms of repeating unit cells (RUC) was developed to predict the mechanical properties of composites. Six… More >

D.N. Dorr, S.D. Frazier, K.M. Hess, L.S. Traeger, W.V. Srubar III^*

Journal of Renewable Materials, Vol.3, No.3, pp. 195-204, 2015, DOI:10.7569/JRM.2015.634108

Abstract A study of the potential for gelatin-based derivatives to serve as biorenewable, biodegradable adhesives for wood and engineered wood products is presented in this article. The effect of gelatin-to-water weight percent on the mechanical, specifically ultimate breaking (bond) strength, and thermal properties was investigated using tensile testing and differential scanning calorimetry, respectively. The breaking strengths of the gelatin-based adhesives were characterized and compared to four commercially available wood adhesives. The effect of 1–5% tannin addition on the mechanical, thermal, and moisture absorption behavior of the gelatin-based adhesives was also investigated. Results show that the gelatin-based More >

K. M. Hess, W. V. Srubar III^*

Journal of Renewable Materials, Vol.3, No.3, pp. 175-182, 2015, DOI:10.7569/JRM.2015.634106

Abstract This article concerns the development and characterization of a protein-based alternative to traditional fiberreinforced polymer (FRP) composites used in construction. In this work, gelatin-based resins were prepared at various gelatin-to-water (g/w) ratios. The effects of g/w ratio and curing time on resin mechanical properties were investigated. Using gelatin resins with a 30% g/w ratio, (i) gelatin-flax and (ii) gelatin-fiberglass composites were fabricated, and their mechanical properties were characterized and compared to both (iii) epoxy-flax and (iv) epoxy-fiberglass composites. Fracture surface morphologies were investigated using scanning electron microscopy. Results indicate that gelatin-flax composites exhibit similar mechanical More >

Yujie Zhang¹, Marc A. Dubé^1,*, Eduardo Vivaldo-Lima²

Journal of Renewable Materials, Vol.3, No.4, pp. 318-326, 2015, DOI:10.7569/JRM.2015.634115

Abstract Renewable monomers containing allylic C-H bonds in their structure are prone to degradative chain transfer in free-radical polymerization, which will dramatically decrease the polymerization rate. In order to understand this mechanism, a kinetic model incorporating a degradative chain transfer mechanism for the free-radical copolymerization of d-limonene (LIM) and n-butyl methacrylate (BMA) was developed using PREDICI. Model predictions offered insight on how degradative chain transfer reactions affect conversion, copolymer composition and molecular weight in the polymerization. Experimental data from copolymerizations at monomer feed compositions (LIM/BMA, mol/mol) of 10/90, 20/80 and 30/70 were compared to the model’s predictions. More >

Mario Alejandro Mejía Escobar^*, Franklin Jaramillo^*

Journal of Renewable Materials, Vol.3, No.4, pp. 302-317, 2015, DOI:10.7569/JRM.2014.634121

Abstract Energy alternatives have been one of the most important research focal areas of the last decade due to the imminent lack of fossil fuels. This motivation has allowed the evolution of the materials science field in areas such as electrochemistry, where high availability, low cost and negligible environmental impact are the desired principal qualities. For this reason, as an example of a photoelectrochemical device, we have proposed the use of natural dyes from 37 agro-industrial wastes in dye-sensitized solar cells. We obtained dyes from red cabbage, radish and roselle wastes with a good stability for More >

Mario Alejandro Mejía Escobar^*, Frankin Jaramillo^*

Journal of Renewable Materials, Vol.3, No.4, pp. 281-291, 2015, DOI:10.7569/JRM.2014.634142

Abstract In recent years, the development of new materials has contributed markedly to improving the efficiency of dye-sensitized solar cells (DSSCs). Mesoporous semiconductors, solid electrolyte, non-conventional catalysts and synthetic dyes without ruthenium have been the focus of study. With respect to the last, lanthanides and porphyrins have presented good properties, but these elements have the same disadvantage as rutheniumbased dyes; being complicated to synthesize and very expensive. These limitations have stimulated much research in the use of natural dyes as sensitizers due to their exceptional photoelectochemical properties and low cost. Furthermore, they are regarded as renewable More >

William Eberts, Matthew T. Siniawski^*, Timothy Burdiak, Nick Polito

Journal of Renewable Materials, Vol.3, No.4, pp. 259-267, 2015, DOI:10.7569/JRM.2014.634137

Abstract Single-ply biocomposite laminates were fabricated with two different woven fabrics and a bio-based resin using a wet layup technique at room temperature. A highly elastic, stockinette weave bamboo fiber fabric and a thicker, inelastic plain weave bamboo fabric were both investigated. The elastic fabric was pre-strained at 25% intervals, ranging from 0–100% of its original length. Samples made with E-Glass and S-Glass, two common glass fiber reinforcements, were also fabricated using the bioresin as benchmarks. The ultimate strength and modulus of elasticity characteristics of the composites were determined using the ASTM D3039/ D3039M-08 standard test… More >

Mashile SP^1,2, MP Tshisikhawe¹

Phyton-International Journal of Experimental Botany, Vol.84, No.2, pp. 473-477, 2015, DOI:10.32604/phyton.2015.84.473

Abstract This paper looked at the leaf architecture characteristics of Vachellia tortilis to determine if either there is or not an effect of the tropic line on plants. Vachellia tortilis leaves were sampled along a national road (N1) in Limpopo province. Sampling points were set 10 km apart away from the Tropic of Capricon in opposite directions. Leaf morphology revealed that leaves of V. tortilis are bipinnately compound with alternate arrangement. The venation pattern of the pinnules was eucamptodromus and brochidodromous with imperfect reticulation. Areoles were imperfect and pentagonal or irregular in shape. More >