Zhigang Wu^1,#, Sicheng Chen^1,#, Jiankun Liang², Lifen Li¹, Xuedong Xi^3,4, Xue Deng¹, Bengang Zhang^3,*, Hong Lei^4,*

Journal of Renewable Materials, Vol.9, No.11, pp. 1959-1972, 2021, DOI:10.32604/jrm.2021.016786

Abstract Alkali lignin was processed by plasma and then used in modification of phenol formaldehyde resin in this study. Chemical structural changes of lignin which was processed by plasma as well as bonding strength, tensile property, curing performance and thermal property of the prepared phenol formaldehyde resin which was modified by the plasma processed lignin were analyzed. Results demonstrated that: (1) Alkali lignin was degraded after the plasma processing. The original groups were destroyed, and the aromatic rings collected abundant free radicals and oxygen-containing functional groups like hydroxyls, carbonyls, carboxyls and acyls were introduced into increase the reaction activity of lignin… More > Graphic Abstract

Jianchao Deng^1,2, Haiying Zhou², Fuming Chen², Shuangbao Zhang^1,*, Ge Wang^2,*

Journal of Renewable Materials, Vol.9, No.9, pp. 1555-1570, 2021, DOI:10.32604/jrm.2021.015461

Abstract Elementary units “bamboo bundle” and “bamboo sliver” were processed and cross-linked as “bamboo-bundle veneer (BBV)” and “bamboo-sliver veneer (BSV)” for preparation of laminated composites. The concept of “high-content-adhesive surface treatment” was raised to improve boards’ performance, rather than increasing adhesive absorption of every layer’s porous unit. That is, some BBVs experienced an extra “dipping & drying” to absorb more resin (named “HBBV”). The effect of the amount of knitting threads was also discussed for influencing BBV’s quality. Results indicated that light transmittance of BBVs decreased as the amount of threads added from 3 to 8, while mechanical stiffness increased. Adding… More >

Xinyi Chen^1,2, Antonio Pizzi^1,*, Xuedong Xi^1,2, Xiaojian Zhou², Emmanuel Fredon¹, Christine Gerardin³

Journal of Renewable Materials, Vol.9, No.6, pp. 1045-1057, 2021, DOI:10.32604/jrm.2021.015066

Abstract Soy-protein isolate (SPI) was used to prepare non-isocyanate polyurethane (NIPU) thermosetting adhesives for wood panels by reacting it with dimethyl carbonate (DMC) and hexamethylene diamine. Both linear as well as branched oligomers were obtained and identified, indicating how such oligomer structures could further cross-link to form a hardened network. Unusual structures were observed, namely carbamic acid-derived urethane linkages coupled with lactam structures. The curing of the adhesive was followed by thermomechanical analysis (TMA). It appeared to follow a two stages process: First, at a lower temperature (maximum 130°C), the growth of linear oligomers occurred, finally forming a physically entangled network.… More >

Xiaojian Chen¹, Wenrui Yao¹, Feifei Gao¹, Dingyuan Zheng¹, Qiong Wang³, Jun Cao^2,*, Haiyan Tan¹, Yanhua Zhang^1,2,*

Journal of Renewable Materials, Vol.9, No.5, pp. 979-992, 2021, DOI:10.32604/jrm.2021.014751

Abstract The morphology and properties of corn starch and cassava starch were compared by SEM, DSC and TGA. The effects of amylose and amylopectin content on starch properties were studied by FT-IR, XRD and XPS. The plywood was pressed with the prepared adhesive and the bonding strength of the plywood was tested to analyze the difference among the adhesives from different plant sources and the difference after blending PAPI prepolymer. FT-IR results showed that the hydroxyl peak of cassava starch was stronger and wider. TGA showed that the residue of cassava starch was lower, but the thermal stability of cassava starch… More >

Yan Song^1,2, Zhixin Wang³, Xin Zhang⁴, Rong Zhang¹, Jinchun Li^1,2,*

Journal of Renewable Materials, Vol.9, No.5, pp. 943-957, 2021, DOI:10.32604/jrm.2021.014131

Abstract Lignin is a natural biopolymer with a complex three-dimensional network, commercially obtained from waste liquid of paper pulp and bioethanol production, and could be a candidate for preparation of environment-friendly bio-based polyphenol material. In the present work, the demethylated wheat straw alkali lignin (D-Lig), prepared by demethylation of wheat straw alkali lignin (Lig) using an in-situ generated Lewis acid, was used to synthesize bio-based phenol formaldehyde resin adhesive (D-LPF) applied in plywood. Effects of synthetic process’s factors, including lignin substitution for phenol, NaOH concentration and molar ratio of formaldehyde to phenol, on the bonding strength and free formaldehyde content of… More >

Jaša Saražin¹, Antonio Pizzi², Siham Amirou², Detlef Schmiedl³, Milan Šernek^1,*

Journal of Renewable Materials, Vol.9, No.5, pp. 881-907, 2021, DOI:10.32604/jrm.2021.015047

Abstract A non-isocyanate-based polyurethane (NIPU) wood adhesive was produced from organosolv lignin, which is a bio-sourced raw material, available in large quantities and produced as a by-product of the paper industry. The formulation of this new lignin-based NIPU adhesive, which is presented, was chemically characterised by Matrix-Assisted Laser Desorption Ionization Time of Flight (MALDI ToF) mass spectrometry and by Fourier Transform Infra-Red (FTIR) spectrometry analyses. The oligomers formed were determined and showed that the three species involved in the NIPU adhesive preparation were formed by the co-reaction of the three reagents used: lignin, dimethyl carbonate, and hexamethylene diamine. Linear and branched… More >

Yinhuan Yang^1,*, Manfeng Gong¹, Xiaoqun Xia¹, Yuling Tang²

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.3, pp. 1239-1249, 2021, DOI:10.32604/cmes.2021.014129

Abstract In order to study the mechanical properties of Z-pins reinforced laminated composite single-lap adhesively bonded joint under un-directional static tensile load, damage failure analysis of the joint was carried out by means of test and numerical simulation. The failure mode and mechanism of the joint were analyzed by tensile failure experiments. According to the experimental results, the joint exhibits mixed failure, and the ultimate failure is Z-pins pulling out of the adherend. In order to study the failure mechanism of the joint, the finite element method is used to predict the failure strength. The numerical results are in good agreement… More >

Achille Gnassiri Wedaïna^1,2, Antonio Pizzi², Wolfgang Nzie¹, Raidandi Danwe³, Noel Konaï^4,*, Siham Amirou², Cesar Segovia⁵, Raphaël Kueny⁵

Journal of Renewable Materials, Vol.9, No.3, pp. 477-493, 2021, DOI:10.32604/jrm.2021.012782

Abstract The Piptadeniastrum Africanum bark tannin extract was characterized using MALDI TOF, ATR-FT MIR. It was used in the development of a resin with Vachellia nilotica extract as a biohardener. This tannin is consisting of Catechin, Quercetin, Chalcone, Gallocatechin, Epigallocatechin gallate, Epicatechin gallate. The gel time of the resin at natural pH (pH = 5.4) is 660 s and its MOE obtained by thermomechanical analysis is 3909 MPa. The tenacity of Urena lobata fibers were tested, woven into unidirectional mats (UD), and used as reinforcement in the development of biocomposite. The fibers tenacity at 20, 30 and 50 mm lengths are… More >

Medjda Amari¹, Kamel Khimeche^1,*, Abdelkader Hima² , Redouane Chebout³, Abderahmane Mezroua¹

Journal of Renewable Materials, Vol.9, No.3, pp. 463-475, 2021, DOI:10.32604/jrm.2021.013680

Abstract Recently, the exploitation of renewable plant resources in the formulation of adhesives is very promising for their availability at low coast, as well as their richness in biomolecules such as polyphenols. In this way, many research studies tannins extracted from different sources such as mimosa, quebracho, and pine have been the subject of very satisfactory recent studies. In this paper, a new complete characterization of the tannins extracted from the bark of eucalyptus globulus harvested from two regions in Algeria was achieved. The structural characterization enabled us to confirm the richness in condensed tannins, particularly in procyanidin and prodelphinidin units.… More >

Zhigang Wu^1,2,#, Jiankun Liang^3,#, Hong Lei^1,*, Bengang Zhang¹, Xuedong Xi¹, Lifen Li²

Journal of Renewable Materials, Vol.9, No.2, pp. 205-218, 2021, DOI:10.32604/jrm.2021.013655

Abstract Based on the ESI-MS and ¹³C-NMR analysis of the forms of glyoxal in acidic and alkaline solutions, the soy-based adhesive cross-linked by glyoxal was prepared in this work. The results showed that glyoxal existed in water in different forms at different pH levels. Under alkaline conditions, glyoxal transformed to glycolate through the intramolecular disproportionation reaction. Under acidic conditions, although some of glyoxal transformed to glycolate as what happened under alkaline conditions, most of glyoxal molecules existed in the form of five- or six-membered cyclic ether structure. No ethylene tetraol or free aldehyde group was actually detected under these conditions. Although… More >