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Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes/issues, but are citable by Digital Object Identifier (DOI).
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Physico-Mechanical Characteristics of Bast Fibres of Sesamum indicum and Sesamum radiatum for Bioprospecting
Ancy S Watson, Suhara Beevy S
, Available online  , doi: 10.1016/j.jobab.2022.07.003
Natural fibres are renewable, inexpensive and biodegradable sources of sustainable materials from plants or animals. Bast fibres, as the notable natural fibres, are gathered from the outer cell layers of the stem of plant. Mature and young bast fibres from two species of Sesamum, namely Sesamum indicum L. and S. radiatum Schumach. & Thonn. were extracted through traditional water retting technique and analyzed for their physical, mechanical and chemical attributes. Anatomical studies revealed polygon shaped phloem (bast fibre) cells with small lumen were similar to jute, in terms of architecture, and bagasse, in terms of lumen size. Upon extraction and subsequent drying, the young stems of S. radiatum were found to yield more bast fibres by mass compared with the rest of the Sesamum samples, that was, 0.59 g (dry weight) of bast fibres from 100 g (fresh weight) of stem. According to stereo microscopic images, the mature S. radiatum fibres had rougher edges than the rest. Both S. indicum and S. radiatum fibre surfaces also seemed to have pores, according to scanning electron microscopy (SEM) images. The porosity appeared to get more pronounced as the plants got older. The Sesamum bast fibres were also found to be extremely hydrophilic with a high-water retention value. The fibres obtained from S. radiatum were determined to be suitable for the textile industry due to their light colour, ideal diameter and length, and water-holding capacity that matched the requirements of fabric manufacturing. Even in the absence of a mordant, the mature fibres showed a significant degree and evenness of Alizarin dye attachment, which might be correlated to the increase in fibre surface roughness with fibre maturity. These fibres were also discovered to be comparable with jute in terms of phloem cell shape (polygonal), diameter (13–15 m), tenacity (12.86–32.54 gf/(g·km–1)), and linear density (2.5–3.3 g/km). It suggested that they might find industrial applications if further research were to be done.
Alternative Wood Treatment with Blends of Linseed Oil, Alcohols and Pyrolysis Oil
Jost Ruwoldt, Kai Toven
, Available online  , doi: 10.1016/j.jobab.2022.07.002
Linseed oil is a common wood treatment agent, which is often blended with naphthenic oil during its application. In this study, we developed new types of linseed oil blends, where the naphthenic oil was substituted with alcohols and pyrolysis oil. As miscibility tests revealed, linseed oil can be blended indefinitely with primary alcohols containing three carbon atoms or more. In addition, kinetic stability of three-component-mixtures was found, which comprised linseed oil, alcohol and pyrolysis oil. The developed blends were further tested for their viscosity and rate of solvent evaporation. At last, trial impregnations of wood were done to test this new treatment agent. The uptake of treatment oil and the effect on water repellency varied, and substituting white spirit with propanol and pyrolysis oil showed potential. The latter were miscible with 50% (wt) linseed oil at concentrations of 37.5% 1- or 2-propanol and 12.5% pyrolysis oil. Compared with the reference case, treatment with this agent markedly decreased the water-uptake of the wood. Our study hence attributes great potential to the newly developed linseed oil blends, which may introduce additional product characteristics and generate value to byproducts via pyrolysis.
Preparation and Properties of Hydrophobic and Transparent Wood
Linhu Ding, Xiaoshuai Han, Lian Chen, Shaohua Jiang
, Available online  , doi: 10.1016/j.jobab.2022.02.001
Natural wood (NW) was treated with sodium chlorite to obtain delignified wood (DW) in this study, then epoxy was impregnated to get transparent wood (TW), and finally the TW was coated with perfluorodecyltriethoxysilane (FAS) to acquire hydrophobic and transparent wood (HTW). The hydroxyl group generated by the hydrolysis of the FAS and the hydroxyl group of the epoxy underwent a dehydration condensation reaction to generate a Si-O-C bond, while the FAS molecules were also dehydrated and condensed to form a Si-O-Si bond according to Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Therefore, the mechanical property and thermal stability of the HTW were better than the TW based on their tensile tests and thermogravimetric analysis (TGA). Due to the large reduction of hydroxyl in epoxy, the hydrophobicity of the HTW was greatly improved compared with the TW, and their contact angles were 113° and 77°, respectively. The results of scanning electron microscopy (SEM) showed that epoxy was filled in the voids of wood. In addition, the coating of the FAS did not obviously reduce the transmittance, and the transmittance of the TW and HTW was 69% and 67% at 750 nm. All in all, the HTW has potential for application in transparent decoration.
Dynamical mechanical behaviors of rubber-filled wood fiber composites with urea formaldehyde resin
Feiyu Tian, Xinwu Xu
, Available online  , doi: 10.1016/j.jobab.2022.05.004
Wood composites glued with thermosetting synthetic resins tend to show inadequate damping performance caused by the cured resinous matrix. Waste rubber maintains prominent elasticity and is feasible to be an optional modifier. To that end, composite panels of granulated tire rubber (GTR) powders and thermal-mechanically pulped wood fibers were fabricated in this study. Urea formaldehyde (UF) resin was applied as the bonding agent (10% based on wood/rubber total weight). Dynamical mechanical analysis (DMA) was conducted to disclose the thermomechanical behaviors of the rubber-filled wood fiber composites. Influence of two technical parameters, i.e., GTR powder size (0.55-1.09 mm) and addition content (10%, 20% and 30% based on wood/rubber total weight), was specifically discussed. The results showed that storage modulus (E') of the rubber-filled composite decreased while loss factor (tan δ) increased monotonously along with elevated temperature. A steady "plateau" region among 110-170℃ was found where both E' and tan δ keep constant. Accordingly, tan δ showed two peak values at 103-108 and 231- 233℃ due to glass transition of lignin and thermal degradation of hemicellulose, respectively. Addition of rubber fillers resulted in lower bending and internal bonding strengths as well as storage modulus values. When the temperature was above 183℃, all the rubber-filled composites showed higher tan δ values than the control. The findings above fully demonstrate the improved damping performance of the UF-bonded wood fiber composites on account of rubber component. Further work is still needed to optimize the rubber/fiber interfacial bonding strength.
Nanocellulose and its derived composite electrodes toward supercapacitors: Fabrication, properties, and challenges
Junlei Xiao, Huiling Li, Hua Zhang, Shuijian He, Qian Zhang, Kunming Liu, Shaohua Jiang, Gaigai Duan, Kai Zhang
, Available online  , doi: 10.1016/j.jobab.2022.05.003
With the increasing demand for sustainable energy storage systems, the development of various advanced materials from a renewable source is imminent. Owing to the advantages of high specific surface area, unique nanostructure, modifiability, and excellent mechanical strength, nanocellulose integrated with other conductive materials, such as nanocarbons, conducting polymers, and metal oxides, has been emerged as promising candidate materials for green and renewable energy storage devices. Besides, nanocellulose-derived carbon materials with good electrical conductivity and tunable microstructures can be fabricated via simple carbonization, which has been widely used as supercapacitor electrode materials. Herein, we present a comprehensive review that focuses on the development of nanocellulose materials for sustainable energy storage, particularly on supercapacitors. The fabrication strategies of nanocellulose-derived hybrid materials are first presented and summarized, followed by highlighting the use of natural nanocellulose for constructing composite electrode materials including two-dimension film electrodes, and three-dimension aerogel electrodes for supercapacitors. In addition, the possible limitations and potentials of nanocellulose in supercapacitors are outlooked.