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Plastic Crisis Underscores Need for Alternative Sustainable-Renewable Materials
Su Shiung Lam, Changlei Xia, Christian Sonne
, Available online  , doi: 10.1016/j.jobab.2022.06.001
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 thermo-mechanical 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.
Evaluating process of auto-hydrolysis prior to kraft pulping on production of chemical pulp for end used paper-grade products
Wenchao Jia, Miaofang Zhou, Chenfeng Yang, He Zhang, Meihong Niu, Haiqiang Shi
, Available online  , doi: 10.1016/j.jobab.2022.05.002
The objective of this work is to systematically evaluate the performance of the hydrolysis-based kraft pulping process and associated pulp and black liquor characteristics. Acacia wood chips were auto-hydrolyzed under various severities, then the hydrolyzed wood chips were kraft pulping. The results indicated that the yield of pulp significantly dropped with intensifying the auto-hydrolysis severity. Meanwhile, the removal rate of pentosan reached 98.6% in the screened pulp at the P-factor of 1 000. The fiber length, fines and fiber crimp of the screened pulp were not affected by the auto-hydrolysis treatment. Auto-hydrolyzed pulps deteriorated fibrillation and beating response of the pulp in a refining process. However, fiber length and fines changed obviously after beating treatment. After auto-hydrolysis, the tensile index of the paper matrices decreased, some particle substances were found on the surface of the pulp fiber, and the solid and organic content of the black liquor were improved.
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.
Mechanism of selective hydrolysis of alginates under hydrothermal conditions
Taku Michael Aida, Yasuaki Kumagai, Richard Lee Smith Jr
, Available online  , doi: 10.1016/j.jobab.2022.04.001
Mechanisms of selective hydrolysis of alginates under hydrothermal conditions were investigated by comparing reactivities of sodium alginate (Na-ALG, 960 ku) solutions and calcium alginate (Ca-ALG) gels as substrates. Under hydrothermal conditions (150℃), hydrolysis of Na-ALG gave product molecular weights of 223, 66, 26 and 17 ku while those of Ca-ALG gave product molecular weights of 340, 102, 45 and 31 ku for reaction times of 10, 20, 30 and 60 min, respectively. The ratios of mannuronic acid (M) to guluronic acid (G) varied only slightly (from 1.3 to 1.2) for Na-ALG over the range of reaction times at 150℃, while ratios (M/G) for Ca-ALG exhibited a remarkable decrease (from 1.1 to 0.8). Diad sequence of alginate products obtained for NaALG were 17%, 23%, 27% and 31% (GG); 30%, 32%, 36% and 38% (MM); and 53%, 46%, 37% and 32% (GM+MG); while for Ca-ALG they were 18%, 22%, 24% and 33% (GG); 26%, 23%, 26% and 18% (MM); and 56%, 54%, 50% and 48% (GM+MG). Reaction mechanisms are proposed for hydrolysis of alginate solutions and alginate gels under hydrothermal conditions; depolymerization of alginates into monomers and monomeric sequences can be controlled not only by hydrothermal conditions, but also by varying the physical state (solution, gel) of the starting materials.
High-fructose corn syrup production and its new applications for 5-hydroxymethylfurfural and value-added furan derivatives: Promises and challenges
Aristide Laurel Mokale Kognou, Sarita Shrestha, Zi-Hua Jiang, Chunbao(Charles) Xu, Fubao Sun, Wensheng Qin
, Available online  , doi: 10.1016/j.jobab.2022.03.004
High fructose corn syrup has been industrially produced by converting glucose to fructose by glucose isomerases, tetrameric metalloenzymes widely used in industrial biocatalysis. Advances in enzyme engineering and commercial production of glucose isomerase have paved the way to explore more efficient variants of these enzymes. The 5-hydroxymethylfurfural can be produced from high fructose corn syrup catalytic dehydration, and it can be further converted into various furanic compounds chemically or biologically for various industrial applications as a promising platform chemical. Although the chemical conversion of 5-hydroxymethylfurfural into furanic compounds has been extensively investigated in recent years, bioconversion has shown promise for its mild conditions due to the harsh chemical reaction conditions. This review discusses protein engineering potential for improving glucose isomerase production and recent advancements in bioconversion of 5-hydroxymethylfurfural into value-added furanic derivatives. It suggests biological strategies for the industrial transformation of 5-hydroxymethylfurfural.
Effects of a poly(hydroxyalkanoate) elastomer and kraft pulp fibres on biocomposite properties and three-dimensional (3D) printability of filaments for fused deposition modelling
Sandra Rodríguez-Fabià, Gary Chinga-Carrasco
, Available online  , doi: 10.1016/j.jobab.2022.03.002
Three-dimensional (3D) printing is a useful technique that allows the creation of objects with complex structures by deposition of successive layers of material. These materials are often from fossil origin. However, efforts are being made to produce environmentally friendly materials for 3D printing. The addition of lignocellulosic fibres to a polymer matrix is one of the alternatives to replace, for instance, glass fibres in composites as reinforcing materials. The fields of biocomposites and 3D printing open innovative application areas for pulp fibres from the pulp and paper industry. In this work, biocomposites of poly(lactic acid) (PLA), poly(hydroxyalkanoate) (PHA) and kraft pulp fibres were prepared in order to find a suitable formulation for filaments for 3D printing. The effect of two different types of kraft fibres (bleached (B) and unbleached (U)) and of PHA on the mechanical and thermal properties of the biocomposites was assessed. The addition of 30% kraft fibres to PLA resulted in an increase of the tensile modulus from 3074 to ~4800 MPa. In the case of biocomposites containing PHA (50% PLA/20% PHA/30% kraft) the increase in modulus was more moderate (PLA+PHA+U:3838 MPa, and PLA+PHA+B:3312 MPa). The tensile strength of PLA (66 MPa) increased to 77 MPa in PLA+kraft biocomposites, while a reduction in strength was observed for PLA+PHA+U (43 MPa) and PLA+PHA+B (32 MPa). Filaments prepared with PLA, PHA and bleached and unbleached pulp fibres showed similar printability of complex geometries, demonstrating that unbleached pulp fibres could also be utilized in the preparation of biocomposites with good mechanical performance and 3D printing properties.
Effects of chitin nanocrystals on coverage of coating layers and water retention of coating color
Ruoshi Gao, Yi Jing, Yeyan Ni, Qiwen Jiang
, Available online  , doi: 10.1016/j.jobab.2021.11.003
This study assessed the applicability of chitin nanocrystals prepared by 2, 2, 6, 6-Tetramethyl-1- Piperidine-1-oxyl radical (TEMPO)-mediated oxidation in traditional papermaking coating color systems. The α-chitin nanocrystals (CTNCs) with different carboxyl content, size, and morphology were prepared from crab shells by alkali pretreatment and TEMPO-mediated oxidation in the water at pH 10, and then the ratio of CTNCs to latex was applied to traditional coating color system to replace part of latex. The results showed that when the amount of NaClO added as co-oxidant in the oxidation was 15.0 mmol/g of chitin, the carboxyl content of alkali-pretreated CTNCs was up to 0.76 mmol/g. The amount of carboxyl groups presented a linear relation with the degree of individualization of nanocrystals and dispersion. When the ratio of latex to CTNCs was 90:10, the water retention value of the coating was 92% lower than that of the pure latex system, and the rheological property was better. The relationship between the addition amount of CTNCs and the surface strength and the coverage of coating layers were also studied, and results showed that when the ratio of latex to CTNCs was 95:5, the surface strength was the highest of 1.45 m/s, and the coverage of coating layers rate reached the highest of 78%.
Characterization of natural fiber from manau rattan (Calamus manan) as a potential reinforcement for polymer-based composites
Linhu Ding, Xiaoshuai Han, Lihua Cao, Yiming Chen, Zhe Ling, Jingquan Han, Shuijian He, Shaohua Jiang
, Available online  , doi: 10.1016/j.jobab.2021.11.002
Researches on novel natural fibers in polymer-based composites will help promote the invention of novel reinforcement and expand their possible applications. Herein, in this study, novel cellulosic fibers were extracted from the stem of manau rattan (Calamus manan) by mechanical separation. The chemical, thermal, mechanical and morphological properties of manau rattan fibers were comprehensively analyzed and studied by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), single fiber tensile test and scanning electron microscopy (SEM). Component analysis results showed that the cellulose, hemicellulose and lignin contents of C. manan fibers were 42wt%, 20wt%, and 27wt%, respectively. The surface of the rattan fiber was hydrophilic according to the oxygen/carbon ratio of 0.49. The C. manan has a crystalline index of 48.28%, inducing a maximum degradation temperature of 332.8℃. This reveals that it can be used as a reinforcement for thermoplastic composites whose operating temperature is below 300℃. The average tensile strength can reach (273.28 ±52.88) MPa, which is beneficial to improve the mechanical properties of rattan fiber reinforced composites. The SEM images displayed the rough surface of the fiber, which helped to enhance the interfacial adhesion between the fibers and matrices in composites. These results indicate the great potential of C. manan fibers as the reinforcement in polymer-based composites.