This work studied the application of sulfonated ZSM-5 zeolite, a bi-functional catalyst for conversion of biomass-derived glucose to HMF. Glucose hydrolysate was obtained by enzymatic hydrolysis of ...rice straw, that was pretreated by sodium hydroxide. Glucose hydrolysate was then subjected to a transformation reaction to achieve HMF using HSO3–ZSM-5 zeolite under the assistance of sonication. The reaction conditions including solvent, temperature, catalyst dosage and reaction time were studied. Suitable conditions, which gave the highest yield of HMF of 54.1% have been found. The HSO3–ZSM-5 zeolite presented a high catalytic efficiency for conversion of glucose to HMF, an important and useful intermediate in the chemical industry.
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IJS, KILJ, NUK, UL, UM, UPUK
This work aimed to investigate the application of a solid acid catalyst, a replacement for mineral acids or enzymes, to biomass conversion for further applications. Sulfonated zeolite, HSO3-ZSM-5, ...was successfully synthesized and characterized by several analysis techniques. The obtained catalyst showed high activity and efficiency in the hydrolysis of pretreated corn cob. Moreover, the acidity of the zeolite product positively influenced the biomass conversion. The influences of reaction parameters such as catalyst loading, reaction time and temperature on the hydrolysis were also established. Under suitable conditions, a hydrolysis yield of ∼54% was achieved. This recyclable solid acid catalyst provided a promising potential for applications in many industrially important hydrolysis processes of biomass.
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Biological organisms produce high-performance composite materials, such as bone, wood and insect cuticle, which provide inspiration for the design of novel materials. Ascidians (sea squirts) produce ...an organic exoskeleton, known as a tunic, which has been studied quite extensively in several species. However, currently, there are still gaps in our knowledge about the detailed structure and composition of this cellulosic biocomposite. Here, we investigate the composition and hierarchical structure of the tough tunic from the species Halocynthia roretzi, through a cross-disciplinary approach combining traditional histology, immunohistochemistry, vibrational spectroscopy, X-ray diffraction, and atomic force and electron microscopies. The picture emerging is that the tunic of H. roretzi is a hierarchically-structured composite of cellulose and proteins with several compositionally and structurally distinct zones. At the surface is a thin sclerotized cuticular layer with elevated composition of protein containing halogenated amino acids and cross-linked via dityrosine linkages. The fibrous layer makes up the bulk of the tunic and is comprised primarily of helicoidally-ordered crystalline cellulose fibres with a lower protein content. The subcuticular zone directly beneath the surface contains much less organized cellulose fibres. Given current efforts to utilize biorenewable cellulose sources for the sustainable production of bio-inspired composites, these insights establish the tunic of H. roretzi as an exciting new archetype for extracting relevant design principles.
Tunicates are the only animals able to produce cellulose. They use this structural polysaccharide to build an exoskeleton called a tunic. Here, we investigate the composition and hierarchical structure of the tough tunic from the sea pineapple Halocynthia roretzi through a multiscale cross-disciplinary approach. The tunic of this species is a composite of cellulose and proteins with two distinct layers. At the surface is a thin sclerotized cuticular layer with a higher protein content containing halogenated amino acids and cross-linked via dityrosine linkages. The fibrous layer makes up the bulk of the tunic and is comprised of well-ordered cellulose fibres with a lower protein content. Given current efforts to utilize cellulose to produce advanced materials, the tunic of the sea pineapple provides a striking model for the design of bio-inspired cellulosic composites.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The effect of the post-annealing process on different properties of poly (L-lactic acid) (PLLA) nanofibers has been investigated in view of their use in energy-harvesting devices. Polymeric PLLA ...nanofibers were prepared by using electrospinning and then were thermally treated above their glass transition. A detailed comparison between as-spun (amorphous) and annealed (semi-crystalline) samples was performed in terms of the crystallinity, morphology and mechanical as well as piezoelectric properties using a multi-technique approach combining DSC, XRD, FTIR, and AFM measurements. A significant increase in the crystallinity of PLLA nanofibers has been observed after the post-annealing process, together with a major improvement of the mechanical and piezoelectric properties.
Wrinkling is a powerful technique for the preparation of surface structures over large areas, but it is difficult to simultaneously control the direction, period, and amplitude of the wrinkles ...without resorting to complicated procedures. In this work, we demonstrate a wrinkling system consisting of a liquid crystal polymer network and a thin layer of gold, in which the direction of the wrinkles is controlled by the alignment of the liquid crystal molecules and the average amplitude and period are controlled by a high-intensity UV irradiation. The UV exposure represses the amplitude and period dictated by the total exposure. Using photoalignment and photomasks, we demonstrate an unprecedented control over the wrinkling parameters and were able to generate some striking optical patterns. The mechanism of the wrinkle suppression was investigated and appears to involve localized photodegradation at the polymer–gold interface, possibly due to the formation of mechanoradicals.
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Increasing energy autonomy and lowering dependence on lithium-based batteries are more and more appealing to meet our current and future needs of energy-demanding applications such as data ...acquisition, storage, and communication. In this respect, energy harvesting solutions from ambient sources represent a relevant solution by unravelling these challenges and giving access to an unlimited source of portable/renewable energy. Despite more than five decades of intensive study, most of these energy harvesting solutions are exclusively designed from ferroelectric ceramics such as Pb(Zr,Ti)O3 and/or ferroelectric polymers such as polyvinylidene fluoride and its related copolymers, but the large implementation of these piezoelectric materials into these technologies is environmentally problematic, related with elevated toxicity and poor recyclability. In this work, we reveal that fully biobased non-isocyanate polyurethane-based materials could afford a sustainable platform to produce piezoelectric materials of high interest. Interestingly, these non-isocyanate polyurethanes (NIPUs) with ferroelectric properties could be successfully synthesized using a solvent-free reactive extrusion process on the basis of an aminolysis reaction between resorcinol bis-carbonate and different diamine extension agents. Structure–property relationships were established, indicating that the ferroelectric behavior of these NIPUs depends on the nanophase separation inside these materials. These promising results indicate a significant potential for fulfilling the requirements of basic connected sensors equipped with low-power communication technologies.
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Rice straw is an agricultural residue from rice production, which can be a potential lignocellulosic feedstock for various value-added products. In this study, silica was extracted from the rice ...straw. The biomass was pre-treated with ethanol and was cooked with 18% w/w sodium hydroxide to extract lignin and silica. The silica was precipitated from the alkaline solution using 30% sulfuric acid to pH 11.5 and was recovered through centrifugation. The obtained solid was washed and then combusted at 575 °C for 6 hours. The obtained ash was dissolved in sodium hydroxide solution at pH 8.0 and then re-precipitated by sulfuric acid to form silica powder, which obtained a yield of about 6.7% w/w dry rice straw. The characteristics of amorphous disk-formed silica, determined using XRD, SEM, EDS, and FT-IR.
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In this study, the antibacterial bleached hardwood kraft pulp-based paper sheets with a base weight of around 125 g/m2 were made with surface sizing by a mixture of oxidated starch and ...additives from acetic acid-treated nanochitosan and nanocellulose prepared from limited hydrolysis of rice straw by dilute sulfuric acid with added hydrogen peroxide. The characteristics of nanomaterials were analyzed by SEM and XRD. The barrier and antibacterial properties of paper were investigated to assess their ability to contain liquid and food products. Using the sizing mixture which has a solids content of 8% with additives improved the mechanical strength of the paper. The best value of tearing strength of 18.94 mN.m2/g was obtained with adding of 0.5% of nanocellulose and 1.5% of nanochitosan. The burst index of paper reached its highest value of 5.07 kP.m2/g when both nanocellulose and nanochitosan were used at the dosages of 1.0%. The antibacterial features on E. coli clearly showed in papers with 2% of nanochitosan or with the mixture of 1% nanocellulose and 1% nanochitosan addition.
Sepiolite (Sep)⁻styrene butadiene rubber (SBR) nanocomposites were prepared by using nano-sized sepiolite (NS-SepS9) fibers, obtained by applying a controlled surface acid treatment, also in the ...presence of a silane coupling agent (NS-SilSepS9). Sep/SBR nanocomposites were used as a model to study the influence of the modified sepiolite filler on the formation of immobilized rubber at the clay-rubber interface and the role of a self-assembled nanostructure in tuning the mechanical properties. A detailed investigation at the macro and nanoscale of such self-assembled structures was performed in terms of the organization and networking of Sep fibers in the rubber matrix, the nature of both the filler⁻filler and filler⁻rubber interactions, and the impact of these features on the reduced dissipative phenomena. An integrated multi-technique approach, based on dynamic measurements, nuclear magnetic resonance analysis, and morphological investigation, assessed that the macroscopic mechanical properties of clay nanocomposites can be remarkably enhanced by self-assembled filler structures, whose formation can be favored by manipulating the chemistry at the hybrid interfaces between the clay particles and the polymers.
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