Publications of Aurore Richel
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See detailChemical characterisation and technical assessment of agri-food residues, marine matrices, and wild grasses in the South Mediterranean area: A considerable inflow for biorefineries
Kammoun, Maroua ULiege; Ayeb, Haitham; Bettaieb, Taoufik et al

in Chemical characterisation and technical assessment of agri-food residues, marine matrices, and wild grasses in the South Mediterranean area: A considerable inflow for biorefineries (2020), 118

The integration of easily available and under-exploited biomasses is considered a sustainable strategy in biorefining approaches. Mediterranean countries, especially Algeria, Morocco, and Tunisia, offer ... [more ▼]

The integration of easily available and under-exploited biomasses is considered a sustainable strategy in biorefining approaches. Mediterranean countries, especially Algeria, Morocco, and Tunisia, offer such under-exploited waste of different origins. This study revealed the chemical composition and phytochemical characteristics of various agri-food side-products, marine residues, and wild grasses collected in the Maghreb region. Results showed that these wastes contained variable proportions of polysaccharides, lignin, constitute molecules (proteins, lipids, and inorganic molecules) and, various secondary metabolites, mainly flavonoids and condensed tannins. Based on this, the Mediterranean waste was divided into three categories. The first category included waste with high lignin content (40 wt%). The second category contained waste with lignin content below 10 wt% and structural carbohydrate content below 50 wt%. Additionally, the waste in this category comprised noticeable amounts of flavonoids and condensed tannins, particularly from thistle, speedwell, and spurge. Finally, the third category included waste with lignin content above 15 wt% and carbohydrate content in the range of 45–55 wt%. The results also showed that the waste in the third category has a chemical composition similar to that of raw materials envisioned for use in European or North American commercial biorefineries. The findings of this study indicate that the biomass waste employed in this study can be used to develop marketable bioproducts and may be a potential raw material for a biorefinery facility. [less ▲]

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See detailSingle and mixed feedstocks biorefining: comparison of primary metabolites recovery and lignin recombination during an alkaline process
Berchem, Thomas ULiege; Schmetz, Quentin ULiege; Lepage, Thibaut ULiege et al

in Frontiers in Chemistry (2020), 8

Cannabis sp. and Euphorbia sp. are potential candidates as indoor culture for the extraction of their high value-added metabolites for pharmaceutical applications. Both residual lignocellulosic materials ... [more ▼]

Cannabis sp. and Euphorbia sp. are potential candidates as indoor culture for the extraction of their high value-added metabolites for pharmaceutical applications. Both residual lignocellulosic materials recovered after extraction are studied in the present article as single or mixed feedstocks for a closed-loop bioprocesses cascade. An alkaline process (NaOH 3%, 30min 160◦C) is performed to separate the studied biomasses into their main components: lignin and cellulose. Results highlight the advantages of the multi-feedstocks approach over the single biomass in term of lignin yield and purity. Since the structural characteristics of lignin affect the potential applications, a particular attention is drawn on the comprehension of lignin structure alteration and the possible interaction between them during single or mixed feedstocks treatment. FTIR and 2D-NMR spectra revealed similar profiles in term of chemical functions and structure rather than novel chemical bonds formation inexistent in the original biomasses. In addition, thermal properties and molecular mass distribution are conserved whether hemp or euphorbia are single treated or in combination. A second treatment was applied to investigate the effect of prolonged treatment on extracted lignins and the possible interactions. Aggregation, resulting in higher molecular mass, is observed whatever the feedstocks combination. However,mixing biomass does not affect chemical structures of the end product. Therefore, our paper suggests the possibility of gathering lignocellulosic residues during alkali process for lignin extraction and valorization, allowing to forecast lignin structure and make assumptions regarding potential valorization pathway. [less ▲]

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See detailEffect of a low melting temperature mixture on the surface properties of lignocellulosic flax bast fibers
Morin, Sophie ULiege; Lecart, Brieuc ULiege; Istasse, Thibaut ULiege et al

in International Journal of Biological Macromolecules (2020)

Bast flax fibers were treated, with or without ultrasound assistance, using a low melting mixture (LMM) composed of lactic acid, d-glucose and water. This LMM treatment affected both lignin and ... [more ▼]

Bast flax fibers were treated, with or without ultrasound assistance, using a low melting mixture (LMM) composed of lactic acid, d-glucose and water. This LMM treatment affected both lignin and hemicelluloses contents and modified the fibers properties identified as crucial parameters in an industrial context, i.e. coloration, wettability, crystallinity, fibers diameter and chemical composition. Surface chemistry of the fibers were investigated through fluorescent tagged carbohydrates binding modules revealing macromolecular rearrangements responsible of both a fibers crystallinity enhancement and an unexpected hydrophobicity. It has been found that LMM treatments bleach fibers, which is considered a beneficial effect independent of the treatments. [less ▲]

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See detailTransformation of monosaccharides to furanic compounds and polymers in deep eutectic solvents
Istasse, Thibaut ULiege; Richel, Aurore ULiege

Conference (2020, February 19)

The conversion of lignocellulosic biomass saccharides into 5-hydroxymethylfurfural (5-HMF) and 2-furfural (2-F) has been proposed as a promising path to produce plastics, solvents and pharmaceuticals from ... [more ▼]

The conversion of lignocellulosic biomass saccharides into 5-hydroxymethylfurfural (5-HMF) and 2-furfural (2-F) has been proposed as a promising path to produce plastics, solvents and pharmaceuticals from renewable resources. 5-HMF and 2-F are generated from the dehydration of hexoses and pentoses respectively. Their cost effective production remains difficult to achieve because of a low reaction selectivity in conventional organic solvents or because of the high cost of more complex reaction media like ionic liquids. As an alternative solution, deep eutectic solvents (DES) prepared by mixing relatively cheap molecules like choline chloride, boric acid and an organic acid can be used to transform hexoses and pentoses to 5-HMF and 2-F at 90°C. In such reaction media, we demonstrate that a synergy between boric acid and α-hydroxylated acids (e.g. lactic acid) increases at least three-fold 5-HMF yield from glucose compared to mixture containing boric acid and an organic acid without an α-hydroxyl moiety. We proposed a mechanism involving the formation of borate esters between boric acid, glucose and the organic acid, bringing the reactants closer. DESs containing boric acid and an α-hydroxylated acid also catalyze the formation of insoluble substances (humins) from aldol additions/condensations reactions of monosaccharides and furanic compounds. Furan rings are incorporated in the insoluble substances but we show that humins formation starts from monosaccharides rather than from 5-HMF or 2-F. Adding another aldehyde in the reaction medium results in its incorporation in the formed humins and enhances selectivity of glucose transformation into 5-HMF. This finding suggests that simultaneous furanics synthesis and functionalization of the insoluble substances by aldol addition / condensation could increase humins value while improving 5-HMF and 2-F production. [less ▲]

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See detailChimie Végétale et valorisation haute technologie: l'exemple de la lignine
Richel, Aurore ULiege

Conference given outside the academic context (2020)

Il existe dans le règne végétal, mais aussi dans certains déchets ou sous-produits (agro-)industriels une molécule unique : la lignine. Cette molécule, bien que complexe d’un point de vue moléculaire, est ... [more ▼]

Il existe dans le règne végétal, mais aussi dans certains déchets ou sous-produits (agro-)industriels une molécule unique : la lignine. Cette molécule, bien que complexe d’un point de vue moléculaire, est devenue un enjeu commercial depuis une dizaine d’années. La lignine possède à ce jour un potentiel d’applications connues entre précurseur pour la manufacture de nanotubes ou de fibres de carbone, agent anti-UV pour des applications cosmétiques, agent de renfort pour la production de matériaux, retardateur de flamme, agent de dépollution des eaux usées, etc. Cette rencontre sera l’occasion de vous présenter un volet de la bio-économie entre réelles opportunités commerciales et recherches académiques de pointe, entre attentes des consommateurs, faisabilité technico-économique et réel impact environnemental. [less ▲]

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See detailSmart ulvan films responsive to stimuli of plasticizer and extraction condition in physico-chemical, optical, barrier and mechanical properties
. Guidarra, M.; Yaicha, H.; Benelhadja, S. et al

in International Journal of Biological Macromolecules (2020), 150

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See detailDesigning natural fibres for biocomposites
Morin, Sophie ULiege; Richel, Aurore ULiege

Poster (2020, January 31)

Incorporating natural fibres in polymer matrices is challenging as both components tend to repel each other. Industrial fibres specifications focus on multiple fibres parameters including fibres aesthetic ... [more ▼]

Incorporating natural fibres in polymer matrices is challenging as both components tend to repel each other. Industrial fibres specifications focus on multiple fibres parameters including fibres aesthetic, composition, cost and safety. The fibre chemico-enzymatic engineering is explored to modify and improve the fibres properties. We have developped in our lab a new and innovative enzymatic process. Our results demonstrate that fibres dispersity in the polymer is enhanced, mechanical resistance and fibres coloration modified after our enzymatic treatment [less ▲]

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See detailDevelopment of a sustainable method for the extraction of suberin-related compounds from biomass using supercritical transesterification
Lecart, Brieuc ULiege; Vanderschuren, Hervé ULiege; Richel, Aurore ULiege et al

Scientific conference (2020, January 31)

Suberin is a biopolyester which has a unique molecular diversity in long chain aliphatic molecules such as omega-hydroxyacids, alpha,omega-dicarboxyacids and their derivatives carrying functionnalities1 ... [more ▼]

Suberin is a biopolyester which has a unique molecular diversity in long chain aliphatic molecules such as omega-hydroxyacids, alpha,omega-dicarboxyacids and their derivatives carrying functionnalities1. However, the use of suberin as a source of building blocks on an industrial scale for the development of new products and materials is hampered by the chemical resilience of suberin. Of all the methods that have been developed to depolymerize and extract suberin, transesterification is one of the most effective methods. However, it has the drawbacks of requiring a catalyst, of being sensitive to water and free fatty acids and of requiring a long purification thereafter. This work is based on the development of a SCTE (supercritical transesterification) method which offers the advantages of being tolerant to the presence of water and free fatty acids while being catalyst-free2. As a result, SCTE allowed to successfully extracting suberin from potato peels, cassava peels and oak bark in less than 1 hour with a high selectivity thus limiting the need for purification. The results also show that by adjusting the duration of the treatment it is possible to obtain a total or partial depolymerization depending on the desired final product. SCTE is therefore a promising method to obtain suberin monomer mixture at a large scale. (1) Gandini, A.; Neto, C. P.; Silvestre, A. J. D. Suberin: A Promising Renewable Resource for Novel Macromolecular Materials. Prog. Polym. Sci 2006, 31, 878–892. https://doi.org/10.1016/j.progpolymsci.2006.07.004. (2) Karki, S.; Sanjel, N.; Poudel, J.; Choi, J. H.; Oh, S. C. Supercritical Transesterification of Waste Vegetable Oil: Characteristic Comparison of Ethanol and Methanol as Solvents. Appl. Sci. 2017, 7 (6). https://doi.org/10.3390/app7060632. [less ▲]

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See detailMechanistic aspects of saccharides dehydration to furan derivatives for reaction media design
Istasse, Thibaut ULiege; Richel, Aurore ULiege

in RSC Advances (2020)

The conversion of abundant hexoses (e.g. glucose, mannose, galactose) and pentoses (e.g. xylose, arabinose) to 5-hydroxymethylfurfural (5-HMF) and 2-furfural (2-F) is subject to intensive researches in ... [more ▼]

The conversion of abundant hexoses (e.g. glucose, mannose, galactose) and pentoses (e.g. xylose, arabinose) to 5-hydroxymethylfurfural (5-HMF) and 2-furfural (2-F) is subject to intensive researches in the hope of achieving competitive production of diverse materials from renewable resources. However, the abundance of literature on this topic as well as the limited number of studies systematically comparing numerous monosaccharides hinder progress tracking. Herein, we compare and rationalize reactivities of different ketoses and aldoses. Dehydration mechanisms of both monosaccharide types are reviewed regarding the existing experimental evidences. Ketoses transformation to furan derivatives likely proceeds through cyclic intermediates and is hindered by side-reactions such as isomerization, retro-aldol reactions and polymerization. Different strategies can improve furan derivatives synthesis from ketoses: limiting the presence of water, improving the dehydration rate, protecting 5-HMF and 2-F reactive moieties with derivatization or solvents interactions and extracting 5-HMF and 2-F from the reaction medium. Contrarily to ketoses, aldoses conversion to furan derivatives is not favored compared to polymerization reactions because it involves their isomerization or a ring contraction. Enhancing aldoses isomerization is possible with metal catalysts (e.g. CrCl3) promoting a hydride shift mechanism or with boric/boronic acids promoting an enediol mechanism. This catalysis is however far more challenging than ketoses dehydration because catalysts activity depends on numerous factors: Brønsted acidity of the medium, catalysts ligands, catalysts affinity for monosaccharides and their accessibility to several chemical species simultaneously. Those aspects are methodically addressed to support the design of new monosaccharides dehydration systems. [less ▲]

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See detailRemote Renewable Hubs for Synthetic Fuel Production
Berger, Mathias ULiege; Richel, Aurore ULiege; Ernst, Damien ULiege

E-print/Working paper (2020)

This paper proposes a framework to study the economics of producing carbon neutral synthetic fuels in remote locations with abundant, high-quality renewable energy resources. More precisely, a mixed ... [more ▼]

This paper proposes a framework to study the economics of producing carbon neutral synthetic fuels in remote locations with abundant, high-quality renewable energy resources. More precisely, a mixed integer linear programming model enabling the analysis and end-to-end optimization of the full supply chain is introduced along with a novel energy system representation facilitating the formulation of such models. An open source software implementation is also made available. The model is leveraged to study the production of carbon neutral synthetic methane from wind and solar energy in North Africa. Results show that the cost of synthetic methane delivery to northwestern European consumers would be around 100 EUR/MWh for wind-powered systems and around 190 EUR/MWh for solar-only systems, based on conservative short-term technology cost estimates. This cost difference can be explained by the fact that key energy conversion technologies such as methanation are fairly inflexible, while wind has higher capacity factors and smoother production profiles than solar, resulting in reduced flexibility requirements and eventual cost savings. [less ▲]

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See detailMonitoring technical lignin partition in aqueous/alcohol biphasic systems according to pH: influences of the molecular structure and solvent characteristics
Schmetz, Quentin ULiege; Muzyka, Claire ULiege; Berchem, Thomas ULiege et al

in RSC Green Chemistry (2020)

This study deals with the comprehension of lignin partition in biphasic systems constituted of an alkaline aqueous phase containing dissolved lignin and a non-miscible alcohol phase. The main parameters ... [more ▼]

This study deals with the comprehension of lignin partition in biphasic systems constituted of an alkaline aqueous phase containing dissolved lignin and a non-miscible alcohol phase. The main parameters studied are the botanical origin of lignins (softwood/hardwood/herbaceous), the solvent (n-butanol/n-pentanol/n-octanol) and the pH (12, 9.5, 7, 3.5). Lignin concentration is measured by UV spectroscopy to calculate partition coefficients. Lignin migration is driven by the protonation of hydroxyl phenolates at pH 12-9.5 and of carboxylates at pH 7-3.5. FTIR spectra revealed various functional groups in migrated fractions as well as their change in conformation. Notably, hydrogen bonding capacity within its chemical groups and with neighboring fragments and solvents are discussed. NMR results suggest a possibility to adjust separation conditions to tune lignin composition including G/S ratio and the content in specific structures (resinol, ferulate, carbohydrate). GPC highlights a wide diversity of polymers of low molecular weight migrating at basic pH whereas increasing high molecular weight is correlated to aqueous phase acidification. The lignins seem to migrate according to similar structural features whatever the botanical origin, leading to very similar polymer distributions in given conditions. In general, butanol appears to be less selective and is able to solubilize a wide range of lignin polymers independently of the origin. This work provides valuable information regarding the separation of homogenous lignin fractions enabling to standardize the chemical and physical properties of the lignins to increase their value and the numerous potential applications as sustainable material. [less ▲]

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See detailMonosaccharides dehydration assisted by formation of borate esters of α-hydroxyacids in choline chloride-based low melting mixtures
Istasse, Thibaut ULiege; Lemaur, Vincent; Debroux, Gwénaëlle et al

in Frontiers in Chemistry (2020)

The synthesis of 5-hydroxymethylfurfural (5-HMF) and 2-furfural (2-F) by hexoses and pentoses dehydration is considered as a promising path to produce materials from renewable resources. Low-transition ... [more ▼]

The synthesis of 5-hydroxymethylfurfural (5-HMF) and 2-furfural (2-F) by hexoses and pentoses dehydration is considered as a promising path to produce materials from renewable resources. Low-transition-temperature mixtures (LTTMs) enable selective (> 80%) dehydration of ketoses to furanic derivatives at moderate temperature (< 100°C). However, aldoses dehydration generally requires higher temperatures and an isomerization catalyst. Chromium trichloride has been reported as one of the most efficient catalyst but its kinetic inertness could limit its performances below 100°C. Consequently, we investigate herein boric acid catalysis of aldoses dehydration in LTTMs based on choline halides and organic acids at 90°C. The limited activity of boric acid regarding furanic compounds synthesis (e.g. 5% 5-HMF yield and 23% glucose conversion after one hour at 90°C with maleic acid) can be enhanced through tetrahydroxyborate esters (THBE) formation with α-hydroxyacids (e.g. 19% 5-HMF yield and 61% glucose conversion after one hour at 90°C). THBE formation is however associated with H3O+ generation favoring the appearance of side products (humins). We demonstrate that boric acid catalysis is not straightforward and that the use of THBE under moderate acidity should be further investigated to limit humins formation and promote furanic derivatives synthesis. [less ▲]

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See detailNovel dipeptidyl peptidase-IV and angiotensin-I-converting enzyme inhibitory peptides released from quinoa protein by in silico proteolysis
Guo, Huimin ULiege; Richel, Aurore ULiege; Hao, Y. et al

in Food Science and Nutrition (2020), 8(3), 1415-1422

Quinoa protein has been paid more and more attention because of its nutritional properties and beneficial effects. With the development of bioinformatics, bioactive peptide database and computer-assisted ... [more ▼]

Quinoa protein has been paid more and more attention because of its nutritional properties and beneficial effects. With the development of bioinformatics, bioactive peptide database and computer-assisted simulation provide an efficient and time-saving method for the theoretical estimation of potential bioactivities of protein. Therefore, the potential of quinoa protein sequences for releasing bioactive peptides was evaluated using the BIOPEP database, which revealed that quinoa protein, especially globulin, is a potential source of peptides with dipeptidyl peptidase-IV (DPP-IV) and angiotensin-I-converting enzyme (ACE) inhibitory activities. Three plant proteases, namely papain, ficin, and stem bromelain, were employed for the in silico proteolysis of quinoa protein. Furthermore, four tripeptides (MAF, NMF, HPF, and MCG) were screened as novel promising bioactive peptides by PeptideRanker. The bioactivities of selected peptides were confirmed using chemical synthesis and in vitro assay. The present work suggests that quinoa protein can serve as a good source of bioactive peptides, and in silico approach can provide theoretical assistance for investigation and production of functional peptides. © 2020 The Authors. Food Science & Nutrition published by Wiley Periodicals, Inc. [less ▲]

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See detailAntihypertensive effect of quinoa protein under simulated gastrointestinal digestion and peptide characterization.
Guo, Huimin ULiege; Hao, Yuqiong; Richel, Aurore ULiege et al

in Journal of the science of food and agriculture (2020)

BACKGROUND: Quinoa protein is a potential source of bioactive peptides. Although some studies have demonstrated its angiotensin converting enzyme (ACE) inhibitory properties, research into its in vivo ... [more ▼]

BACKGROUND: Quinoa protein is a potential source of bioactive peptides. Although some studies have demonstrated its angiotensin converting enzyme (ACE) inhibitory properties, research into its in vivo effect on blood-pressure regulation and peptide characterization remains limited. RESULTS: Quinoa protein hydrolyzate (QPH) was prepared by simulated gastrointestinal digestion. QPH lowered the systolic blood pressure (SBP) and diastolic blood pressure (DBP) in spontaneously hypertensive model rats (SHRs) from 2 h to10 h after oral administration, effectively controlling blood pressure in these SHRs. An in vitro study showed that QPH is capable of inhibiting ACE activity. This was attributed to the activity of a number of low-molecular-weight peptides. With relatively high scores predicted by PeptideRanker, three promising bioactive peptides, FHPFPR, NWFPLPR, and NIFRPF, were further studied and their ACE-inhibition effects were confirmed with IC(50) values of 34.92, 16.77, and 32.40 μM, respectively. A molecular docking study provided insights into the binding of ACE with peptides, and revealed that the presence of specific amino acids in the peptide sequence (Pro, Phe, and Arg at the C-terminal, and Asn at the N-terminal) could contribute to the interaction between ACE and peptides. CONCLUSION: These results demonstrated the potential of QPH for the management of hypertension, which indicates that it could be a good candidate for inclusion in functional foods to control high blood pressure. © 2020 Society of Chemical Industry. [less ▲]

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See detailIn vitro prebiotic potential of agricultural by-products on intestinal fermentation, gut barrier and inflammatory status of piglets
Uerlings, Julie ULiege; Schroyen, Martine ULiege; Bautil, An et al

in British Journal of Nutrition (2020), 123(3), 293-307

The inclusion of fibre-rich ingredients in diets is one possible strategy to enhance intestinal fermentation and positively impact gut ecology, barrier and immunity. Nowadays, inulin-type fructans are ... [more ▼]

The inclusion of fibre-rich ingredients in diets is one possible strategy to enhance intestinal fermentation and positively impact gut ecology, barrier and immunity. Nowadays, inulin-type fructans are used as prebiotics in the feed of piglets to manipulate gut ecology for health purposes. Likewise, some by-products could be considered as sustainable and inexpensive ingredients to reduce gut disorders at weaning. In the present study, chicory root and pulp, citrus pulp, rye bran and soya hulls were tested in a three-step in vitro model of the piglet's gastro-intestinal tract combining a pepsin-pancreatin hydrolysis (digestion), a dialysis step using cellulose membranes (absorption) and a colonic batch fermentation (fermentation). The fermentation kinetics, SCFA and microbiota profiles in the fermentation broth were assessed as indicators of prebiotic activity and compared with the ones of inulin. The immunomodulatory effects of fermentation supernatant (FS) were investigated in cultured intestinal porcine epithelial cells (IPEC-J2) by high-throughput quantitative PCR. Chicory root displayed a rapid and extensive fermentation and induced the second highest butyrate ratio after inulin. Citrus pulp demonstrated high acetate ratios and induced elevated Clostridium clusters IV and XIVa levels. Chicory root and pulp FS promoted the intestinal barrier integrity with up-regulated tight and adherens junction gene expressions in comparison with inulin FS. Chicory pulp FS exerted anti-inflammatory effects in cultured IPEC-J2. The novel approach combining an in vitro fermentation model with IPEC-J2 cells highlighted that both chicory root and pulp appear to be promising ingredients and should be considered to promote intestinal health at weaning. © The Authors 2019. [less ▲]

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See detailFibres surface macromolecular rearrangement for biocomposites production
Morin, Sophie ULiege; Meddeb, Fatma; Beauregard, Marc et al

Poster (2019, November)

Plastics are today fulfilling structural and mechanical functions in cross-disciplinary domains. In a context of reducing the environmental issues, decreasing the amount of plastic is a global concern ... [more ▼]

Plastics are today fulfilling structural and mechanical functions in cross-disciplinary domains. In a context of reducing the environmental issues, decreasing the amount of plastic is a global concern. One solution to reduce the use of pure and unsustainable material is biocomposites. These materials are composed of natural fibres and polymer matrices, and possess hybrid properties of the initial components. These natural fibres are cellulose-rich which confer them a high mechanical resistance comparable to glass fibres which have been for years incorporated in composites at the industrial scale. Here, natural bast flax fibres were modified to modulate their properties. A treatment able to enhance the aesthetical and physico-chemical fibres properties was developed. The treatment lead to unexpected hydrophobic behaviour and an enhance crystallinity. Such results suggested that the fibres surface composition was modified. For industrial application, such as biocomposites, interfaces play a crucial role in the final material properties. Recombinant proteins were used to characterize the fibres surface. These fluorescent tagged proteins are detecting specifically polysaccharides such as cellulose, xylan and mannan. The amount of polysaccharides detected at the fibres surface clearly increased after the treatment. Noteworthy, this macromolecular modification of the fibres surface is correlated to the apparition of the unexpected fibres properties. Side beneficial effect are also detected after treatment and are completely independent to the variation of the fibres surface composition. [less ▲]

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See detailOne-step enzymatic grafting of ferulic acid with cellulose to enhance matrices–fibres compatibility in bio-composites
Morin, Sophie ULiege; Bockstal, Lauris ULiege; Jacquet, Nicolas ULiege et al

in Journal of Materials Science (2019)

Bio-composites elaboration is limited by poor interfaces between cellulose and polymer matrices and the cellulose degradation. Achieving cellulose grafting with ferulic acid should enhance those resulting ... [more ▼]

Bio-composites elaboration is limited by poor interfaces between cellulose and polymer matrices and the cellulose degradation. Achieving cellulose grafting with ferulic acid should enhance those resulting bio-composites mechanical properties. Therefore, a cellulose suspension was modified with ferulic acid using laccase under reaction conditions set at 60 °C, acetate buffer pH 5 for 24 h. Grafted cellulose fibrils were extruded in polypropylene-grafted maleic acid (PPgMA) for mechanical properties studies. Even if ferulic acid interacted with cellulose without any enzyme presence, the acid resilience was only detected for cellulose fibres modified with ferulic acid proving the surface grafting. Cellulose fibrillary lengths were unaffected by the enzymatic treatment suggesting a tiny coating. The resulting bio-composites had a Young modulus reduction of 12%. The elongation at maximal stress had 23% improvement, corresponding to a material mechanical resistance. This result was also confirmed by bio-composite elaboration with natural fibres under the same conditions. Ferulic acid and cellulose blends have improved the hardness properties of the resulting bio-composites with PP-PPgMA. [less ▲]

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See detailDevulcanisation and reclaiming of tires and rubber by physical and chemical processes: A review
Bockstal, Lauris ULiege; Berchem, Thomas ULiege; Schmetz, Quentin ULiege et al

in Journal of Cleaner Production (2019)

Since their creation, tires have been constantly improved to fulfil the numerous applications they have been employed in. Although tires consisted of simple rubber bands in the late 20th century, nowadays ... [more ▼]

Since their creation, tires have been constantly improved to fulfil the numerous applications they have been employed in. Although tires consisted of simple rubber bands in the late 20th century, nowadays tires are a highly more complex piece of technology. Due to this more complex structure induced by the presence of other components (like metals and textiles) and a wide variety of polymers used in tire manufacturing, recycling and reclaiming processes are constantly more difficult. Taking into account the global tire demand as well as the amount of rubber involved and their end-of-life fate is mandatory for a sustainable development. The aim of this review is to present and explore physical and chemical processes that are employed in order to recycle tire and reclaim rubber. Well settled techniques such as mechanical, thermo-mechanical, cryo-mechanical grinding and sulfide processes are presented as well as more sustainable technologies such as ionic liquid, eutectic solvents and microwave and catalysis. [less ▲]

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