Surface wettability is crucial in applications ranging from biomaterials to coatings. This study investigates the wettability of cellulose nanocrystals (CNCs) modified with biobased agents, methyl cellulose (MC), ethyl cellulose (EC), and tannic acid (TA), in alkane solvents. Contact angles were measured in a temperature-controlled setup with water droplets placed on surfaces immersed in heptane or hexadecane. MC-modified CNCs showed superhydrophilic behavior, while EC addition imparted hydrophobicity. On the other hand, TA-coated CNCs and unmodified CNCs remained in the hydrophilic region. The pure modifiers were generally more hydrophobic than their CNC-bound forms, likely due to interfacial conformation. Temperature increase led to more hydrophobic surfaces overall. Wettability kinetics revealed that MC-coated CNCs spread water faster than MC alone due to a precursor water layer. These materials show promise for selective sorption: CNC@MC as water sorbents in oil and CNC@EC aerogels as reversible oil sorbents in water. This work enhances our understanding of CNC surface tuning for functional surfaces and environmental remediation.

Understanding the microstructure of cellulose hydrogels is critical for tailoring their material design. This study aims at gaining further understanding of the links between the initial solution state (semi-dilute, concentrate, anisotropic) and the resulting self-organization of the hydrogel microstructure. SAXS, WAXD, liquid-state AFM and μCT helped covering a broad range of scales ranging from ∼1 nm to 1 mm. The presence of crystalline cellulose hydrates a few nanometre thick was evidenced by WAXD and their size was mostly influenced by the initial degree of polymerization, as confirmed by SAXS. Moreover, the microstructure of the physical cellulose hydrogels displayed a fractal organization at both nanoscale and microscale. The SAXS characterisations highlighted structures of characteristic lengths ca. 13-30 nm and provided a holistic picture of the self-assembly mechanism in which concentration and DP are mere expressions of the underlying physics. Liquid-state AFM also evidenced the existence of internal textures with fractal dimensions between 2.3 and 2.9, with a tendency to form globular aggregates (as opposed to more planar ones) at low concentrations. Finally, μCT gave further information as to the role of shrinkage while demonstrating the existence of another microstructural scale in the 100-400 μm range.

The presence of drying cracks can significantly affect soil hydromechanical behavior, which has effects on soil performance in civil engineering. One innovative approach that has received much interest in the last decade is using microbially induced calcium carbonate precipitation (MICP) for soil reinforcement and stabilization. A series of clay specimens with varying moisture levels and concentrations of cementation solution were carefully prepared. All these samples were subjected to a series of mechanical tests to assess the improvement in the clay's mechanical characteristics. These tests covered various conditions, ranging from unsaturated to saturated states of the clays. The results showed that the strength of clays was significantly improved, and the most significant increase in mechanical strength was observed with the 1.4 M MICP solution. The precipitation of CaCO3 was quantified using a calcimeter. In addition, composition analysis by X-ray diffraction and attenuated total reflectance infrared spectroscopy confirmed the presence of calcium carbonate crystals and indicated residual urea and calcium acetate.

The development of porous, water-resistant cellulose-based materials with shape-recovery performance requires control of the swelling behaviour of these materials. In this context, TEMPO-oxidized CNF (CNFt) cryogels, were prepared by non-directional (ND) and unidirectional (UD) freezing step followed by freeze-drying to obtain lightweight porous materials (22.6 kg m -3 and 98% air content), CNFt-ND ou CNFt-UD, with different pore morphologies. Indeed, honeycomb-like or lamellar structures were obtained as evidenced by microscopy and X-ray tomography analysis. Determination of cryogels absorption capacities in water (pH 6) or HCl (pH 2) solution showed different swelling behaviours depending on the charge state of carboxyl groups, but also on pore morphology NFCt cryogels. Measurements of 1 H T 2 relaxation times using Low-Field (LF) NMR demonstrated the appearance of different population of water molecules characterized by different mobilities due to the structuration of NFCt gel during the freeze-casting procedure. Finally, tests of compression cycles on H 2 O- or HCl-swollen NFCt-ND and NFCt-UD cryogels demonstrated the higher compressive resistance of swollen-cryogels after protonation and a recovery shape performance of about 87% was obtained after 50 compression cycles.

An original approach has been developed to investigate the behaviour of linalool, a volatile compound widely used in the flavour and fragrance industry, incorporated in a model lamellar emulsion stabilized by an alkyl polyglucoside (APG). The surface activity of amphiphilic linalool was first studied in aqueous solutions, to predict its partition in multiphase colloidal systems. Results showed the high interfacial activity of linalool and its ability to act as a co-surfactant. The air/matrix partition coefficient was determined using headspace gas chromatography (HS-GC) and highlighted the different interactions between linalool and the emulsion phases. The molecular organization of lamellar emulsions was affected by the addition of linalool, as evidenced by combined microscopic observations, static light scattering (SLS) and X-ray diffraction measurements. As microstructure and rheological properties are closely linked, the viscoelastic properties of the samples were also investigated. The particle diameter, viscoelastic parameters and consistency of the emulsions were found to decrease with the addition of linalool. Finally, some textural and sensory properties of emulsions were evaluated and showed that the effect of linalool on the microstructure of the samples could also be perceived at the macroscopic scale, on their organoleptic properties. Our original approach could be used as a powerful tool for the future development of flavoured or fragranced emulsions.

Encapsulation revolutionizes industries through enhanced stability, controlled release, and targeted performance of active ingredients. The novel aspect of this study explores the impact of the wall material-to-active (WM:A) ratio on the stability of ascorbic acid (AA) encapsulated in a maltodextrin (MD) and gum arabic (GA) blend (2:1 w/w). Microparticles were spray-dried and analyzed using SEM, TGA, DSC, thermal stability, and antioxidant activity assessments. Stability tests under different conditions revealed that a higher WM:A ratio (7:1) improved the active stability and antioxidant activity during storage, highlighting its importance in the encapsulation process. SEM analysis confirmed particles with no cracks, and the particles demonstrated excellent thermal stability up to 200 °C with minimal degradation. These findings underscore the critical role of the WM:A ratio in determining the stability of encapsulated AA within a carbohydrate matrix, offering valuable insights for advancing encapsulation technologies.

Radiopaque polyurethanes are extensively used in biomedical fields owing to their favorable balance of properties. This research aims to investigate the influence of particle concentration on various properties, including rheological, radiopacity, structural, thermal, and mechanical attributes, with a thorough analysis. The findings are benchmarked against a commercial product (PL 8500 A) that contains 10% weight barium sulfate. Two more thermoplastic polyurethanes (TPU) were formulated with two different concentrations of barium sulfate (10 wt.% and 20 wt.%) and compared to the commercially available product. FTIR demonstrated similar absorption bands among all samples, indicating that the fabrication method did not impact the TPU matrix. DSC indicated a predominantly amorphous structure for PL 8500 A compared to the other samples, while the kinetic degradation was more influenced by the higher barium sulfate content. The rheological analysis showed a decrease in the complex viscosity and storage modulus with the radiopacifier and an increase in the radiopacity, as demonstrated by the X-radiography. X-ray microtomography showed a more spherical particle format with a heterogeneous particle structure for PL 8500 A compared to the other polyurethanes. These findings enhance the comprehension of the structure–property relationships inherent in these materials and facilitate the development of customized materials for targeted applications.

The wetting dynamics of molten thermoplastic polymers, which are known to influence the force balance of the triple line, are not understood properly despite their importance in many industrial processes. In particular, the influence of the molecular weight Mn on the polymer dynamic wetting behavior is still unclear. In this work, we investigate how the dynamic equilibrium of the moving contact line between poly(ethylene glycol) and cellulosic substrates is influenced by Mn. After a careful assessment of the rel-evant material properties, dynamic wetting experiments are conducted using the Wilhelmy method. Our investigations reveal an influence of Mn on the evolution of all of the measured quantities. The dynamic wetting behavior is shown to relate to the polymer chain size, and to display a transition at the critical weight of entanglement Mc . This study should help defining guidelines for formulating and choosing polymers for various processes, such as composites manufacturing.(c) 2023 Elsevier Ltd. All rights reserved.

Microcrystalline cellulose (MCC) has unique properties and its use as reinforcement for polymer composites has been increasing. However, the intrinsic incompatibility with most polymers requires surface modification to improve chemical compatibility prior to its incorporation into a polymer. In this paper, a grafting amount and structural characteristics of MCC functionalized with 3-aminopropyltriethoxysilane (APTES) (MCC-Si) at different contents was performed. We reported a comparison of three different methods for quantifying the APTES grafting amount: from TGA curves, nitrogen content, and silicon content. Supplementary analyses were performed: solid-state 13 C and 29Si nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy with energy dispersive X-ray (SEM-EDX). A deep study of structural properties by X-ray diffraction was also conducted. A better correlation for grafting amount of APTES onto MCC was observed for nitrogen content method than residual mass according to the Pearson’s correlation. 13 C NMR revealed all the carbon structures from cellulose and side bands for MCC-Si samples and from APTES molecules and 29Si NMR revealed T structures. The silane treatment did not alter the shape of MCC and all treated samples showed Si characteristic peak at ~ 1.75 kEv. The exposure to APTES in an acidic medium caused several effects on the MCC, splitting larger Iβ crystallites in half and along the more reactive hydrophilic sides. The diameter of the smaller IVI crystallites was largely reduced by the treatment, especially when the silane concentration was 1:5 (m/v), above which the diameter increases again.

In the last decades, the amount of dredged sediments (DS) increased in France harbours. Dredged sediments consist of fine soil collected from the deepening, broadening and maintaining of public waterways. The present study reports the investigation of the beneficial reuse of dredged sediments collected from Le Havre (France) harbour as fired material for sustainability requirements. The main challenge is the use of untreated dredged sediments from land deposit of the Seine estuary and port areas as building material, especially for fired bricks manufacture. The chemical, mineralogical and particle size compositions of the raw material were assessed using X-ray fluorescence (XRF), X-ray diffraction (XRD) and laser particle sizer, respectively. The results indicate that the main oxide components are SiO2 and CaO3, while quartz and calcite are the main mineral phases. Lesser amounts of feldspar, chlorite, kaolinite, muscovite and halite were also determined. The physical properties of the raw clay material, including plasticity, organic content and salinity, were investigated in order to assess the product suitability as building material. Ceramic properties such as linear shrinkage, water absorption, bending strength and mineral neo-formations were also investigated in fired bricks at temperatures ranging from 700 to 1000 °C. A high mechanical strength has been obtained at a temperature of 900 °C. The use of ternary diagrams indicates that the raw material falls inside the industrial domain, and ceramic tests show that the raw material could be used in brick making because of its firing behaviour and mechanical resistance. As regards environment sustainability, chemical analysis reveals that the levels of metal traces from leaching tests remain low and within regulatory limits.

Hypothesis: The temperature dependence of the static contact angle could a priori be predicted by using surface tension partitioning. An original model based on the transition state theory is also introduced. This model considers thermocapillary fluctuations on the droplet surface near the triple line and the self-affine pinning of this triple line against a solid substrate modeled with a pseudo-periodic distribution of adsorption sites. Experiments: The temperature dependence of the static contact angle was studied for a representative range of liquids with different polarities and on a wide array of solid substrates for temperatures ranging from 25 to 240 ?C. Atomic force microscopy (AFM) was also used to quantify the surface roughness of the solid substrates. Findings: Whereas the surface tension partitioning failed to bring consistent results above room temperature, the transition state model proved very useful, thereby opening a way to yield predictive contact angle values with temperature variations. The introduction of a topological dimension in the equations Hypothesis: The temperature dependence of the static contact angle could a priori be predicted by using surface tension partitioning. An original model based on the transition state theory is also introduced. This model considers thermocapillary fluctuations on the droplet surface near the triple line and the self-affine pinning of this triple line against a solid substrate modeled with a pseudo-periodic distribution of adsorption sites. Experiments: The temperature dependence of the static contact angle was studied for a representative range of liquids with different polarities and on a wide array of solid substrates for temperatures ranging from 25 to 240 degrees C. Atomic force microscopy (AFM) was also used to quantify the surface roughness of the solid substrates. Findings: Whereas the surface tension partitioning failed to bring consistent results above room temperature, the transition state model proved very useful, thereby opening a way to yield predictive contact angle values with temperature variations. The introduction of a topological dimension in the equations yields a unified model that covers normal wetting (perfectly bonded liquids on smooth surfaces) but also the onset of Cassie-Baxter and Wenzel states on real surfaces. Moreover, the model encompasses the transition to complete wetting. (c) 2021 Elsevier Inc. All rights reserved.

The potential for a facile aqueous-based solvent processing route for the synthesis of all-cellulose composites (ACCs) is explored using aqueous solutions containing tertabutylphosphonium hydroxide (TBPH). Specifically, ACC laminates are prepared via the partial dissolution of a woven textile of cellulose II using aqueous TBPH solutions. The dissolved cellulose was then regenerated to reform a cellulose II matrix phase in situ that acts to bond the original undissolved fibres. The hygroscopic behaviour and dissolution analysis of the solvent system showed wide range in the choice of processing conditions suited to the production of ACC laminates via TBPH. The effect of solvent concentration on the microstructure, crystallinity and tensile properties of ACCs is reported. The use of TBPH enables reductions in the processing cycle time and improved control over the properties of ACCs, indicative of a promising solvent system for the upscaled production of ACCs and their laminates.

Abstract Microcrystalline cellulose (MCC) has unique properties and its use as reinforcement for polymer composites has been increasing. However, the intrinsic incompatibility with most polymers requires surface modification to improve chemical compatibility prior to its incorporation into a polymer. In this paper, an in-depth study of silanization of MCC using 3-aminopropyltriethoxysilane (APTES), at different concentration, was done. The grafting amount of APTES onto MCC was determined by different methods: from residual mass and from nitrogen content. Solid-state 13C and 29Si nuclear magnetic resonance (NMR), field emission scanning electron microscopy with energy dispersive X-ray (SEM-EDX), spectroscopy plasma optical emission spectrometry (ICP), and a deep study of structural properties by X-ray diffraction were carried out. A better correlation for grafting amount of APTES onto MCC was observed for nitrogen content method than residual mass according the Pearson’s correlation. 13C NMR revealed all the carbon structures from cellulose and from APTES molecules and 29Si NMR revealed D, T and Q Si structures. The silane treatment did not alter the shape of MCC and all treated samples showed Si characteristic peak at ~ 1.75 kEv. From ICP was observed higher Si content before MCC addition than after, evidencing, once again, APTES grafting. The exposure to APTES in acidic medium caused several effects on the MCC, splitting larger Iβ crystallites in half and along the more reactive hydrophilic sides. The diameter of the smaller IVI crystallites was largely reduced by the treatment, especially when the silane concentration was 1:5 (m/v), above which the diameter increases again.

Brazil is the second-largest world producer of pineapple and generates almost 45% of its initial mass in wastes after industrialization, mainly due to the inappropriate deposition of peel and crown, which contribute to environmental damage. In this study, pineapple crown fibers (PCF) residues were investigated as an essential alternative to produce cellulose nanocrystals (CNC). It was used a free-chlorite hydrolysis reaction combined with sulfuric acid using different times and acid concentrations to obtain CNC after obtaining of the bleached cellulose. CNC`s were characterized by zeta potential, TGA, XRD, FTIR, and TEM. The main results showed that the chemical treatments were efficient in the removal of amorphous components, increasing the fiber whiteness and the crystallinity index. The best result obtained was for a concentration of 64% of H2SO4 for two hours with values of particle size of c.a. 140 nm and Zeta potential of − 47.96 mV, validating the use of the PCF for CNC.

This work consists in an experimental investigation of forced dynamic wetting of molten polymers on cellulosic substrates and an estimation of models describing this dynamic. A previous work of Pucci et al. (2018) showed that for totally wetting liquids (as paraffin oils), temperature-induced variations in dynamic wetting are included into the capillary number (Ca) and then a master curve of dynamic contact angle (θd) as a function of Ca can be obtained. The hydrodynamic theory (HDT) correctly describes the dynamic wetting for Ca>2·10−3. For lower Ca, a change in the dynamic wetting behavior was observed. Here, partially wetting liquids (polyethylene glycols, a.k.a. PEGs) at different molecular weight (Mn) were used at temperatures above their melting point to investigate the dynamic wetting behavior on cellulosic substrates for a large range of Ca. It was found that the dynamic curves of θd vs. Ca depend on Mn. Moreover, the HDT correctly describes the experimental measurements for Ca>2·10−3. Below this threshold the dynamic contact angle decreases toward the static one. A linear correlation between parameters obtained fitting the HDT and the molecular weight of polymer was found. The prediction of dynamic wetting for low Ca (Ca < 2·10−3) with the molecular kinetic theory (MKT) was also evaluated and discussed.

To overcome water scarcity issues in arid and semi-arid regions, Managed Aquifer Recharge (MAR) remains a viable and suitable solution to manage and restore aquifers. However, clogging represents a major issue that can affect the durability and efficiency of MAR structures. The aim of this study was to evaluate the extent of clogging in MAR sites (Berrechid, Morocco). To achieve this objective, two field-based studies were undertaken: the first one consists of implantation of sand-filled columns in the recharge sites to evaluate the surface and subsurface clogging. The second one consists of the implantation of pickets over a 750 m(2) area in each recharge site to measure the extent of deposit thickness on the surface of the wadi bed. Results show that, despite the low rainfall (<1.4 mm/day) and the short period (91 days) of the study, the deposits thickness exceeds 3 cm in a large part of the MAR. The suspended solids concentrations measured in recharge sites ranged from 1.1 to 1.4 g/L. Due to the particles retention, the estimation of the saturated hydraulic conductivity (k) of the sand declines over 90% in the immediate entrance of the columns. The k values measured in situ during the drying period ranged from 10(-5) to 10(-6) m/s. The k values of the cake formed, without cracks, was about 10-8 m/s. The presence of cracks drives the entire infiltration. However, due to the high plasticity index of theMAR soil, a slight reduction of cracks opening during wetting cycles is observed. In addition, particles deposited in these cracks, would contribute actively to the reduction of infiltration. The results of this study clearly showed theMAR sites vulnerability in semi-arid regions due to physical clogging. (C) 2020 Elsevier B.V. All rights reserved.

Hydrochloric acid hydrolysis in its gas form was used to produce cellulose nanoparticles from flax shives with a very high yield (> 90%). The efficiency of the transformation was examined by gravimetry, atomic force microscopy and transmission electron microscopy. A novel purpose-built anisotropic line-broadening X-ray diffraction model was used. This XRD method uses a parametric shape in order to address the issue of strongly broadened and overlapping Bragg rays that are characteristic of nano-sized crystallites. This method demonstrated the remarkable stability of the crystallite shapes during hydrolysis and its sensibility was sufficient to detect a minor co-crystallization along the hydrophilic faces. The presence of amorphous material strictosensu in the form of individual and randomly oriented chains was not necessary to describe the diffractograms accurately. Thermal FTIR with isotopic exchange was also performed using deuterium oxide to characterize the accessibility of the materials between 20 and 260 °C. Further, back-exchange experiments were performed in order to quantify the hysteretic amount of deuterium that was trapped by microstructural reorganization. These experiments showed that hydrolysis cancelled any form of deuterium trapping (water-induced co-crystallization). For the first time, thermal FTIR demonstrated that isotopic labelling of cellulose sources can produce false positives when conducted at room temperature and thermal FTIR can unambiguously distinguish between labelled cellulose groups and free deuterium oxide, which is paramount when measuring the higher accessibility of the nanocelluloses. It was also demonstrated that the high-temperature hydrogen bond reorganization and thermal degradation of the cellulose chains strongly depend on the hydrolysis and on the microstructure of the substrate.

Ce travail a pour objectif de calibrer un protocole de mesure permettant d'identifier les parametres cles dans les phenomenes de dynamique de mouillage lors de la mise en oeuvre de composites. Pour valider la procedure, des materiaux modeles ont ete etudies : des films cellulosiques en tant que substrats, et des paraffines et polyethylene glycols comme liquides. La procedure experimentale a consiste a caracteriser le substrat en termes de morphologie et de chimie de surface, en montrant qu'en premiere approximation on peut s'affranchir des heterogeneites de surface. La caracterisation de liquides en fonction de la temperature et en fonction de la masse molaire a ete ensuite analysee en prenant en compte l'etat fondu des polymeres. Les conditions de temperature et de masse molaire ont ete ensuite considerees en dynamique de mouillage et demouillage. Les resultats ont bien ete decrit par l'approche hydrodynamique pour un certain intervalle de valeur du nombre capillaire. Sur la base de ces modeles, des parametres physiques ont ete estimes, en precisant l'influence de la temperature et des longueurs de chaine de polymeres sur la dynamique de mouillage. Abstract The aim of this study was to set an experimental protocol in order to identify key parameters in wetting dynamics during liquid composite manufacturing. To validate the procedure, model materials were studied : cellulose films as substrates, and paraffins and polyethylene glycols as liquids. The experimental procedure consisted of characterizing the substrates in terms of morphology and surface chemistry, showing that, as a first approximation, it was possible to consider substrates as model surfaces without physico-chemical defects. The characterization of liquids as a function of temperature and molar mass was then performed, considering an additional issue : the molten state of polymers. Temperature conditions and molar mass were then considered in wetting and dewetting dynamic. The results were well described by the hydrodynamic approach for a range of capillary numbers. Using these models, physical parameters were estimated, explaining the influence of temperature and polymer chain lengths on wetting dynamics.

A cotransport study of heavy metals and kaolinite particles in sand column with and without flax geotextiles was carried out. The objectives were to evaluate the potential role of kaolinite in heavy metals transfer and to analyse the influence of flax geotextiles on the transfer of these pollutants. The adsorption rates of heavy metals on the kaolinite particles were, respectively, 53%, 65% and 25% for copper, lead, and zinc. The injection of kaolinite with heavy metals resulted in a significant decrease in the retention efficiency of copper and lead in the filter. The presence of kaolinite in the injected solution has virtually no influence on the effectiveness of zinc fixation in the filter. The retention of heavy metals is in the order of Zn > Cu > Pb with a significant drop of retention efficiency of 34% for copper, 67% for lead, and less than 1% for zinc. The presence of kaolinite in the injected solution reversed the retention order of heavy metals when metals solution was injected alone. Flax geotextiles increase the ability of the filter to retain soluble and attached heavy metals. It improves the sand retention capacity and it retains soluble and attached metals in its structure.