The aim of this paper is to synthesize montmorillonite/TiO2-nanoparticles (MMT/TiO2 and montmorillonite/TiO2-nanotubes (MMT/TiO2-NTs) photocatalysts through a simple wet agitation method based on ...TiO2 nanoparticles and MMT. They are likely to accumulate the effect of adsorption and photodegradation. Then, the photocatalysts are applied to degrade the rhodamine B in dye effluents. The structural characterizations of photocatalysts are investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDX). The photocatalytic activities and effectiveness of photocatalysts are evaluated through rhodamine B degradation at different concentrations under dark and UV-C irradiation conditions. The results show that the synthesized TiO2-NTs have an average tube diameter of 5 nm and a tube length at least about 110 nm, which are intercalated into MMT sheets in MMT/TiO2-NTs photocatalyst. Meanwhile, TiO2 nanoparticles are immobilized on the surface of MMT sheets in the MMT/TiO2 photocatalyst. The photocatalytic effectiveness of rhodamine B degradation of TiO2-NTs shows a significantly enhance compared to that of TiO2 nanoparticles. However, photocatalytic performance of MMT/TiO2-NTs is lower than that of MMT/TiO2. The degradation effectiveness of MMT/TiO2 photocatalyst reaches to 100% for 3 ppm and 90% at 10 ppm of rhodamine B, while these values are 97.5% and 85.5%, respectively, recorded for MMT/TiO2-NTs.
•MMT/TiO2 and MMT/TiO2-NTs are successfully synthesized with high photocatalytic activities.•MMT/TiO2 and MMT/TiO2-NTs photocatalysts showed an excellent rhodamine B degradation.•Photocatalytic efficiency reached to 97.5% and 100% for MMT/TiO2-NTs and MMT/TiO2.•The localization of TiO2 at the surface of MMT sheets maximized the efficiency.
Imbibition of water and silicone oil in poplar and spruce is investigated at the anatomical level by X-ray tomography observations and at the macroscopic level by imbibition kinetics. Imbibition ...mechanisms depend on both liquid and species. In poplar, oil penetrates vessels with a small contact angle, consistent with the value measured on solid wood (ca. Formula: see text). Surprisingly, no direct penetration of water was observed in vessels. The large contact angle for water blocks the capillary rise at the scars between vessel cells. In spruce, oil and water penetrate primarily in latewood, where bordered pits remain open. Subsequently, water slowly invades the rest of the growth ring, while transversal migration is quasi-absent for oil. These 3D observations were quantified to feed a simple imbibition model that satisfactorily simulates macroscopic imbibition kinetics. A 1D approach is sufficient for oil imbibition while a 2D approach is required for water, revealing dual scale effects.
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•High-performance PU foam nanocomposites were successfully fabricated.•A multi-methodological and modern approach was used to evaluate the flame resistance.•PU reinforced ZnO/MgO NPs ...and ATH exhibited an improvement inflame retardancy.•PU nanocomposites showed excellent thermal stability and compressive strength.
In this work, we present the influence of zinc oxide (ZnO) and magnesium oxide (MgO) nanoparticles (NPs) combined with aluminum hydroxide (ATH) on the physicochemical properties and flame-retardant behavior of rigid polyurethane (PU) foam. Adding these kinds of NPs and ATH exhibit a significant influence on the morphological, structural, thermal stability, and mechanical properties of PU nanocomposites. Flammability including horizontal, vertical burning, and limiting oxygen index (LOI) tests were performed to evaluate the flame retardancy of PU nanocomposites. It could be observed that the effects of cell structureand density were close to the fire retardancy of PU nanocomposite foam. Whereby, a combination of ZnO and MgO NPs and ATH led to reduce cell size and increase density value of PU foams, thus playing the increased their flame retardancy. The flaming time of PU and its nanocomposites took 71 s and 59–62 s to self-quench the fire, respectively, and lost ∼84 % of their weight. The addition of 125 php ATH to PU nanocomposites led to a decrease in burning time to 9–10 s and a loss of ∼61 % of their weight. LOI value increased to 24 % with the incorporation of 5 php ZnO, MgO NPs, and 125 php ATH NPs into the PU foam.
Thermal conductivity measurement.
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•The hygrothermal properties of bamboo particles are studied.•Novel binders from natural resources are used for building bio-insulation ...materials.•Influence of high relative humidity on durability of bamboo particles is investigated.•Thermal insulation of bio-materials is evaluated under different humidity conditions.
Bio-insulating materials are well known to reduce the environmental impact of constructions and are able to regulate the indoor temperature and humidity of buildings. This study investigates the influence of high-absorbing bio-glues based on a protein and lignin compound on moisture transfer and storage as well as on thermal performance of bamboo particleboards. The investigations are based on the moisture buffer value, vapor permeability, isothermal vapor sorption and thermal conductivity. Simultaneously, the mechanical properties and mold growth of these materials, manufactured for the study, are also investigated. The results demonstrate excellent moisture buffer capacity, from 2.13 to 3.26 g/(m2·%RH). The vapor sorption isotherm results exhibit the materials’ high moisture storage, and the vapor permeability behaves like commercial bio-insulating materials. The thermal conductivity of particleboards shows a low value, in accordance with their density and variation in moisture content. In addition, the results indicate mold appearance on the surfaces of specimens after 14 days exposure to 84% relative humidity. Moreover, a comparison of the hygrothermal characterizations between bamboo particleboards and fiberboards (Nguyen et al., 2017) is carefully made to highlight the exceptional features of those bio-boards.
This review paper proposes a critical overview of experimental techniques and innovative experimental methods to observe and deeply understand the migration of water inside wood and biosourced ...materials. The state of the art of the knowledge of water transfer phenomena are first presented, namely liquid and bound water migration, together with shrinkage/swelling. Then, the papers presenting the 3D imaging techniques at high resolution offered by recent technologies, such as magnetic resonance imaging, X-ray tomography
,
and in situ tomography-mechanical tests. They enable visualization and analysis of water transfer mechanisms in eco-responsible materials such as natural fiber-concretes, wood, and biobased insulating materials. The 2D and 3D images processed with specific software packages allow for an overview of the distribution and orientation of the material components, as well as the moisture-content field which affects most properties of the materials such as mechanical properties (compression and tensile strength), hygro-thermal performance, as well as durability. Finally, the Digital Volume Correlation method allows for the observation and evaluation of deformation, cracks and failure mechanisms resulting from either a mechanical or hydric loading. The paper intends to help the reader to acquire a deep understanding of water imbibition and drying mechanisms in such materials.
A model of lignin-protein-bamboo fibers network.
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•Bamboo fiberboards were manufactured using different bio-glues.•Hygrothermal properties depend on the glue.•The fiberboards exhibited ...‘Excellent’ and ‘Good’ moisture buffer value.•Relationship between thermal conductivity and moisture content was investigated.
This study focuses on manufacturing by thermo-pressing new low-environmental-impact bio-insulation fiberboards from bamboo fibers and bone glue, modified with sodium lignosulfonate. The aims are to measure moisture buffer value, water vapor permeability, bending properties, thermal conductivity and vapor sorption isotherms of these materials. The moisture buffer values of these materials belong to the “excellent” category, ranging from 2.5 to 3.9g/(m2.%RH), higher than the value for bamboo fiberboard without glue (1.7g/(m2.%RH). The water vapor diffusion resistance factor ranges from 8 to 17, which is similar with other fiber insulation materials. The bending properties show a significant improvement when 30% (w/w) glue is used, the glue being a mixture between bone and sodium lignosulfonate glues. Moreover, the variation in thermal conductivity of the fiberboards with relative humidity and moisture content is investigated to evaluate the hygrothermal performance of the fiberboards. The results are promising for both thermal insulation and moisture buffering, thus these fiberboards could be used for passive control of indoor environment.
Bio-based materials with linear low density polyethylene (LLDPE) and a high content of thermoplastic starch (TPS) were prepared using the twin-screw extruder. The 25 μm thick films were blown with a ...Haake Polydrive internal mixer using a temperature profile with three zones: 160 °C, 170 °C and 165 °C. Morphology as well as thermal properties of the materials was investigated by field emission scanning electron microscopy (FE-SEM), differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). As revealed by FE-SEM, a good dispersion of the TPS phase in LLDPE matrix was obtained. The DSC result confirmed the remarkable influence of TPS phase on crystallinity of LLDPE. Biodegradation of material in the form of film specimens were determined by weight loss, morphological surface change and mechanical properties. The results show more than 10% of the bio-film's weight is degraded after 5 months in the compost environment.
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•Using modified extruder to manufacture biomaterials with high starch content.•Influence of cassava starch on biodegradable and some properties of blends.•Investigating biodegradability of biomaterial film at different compost environments.•Investigating the behavior and properties of film during biodegradable process.
Thermal conductivity measurement.
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•Insulation materials based on bamboo fibers and bio-glue were manufactured.•The thermo-pressing conditions were optimized for bamboo ...fiberboards.•Higher bone glue amount led to increase the bending properties and water resistance.•Relationship between thermal conductivity and humidity was investigated.
Reducing energy consumption for future buildings using bio-based insulation materials is currently one of the most attractive research pursuits. The specific purpose of this research was to optimize thermo-pressing conditions for new low-environmental-impact bio-insulation fiberboards from bamboo fibers and protein-based bone glues. The microstructure, thermal insulation, water sensitivity, and mechanical properties of these fiberboards were investigated in this study. As illustrated by the results, protein-based bone glue acts as a good internal binder for bamboo fiberboards when 30% (w/w) of glue was added and elaborated under specific thermo-pressing conditions (150kgf/cm2, 160°C) during 15min. Indeed, this board presents the best mechanical properties and water resistance due to the effective adhesion of the proteins. The thermal conductivity of all the fiberboards is in a low range, between 0.0582 and 0.0812 (W.m−1K−1) at 57% RH and 25°C, and it changes according to relative humidity levels and moisture content variation. The bamboo fibers have great potential for buildings thermal insulation with a thermal conductivity below 0.082Wm−1K−1.
This paper describes the effect of inorganic adsorbents on the hygrothermal performance of insulating materials. The addition of the inorganic adsorbents leads to significant effect to the ...microstructure and mechanical properties of these materials. The thermal conductivity rang of the materials containing adsorbents from 0.095 to 0.116 (W/m
−1
K
−1
) is lower than that of those without adsorbents (0.121 (W.m
−1
K
−1
)), resulting in reducing the heat consumption of these insulation materials. The kinetics and isotherms water vapor adsorption confirm an increase in moisture uptake capacity at low relative humidity (33%) and small variation of moisture adsorption capacity at high relative humidity (75%) in the presence of the adsorbents. The moisture buffering of the boards containing different adsorbent contents is improved with an excellent moisture buffer value up to 2.7 g/(m
2
.%RH).
Graphical abstract
The thermal conductivity measurement in RH-Boxes.
This study focused on the modification of montmorillonite (Mt) using the new modifying agent monoglyceride (M-Gly). M-Gly formed a self-assembled structure in Mt. interlayers, which may be used for ...further study in clay mineral polymer nanocomposite (CPN) and cosmetic additives. The X-ray diffraction results showed the d001-value of Mt. increasing up to 16 Å in solvent and >60 Å in the melting method compared to 10 Å with neat Mt. This implies that when the melting method is applied using the internal thermomixer device with a high shear rate, the interlayer space of Mt. is expanded considerably. The transmission electron microscopy results showed there was good dispersion of the organoclay layers in modified Mt. This means that the clay minerals layer structure was disordered with two- or three-layer stacks that were separated after modification. The thermogravimetric analysis also showed the thermal stability of the modified specimens in each method and evidenced the insertion and elimination of M-Gly from the interlayer space of Mt. during the modification process.
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•A simple and effective method was found to modify Mt•The interlayer space of Mt expanded up to 16 Å in the solven method•The thermal internal mixer showed an impressive increase in the interlayer space of Mt at least 60 Å.
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