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Starch/nanocellulose nanocomposite is of interest because of its potential applications in the field of biodegradable food packaging and biomedical applications thanks to its safe, biodegradable, fabricated by simple traditional methods, and cheap. The starch reinforced by nanocellulose significantly improved the physicochemical properties, especially the mechanical properties, thermal stability as well as barrier properties, compared to the starch matrix. With outstanding advantages compared to polymer nanocomposites derived from petroleum, the starch/nanocellulose composite is considered a potential agent for biodegradable food packaging and biomedical technology.

Rice husk is one of the most abundant biomass resources in the world, yet it is not effectively used. This study focuses on the sustainably rice-husk-extracted lignin, nano-lignin (n-Lignin), lignin-capped silver nanoparticles (LCSN), n-Lignin-capped silver nanoparticles (n-LCSN), and lignin-capped silica-silver nanoparticles (LCSSN), and using them for antibacterial activities. The final n-Lignin-based products had a sphere-like structure, of which the size varied between 50 and 80 nm. We found that while n-Lignin and lignin were less effective against Escherichia coli than against Staphylococcus aureus, n-Lignin/lignin-based hybrid materials, i.e., n-LCSN, LCSN, and LCSSN, were better against E. coli than against S. aureus. Interestingly, the antimicrobial behaviors of n-LCSNs could be further improved by decreasing the size of n-Lignin. Considering the facile, sustainable, and eco-friendly method that we have developed here, it is promising to use n-Lignin/lignin-based materials as highly efficient antimicrobials without environmental concerns.

Building with earth is an ancient technique which has been the object of numerous studies during the last decade, due to sustainable properties of the material. To improve the mechanical properties and the durability of earthen material, hydraulic binders are usually added (e.g. cement or lime). Other binders with lower carbon footprint are investigated to reduce the environmental impact of stabilised earth material. The present paper investigated a geopolymer-stabilised compacted earth (GSCE). The geopolymer was obtained by using fly ash and an alkaline activator solution (a mixture of Na2SiO3 and NaOH). First, a parametric study was performed to identify the important factors to be investigated. Then, 360 specimens were manufactured and tested under uniaxial compression, to investigate influences of different factors on the compressive strength: Na2SiO3/NaOH ratio (1, 1.5 and 2); the mixing procedure; curing temperature (ambient, 60 and 90 °C) and evolution of compressive strength as a function of time (7, 14, 28, 56, 90 and 180 days). The scanning electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy techniques were applied to investigate the microstructure of GSCE specimens. The geopolymerisation in the specimens was verified by using these techniques. It was shown that the chemical bond C-H (a product of reactions between the activator and CO2 in the air) influenced the evolution of the compressive strength in function of time. The results showed, that after 28 days, the compressive strength of GSCE continued to increase 20–25% until 56 days. The unstabilised and cement-stabilised specimens were also tested and compared with GSCE specimens.

Spent coffee grounds (SCGs) represent a huge amount of global waste whose post-use disposal triggers environmental issues. In this study, SCGs were successfully treated and modified to improve the mechanical properties of biobased composites with epoxy matrix. A two-step treatment was proposed, pretreating by a NaOH solution and modifying by maleic anhydride (MA). MA acts as a coupling agent to create the internal network in composite through the interaction between functional groups. Accordingly, MA improves the interface between phases in composite, ensures a better physical property compared to the composite without modification. Consistently, the two-step treatment depicts improved mechanical properties: flexural modulus and flexural strength increased to 3053 MPa and 45 MPa, respectively, compared to 2429 MPa and 33 MPa for composite with pure SCGs.

Antibacterial materials have been developed for a long time but bacteria adapt very quickly and become resistant to these materials. This study focuses on the synthesis of a hybrid material system from lignin and silver/silica nanoparticles (Lig@Ag/SiO

In the context of novel environmental and energy regulations in construction (RE2020), biocomposites derived from bamboo fibers, bamboo powders, and biodegradable poly(lactic)acid polymer, all of which are renewable resources, have been investigated to meet the criteria of the novel regulations. In this work, the biocomposites were manufactured by twin-screw internal mixing at 170 °C for 5 min with a rotation speed of 60 rpm. The composites sheets were then shaped on a hydraulic press at 185 °C. Pore characterization including pore volume fraction, 3D-pore structure and morphology, and pore distribution of these materials were investigated using X-ray tomography combined with image processing (Avizo). The results show that when the bamboo fibers content is increased, an augmentation in the pore volume fraction and the number of large-volume pores could be observed. In turn, the bamboo powder-containing sheet had a significant increase in pore volume fraction, while a higher quantity of smaller pores, with uniform size, could be observed. The water absorption capacity of these composite increases with the increase of the amount of pore distribution, pore connection, and pore volume fraction. In addition, the orientation of the fibers in 3D observation, flexural mechanical properties, and thermal stability of the biocomposites are also reported in this study.

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/(m2.%RH).

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. $$20^{\circ }$$ 20 ∘ ). 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.

This study aims at identifying the mechanisms of oil and water imbibition in heartwood and sapwood of Douglas-fir through a combination of original experiments with magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) relaxation measurements for oil and free water, and deformation measurements for bound water. Experiments by weighing are performed to verify whether the imbibition process is also consistent with Washburn law. All the results are discussed taking into account the structure of wood (tubular tracheids closed at their tips, but possibly connected to each other via open pits on the side faces) and the preparation of samples. The observation of relatively fast oil flow imbibition confirms that sapwood exhibits a connected hydraulic network through which a liquid can a priori flow and climb along the structure. However, the spontaneous water imbibition is strongly damped by its very poor wetting when in contact with cell-walls only partially saturated with bound water, so that the diffusion of bound water control the uptake dynamics. However, due to preferentially closed pits, the heartwood does not exhibit a continuous hydraulic network and water essentially penetrates into wood by diffusion through the cell walls.

The aim of this paper is to synthesize montmorillonite/TiO

International audience; Cultured marble is a blend of unsaturated polyester and calcium carbonate that is combined with pigments and additives to produce a wide range of colours and realistic, natural-looking patterns. This study aims to investigate process conditions (catalyst, temperature, cured time, etc …) of cultured marble at high temperatures. The optimized process conditions are obtained by thermal analysis from DSC with a temperature of 110°C and curing time of 20 min, respectively. The optimum catalyst for process conditions in a bulk moulding compound (BMC) machine is 2 phr of benzoyl peroxide (BPO). The styrene amount in UP resin is determined at 37.40% by the Gas chromatography-mass spectroscopy – headspace (GCMS-HS) technique. Anhydride maleic (MA) is found to improve outstanding mechanical properties in terms of flexural properties, the strength of impact, and the resistance of volume shrinkage of UP resin in cultured marble material.

This study aims to produce novel composite artificial marble materials by bulk molding compound processes, and improve their thermal and mechanical properties. We employed stearic acid as an efficient surface modifying agent for CaCO3 particles, and for the first time, a pretreated, recycled, polyethylene terephthalate (PET) fibers mat is used to reinforce the artificial marble materials. The innovative aspects of the study are the surface treatment of CaCO3 particles by stearic acid. Stearic acid forms a monolayer shell, coating the CaCO3 particles, which enhances the compatibility between the CaCO3 particles and the matrix of the composite. The morphology of the composites, observed by scanning electron microscopy, revealed that the CaCO3 phase was homogeneously dispersed in the epoxy matrix under the support of stearic acid. A single layer of a recycled PET fibers mat was pretreated and designed in the core of the composite. As expected, these results indicated that the fibers could enhance flexural properties, and impact strength along with thermal stability for the composites. This combination of a pretreated, recycled, PET fibers mat and epoxy/CaCO3-stearic acid could produce novel artificial marble materials for construction applications able to meet environmental requirements.

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.

Herein, we successfully developed a novel three dimensional (3D) opened networks based on nitrogen doped graphene‑carbon nanotubes attaching with gold nanoparticles (N-GR-CNTs/AuNPs) to apply for non-enzymatic glucose determination. It was demonstrated that the N-GR-CNTs/AuNPs modified electrode exhibited good behavior for glucose detection with a long linear range of 2 μM to 19.6 mM, high sensitivity of 0.9824 μA·mM-1·cm-2, low detection limit of 500 nM, and negligible interference effect. The high performance of the N-GR-CNTs/AuNPs based sensor was assumed due to the outstanding catalytic activity of AuNPs well dispersing on N-GR-CNTs networks, which exhibited as a perfect supporting scaffold due to the enhanced electrical conductivity and large surface area. The obtained results indicated that the N-GR-CNTs/AuNPs hybrid is highly promising for sensitive and selective detection of glucose in sensor application.

In this study, a hybrid of titanium dioxide, benzophenone and ethylene vinyl acetate (TiO2-BP-EVA) was used as a novel catalyst to accelerate photo-oxidization reaction of low-density polyethylene (LDPE) film under ambient conditions. The degradation of the LDPE films (thickness of ~25 μm) containing different catalyst concentrations were successfully investigated by different techniques, such as Fourier-transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (SEM), differential scanning calorimetry (DSM), thermogravimetric analysis (TGA) and mechanical tests. The results showed that the use of catalyst in which TiO2-BP content (1/3 w/w) is 0.5 phr (parts per hundred resin) and EVA content is 4.5 phr in a LDPE film provided the best degradation rate. The carbonyl index of the polymer film achieved the highest value without an equilibrium stage. Besides, the carbon-carbon backbone of the polymer was completely broken down consistent with the deformation of the surface. In addition, the mechanical properties impressively dropped after 3 months’ exposure. The obtained results imply that the TiO2-BP-EVA compound can be considered as an efficient catalyst for the photodegradation of LDPE polymer.

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 (150 kgf/cm2, 160 °C) during 15 min. 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 0.082 Wm−1K−1.

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.

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 3.9 g/(m2.%RH), higher than the value for bamboo fiberboard without glue (1.7 g/(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.

International audience; 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 claymineral 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 shearrate, the interlayer space of Mt. is expanded considerably. The transmission electron microscopy results showedthere was good dispersion of the organoclay layers in modified Mt. This means that the clay minerals layerstructure was disordered with two- or three-layer stacks that were separated after modification. The thermogravimetricanalysis also showed the thermal stability of the modified specimens in each method and evidencedthe insertion and elimination of M-Gly from the interlayer space of Mt. during the modification process.

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.

Linear low density polyethylene (LLDPE)/thermal plastic starch (TPS) blend was studied to prepare the biobased nanocomposite material using organoclay nanofil15 (N15) modified by alkilammonium as the reinforced phase. The LLDPE/TPS blend and its nanocomposites were elaborated by melt mixing method at 160 °C for 7 min. And the compounded sample was filmed by blowing method at three different zones of temperature profile which are 160-170-165 °C. The good dispersion of clay in the polymer blend matrix is showed by X-ray diffraction (XRD) and transmission electronic microscopy (TEM), and a semi-exfoliated structure was obtained. The thermal and mechanical properties of materials are enhanced when N15 is added to the mixture. The effect of N15 on morphology and particles size of TPS phase is also investigated. The biodegradation test shows that more than 60% in weight of LLDPE/TPS film is degraded into CO2, H2O, methane and biomass after 5 months in compost soil.

The reliability of a model is its accuracy in predicting the physical phenomena using the known input parameters. It also depends on the model's ability to estimate relevant parameters using observations of the physical phenomena. In this paper, the reliability of the VTT model is investigated under these two criteria for various given temperature and relative humidity constant in time. First of all, experiments are conducted on bamboo fiberboard. Using these data, five parameters of the VTT model, defining the mold vulnerability class of a material, are identified. The results highlight that the determined parameters are not within the range of the classes defined in the VTT model. In addition, the quality of the parameter estimation is not satisfactory. Then the sensitivity of the numerical results of the VTT model is analyzed by varying an input parameter. These investigations show that the VTT mathematical formulation of the physical model of mold growth is not reliable. An improved model is proposed with a new mathematical formulation. It is inspired by the logistic equation whose parameters are estimated using the experimental data obtained. The parameter estimation is very satisfactory. In the last parts of the paper, the numerical predictions of the improved model are compared to experimental data from the literature to prove its reliability., 33 pages, 10 figures, 9 tables, 29 references. Other author's papers can be downloaded at http://www.denys-dutykh.com/

This study focuses on manufacturing bio-insulation fiberboards from bamboo fibers and bone glue, modified with sodium lignosulfonate. The microstructure of these boards is investigated by mercury intrusion porosimetry. The porosity and average pore size of boards are decreased; however, the specific pore surface is increased with the presence of bio-glues in boards. The hygric properties are examined through kinetics of water vapor sorption at equilibrium states. The thermal conductivity and bending properties are also studied. The thermal conductivity is dependent on relative humidity levels and moisture content of the fiberboards. The bending property is increased with 30% (w/w) of mixture glue between bone and sodium lignosulfonate in boards.

In this study, biocomposites were prepared by using an unsaturated polyester and Luong bamboo fibers (BFs). Fibers separated from bamboo body by mechanical method had size distribution mainly between 0.24 and 0.40 mm diameter and 1–2.5 cm length. Some factors having effect on properties of materials, such as fiber content, type, and concentration of coupling agents were also studied. As a result, composite materials showed good properties at 90 phr of BFs that were modified by 0.7% vinyl-functional silane coupling agent.

In order to save energy used to heat or cool buildings and to improve the inhabitants comfort, control of humidity inside buildings must be improved. This can be done by using buffering materials able to absorb and release moisture when necessary. Natural fibers and mineral absorbent are good candidates to manufacture such materials. The aim of this research is to mix bamboo fibers with attapulgite to evaluate the influence of this mineral absorbent on the hygric behavior of the fiberboards. The hygric properties are slightly improved by the attapulgite and thus bamboo fiberboards can be used as building insulation materials able to participate to the indoor moisture control.

This study focuses on the preparation of thermoplastic polyurethane (TPU) nanocomposite using Vietnamese montmorillonite (MMT) as the reinforced phase. The MMT was previously modified by intercalating polyethylene oxide (PEO) and polyvinyl alcohol (PVA) molecules between the clay layers. X-ray diffraction (XRD) results of organoclays revealed that galleries of MMT were increased to 18.2 Å and 27 Å after their intercalation with PEO and PVA, respectively. Thermoplastic polyurethane (TPU) nanocomposites composed of 1, 3, 5, and 7%wt organoclays were synthesized. The result of XRD and transmission electron microscopic (TEM) analyses implied that the PEO modified MMT was well dispersed, at 3%wt, in polyurethane matrix. Fourier Transform Infrared Spectroscopic (FTIR) has confirmed this result by showing the hydrogenous interaction between the urethane linkage and OH group on the surface of silicate layer. Thermogravimetric (TG) showed that the organoclay samples also presented improved thermal stabilities. In addition, the effects of the organoclays on mechanical performance and water absorption of the PU nanocomposite were also investigated.