Extraction de composés hydrophiles non ionisables des eaux par entraînement à la vapeur suivi d'une rétention sur résine XAD-4

L'efficacité de l'extraction sur résine XAD-4 a été étudiée à partir de neuf composés hydrophiles non ionisables (alcools, aldéhydes, cétones, esters). Le facteur de capacité (k') est déterminé expérimentalement par élution frontale de différentes fractions volumiques de méthanol. Les rendements de récupération sont évalués pour quatre solvants. L'efficacité maximale et le facteur de concentration optimal sont définis en fonction du volume de percolation et du volume d'élution. Le rendement moyen est de 80 % après élution par l'acétone.L'entraînement dynamique à la vapeur est par ailleurs développé pour concentrer les composés dans 200 ml de distillat à partir de 4 litres d'échantillon. Le rendement moyen est de 77 %. Ces deux techniques sont associées afin d'accroître la spécificité de la méthodologie analytique vis-à-vis des composés hydrophiles non ionisables. Après un entraînement de l'échantillon d'eau, le condensat est ensuite percolé sur une colonne de résine XAD-4 (7 cm x 1,5 cm), l'élution s'effectuant par 14 ml d'acétone. L'éluat est alors concentré, à température ambiante, par un courant d'azote jusqu'à 4 ml, puis analysé par un chromatographe en phase gazeuse. Cette méthodologie a été appliquée à un eau naturelle artificiellement polluée par 15 composés hydrophiles non ionisables. Les rendements de récupération sont compris entre 42 % et 83 % (rendement moyen de 63 %).Non-ionic hydrophilic compounds are very often used as solvents in industrial activities or for domestic use. These products are generally alcohols, aldehydes, ketones and esters. Although they are not very dangerous for the environment at low concentrations, for hazardous pollution conditions there is a need to be able to identify and quantify such compounds. Chlorination of humic substances during drinking water treatment can also generate chlorinated by-products (chlorinated ketones).Because of their solubility in water, it is necessary to concentrate and extract these compounds before gas chromatography analysis. In this study, we describe a method where liquid/gas (steam distillation) and liquid/solid (XAD-4 resin) extractions were combined. The aim of this work was to define analytical conditions to obtain the best efficiency for the overall method.In the first phase, we developed the liquid/solid extraction on XAD-4 resin by studying capacity factors, elution volumes and percolated water volumes. The sorption of nine non- ionic hydrophilic compounds (ethanol, butanol-1, pentanol-1, ethyl acetate, n-butyl acetate, methylisobutylketone, cyclohexanone, diisobutylketone, butanal) from water onto microparticulate XAD-4 resin, and their subsequent recovery into water-methanol mixtures, was used to estimate the capacity factor (k'water) for each analyte. According to the capacity factor values, we could define three classes of compounds:1. highly hydrophilic compounds such as ethanol, which were not very well retained by the resin (k'water=11); 2. moderately hydrophilic compounds such as ethyl acetate, butanol-1, butanal, pentanol-1 for which capacity factors were less than 100; 3. weakly hydrophilic compounds that were well retained by the resin, such as diisobutylketone with a capacity factor equal to 1770. Subsequently, mobilization/recovery by frontal elution into each of four different solvents (dichloromethane, acetone, acetonitrile, methanol) was studied in order to define for each of the analytes an optimal recovery procedure. Recoveries were dependent on the volume of the water sample passing through the column (100 mL, 200 mL, 400 mL) and on volume of solvent used for the elution. The best recoveries were observed when 200 mL of water were passed through the column and when the elution was performed by 14 mL of acetone. Mean recovery was 80%. Methylisobutylketone, pentanol-1 and ethyl acetate were extracted with yields higher than 80%, whereas butanal and 2,2-dichloroethanol showed a poor recovery of around 60%.In the second phase of the study, steam distillation was also assessed as a technique for the concentration of analytes (200 mL condensate from 4 litres aqueous sample). Mean recovery was 77%. Higher recoveries were observed for ethyl acetate, butanol-1, pentanol-1 and 1,1- dichloroacetone. Dichloroethanol was not extracted with a suitable recovery (yield around 33%).The two extraction methods were combined to increase the extraction specificity for non- ionic hydrophilic compounds. In a preliminary concentration step, the analytes were recovered by steam distillation from 4 litre water samples. Analytes were sorbed from the condensate onto a 7 cm x 1.5 cm column of XAD-4 resin, then eluted with 14 mL acetone. The column eluate was concentrated to 4 mL, at room temperature in a gentle stream of nitrogen, and analyzed by gas chromatography.The extraction procedure was applied to 18 compounds (butanol-1, pentanol-1, hexanol-1, octanol-1, decanol, 2,2-dichloroethanol, ethyl acetate, n-butyl acetate, methyl hexanoate, methyl octanoate, methylisobutylketone, diisobutylketone, 1,1-dichloroacetone, octanone-2, butanal, hexanal, octanal, benzaldehyde) in spiked ultrapure water and also to 15 compounds (same compounds except for benzaldehyde and 2,2-dichloroethanol) in spiked natural water. Mean recovery percentages for the analytes in ultrapure water and in natural water were respectively around 60% and 63%. These results demonstrate that the ionic composition of the water medium did not interfere with the efficiency of the complete method. In the case of spiked natural water, recovery yields ranged between 42% (butanol- 1) and 83% (octanol-1).Keywords

Instrumented Indentation of Super-Insulating Silica Compacts

International audienceHighly porous silica compacts for superinsulation were characterized by instrumented indentation. Samples showed a multi-scale stacking of silica particles with a total porous fraction of 90 vol %. The two main sources of silica available for the superinsulation market were considered: fumed silica and precipitated silica. The compacts processed with these two silica displayed different mechanical properties at a similar porosity fraction, thus leading to different usage properties, as the superinsulation market requires sufficient mechanical properties at the lowest density. The measurement of Young's modulus and hardness was possible with spherical indentation, which is an efficient method for characterizing highly porous structures. Comparison of the mechanical parameters measured on silica compacts and silica aerogels available from the literature was made. Differences in mechanical properties between fumed and precipitated compacts were explained by structural organization

Assessment of VOCs Material/Air Exchanges of Building Products Using the DOSEC®-SPME Method

ACTInternational audienceUsing low emissive materials in building is an effective way to reduce indoor concentrations of pollutants such as VOCs. Material emissions are assessed by the ISO 16000-9 standard. This procedure is time-consuming and is not suitable for on-site measurements. This work aimed in assessing an alternative method, DOSEC\textregistered-SPME, for simple measurements. To validate it, emissions of 30 materials were characterized by both ISO 16000-9 and DOSEC\textregistered-SPME. A first correlation was found between the two methods for formaldehyde emissions of raw materials. This encouraging result allows considering the development of new decision making tools for the selection of healthy building materials

Annex 65, Long-Term Performance of Super-Insulating-Materials in Building Components and Systems. Report of Subtask II: Scientific Information for Standardization Bodies dealing with Hygro-Thermo-Mechanical Properties and Ageing

This subtask is divided in two actions:Action 2A: Materials Assessment & Ageing Procedures (Experiments & Simulation)Action 2B: Components & Systems Assessment (Experiments & Simulation)As their structures and microstructures are completely different, Super-Insulating Materials (SIMs) cannot be compared directly to traditional insulating materials. Worldwide acceptance of these materials will be improved if the hygro-thermal and mechanical properties of SIM can be clearly articulated and reproduced. In particular, nano-structured materials used to manufacture a SIM are characterized by a high specific area (m\ub2/g) and narrow pores (smaller than 1 μm) which make them very sensitive to gas adsorption and condensation, especially in contact with water molecules.Therefore, methods of characterization must be adapted, or new methods developed to measure the microstructural, hygro-thermal and mechanical properties of these materials and their barrier films.In parallel, modelling methods to describe heat, moisture and air transfer through nano-structured materials and films will have to be developed (adsorption and desorption models, diffusion models, freeze-thawing …).Of course, a few methods will be common to all SIMs, but due to their structural differences some specific modelling methods have to be developed.SIMs can offer considerable advantages (low thickness, low Uvalue) ; however potential drawback effects should be considered in the planning process in order to optimise the development of these extraordinary properties (very low thermal conductivity) and to prevent negative publicity which could be detrimental to this sector of emerging products. This is why ageing tests will be set according to realistic conditions (temperature, moisture, pressure, load …) as set out in SubTask 3A. One objective of artificial ageing is to understand potential degradation processes that could occur. The durability of hydrophobic treatment is one of these processes and will also be subject to discussion and investigation.At the component scale, additional characterizations are needed as panels or rolls are sold by manufacturers. In particular, thermal bridges will be carefully investigated, as the extraordinary thermal performance of SIMs are sensitive to the influence of thermal bridges

Annex 65, Long-Term Performance of Super-Insulating-Materials in Building Components and Systems. Report of Subtask I: State of the Art and Case Studies

The objective of this subtask I is to present the main characteristic of SIM (Super Insulating Materials) compared to traditional materials.Two main SIM are considered:- VIP (Vacuum Insulation Panel)- APM (Advanced Porous Materials).Moreover, the present report provides an up-to-date catalogue of commercially available materials & components with technical description and data of each product and information about the application domains and the implementation rules.An overview on all the application areas such as external & internal wall insulation, roofs, floors, ceilings …are investigated through a few case studies.Finally, preliminary results about Life Cycle Assessment of SIM are presented at the end of the report

Annex 65, Long-Term Performance of Super-Insulating-Materials in Building Components and Systems. Report of Subtask III: Practical Applications – Retrofitting at the Building Scale – Field scale

More than 80% of the energy consumption will be influenced by the existing building stock. Accordingly, building renovation has a high priority in many countries. Furthermore, several studies have shown that the most efficient way to curb the energy consumption in the building sector (new & existing) remain the reduction of the heat loss by improving the insulation of the building envelope (roof, floor, wall & windows). All since the first oil crisis in 1973-1974, the national building regulations require improvement of the thermal performance of the building envelope to significantly reduce the energy use for space heating. Following the regulations, the energy efficiency of new buildings has improved. In Europe, targeting to an average U-value close to 0.2 W/m2\ub7K is optimal. Using traditional insulation materials this means an insulation thickness of about 20 cm. Thus, the thickness of internal and/or external insulation layers becomes a major issue of concern for retrofitting projects and even for new building projects in cities. Therefore, there is a growing interest in the so-called super-insulating materials (SIM). The scope of the present work covers two different types of SIMs:• Advanced Porous Materials (APM), where the gaseous heat transfer is hindered significantly by the fine structure in the sub-micrometre range, and• Vacuum Insulation Panels (VIP), where the contribution of gaseous conductivity to the total heat transfer is suppressed by evacuation.For Advanced Porous Materials (APM) one might distinguish between• porous silica e.g. based on fumed silica, and• aerogels.For Vacuum Insulation Panels (VIP) one might distinguish between:• different core materials: fumed silica, glass fibre, PU, EPS, others;• different envelopes: metalized film, aluminium laminate, stainless steel, glass, or combinations;• with or without a getter and/or a desiccant.The objective of this Annex 65 Subtask 3 report is to define the application areas of SIM and to describe the conditions of the intended use of the products. Indeed, it’s clear that the requested performance of the SIM will strongly depend on the temperature, humidity and load conditions. For building applications, storage, handling and implementation requirements are also described. Common and specific numerical calculations will be performed at the building scale to assess the impact of SIM on the performance of the building envelope.SIM was used in almost all building components with different environmental condition (boundary condition) and in different climate zone. The moisture and temperature conditions in building components can cause moisture/temperature induced stresses and the stresses can cause damage in sensitive super insulation material e.g. VIPs. Thus, to convince the conservative market of construction, it needs, in addition to laboratory measurements, real condition/environmental measurements of commercially realized objects (new buildings as well as refurbishments) under several years of operation.The long-term performance of super insulation materials has to be determined based on case studies in field and laboratory. Full scale experiments provide knowledge of practical and technical difficulties as well as data for service life estimation. For certain conclusions to be drawn from the case studies, monitoring is essential. Unfortunately, monitoring is only performed in few case studies. In this report these experiences are gathered and evaluated from a long-term performance perspective.APMs have been commercially successful in the building industry in niche applications typically with space restrictions since the early 2000s. Therefore, over the last years, a number of state-of-the-art reviews have focused on applications of advanced porous materials, such as aerogels, used as thermal insulation in buildings. VIPs, on the other hand, have also been used in other applications than buildings, such as refrigerators and transport boxes. The different applications areas have been identified by numerous researchers. However, in most studies of VIPs available in the literature, it was only the thermal performance of the assembly that was investigated. However, also the moisture performance is important to consider since changes to existing structures will influence the risk for moisture damages.In the Annex, the gathered case studies cover a wider range of SIM i.e. aerogel blankets, AB, (7 case studies), silica-based boards, SB, (3 case studies) and VIP (22 case studies). The aim was to gather information from projects where SIMs were used in different assemblies. Some of the projects have been monitored, i.e. sensors were installed to monitor the temperature, relative humidity or heat flux through the assemblies, while only three have been followed up, i.e. where a third party have analysed the results of the monitoring. The case studies are presented and specific and general conclusions from each application are made.The case studies showed that aerogel blankets are possible to install in up to five layers (50 mm) without too much difficulty. The evaluations showed that the performance of the aerogel blankets was maintained over the evaluation period. For VIPs, it is difficult to evaluate the performance when installed in the wall. In one of the case studies in the report, the external air space made it impossible to identify the different panels by thermography. Only indirect methods, like evaluation of the measured temperatures in the wall, can be used to follow the long-term performance of the panels. In another case study, hybrid insulated district heating pipes were installed at two locations in a district heating system with temperatures up to 90\ub0C. Measurements during the period 2012 to 2015 showed no sign of deterioration of the VIPs and the temperature profile over the pipes was constant. An existing masonry wall was insulated with VIP-foam sandwich (XPS-VIP-XPS). It showed satisfactory and promising performance for a period of six years (2011-present). The analysis of the data obtained from continuous temperature monitoring across each insulation layer indicated the aging of VIP remains insignificant.In the framework of IEA EBC Annex 65 a common simulation-based procedure was introduced with the scope to identify potential critical hygrothermal working conditions of the SIM, which were identified as main drivers of the ageing effect. The study highlights that some physical phenomena (such as thermal bridging effects, the influence of temperature on the thermal conductivity and the decay of performance over time depending on the severity of the boundaryconditions) should be carefully evaluated during the design phase in order to prevent the mismatch between expected/predicted and the actual thermal performance.As general guidelines to mitigate the severity of the operating conditions of VIP, a list of recommendation are in the following summarised:• For the external wall insulation with VIP in solar exposed fa\ue7ade, the adoption of ventilated air layer could dramatically reduce the severity of the VIP operating conditions. Alternatively, light finishing colour are warmly encouraged to mitigate the surface temperature.• The protection of VIP with thin traditional insulation layer is always encouraged.• The application of VIP behind heater determines high value of surface temperature field which could potentially lead to a fast degradation of the panel. A possible solution to mitigate the severity of the boundary conditions could be the coupling of VIP with a radiant barrier, or the protection of VIP with thin insulation layer when it is possible.• In roof application, light colour (cool roof), performant water proof membrane, ventilated airspace and gravel covering layer (flat roof) represent effective solutions to mitigate the severe exposure.• In presence of wall subjected to high driving rain, it is preferable to adopt ventilated fa\ue7ade working as rain-screen to prevent the water absorption.Furthermore, to provide designers, engineers, contractors and builders with guidelines for the applications of vacuum insulation panels (VIPs) and Advanced Porous Materials (APMs) examples are given of methods that may be used to verify the quality and thermal performance of SIMs after installation. A comprehensive account of transport, handling, installation and quality check precures are presented. The main purpose of the descriptions is to promote safe transport, handling and installation. In the case of VIPs the primary issue is that of protecting the panels whereas the main concern for APMs is the safety in handling of the material.During the work of the Annex several questions regarding the long-term performance of SIMs on the building scale have been identified and discussed. Four main challenges were identified:• Knowledge and awareness among designers concerning using SIM• Conservative construction market• Cost versus performance• Long-term performance of SIMsFinally, SIMs for building applications have been developed in the recent decades. Theoretical considerations and first practical tests showed that VIP, especially those with fumed silica core, are expected to fulfil the requirements on durability in building applications for more than 25 years. Both VIPs and APMs have been successfully installed over the past 15 years in buildings. However, real experience from practical applications exceeding 15 years is still lacking, especially when considering third-party monitoring and follow up of demonstrations

Impact of fillers / matrix coupling on rheological properties of silica / rubber nanocomposites : application to extrusion volume defects

La structure et les propriétés rhéologiques de nanocomposites élastomère (BR ou SBR)/silice ont été étudiées dans cette thèse dans le but de mieux comprendre, par la suite, l’origine des défauts volumiques qui peuvent être observés à l’extrusion de ces mélanges. Des mélanges modèles simplifiés ont été réalisés au laboratoire et majoritairement étudiés dans ce travail de thèse. La structure de ces nanocomposites a été caractérisée par des mesures de taux d’élastomère lié, des analyses en RMN ainsi que des observations microscopiques (MEB ou MET). Ces dernières ont souligné l’existence de microstructures similaires pour les mélanges à base de BR dans la gamme de températures et de vitesses de mélangeage étudiée. A première vue, l’absence de différence quant à la distribution ou la dispersion des charges suggère donc que les différences de propriétés rhéologiques résident davantage dans les interactions gomme/charges. Les analyses en RMN ont, quant à elles, permis la détermination des taux de greffage du silane incorporé aux mélanges pour coupler les charges aux chaines élastomères. Il a été observé qu’une augmentation de la température de mélangeage favorise le greffage du silane. Les analyses RMN ont également mis en évidence la présence de réactions de pré-réticulation. Les taux de greffage ont alors pu être reliés aux conditions de mélangeage, via l’établissement d’une loi corrélant les taux de greffage silane/BR à un paramètre d’équivalence temps-température. Ce dernier est représentatif de l’histoire thermique subie par le mélange lors de sa préparation. La structure des mélanges a été corrélée aux propriétés rhéologiques caractérisées par des mesures en rhéologie dynamique, en fluage et en élongation. Les temps de relaxation moyens ou l’indice de strain hardening « SHI », issus de ces mesures, ont montré une augmentation avec la croissance des taux de greffage déterminés en RMN. Ces comparaisons ont également mis en évidence l’impact de la vitesse de mélangeage dont l’augmentation tend à diminuer le rhéoépaississement. Il existe donc au cours du mélangeage une compétition entre les réactions de greffage et les phénomènes de rupture qui induisent respectivement une croissance ou une réduction de la taille des amas d’agrégats connectés ; ces derniers étant à l’origine de l’augmentation du rhéoépaississement. Un modèle rendant compte de cette compétition a été proposé afin d’estimer l’évolution du SHI en fonction du taux de greffage et de la vitesse de mélangeage. Pour finir, les propriétés rhéologiques ont été comparées aux défauts volumiques caractérisés par profilométrie. Cette comparaison a mis en évidence l’existence de lois uniques reliant ces descripteurs rhéologiques au niveau de bosselageThe structure and rheological properties of elastomer (BR or SBR)/silica nanocomposites were studied in this work in order to understand the causes of volume defects observed during blends extrusion. Simplified model blends were prepared in laboratory internal mixer and mainly studied in this work. Nanocomposites structure was characterized by bound rubber measurements, NMR analysis and microscopic observations (SEM or TEM). These last observations have highlighted the existence of similar microstructures for BR blends in the range of studied mixing temperature and speeds. At first sight, the absence of difference in the fillers distribution or dispersion suggests that silica/rubber interactions have main impact on rheological properties. NMR analysis allowed the determination of silane grafting rate. TESPT silane was incorporated in blends to couple fillers to elastomer chains. It has been observed that the mixing temperature increase promotes the grafting of the silane. NMR analysis also demonstrated the presence of pre-crosslinking reactions. Grafting rates were then connected to the mixing conditions, through the establishment of a law correlating the silane/BR grafting rate to a time-temperature equivalence parameter. This parameter is representative of the thermal history undergone by the blend during its preparation. Blend structure was correlated to rheological properties characterized by dynamical rheology, creep and elongation measurements. Relaxation times or strain hardening index "SHI", determined thanks to these measurements, increase with the growth of grafting rate. These evolutions have also highlighted the impact of the mixing speed on rheological properties. The increase of mixing speed tends to reduce the shear thickening. Therefore, a competition between the grafting reactions and breaking phenomena occurs during blending. Grafting and breaking phenomena respectively induce growth or reduction of the size of connected aggregates clusters. The latter are responsible of the increase in the strain hardening. A model accounting for this competition has been proposed to estimate the evolution of SHI as a function of grafting and mixing speed. Finally, rheological properties were compared to volume defects characterized by profilometry. This comparison showed the existence of unique laws correlating these rheological descriptors to the intensity of volume instabilitie

Impact du couplage charges / matrice sur les propriétés rhéologiques de nanocomposites silice / élastomère : application aux défauts volumiques d’extrusion

The structure and rheological properties of elastomer (BR or SBR)/silica nanocomposites were studied in this work in order to understand the causes of volume defects observed during blends extrusion. Simplified model blends were prepared in laboratory internal mixer and mainly studied in this work. Nanocomposites structure was characterized by bound rubber measurements, NMR analysis and microscopic observations (SEM or TEM). These last observations have highlighted the existence of similar microstructures for BR blends in the range of studied mixing temperature and speeds. At first sight, the absence of difference in the fillers distribution or dispersion suggests that silica/rubber interactions have main impact on rheological properties. NMR analysis allowed the determination of silane grafting rate. TESPT silane was incorporated in blends to couple fillers to elastomer chains. It has been observed that the mixing temperature increase promotes the grafting of the silane. NMR analysis also demonstrated the presence of pre-crosslinking reactions. Grafting rates were then connected to the mixing conditions, through the establishment of a law correlating the silane/BR grafting rate to a time-temperature equivalence parameter. This parameter is representative of the thermal history undergone by the blend during its preparation. Blend structure was correlated to rheological properties characterized by dynamical rheology, creep and elongation measurements. Relaxation times or strain hardening index "SHI", determined thanks to these measurements, increase with the growth of grafting rate. These evolutions have also highlighted the impact of the mixing speed on rheological properties. The increase of mixing speed tends to reduce the shear thickening. Therefore, a competition between the grafting reactions and breaking phenomena occurs during blending. Grafting and breaking phenomena respectively induce growth or reduction of the size of connected aggregates clusters. The latter are responsible of the increase in the strain hardening. A model accounting for this competition has been proposed to estimate the evolution of SHI as a function of grafting and mixing speed. Finally, rheological properties were compared to volume defects characterized by profilometry. This comparison showed the existence of unique laws correlating these rheological descriptors to the intensity of volume instabilitiesLa structure et les propriétés rhéologiques de nanocomposites élastomère (BR ou SBR)/silice ont été étudiées dans cette thèse dans le but de mieux comprendre, par la suite, l’origine des défauts volumiques qui peuvent être observés à l’extrusion de ces mélanges. Des mélanges modèles simplifiés ont été réalisés au laboratoire et majoritairement étudiés dans ce travail de thèse. La structure de ces nanocomposites a été caractérisée par des mesures de taux d’élastomère lié, des analyses en RMN ainsi que des observations microscopiques (MEB ou MET). Ces dernières ont souligné l’existence de microstructures similaires pour les mélanges à base de BR dans la gamme de températures et de vitesses de mélangeage étudiée. A première vue, l’absence de différence quant à la distribution ou la dispersion des charges suggère donc que les différences de propriétés rhéologiques résident davantage dans les interactions gomme/charges. Les analyses en RMN ont, quant à elles, permis la détermination des taux de greffage du silane incorporé aux mélanges pour coupler les charges aux chaines élastomères. Il a été observé qu’une augmentation de la température de mélangeage favorise le greffage du silane. Les analyses RMN ont également mis en évidence la présence de réactions de pré-réticulation. Les taux de greffage ont alors pu être reliés aux conditions de mélangeage, via l’établissement d’une loi corrélant les taux de greffage silane/BR à un paramètre d’équivalence temps-température. Ce dernier est représentatif de l’histoire thermique subie par le mélange lors de sa préparation. La structure des mélanges a été corrélée aux propriétés rhéologiques caractérisées par des mesures en rhéologie dynamique, en fluage et en élongation. Les temps de relaxation moyens ou l’indice de strain hardening « SHI », issus de ces mesures, ont montré une augmentation avec la croissance des taux de greffage déterminés en RMN. Ces comparaisons ont également mis en évidence l’impact de la vitesse de mélangeage dont l’augmentation tend à diminuer le rhéoépaississement. Il existe donc au cours du mélangeage une compétition entre les réactions de greffage et les phénomènes de rupture qui induisent respectivement une croissance ou une réduction de la taille des amas d’agrégats connectés ; ces derniers étant à l’origine de l’augmentation du rhéoépaississement. Un modèle rendant compte de cette compétition a été proposé afin d’estimer l’évolution du SHI en fonction du taux de greffage et de la vitesse de mélangeage. Pour finir, les propriétés rhéologiques ont été comparées aux défauts volumiques caractérisés par profilométrie. Cette comparaison a mis en évidence l’existence de lois uniques reliant ces descripteurs rhéologiques au niveau de bosselag

Propriétés morphologiques et optiques des surfaces rugueuses

PARIS-MINES ParisTech (751062310) / SudocSudocFranceF

Determination of VOC emissions from French wood products

International audienceIn order to improve indoor air quality (IAQ), it appears necessary to have analytical protocol for the measurement and health evaluation of building product emissions. In this context, the CTBA (French Wood Technical Centre) and the CSTB (French Building Technical Centre), set up and tested a methodology to characterise emissions of Volatile Organic Compounds (VOCs) from wood building materials. This methodological tool called "Bench of Quality", aims at measuring VOC emissions from building products with laboratory emission test chamber method (European Standard prEN 13419 : 2002) and evaluating the resulting health impact. In all, 15 wood building products were tested : solid wood, wood based panels (particleboards, particleboards with melamine on top, unsanded and painted plywood), glulam, laminate flooring. Results showed that Standard prEN 13419 can readily be applied to solid wood products. A standardised methodology is now available for French wood manufacturers to determine IAQ performances of their products and to confront them with other building products