Palacios-Trujillo, A.; de Gracia, A.; Haurie, L.; Cabeza, L. F.; Fernández , A.I.; Barreneche, C. Materials Vol. 11, num. 1, p. 171-1-171-12 DOI: 10.3390/ma11010117 Data de publicació: 2018-01-12 Article en revista
The implementation of organic phase change materials (PCMs) in several applications such as heating and cooling or building comfort is an important target in thermal energy storage (TES). However, one of the major drawbacks of organic PCMs implementation is flammability. The addition of flame retardants to PCMs or shape-stabilized PCMs is one of the approaches to address this problem and improve their final deployment in the building material sector. In this study, the most common organic PCM, Paraffin RT-21, and fatty acids mixtures of capric acid (CA), myristic acid (MA), and palmitic acid (PA) in bulk, were tested to improve their fire reaction. Several flame retardants, such as ammonium phosphate, melamine phosphate, hydromagnesite, magnesium hydroxide, and aluminum hydroxide, were tested. The properties of the improved PCM with flame retardants were characterized by thermogravimetric analyses (TGA), the dripping test, and differential scanning calorimetry (DSC). The results for the dripping test show that fire retardancy was considerably enhanced by the addition of hydromagnesite (50 wt %) and magnesium hydroxide (50 wt %) in fatty acids mixtures. This will help the final implementation of these enhanced PCMs in building sector. The influence of the addition of flame retardants on the melting enthalpy and temperatures of PCMs has been evaluated.
Maldonado, A.; Lacasta, A.M; Giró-Paloma, J.; Chimenos, J. M.; Haurie, L.; Formosa, J. Construction & building materials Vol. 155, p. 209-216 DOI: 10.1016/j.conbuildmat.2017.07.227 Data de publicació: 2017-11-30 Article en revista
Magnesium Phosphate Cement (MPC) has become an essential reference for investigators seeking alternatives to the use of Ordinary Portland Cement (OPC) in building sector because of its high environmental impact. The research group developed a MPC formulated with low-grade MgO (LG-MgO) by-product, which could be considered as a sustainable MPC (sust-MPC). This research focuses on the incorporation of different percentages of Microencapsulated Phase Change Materials (MPCM) into sust-MPC, due to their ability to reduce energy consumption of heating, ventilating, and air conditioning (HVAC) systems. The study consists of an exhaustive characterization of thermal sustainable MPC (TS-MPC) dosages which incorporate air-entraining additive (AEA) and MPCM to improve their thermal behaviour. Thus, TS-MPC would reduce the use of HVAC systems contributing to the decrease of CO2 emissions and increasing energy efficiency in buildings. Moreover, properties such as bulk density, porosity, thermal conductivity, modulus of elasticity, compressive strength, and flexural strength are analysed to evaluate the potential use of these cements as a part of a passive conditioning system. Results show the proper behaviour of these cements to reduce thermal oscillation in buildings. Experimental results demonstrated the relation between the amount of the MPCM and the AEA percentage as well as the thermal and mechanical properties of the TS-MPC due to their contribution to increase the porosity. Furthermore, it should be noted the increase of porosity and the reduction of thermal conductivity of the optimal formulation, which are 60% higher and 50% lower than the sust-MPC obtained without MPCM and additive, respectively.
Elvira, J.C.; Chimenos, J. M.; Isabal, C.; Monton, J.; Formosa, J.; Haurie, L. Construction & building materials Vol. 126, p. 936-942 DOI: 10.1016/j.conbuildmat.2016.09.107 Data de publicació: 2016-11-15 Article en revista
Serrano, S.; Barreneche, C.; Navarro Ezquerra, A.; Haurie, L.; Fernández , A.I.; Cabeza, L. F. Energy and buildings Vol. 127, num. September 2016, p. 1-9 DOI: 10.1016/j.enbuild.2016.05.056 Data de publicació: 2016-09-01 Article en revista
The building sector is one of the highest energy consumers representing around 30% of total energy use. One of the recommendations of the IEA (International Energy Agency) to reduce energy consumption in buildings is to enhance the thermal performance of building envelopes. In the present study, PCM (Phase Change Material) gypsum materials have been manufactured using three different PCM inclusion methods and a thin layer of gypsum without PCM is added as external layer with the aim of improving the fire reaction behaviour. By performing a detailed physical, mechanical and thermal characterization, the suitability of the materials to be implemented in the building envelope as inner coating is demonstrated. Results show that also the thermal properties are improved in the three cases by the addition of PCM. Moreover, the negative effect of adding paraffin wax PCM into gypsum against flame can be easily reduced by the addition of a thin gypsum layer, which is a low tech and cheap solution without extra environmental impact.
Lacasta, A.M; Haurie, L.; Monton, J.; Navarro Ezquerra, A.; Giraldo, P.; Sotomayor, J.; Palumbo, M. World Conference on Timber Engineering p. 5387-5395 Data de presentació: 2016-08-24 Presentació treball a congrés
It is widely acknowledged that wood is a combustible and flammable material. However, not all woods have the same fire behaviour; this can change significantly depending on the type and species of wood. Usually, hardwoods have better fire behaviour in comparison with softwoods. This is often due to their physical structure
(morphology), their density and hardness and also their moisture content. However, in some cases the main cause is their chemical composition. Some tropical woods with relatively low density present better fire behaviour than other with high density. This indicates that other aspects such as the content of extracts, exudates (oils, waxes, mucilage, tannins etc.) and minerals can greatly influence their fire performance. In this study, seven Mexican tropical wood were characterized in order to determine their fire behaviour. For this purpose, an extensive series of laboratory tests were conducted. The results show a different behaviour in all the species studied, in some cases, with very significant differences. It is observed that although there is some correlation between high density and hardness of the species and their good fire behaviour, these factors are not always determinant. In some species, other factors as anatomy and composition of wood are more relevant to achieve a better fire behaviour.
tPhase change materials are a promising strategy to reduce energy consumption in a wide range of appli-cations including the building sector. Many studies have been done to evaluate the impact of PCM onthermal properties of building materials, however there exists little information on the influence ofPCM on other properties of the support materials. This knowledge is necessary to determine the fea-sibility to apply and use building materials containing PCM. In this paper, the effect of the addition ofdifferent percentages of microencapsulated phase change material on the properties of two commercialsingle layer mortars has been studied. Physical and thermal properties as well as fire reaction have beenevaluated.
Pastor, E.; Corberó, B.; Rios, O.; Giraldo, M.; Haurie, L.; Lacasta, A.M; Cuerva, E.; Planas, E. International Conference of Applications of Structural Fires Engineering p. 435-440 DOI: 10.14311/asfe.2015.069 Data de presentació: 2015-10-15 Presentació treball a congrés
Fire safety community is currently concerned about the response of some widely used insulating materials in case of fire, due to the fact that existing regulations do not show how these materials behave in real conditions, which in some applications may be indeed critical. Within this context, several institutions have recently carried out large-scale tests with the aim of testing such insulator’s contribution to fire growth. In this paper we present a set of large scale tests of compartment and façade fires involving materials and configurations of different nature. Our experiments provided evidence that mineral wool insulator preserves its properties in case of fire, whilst other polymeric-type insulators contribute to fire growth in conditions close to the ones present in real fires.
The present paper presents further results of an on-going research previously exposed in the first
COST FP1404 meeting in April 2015. The research focuses on the analysis of the smouldering
combustion of an innovative thermal insulation rigid board based on vegetal pith and a natural gum
(corn pith and sodium alginate) which is completely compostable
lmprovement of the fire behaviour of flax fabrics treated with silica
coatings containing expandable graphite preparad through sol-gel treatment
has been studied. Results show that silica coating containing expandable
graphite enhances the flax fabric fire behaviour.
Organic PCM stands for an alternative to the enhancement of thermal inertia inside buildings.
In contrast, its fire reaction is an inconvenient for being used in thermal energy storage. This
study focuses on evaluating fire behaviour of paraffin and fatty acid mixture ( capric acid and
palmitic acid) and improving its flammability properties by the addition of flame retardants.
In order to compare the flammability of PCM, the heat release rate was measured in a
pyrolysis combustion flow calorimeter (PCFC). On the other hand, severa! percentages of
flame retardants such as ammonium polyphosphate, hydromagnesite and magnesium
hydroxide were added to organic PCM. The flame retardants influence into paraffin and fatty
acid mixture was tested by the dripping test. As a result, the fire reaction of fatty acid
mixtures was enhanced by the addition of 50% in weight of endothermic flame retardants
systems. No improvement was observed in paraffin RT-21. The results obtained in the PCFC
indicate that in case of fire paraffin would contribute more than the fatty acid mixture to fire
Niubó, M.; Haurie, L.; Formosa, J.; Chimenos, J.M.; López-Cuesta, J.M. Asia-Europe Symposium on Processing and Properties of Reinforced Polymers p. 144 Data de presentació: 2015-02-03 Presentació treball a congrés
Poly(methyl methacrylate) (PMMA) is widely used in different industrial sectors due to
the combination of properties, such as transparency, mechanical resistance or UV durability.
PMMA flammability is however one of its main limitations.
One of the flame retardant strategies is the incorporation of phosphorous flame
retardants (PFR) into PMMA [1,2]. Wollastonite is widely used as filler in PMMA matrix due
to its interfacial interaction enhanced by the addition of stearic acid. The combination of
wollastonite with ammonium polyphosphate has already been analyzed by Quach et al. 
obtaining noteworthy flame retardant properties in PS matrixes.
In this work we have studied the effect of a wollastonite/APP system on PMMA as well
as the flame retardant properties of a chemically bonded phosphate ceramic (CBPC)
formulated with magnesium oxide and potassium monophosphate. The main interest of this
CBPC is the use of an industrial by-product as a source of low-grade magnesium oxide .
Composites with loadings of 50% of filler were prepared and further characterized. Promising
results have been obtained with both PFR systems in terms of peak of heat released rate
reduction in cone calorimeter tests.
Haurie, L.; Niubó, M.; Formosa, J.; del Valle-Zermeño, R.; Xuriguera, E.; Fernández , A.I.; Chimenos, J.M. Asia-Europe Symposium on Processing and Properties of Reinforced Polymers p. 170 Data de presentació: 2015-02 Presentació treball a congrés
During the production of caustic calcined magnesia, one of the by-products generated is
a low-grade rnagnesiurn hydroxide (LG-MH). This LG-MH contains around 60% of
rnagnesiurn hydroxide and rnagnesiurn and calciurn carbonates as rnain rninor phases [ 1]. This
cornposition suggests that this by-product could be an interesting option as low cost
endothermic flarne retardant. In a previous work we have obtained prornising results in the
use of LG-MH as flarne retardant in EVA .
In this case, several formulations of EVA filled with O, 40, 45, 50 and 60% of LG-MH
were prepared and further cornpared with formulations of EVA and alurninurn hydroxide. The
fire behavior has been evaluated by rneans of lirniting oxygen index, srnoke density and
pyrolysis cornbustion flow calorirneter. On the other hand, we have characterized the
mechanical properties of the cornposites, the physicochernical properties of the LG-MH as
well as the particle size distribution and therrnal decornposition.
Irnprovernents in the fire properties of LG-MH/EVA sarnples have been observed in the
sarnples containing at least 45% of LG-MH filler loading. Higher LG-MH loadings give rise
to enhanced fire properties. However, filler loading causes a decrease in mechanical
properties, especially elongation at break.
Gypsum has two important states (fresh and hardened states), and the addition of phase change materials (PCM) can vary the properties of the material. Many authors have extensively studied properties in the hardened state; however, the variation of fresh state properties due to the addition of Micronal DS 5001 X PCM into gypsum has been the object of few investigations. Properties in fresh state define the workability, setting time, adherence and shrinkage, and, therefore the possibility of implementing the material in building walls. The aim of the study is to analyze, compare and evaluate the variability of fresh state properties after the inclusion of 10% PCM. PCM are added into a common gypsum matrix by three different methods: adding microencapsulated PCM, making a suspension of PCM/water, and incorporating PCM through a vacuum impregnation method. Results demonstrate that the inclusion of PCM change completely the water required by the gypsum to achieve good workability, especially the formulation containing Micronal DS 5001 X: the water required is higher, the retraction is lower (50% less) due to the organic nature of the PCM with high elasticity and, the adherence is reduced (up to 45%) due to the difference between the porosity of the different surfaces as well as the surface tension difference.
In a fire scenario, huge amounts of heat are generated and high temperatures rapidly achieved in such a way that the integrity of structural materials becomes compromised. One of the aims of passive fire protection is the use of building materials that are able to absorb at least part of that heat and maintain the structural materials under critical temperatures for longer times in order to gain evacuation time. Gypsum panels are commonly used in building walls, but they only absorb heat at temperatures around 110 degrees C. We use three inorganic fillers, Mg(OH)(2), Ca(OH)(2) and CaCO3, which undergo endothermic transitions at high temperatures to obtain an improved panel with a richer heat-absorbing profile. With this formulation, the time to reach temperatures of the order of 500 degrees C, critical for steel and reinforced concrete, is significantly increased. In this work, we focus on the kinetics of the endothermic fillers as an essential ingredient for further spatially extended simulations that include macroscopic heat and mass transfer phenomena or sample heterogeneities. However, kinetics may be affected as well by heat transfer effects that occur at molecular levels. Copyright (c) 2014 John Wiley & Sons, Ltd.
The present work focuses on the reaction to fire of a cement mortar containing phase change material (PCM), which is embedded in a lightweight aggregate, for buildings. Several samples containing different PCM mass fractions have been prepared and tested in order to study the influence of the quantity of PCM on fire behaviour. The enthalpy-temperature of the PCM curve has been measured using the T-history method, and the effect of the PCM on the thermal behaviour of the cement mortar material has been studied using an experimental setup. With the aim of characterizing the reaction of the composite material to fire, various small scale laboratory tests have been carried out, paying special attention to the production of burning drops during combustion, smoke release and flame persistence. (C) 2014 Elsevier B.V. All rights reserved.
The energy consumption in buildings has increased in the last years due to the energy demand
for thermal comfort. The improvement of thermal properties in building materials is one of the
key points to achieve a reduction of the energy demand. Thermal energy storage (TES) is an
alternative to save energy that has been investigated extensively in recent years. The addition of
phase change materials (PCM) in a material increases its thermal inertia because PCM are able
to store and release energy in sensible and latent heat. In this paper coatings used in the outer
walls of buildings are studied, in particular single layer mortar. Microencapsulated paraffin
PCM is added into the material to improve the thermal properties of the building envelope. The
use of PCM combined with thermal insulation can reduce the energy consumption of buildings
by absorbing heat gains and reducing the heat flow. Two types of single layer mortar
Weber.Therm.Mineral commerzialized by Weber Saint Gobain incorporating different
percentages of microencapsulated PCM type Micronal® DS5001 (20%, 10% and 0%) in their
formulations are studied in this paper. The main objective of this work is to analyze the effect of
PCM addition on the properties of two single layer mortars. Fresh mortar properties, as well as
fire behavior, physical, mechanical and thermal properties of hardened mortar have been
evaluated. The results show that physical and mechanical properties of single layer mortar are
affected by the addition of microencapsulated PCM. Compressive strength decreases 60% with
the addition of 20% of PCM in the formulation while the formulation with 10% of PCM has
approximately the same compressive strength than a single layer mortar without PCM. The
addition of PCM in the formulation decreases in 35% the adherence of the single layer mortar to
a concrete surface. The presence of PCM in the mortar formulation worsens the fire behavior,
due to the organic, and therefore flammable, composition of Micronal® DS5001. Flammability
increases according to the percentage of PCM added. As a general conclusion, physical and
mechanical properties of the single layer mortar become worse when the percentage of the
added microencapsulated PCM is increased. Nevertheless, an improvement of thermal
properties is expected and the quantification will be done that could justify the addition of PCM
to some extent.
The present work deals with the development of new rigid polypropylene composite foams filled with high amounts of flame-retardant systems based on synthetic hydromagnesite, a basic magnesium carbonate obtained from an industrial by-product. A partially-interconnected cellular structure with a cell size around 100 micrometers was obtained for the hydromagnesite-filled PP foams. A 40% reduction of this cell size was observed when a small amount of a combination of montmorillonite and graphene layered nanoparticles was added to the hydromagnesite. The combination of hydromagnesite with an intumescent additive (ammonium polyphosphate) and layered nanoparticles led to improved thermal stability. In particular, the intumescent additive delayed the beginning of the thermal decomposition temperature and the layered nanoparticles split the second step of thermal decomposition in a third peak observed
at higher temperatures. Improved flame retardancy, measured by means of cone calorimetry, was observed in the samples containing the intumescent additive. A novel normalized parameter, called foam efficiency ratio (FER), which takes into account the expansion ratio of the foam and the relation of its fire properties with that of the base solid, was also analyzed.
The present work deals with the development of new rigid polypropylene composite foams filled with high amounts of flame-retardant systems based on synthetic hydromagnesite, a basic magnesium carbonate obtained from an industrial by-product. A partially-interconnected cellular structure with a cell size around 100 μm was obtained for the hydromagnesite-filled PP foams. A 40% reduction of this cell size was observed when a small amount of a combination of montmorillonite and graphene layered nanoparticles was added to the hydromagnesite. The combination of hydromagnesite with an intumescent additive (ammonium polyphosphate) and layered nanoparticles led to improved thermal stability. In particular, the intumescent additive delayed the beginning of the thermal decomposition temperature and the layered nanoparticles split the second step of thermal decomposition in a third peak observed at higher temperatures. Improved flame retardancy, measured by means of cone calorimetry, was observed in the samples containing the intumescent additive. A novel normalized parameter, called foam efficiency ratio (FER), which takes into account the expansion ratio of the foam and the relation of its fire properties with that of the base solid, was also analyzed.
Rosell, J.; Haurie, L.; Navarro Ezquerra, A.; Rodriguez Cantalapiedra, I. Construction & building materials Vol. 55, num. March, p. 423-430 DOI: 10.1016/j.conbuildmat.2014.01.007 Data de publicació: 2014 Article en revista
The influence of the slaking method on the characteristics of lime putties has been investigated. There has
been used the same raw lime, calcined in a traditional kiln, to perform in situ traditional slaking processes
as well as laboratory controlled slaking processes. The obtained lime putties were characterized using different instrumental techniques such as X-ray diffraction (XRD), X-ray fluorescence (XRF), thermogravimetric
analysis (TGA), specific surface area (BET), particle size using laser dispersion and viscosity.
Particle morphology using scanning electron microscope (SEM) was also studied. The amount of water
used during slaking as well as the temperatures distribution give raise to differences in the particle size
distribution and in the resulting hydration products.
According to the International Energy Agency, the energy use in buildings accounts up to 38% of global energy consumption reaching in developed countries the 45% of the energy use in buildings in 2012. A substantial increase in global energy consumption has been recorded in recent years and a reduction of the energy demand for thermal comfort in buildings is mandatory. This reduction can be achieved by the development of new materials to be implemented in building envelopes. Thermal energy storage (TES) is an alternative to save energy and it has been investigated extensively in recent years. The addition of phase change materials (PCM) in a material increases its thermal inertia because PCM are capable to store and release energy as sensible and latent heat, therefore the energy consumption can be reduced. In this study, phase change materials (PCM) are added into a common gypsum matrix (E-35) by three different methods: adding microencapsulated PCM (Micronal® 5001X), making a suspension of the PCM in water, and incorporating the PCM through an impregnation method. RT-21 paraffin waxes PCM were used in the suspension and impregnation formula. Gypsum has two important states during the implementation process: fresh and hardened states. Properties in fresh state define the workability of the material: adherence, consistency, working and setting times, etc. The addition of PCM into the gypsum matrix modifies all these properties so, the aim of the paper is to analyze, compare and evaluate the variability of the properties during fresh state after the inclusion of PCM by three different methods (microencapsulated, suspension and impregnation process).
This research work aims to study the porosity of these CBPC formulated with LG-MgO
as a function of the amount of setting retardant admixtures, such as boron compounds or
polyphosphates. These additives improve the fluidity of the fresh paste and its
workability, shifting the equilibrium of acid - base reaction between the metal oxide and
the phosphates. By this way, the initial setting time can be delayed and the release of the
heat flux from exothermic reaction decreased. Both parameters have a direct influence
on the percentage and the size of the pores generated, which leads to a variation of the
capillarity and permeability of these materials. Moreover, the vibration of the slurry
during the setting process allows eliminating the air retained during its homogenization
and from the water vapour generated as a result of the exothermal reaction. This results
in a lower porosity and / or a decrease in the pore size, and therefore affects the material
properties. The study of vibration time can be a working parameter to control the
porosity and the pore size for the above mentioned as well as others
In this study we have studied the influence of cement reactive additions and additives
on the workability and mechanical properties of the Portland cement. In order to obtain
maximum information and evaluate possible interactions between factors we have used
an Experimental Design (DoE).
We have tested two types of cement, one without additions (CEM I 42,5R) and the other
one with a content of fly ashes between 6 and 20% (CEM II/A-V 42,5R). The
experimental planning was based on DoE response surface methodology. Therefore, we
have developed two identical experiments designs, one for each type of cement. Thus,
we prepared several mortar formulations keeping constant the aggregate and cement
amount and varying the water and superplasticizer additive content. Fresh mortar
properties, such as workability and density, together with mechanical properties at
different ages (7, 28 and 90 days) were measured.
The use of DoE allows us to obtain prediction models giving not only the influence of
one variable on the studied property, but also the interaction between two variables.
Furthermore, variation of the mortar properties is represented graphically based on the
Response surface analysis offers the possibility to optimize the dosages according to the
desired requirements. In this manner, an optimal mortar formulation is obtained that
provides compressive strength up to 80Mpa at 90 days of age.
Boron-based formulations are used to improve the service life of timber. On the one hand, boron-treated wood increases resistance to biological attacks (e.g. by fungi and insects), and on the other hand, it renders wood more resistant to burning. In the present study, we analyse the fire behaviour of some water-borne formulations containing boron. A completely inorganic formulation (disodium octaborate tetrahydrate (DOT)) is compared with new-generation tannin-based wood preservatives in which the flavonoid network is used to fix the boron to wood. The study of the fire behaviour was carried out according to four specific fire tests: (i) dripping; (ii) short-term exposure; (iii) long-term exposure and (iv) the limiting oxygen index. The Scots pine (Pinus sylvestris L.) specimens treated with DOT have shown a complete efficacy against fire after all tests were completed. It should also be noted that very positive results have also been achieved by the tannin-based solutions. DOT has to be preferred when high performance is required, but exclusively for interior applications. The use of tannin-based formulations can be suitable for outdoor fire protection and also for indoor applications when specific aesthetic requirements should be fulfilled
Haurie, L.; Lacasta, A.M; Alvarez, A.; De Redondo, V.; Velasco J.I. Construction & building materials Vol. 42, num. May 2013, p. 266-270 DOI: 10.1016/j.conbuildmat.2012.12.012 Data de publicació: 2013-05 Article en revista
In this work we have studied the effect of different flame retardants on the fire behavior and mechanical properties of epoxy mortars. Flame retardants acting under different mechanisms of action have been compared: phosphate flame retardants as well as magnesium hydroxides and carbonates. Besides the commercial flame retardants we have also used a magnesium basic carbonate obtained from an industrial by-product. The use of an alternative based on an industrial by-product combines an economic and sustainable solution. Different formulations of flame retarded epoxy mortars have been prepared and characterized. The obtained results prove the effectiveness of the tested flame retardants on the improvement of the fire properties of the epoxy mortars without a significant decrease on their mechanical properties.
This paper is a teaching activity carried out on the subject of Building Materials from Building Engineering studies. This subject is developed in the second year and lasts for a four month period. The student teacher ratio is around 60:1.
The goal of this work was the development of a new building material obtained from waste materials. Students were divided in teams of three students chosen by themselves. This activity helped students to develop knowledge about different materials and make them aware of the importance and possibilities to profit waste materials.
Students should work with materials studied in the subject, mainly clay, glass, steel, wood and plastics. Before beginning they must do an important bibliographic research about the topic they wanted to develop. The university provided the use of lab facilities and the guidance of the teacher. Besides following up the work, the teacher encouraged the students to perform some tests on the new material obtained. Finally they should come out with a poster and a sample of the material.
Results got from different works differed substantially according to the interest and time dedicated to them. Most of the students abused of the use of polymeric resins to elaborate the new materials, and therefore, even using wastes the new materials were not so sustainable. The use of natural materials such as cane fibres leaded to materials with interesting insulation and structural properties.
It was a very good experience to attract students to materials research. Finally we discovered in order to get profitable results, this kind of activity should cover a longer period and should count with the continuous guidance of the teachers.
En el presente trabajo se han preparado y caracterizado espumas ignífugas de poliolefinas libres de halógenos. Se ha utilizado para ello una formulación comercial, empleada típicamente en la industria de cables, y se le ha añadido pequeños porcentajes másicos (entre 2 y 4%) de dos sistemas retardantes de llama: "sílice-borato de zinc" y manolaminillas de "montmorillonita y grafeno expandible". Durante la caracterización celular de las espumas, preparadas por espumación química utilizando como agente espumante azodicarbonamida, se ha constatado que la presencia de las nanopartículas promovía una estructura celular con tamaño de celda más pequeño. Mediante un análisis termogravimétrico, se ha observado un aumento del residuo inorgánico de la formulación base a temperaturas superiores a 500ºC. Esta observación puede ser debida, en cierta medida, a un efecto sinérgico entre ambos sistemas retardantes de llama, el cual promueve una mayor estabilidad térmica de la formulación base. Durante la caracterización del comportamiento frente al fuego mediante ensayos de cono calorimétrico, se ha constatado que el sistema "síliceborato de zinc" retarda en tiempo hasta ignición de la llama (mayores valores de TTI) y que la presencia de las nanopartículas disminuye el valor del PHRR (máxima tasa de liberación de calor).
Phase change materials (PCM) have been proved to be an effective tool to regulate indoor temperature fluctuations and reduce the energetic demand of buildings [1,2]. Paraffins are among the most common PCM used for thermal storage in building applications. A broad range of melting temperatures, with an elevated heat of fusion associated, can be obtained varying the length of the hydrocarbon chain that forms the paraffins. Furthermore, they exhibit numerous benefits such as the nearly absence of supercooling, chemical stability, low vapor pressure during the phase change and no phase segregation . These paraffins can be incorporated in several forms to building materials like gypsum or concrete .
Despite all these advantages, one major concern regarding the paraffins as PCM is their possible contribution to flame propagation in case of fire . Several authors have tried to improve this aspect by combining the paraffins with HDPE polymers to obtain a form-stable PCM . Blends of paraffin and polyethylene usually contain some inorganic filler, which can act improving both the thermal conductivity as well as the flame retardancy of the system [3, 7]. Microencapsulated PCM or paraffins adsorbed in a substrate are designed to be incorporated directly into the building material and, therefore blending with HDPE is less interesting. Another possibility to increase the fire performance of the PCM is the addition of flame retardants directly into the matrix-PCM mixture. Paraffins usually present their combustion between 220-320ºC and therefore the flame retardants selected should act in this temperature range.
In this work we have studied the effect of different loads of PCM on the fire behaviour of gypsum boards. In order to improve the fire behaviour of the gypsum-PCM system, two different types of flame retardants have been added. We have chosen two endothermic flame retardants: aluminium hydroxide (ATH) and a synthetic basic magnesium carbonate, hydromagnesite (HM), obtained from an industrial by-product. Both FR have an endothermic decomposition starting around 200ºC and can be found among the cheapest alternatives to achieve flame retardancy.