Fire Retardant Properties Research Articles

Polydopamine primed phosphorylated sepiolite-polypropylene nanocomposite with enhanced thermal, rheological, and flame retardant properties

Phosphorous-based fire-retardant materials are considered eco-friendly and can be reinforced in polymers or functionalized on the polymer backbone to reduce combustibility. Herein, sepiolite fiber (Spl) was first primed with polydopamine (PDA), and the amine group density was increased by Michael's addition of EDA to further graft H3PO3. The stepwise modifications and formation of the phosphorylated Spl-PDA-P and Spl-PDA-EDA-P were established by analyzing surface chemical structure, surface and internal morphology, and surface area. Further, the Spl-based fillers were reinforced in the PP matrix, and the nanocomposites were systematically characterized for thermal stability, mechanical property, flow behavior, and fire-retardant properties. The PP_Spl-PDA-EDA-P nanocomposite at 5% filler loading has a tensile and flexural strength of 36.3 MPa and 50.6 MPa, respectively. The flow property was established by determining melt flow index (MFI) of 13.3 ± 0.75 g/10 min and melt rheological properties. After phosphorylation, the Spl-based fillers have shown shear thinning behavior with increased filler loading. Finally, the prepared nanocomposites were evaluated for fire retardant properties by determining the limiting oxygen index (LOI) and UL-94 vertical burning test. The neat PP has an LOI of 17.5, and a maximum improvement was observed in the case of PP_Spl-PDA-EDA-P with an LOI of 30.2. Overall, the grafting of H3PO3 on PDA coated Spl has created a robust filler to impart fire-retardant property in combustible PP.

Synergic flame-retardant effect of cellulose nanocrystals and magnesium hydroxide in polyurethane wood coating

In this paper, a wood coating based on waterborne polyurethane (WPU)/nano-cellulose crystalline (CNC)/Magnesium hydroxide (MH) was prepared. Efficient dispersion of MH in WPU in presence of 5 wt% of CNCs was observed by biological microscope leading to a material with improved esthetic, thermal and fire-retardant properties and mechanical performance. By thermogravimetric analysis (TG/DTG) and comparison with WPU, the maximum weight loss rate (RTmax) of WPU/CNC/MH coating decreased dramatically from 13.2 to 6.63, and the residue increased sharply from 4.69% to 40.55%. The results of pyrolysis combustion flow calorimeter (PCFC) showed that the flame-retardant performance of the composite coating is also greatly improved, and the peak of heat rate release (pHRR) being reduced from 350 w/g to 121 w/g. When applied to the wood panels, according to the Limiting oxygen index (LOI) experiment, for MH < 40 wt%, the combustibility grade is B2 level (combustible material), whereas for MH > 40 wt% the grade is B1 level (flame retardant material).

Development and Characterization of High Environmentally Friendly Composites of Bio-Based Polyamide 1010 with Enhanced Fire Retardancy Properties by Expandable Graphite.

Bio-based polyamide 1010 was melt-compounded with different percentages (2.5 to 10.0 wt.%) of expandable graphite (EGr) as an environmentally friendly solution to improve the flame retardancy properties. The mechanical, morphological, thermal and fire retardancy properties (among others) are analysed. The novelty of the article lies in the use of fully removable polyamide. The effect of the incorporation of EGr in the properties of this polymer was analysed and characterised. The incorporation of EGr into the PA1010 matrix led to very promising results. Mechanically, the EGr provided increased stiffness and a tensile strength up to 7.5 wt.%, verifying good mechanical performance. The DMTA results also show how the incorporation of EGr in the PA1010 matrix clearly increases the stiffness of the composites over the entire temperature range analysed. In terms of physical properties, water absorption of PA1010 was reduced particularly in the 10% EGr, which reduces the water absorption of PA1010 by 20%. In terms of flame retardant properties, with the incorporation of EGr, a significant reduction in the heat release rate (HRR) values as the concentration of the additive increases and a reduction in the maximum peak heat release rate (pHRR) can be observed for all compounds. In particular, it goes from 934 kW/m2 for neat polyamide to a value of 374 kW/m2 with 10% EGr. Finally, an improvement in the UL-94 rating of the 7.5 and 10% EGr composites was also observed, going from V-2 in the PA to V-1 in these composites.

Flame-Retarding Properties of Injected and 3D-Printed Intumescent Bio-Based PLA Composites: The Influence of Brønsted and Lewis Acidity of Montmorillonite.

The influence of processing intumescent bio-based poly(lactic acid) (PLA) composites by injection and fused filament fabrication (FFF) was evaluated. A raw (ANa) and two acidic-activated (AH2 and AH5) montmorillonites were added to the intumescent formulation, composed by lignin and ammonium polyphosphate, in order to evaluate the influence of the strength and the nature (Brønsted or Lewis) of their acidic sites on the fire behavior of the composites. The thermal stability and the volatile thermal degradation products of the composites were assessed. The injected and 3D-printed composites were submitted to cone calorimeter (CC), limit oxygen index (LOI), and UL-94 flammability tests. A similar tendency was observed for the injected and 3D-printed samples. The high density of strong Lewis sites in AH2 showed to be detrimental to the fire-retarding properties. For the CC test, the addition of the intumescent composite reduced the peak of heat released (pHRR) in approximately 49% when compared to neat PLA, while the composites containing ANa and AH5 presented a reduction of at least 54%. However, the addition of AH2 caused a pHRR reduction of around 47%, close to the one of the composite without clay (49%). In the LOI tests, the composites containing ANa and AH5 achieved the best results: 39% and 35%, respectively, for the injected samples, and 35 and 38% for the 3D-printed samples. For the composite containing AH2 the LOI values were 34% and 32% for injected and 3D-printed samples, respectively. Overall, the best performance in the flammability tests was achieved by the composites containing clays with only weak and moderate strength acidic sites (ANa and AH5).

Synthesis of bio-based flame-retardant epoxy co-curing agent and application in wood surface coating

A phosphaphenanthrene-containing epoxy co-curing agent (PDD) was successfully synthesized by a one-pot nucleophilic addition reaction from protocatechualdehyde (PH), 4,4′-diaminodiphenylether (DDE) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). The chemical structure of the PDD was characterized with FTIR, NMR and HRMS techniques. The physical properties of the coatings containing PDD were comparable to the EP-0 (control group phosphorus content with of 0). Various loadings of PDD and 4,4′-diaminodiphenylmethane (DDM) were incorporated into commercial epoxy resin to fabricate epoxy coating on wood surface to achieve flame retardancy. The thermal stability and fire-retardant properties of epoxy coatings were evaluated by thermogravimetric analysis (TGA), limiting oxygen index (LOI), differential scanning calorimetry (DSC) and cone calorimetry (CCT). With 1.09 wt% phosphorus content, the epoxy coating exhibited excellent flame retardancy, LOI value reached 32.6%, total heat release (THR) and total smoke release (TSP) of the EP-1.09 coated wood samples were declined by 39.8% and 61.4%, respectively. Moreover, PDD played an effective flame-retardant action both in the gas and condensed phase, not only promoting formation of continuous and dense char layer but also releasing phosphorous radicals and nonflammable gases. Hence, the bio-based co-curing agent endowed flame-retardant performance to epoxy and wood for developing functional thermosetting coating.

Investigation on the physio-mechanical properties of carpet waste polymer composites incorporated with multi-wall carbon nanotube (MWCNT)

In the structural functions of polymer components, the material's thermal stability and moisture absorption efficiency play a vital role in defining durability and physio-mechanical performance. This article emphasizes the experimental investigation of polymer (Epoxy) composites fabricated from carpet waste and Carbon nanomaterial (CBN). The supplement of Multi-wall carbon nanotube (MWCNT) into the epoxy/carpet waste polymer composites is proposed to enhance the physio-mechanical properties. The experimentation was performed to check the synergistic effect of nanomaterials in five configurations with different wt.% of MWCNT in the proposed composites. The water absorption, swelling rate, fire retardant and compression performance of the discarded carpet polymer composite modified with MWCNT have been investigated. The effect of water dipping and dry condition was completed to evaluate the composite feasibility. In addition, the fire-retardant properties of developed materials were analyzed using the fire (horizontal) setup process. The results found that incorporating the MWCNT nanoparticles into discarded carpet polymer composites can improve the compression strength. It was noticed that the few quantities of water were absorbed with less swelling effect at the 0.25 wt.% of MWCNT. The modified epoxy nanocomposites have higher specific properties values when compared to neat (discarded carpet polymer) composites. The fire retardancy properties have been enhanced remarkably with a supplement of lower nanomaterials wt.%. The findings show that the proposed carpet waste/MWCNT/polymer composites could be recommended for lightweight functions such as roadside barriers, wall tiles, toys, decorative frames, insulating materials, etc.

Highly flexible and compressible polyimide/silica aerogels with integrated double network for thermal insulation and fire-retardancy

• Polyimide/silica (PSi) aerogel with integrated double network and anisotropic structure was fabricated. • The PSi aerogel could withstand 500 cyclic compression test in the radial direction with a high silica content of 60 wt%. • The PSi aerogel exhibited ultra-low thermal conductivity of 21.2 mW m −1 K −1 in the radial direction. • The PSi aerogel exhibited structure integrity when subjected to a flame of a propane/butane blowlamp (∼1200 °C). The materials with thermal insulating and fire-retardant properties are highly demanded for architectures to improve the energy efficiency. The applications of conventional inorganic insulating materials such as silica aerogels are restricted by their mechanical fragility and organic insulating materials are either easily ignitable or exhibit unsatisfactory thermal insulation performance. Here, we report an organic/inorganic composite aerogel with integrated double network structure, in which silica constituent homogeneously distribute in the anisotropic polyimide nanofiber aerogel matrix and strong interfacial effect is formed between two components. The integrated binary network endows the polyimide/silica composite aerogels with outstanding compressibility and flexibility even with a high inorganic content of 60%, which can withstand 500 cyclic fatigue tests at a compressive strain of 50% in the radial direction. The resulting composite aerogel exhibits a combination of outstanding insulating performance with a low thermal conductivity (21.2 mW m −1 K −1 ) and excellent resistance to a 1200 °C flame without disintegration. The high-performance polyimide/silica aerogels can decrease the risk brought by the collapse of reinforced concrete structures in a fire, demonstrating great potential as efficient building materials.

A hyperbranched P/N/B-containing oligomer as multifunctional flame retardant for epoxy resins

Flame-retardant epoxy resins (EPs) with superior optical, mechanical and dielectric properties are highly desired in high-tech industries. In this work, a multifunctional hyperbranched additive (BDHDP) was synthesized for EPs. Our results showed that BDHDP catalyzed the curing of epoxy resin because of its tertiary amine and hydroxyl groups. At a low addition level (<3.0 wt%), BDHDP increased the glass-transition temperature and maintained the optical transmittance of epoxy thermoset . Meanwhile, BDHDP improved the mechanical strength and toughness, and reduced the dielectric constant and loss of EP because of the rigid phosphaphenanthrene groups and intra-molecular cavities. Moreover, BDHDP reduced the heat release and smoke generation during the EP combustion. Adding 1.5 wt% of BDHDP led to a UL-94 V-0 rating, and reduced the total smoke production by 16.4%. Hence, this study offers an effective method to create transparent EP thermosets with outstanding mechanical, dielectric and fire-retardant properties via incorporating a P/N/B-containing hyperbranched oligomer .

Thermoplastic Starch/Ternary Deep Eutectic Solvent/Lignin Materials: Study of Physicochemical Properties and Fire Behavior

The goal of the work was to prepare thermoplastic starch (TPS), for the first time plasticized with ternary deep eutectic solvents (DESs) based on urea/resorcinol/choline chloride (URCC) in a 2:1:1 molar ratio and enriched with lignin as an environmentally friendly functional alternative for agricultural plastics. Potato starch was effectively modified with DES via twin-screw extrusion in the presence of lignin up to 10 pph (L10) without significant loss of elasticity (tensile strength 7.4 MPa, elongation at break 65%) and good thermocompressing properties (dynamic mechanical thermal analysis (DMTA) results) of highly amorphous materials (X-ray diffractometry (XRD) results) physically modified with DES (Fourier transform infrared (FTIR) results). The URCC mixture acted both as the plasticizer and as dissolving media for lignin, facilitating mutual processing. Moreover, cone calorimetry analysis of TPS materials revealed that they exhibited better fire-retardant properties than polymers commercially used as agricultural plastics (PE, PP, and PLA). Obtained results indicate that TPS/DES and TPS/DES+L materials can be used as, e.g., biodegradable, safe, and functional mulches that do not have to be removed from the cultivating fields.

Lignin use in nonwovens: A review

While lignin has been gaining wide research interest for a variety of applications across many industries, relatively little work has been published on its applications in nonwovens. Consequently, this article offers an overview of the underlying principles and both the present and future applications of lignin within the nonwoven industry. Due to the distinct structure of lignin, processing, fiber production, composites with polymers, dye dispersant, and fire-retardant applications are all unique opportunities for lignin application in nonwovens discussed in this review. Conventional nonwoven processing techniques, such as electrospinning, have been reported to successfully produce lignin-based nonwovens, specifically lignin/polymer composite nonwovens. This account points to pivotal polymer matrix/lignin composite compatibility issues that define various processing technologies. However, lignin use is not limited to incorporation within nonwoven fibers mats and is currently used in dye dispersion with the potential of phase out petroleum-based dye dispersants. Finally, the high phenolic content of lignin endows it with fire-retardant and antimicrobial properties, among others, that present additional opportunities for lignin in the nonwoven industry. Throughout this review, an effort is made to outline the advantages and challenges of using lignin as a green and sustainable ingredient for the production of nonwoven materials.

NiFe prussian blue analogue nanocages decorated magnesium hydroxide rod for enhancing fire safety and mechanical properties of epoxy resin

Inspired by the structure of corn, a NiFe Prussian blue analogue nanocages decorated magnesium hydroxide composite was synthesized for the first time using magnesium hydroxide rods (RMH) as the “corn cob”, a Prussian blue analogue (PBA) as the “corn kernels” and polydopamine (PDA) as the membrane linking RMH and PBA. Subsequently, the RMH@PDA@PBA composite was introduced into epoxy resin (EP) to improve its fire retardancy and mechanical properties. The composition, structure and morphology of the RMH@PDA@PBA-incorporated EP composite were investigated. The tensile strength of EP with 3 wt.% RMH@PDA@PBA reached 41.77 MPa, which is higher than that of neat EP (40.51 MPa). The fire-retardant assessments illustrated that the limiting oxygen index and vertical burning tests (UL-94) of EP composite with 3 wt.% RMH@PDA@PBA progressed to 32.3% and the V-0 level as compared to those of virgin EP (24.4% and no rating). In addition, as compared to virgin EP, the peak heat release rate , peak smoke production rate, total heat release at 200 s and total smoke production at 200 s of EP/3RMH@PDA@PBA decreased by 43.1%, 50.0%, 43.9% and 56.3%, respectively. The investigation of the underlying mechanism revealed that the flame retardancy and smoke suppression of EP/3RMH@PDA@PBA were attributed to the endothermic decomposition of RMH, “gauze barrier” mechanism of MgO/FeO, catalytic charring effect of Fe derivatives (MgO/FeO, FeNi 3 , Fe 5 C 2 , Fe 2 N, etc.) and free radical scavenging effect of PBA@Fe[Ⅲ]. Thus, this study on bio-inspired hierarchical nanostructures paves a new pathway for the efficient production of fire-safe polymers. • A novel low-cost RMH@PDA@PBA with corn structure was first prepared. • The RMH@PDA@PBA significantly improves the fire safety of epoxy resin. • 3 wt.% RMH@PDA@PBA endowed epoxy resin with UL-94 V-0 and reduced smoke production. • The addition of RMH@PDA@PBA enhanced the mechanical properties of epoxy resin.

Fire retardancy, thermal, and physico-mechanical properties of semi-rigid water-blown polyurethane foam from palm oil-based polyol

This paper presents the experimental work undertaken to assess rigid palm oil-based polyurethane (PU) foam. The bio-composite foam was characterized to determine its foaming kinetics and morphology, as well as fire retardancy, thermal, and mechanical responses, which was later compared with its petrochemical-based counterpart. The palm oil-based foam displayed poor fire-retardancy performance based on Limiting Oxygen Index (LOI) and UL-94 Vertical Combustion Test. Although less char residue was produced, the palm oil-based PU foam exhibited higher onset degradation temperatures, indicating improved thermal stability. The Scanning Electron Microscopy (SEM) revealed finer cell sizes for the bio-based foam and a higher fraction of open cell structures, which affected its density and compressive properties. As a conclusion, the palm oil-based PU foam is a viable alternative to be utilized in low load-bearing and thermal environment applications.

A biobased flame retardant towards improvement of flame retardancy and mechanical property of ethylene vinyl acetate

A new biobased flame retardant (MHPA) with remarkable compatibility was synthesized via a facile and low-cost neutralization reaction of magnesium hydroxide (MH) and phytic acid (PA). By blending the prepared MHPA into ethylene vinyl acetate (EVA), the fire retardancy, smoke suppression and mechanical properties of the composites were significantly improved. When 50 wt% of MH was added into EVA matrix, the value of limiting oxygen index (LOI) reached 26.1%. Whereas, when 10 wt% MH in the EVA composites (with initial 50 wt% MH) was replaced by MHPA, the resulted EVA composites had a LOI value of 30.8%, indicating high efficiency of addition of MHPA to improve flame retardancy. Moreover, the heat release rate (HRR) and total smoke production (TSP) of the EVA composites reduced by 54.4% and 27.6%, respectively, suggesting that incorporation of MHPA could effectively hinder rapid degradation of EVA composites during burning process. The fire-retardant mechanism may reside in that the MHPA combined with MH can present the excellent carbonization and expansion effects. This study illustrates that the biobased MHPA has a broad application prospect to develop flame-retardant EVA composites.

Tailoring nano-fibrillated polystyrene composite with enhanced fire retarding properties for foam applications

This work proposes a novel technique to address the detrimental effect of high loading of halogen-free flame retardants (FRs) on foaming of polymer composites. This is the first time nano-fibrillation is applied to tailor FR composites for foam applications with desired microcellular structure. As highlight of this work, the presence of polytetrafluoroethylene (PTFE) nanofibrils serves multiple roles by compensating for reduced foaming behavior of highly-filled matrix, and contributing to enhancing FR efficiency and stiffness. Inclusion of 1 wt% nanofibrils in polystyrene (PS) filled with 30 wt% expandable graphite (EG), tunned melt rheological properties leading to improving cell density up to two orders of magnitude. The average cell size of the foam also decreased from 103 μm to 10 μm, with respect to PS/EG, improving compressive strength and modulus. The entangled PTFE nanofibrils transformed the fluffy char layer into a dense one, preventing matrix disintegration and dripping to meet UL94-V0. This was confirmed by reduced fire growth rate (FIGRA), peak heat release rate (PHRR) and peak smoke production rate (PSPR) in cone calorimetry. The unique characteristics of this composite make it promising for fabricating FR polymeric foams for various applications including automotive, aerospace, electronics and construction, necessitating high fire safety level.

Development of fire retarding composite board for fire compartmentation application using waste denim: A review

This paper represents a comprehensive review work to understand the utter need to recycle denim waste and its use as a structural member with good mechanical and fire retardant properties for compartmentation under Passive Fire Protection systems. At present the amount of denim waste recycled is very small as compared to what is landfilled and studying the rate of denim waste generation and its associated problems there is certainly a scope for new effective denim waste recycling methods. This paper includes an intensive review on the best present fire retardant and mechanical properties improving methodologies for denim fabrics. Despite the fact that denim fabric is virtually entirely made of cotton (99%), the spinning process increases the LOI value from 18.5 percent (cotton) to 20.1 percent (denim). Various compositions, formulations, and application tactics of various fire retardants, such as boron-based, phosphorus-based fire retardants, and so on, were investigated to improve the composite's fire retardancy upto 89 percent. To considerably improve the physical and mechanical characteristics of the composite, different composite manufacturing processes such as film stacking, compression molding, resin transfer molding, vacuum infusion, hand lay-up, and hot pressing method were investigated. According to the findings, denim based composite boards have huge potential for fire compartmentation application. This paper provides the direction towards development of such boards which will not just help in denim waste management but also provide important component of passive fire protection for much needed building fire safety.

Biomass-derived cellulose nanofibers and iron oxide-based nanohybrids for thermal insulation application.

In recent years, due to high energy consumption in the building sector and subsequent environmental issues, environment-friendly and cost-effective thermally insulating materials are in high demand to improve the energy efficiency of buildings. Current commercially available thermal insulating materials (polystyrene) always pose a challenge due to their non-biodegradability and poor insulating performance. To this end, biomass-derived aerogels are attracting significant interest as renewable and sustainable insulating materials. In this work, we have developed a facile strategy for synthesizing cellulose nanofibers from biomass-derived wood pulp as a cost-effective starting material by TEMPO-oxidation, and further incorporating iron oxide nanoparticles to make a nanohybrid. Interestingly, in these nanohybrids, the functional attributes like mechanical strength and flammability were improved to a great extent and thus overcoming the limitations of the commercially available thermal insulating materials in terms of their stability and durability. Most importantly, these nanohybrids demonstrated very low thermal conductivity, as low as 0.024 W m−1 K−1, indicating the better insulating potential of these nanohybrids as compared to other conventional insulating materials.

3D Printing of Nacre-Inspired Structures with Exceptional Mechanical and Flame-Retardant Properties.

Flame-retardant and thermal management structures have attracted great attention due to the requirement of high-temperature exposure in industrial, aerospace, and thermal power fields, but the development of protective fire-retardant structures with complex shapes to fit arbitrary surfaces is still challenging. Herein, we reported a rotation-blade casting-assisted 3D printing process to fabricate nacre-inspired structures with exceptional mechanical and flame-retardant properties, and the related fundamental mechanisms are studied. 3-(Trimethoxysilyl)propyl methacrylate (TMSPMA) modified boron nitride nanoplatelets (BNs) were aligned by rotation-blade casting during the 3D printing process to build the “brick and mortar” architecture. The 3D printed structures are more lightweight, while having higher fracture toughness than the natural nacre, which is attributed to the crack deflection, aligned BN (a-BNs) bridging, and pull-outs reinforced structures by the covalent bonding between TMSPMA grafted a-BNs and polymer matrix. Thermal conductivity is enhanced by 25.5 times compared with pure polymer and 5.8 times of anisotropy due to the interconnection of a-BNs. 3D printed heat-exchange structures with vertically aligned BNs in complex shapes were demonstrated for efficient thermal control of high-power light-emitting diodes. 3D printed helmet and armor with a-BNs show exceptional mechanical and fire-retardant properties, demonstrating integrated mechanical and thermal protection.

Flame retardant characteristics of polymerized dopamine hydrochloride coated jute fabric and jute fabric composites

In this paper, fire resistance of natural fabrics and their composites were experimentally investigated. Special interest was given to use bio based materials such as lignin, chlorophosphates, levulinic acid and cardanol in order to exploit their capability to be utilized as flame retardants. Dopamine hydrochloride was polymerized to polydopamine (PDA) and coated to jute fabric surface. Scanning electron microscope (SEM) and thermogravimetric analysis (TGA)/derivative thermogravimetric (DTG) analyses were performed to examine surface morphology and effect of PDA to degradation behaviour of jute fabrics. Real fire behaviour of non-coated and coated fabrics was observed with torch burn test. UL-94 horizontal flame propagation test was also utilized for composite samples. Limiting oxygen index (LOI) testing that measures the minimum amount of oxygen required for combustion, was carried out for assessing the ability of the composite samples for their ability against flammability. PDA was seamlessly coated on the surface of the jute fabrics with its surface-active feature without damaging the structure of the fabric as observed in the SEM images. With the support of this coating on the fabric surface, the increase of the decomposition temperature of the material can be clearly seen in TGA/DTG analyses and torch burn test showed the increase in the ignition time. UL-94 horizontal testing resulted in decrease in flame propagation rate of PDA coated composite samples. In addition to this, when the mass loss rates after combustion were examined, it was seen that there is a decrease in mass loss in the coated fabrics. Jute fabrics, a type of natural fabric, can be efficiently coated with PDA, and the fire retardant property of the PDA coating on natural fabrics has been clearly demonstrated.

Mechanical and fire retardant behaviour of Flax/Sisal fiber hybrid composites

Bio-fiber embedded polymers play major role in the fabrication of environmental friendly materials due to their bio-degradable in nature, meticulous strength, low density, high modulus and reduced carbon footprint on the nature. Among many fibers sisal fiber and flax fiber are gaining attention as they possess satisfactory mechanical strength, eco-friendly, abundantly available and cheaper compare to bamboo, kenaf, banana fibers etc,. Sisal and flax fiber will a play an important character to manufacture a various range of automobile products with epoxy resin. Present paper deals the tensile, flexural, compression, moisture absorption behaviour and fire retardant properties of dissimilar weight percentage of NaOH treated sisal/flax fiber incorporated composites. Composites were fabricated by compression molding technique. A 40 wt% of composites shows higher tensile, flexural and compression strength compared to other composites. Burning rate of composite samples is increased with the adding of fiber wt.%. Fractured surface of composite specimens are analysed by Scanning Electron Microscopy.

INFLUENCE OF PHASE CHANGE MATERIALS (PCMs) ON POLYURETHANE (PU) FOAM FIRE-RETARDATION

Polyurethane (PU) foam is a material that has long been regarded as a good thermal insulator for building purposes due to many advantageous attributes, such as cost and feasibility. Yet, to further develop its performance, many studies have focused on the potential of using the micro-structure of PU foam as an encapsulation for PCMs. Despite the apparent advantageous outcome of this premise, from the perspective of thermal performance, fire-retardation issues may pose as a threat. PU foam is known for its inherent poor fire-retardation properties. With the addition of PCMs, especially wax-based, it is possible that the fire-retardation would worsen. This would translate into additional costs in terms of application of treatments to counter the disadvantageous hazardous properties. In this study, an empirical investigation is carried out with the aim of determining whether addition PCMs to PU foam would influence its retardation, and to which extent. In this context, granules of wax-based PCMs are encapsulated in to closed-cell rigid PU foam via a simplified amalgamation method. Two concentrations of PCM content are presented in this paper. Then, fire-retardation testing is performed on specimens to compare the performance of the created PU/PCM specimens with this of regular PU specimens. The outcome of this empirical investigation further confirms that addition of PCM to PU foam is disadvantageous in terms of fire-retardation, and that the amount of added PCM is of considerable influence on this.