Effect of phytic acid-modified layered double hydroxide on flammability and mechanical properties of intumescent flame retardant polypropylene system (original) (raw)
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Fire Safety Journal, 2019
Improving the efficiency of traditional flame retardant additives is a challenging task in the field of wood polymer composites (WPCs). In this work, novel flame retardant system for WPCs was developed based on the combination of ammonium polyphosphate (APP) with phytic acid modified layered double hydroxide (Ph-LDH). Thermogravimetric analysis illustrated that the incorporation of Ph-LDH resulted in earlier thermal degradation of the WPCs with more thermally stable products during degradation, giving improved char formation. Limiting oxygen index (LOI), vertical burning (UL-94) and cone calorimetry tests were used to study the flammability of WPCs and the results showed that the addition of Ph-LDH had a synergistic effect on their fire performance. The char residues of the WPCs after the cone calorimetry tests were characterised by scanning electron microscopy (SEM). Mechanical properties of the flame retardant WPCs were analysed using impact and tensile tests. Partial substitution of APP with polypropylene (PP) resulted in a deterioration in the tensile and impact properties, while coincorporation of nano-fillers led to an enhancement of the mechanical performances of the flame retardant WPCs. This WPC with good flame retardant and mechanical properties could potentially be used in the fields of building or furniture which require high flame retardancy.
Effect of Fillers on the Fire Retardant Properties of Intumescent Polypropylene Compounds
Polymers and Polymer Composites, 2008
The effects of fillers, including ammonium polyphosphate (APP), aluminium trihydrate (ATH) and talc, and the effect of polyethylene vinyl acetate (EVA) as an interfacial agent, were investigated on the flame retardant properties of intumescent polypropylene (PP), by using mechanical testing, to measure the tensile and Izod impact strengths, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and the limiting oxygen index (LOI) test method. SEM studies showed that the dispersion of flame retardant particles in the PP matrix improved with the use of EVA. Tensile strength decreased but elongation at break and impact resistance of PP/APP/EVA and PP/ATH/EVA composites increased by using 10 wt.% of EVA. Using 12 wt.% of talc in PP/APP/PA-6/EVA led to increasing impact resistance and decreasing tensile strength and elongation at break of the composite. EVA prevented the exudation of additives to the composite surface, and consequently the fire retardant properties of the c...
Polymer Degradation and Stability, 2013
This paper describes the effectiveness of novel phosphorousenitrogen intumescent flame retardant system (ammonium polyphosphate 202 and PPM Triazine HF e trademark, abbrev. IS) on fire retardancy and thermal stability properties of polypropylene (abbrev. PP) at incorporation level below the standard amount required for intumescent flame retardant system. UL-94 vertical burning test revealed that the addition of 20 wt.% of IS into neat PP is enough to reach V-0 rating (short burn without dripping). Further, a higher increase of the oxygen concentration for ignition was also found with the addition of the novel intumescent flame retardant to neat PP; LOI value of neat PP by addition of 20 wt.% IS rose from 19 to 31 vol.%.
Polymer Composites, 2015
Two phosphorous containing reactive flame retardants namely Triallyl phosphate (TAP) and diethylene glycol modified tetra-allyl phosphate (DTAP) are synthesized and incorporated successfully in commercial Unsaturated polyester (UPR) in various amounts (5, 10, and 15 phr) to yield flame retardant unsaturated polyester (FRUPR) composites. The structures of reactive flame retardant monomers are confirmed by FTIR, 1 H-NMR, and 31 P-NMR spectroscopy. Further, FRUPR composites are characterized for their mechanical, thermal, and flame retardant properties. It is observed that tensile strength and hardness of composites are enhanced with the addition of flame retardants; however, flexural strength and impact resistance are lowered. Differential Scanning Calorimetry (DSC) study reveals that there is a significant increase in glass transition temperature with the addition of flame retardants suggesting the formation of dense and cross-linked structure in FRUPR composites. Thermal stability and the flame retardant properties are also observed to be improved with the increase in concentration of flame retardant in UPR as evidenced from Thermo-gravimetric analysis (TGA). Beyond 10 phr concentration of flame retardants, all composites show V-0 rating on UL-94 test. Also, increase in phosphorous content in composites leads to gradual improvement in limiting oxygen index values.
Fire and Materials, 2019
In this work, an efficient approach to improving the fire retardancy and smoke suppression for intumescent flame-retardant polypropylene (PP) composites is developed via incorporating functionalized sepiolite (organo-modified sepiolite [ONSep]). The PP composites with different amounts of intumescent flame retardants and ONSep were prepared by melt compounding. The morphology, thermal behavior, fire retardancy, smoke suppression, and mechanical property of flame-retardant PP composites were studied. The results indicate an appropriate amount of ONSep in the flame-retardant PP composites can increase thermal degradation temperature and char formation as well as a reduction of the peak heat release rate and total heat release; moreover, the addition of ONSep significantly decreases the CO production, total smoke production, smoke production rate, and smoke temperature. Simultaneously, the impact strength of intumescent flame-retardant PP composite is also maintained by introducing an appropriate amount of ONSep as compared with that without ONSep. KEYWORDS flame/fire retardancy, mechanical properties, nanoparticles, polymer-matrix composites 1 | INTRODUCTION Polypropylene (PP) is widely used in a variety of applications, including transportation, construction, electronic appliances, and general household materials for its excellent physical and mechanical properties, low density, ease of processing, good chemical resistance, etc. 1,2 Nevertheless, the flammability characteristics of PP is one of the main drawbacks limiting its wide application. 3,4 In order to expand its application, significant work has been performed to improve fire safety of PP. Halogen-containing flame retardants have been widely applied to PP because of their high efficiency as radical scavengers during combustion, even in low loading levels. However, this kind of additive releases significant amounts of toxic gases and corrosive smoke during combustion. 5,6 Thus, advanced halogen-free and low-smoke flame retardant systems are one of the most popular topics in current polymer materials research and development, such as metal hydroxides and intumescent flame retardants (IFRs). Metal hydroxides like aluminum trihydroxide (ATH) or magnesium dihydroxide (MDH) can decompose during heating, releasing water and forming a char layer that reduces the temperature and decomposition rate of the polymer substrate. 7,8 However, very high concentrations greater than 50 wt% of these additives must be used to achieve good flame retardancy, and the physical and mechanical properties of PP are negatively impacted. Recently, IFR is considered to be one of the most promising flame retardants to replace halogen-containing flame retardants because of its environmentally friendly, high-efficiency, anti-dripping, and low
Polymer Degradation and Stability, 2009
The preparation of new layered double hydroxides/unsaturated polyester (LDH/UP) nanocomposites was performed and the effect of LDH on the resin properties was studied. Two different organo-LDHs have been prepared, adipate-LDH (A-LDH) and 2-methyl-2-propene-1-sulfonate-LDH (S-LDH); in order to evaluate the influence of these nanofillers, samples with two different concentrations were dispersed in the matrix. The physical, thermal, mechanical and fire reaction properties of nanocomposites were studied. Intercalated layered structures were observed for the different organo-LDH loadings (1 and 5 wt%). Mechanical properties studied under flexural tests show that incorporation of organo-LDH in the resin reduces the flexural strength of polyester resin while the flexural modulus is unchanged for the S-LDH/UP composites and increased with 1 wt% of A-LDH. Adding 1 wt% of A-LDH to the resin produces an important reduction on the flexural strength, but an increase of the flexural modulus. The study of fire reaction properties, using cone calorimeter, suggested a significant reduction in the UP flammability, by 46 and 32%, by incorporating 1 wt% of A-LDH and 5 wt% S-LDH, respectively. Mass loss curves show enhanced char formation with the different loads tested while the amount of evolved smoke remains quite unchanged.
A study on various fire retardant additives used for fire reinforced polymeric composites
AIP Conference Proceedings , 2022
The growing environmental awareness and natural resources scarcity various fully biodegradable polymer systems development and utilization initiates poly lactic acid (PLA) and copolymers biodegradable polymer, extensive attention as they biodegradability, numerous renewable sources, and excellent mechanical and thermal properties like advantages other polyester resins like PLA inherent chemical composition and molecular structures due to very poor fire resistance the aviation and electrical industry PLAs widespread use low thermal resistance, combustion and drip hampered flame retardant modification essential Combustion-type flame retardants polymer by physical means incorporated materials production convenient industry widely in used. Flame retardants certain chemical compounds polymers paralytic reactions slow or inhibit or combustion oxidative reactions They mainly halogen, phosphorus and metal hydroxides containing compounds Halogen flame retardant drawbacks metal components highlight ability combustion during hydrogen formed toxicity and some governments or organizations halogen controlled flame retardants use restrict proposed halogen-free flame-retardant additives indomethacin flame retardant (IFR) considerable attention and polypropylene (PP) and polyethylene (PE) such as polymers used their low smoke, no toxicity, and halogen absence benefits. and corrosive gas production In general an IFR system three basic components char-forming agent carbonization catalyst, and a blowing agent combustion during IFR multi-cellular structure combustible layer a physical that acts barrier gas and compressed between heat and mass transfer reducing reducing the burning melt in thermoplastic flame-retardant conversion is a particular problem. Drops melting burning surface area increase fire intensity increase faster fire spread viscosity Melting coal formation strong impact PLA, polyethylene terephthalate (PET), and poly butylenes succinct (PBS) like Linear polymers branched or thermo set polymers compared low melt viscosity burning test during serious melt dripping layered silicates thermal stability improve reduce filler concentration flammability low investigations found.
International Journal of Polymer Science, 2015
The effect of particle size reduction of the components of a common intumescent flame retardant system, consisting of pentaerythritol (PER) and ammonium polyphosphate (APP) in a weight ratio of 1 to 2, was investigated on the flammability and mechanical performance of flame retarded polypropylene (PP) compounds. Additives of reduced particle size were obtained by ball milling. In the case of PER, the significant reduction of particle size resulted in inferior flame retardant and mechanical performance, while the systems containing milled APP noticeably outperformed the reference intumescent system containing asreceived additives. The beneficial effect of the particle size reduction of APP is explained by the better distribution of the particles in the polymer matrix and by the modified degradation mechanism which results in the formation of an effectively protecting carbonaceous foam accompanied with improved mechanical resistance. Nevertheless, 10% higher tensile strength was measured for the flame retarded PP compound when as-received APP was substituted by milled APP.
Polymers, 2020
A raw montmorillonite (Mt) was submitted to different acidic activation times in order to investigate the influence of the strength and the nature (Brønsted and Lewis) of acidic sites on the synergistic action with an intumescent formulation (IF) composed of ammonium polyphosphate (APP) and pentaerythritol (PER) when incorporated into a polypropylene (PP) matrix. The acidity of the Mt samples was quantified by ammonia temperature-programmed desorption (TPD-NH3) and Fourier transform infrared spectroscopy (FTIR) with pyridine adsorption. The mineral clays were also characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), nitrogen adsorption analysis and particle size distribution. Thermogravimetric analysis (TGA), limit oxygen index (LOI) and UL-94 were performed to evaluate the flame-retardant properties and the thermal stability. The TGA results show that the final residue increased 2 to 3 fold in comparison to the values predicted theoretically. The flammability properties achieved a maximum for the system containing an excess of moderate-strength Brønsted sites relative to the Lewis ones, reaching 38% in the LOI test. This result suggests that the presence of these Brønsted acidic sites is important, as they take part in the esterification reaction between APP and PER which gives rise to the char formation. The FTIR-Pyr adsorption and flammability results indicate that both the nature and strength of the acidic sites influence the flame-retardant properties.
Polymer Degradation and Stability, 2006
An intumescent system consisting of ammonium polyphosphate (APP) as an acid source and blowing agent, pentaerythritol (PER) as a carbonific agent and natural zeolite (clinoptilolite, Go¨rdes II) as a synergistic agent was used in this study to enhance flame retardancy of polypropylene (FR-PP). Zeolite was incorporated into flame retardant formulation at four different concentrations (1, 2, 5, and 10 wt%) to investigate synergism with the flame retardant materials. Filler content was fixed at 30 wt% of total amounts of flame retardant PP composites. Zeolite and APP were treated with two different coupling agents namely, 3-(trimethoxysilyl)-1-propanethiol and (3-aminopropyl)-triethoxysilane for investigation of the influence of surface treatments on mechanical properties and flame retardant performance of composites. Maleic anhydride grafted polypropylene (MAPP) was used for making polypropylene hydrophilic. Flammability of FR-PP composites was measured by the determination of limiting oxygen index (LOI). The LOI values reached to a maximum value of 41% for mercapto silane treated APP:PER (2:1) PP composite containing 5 wt% zeolite. The tensile strength of composites was increased by the addition of MAPP and elongation at break of composites was increased with silane treatments.