Average Rate Of Heat Emission Research Articles

Cascade computational model for prediction impact of transient depth change on combustion parameters of certain timber species under continuous heating rate

The purpose of this research is to examine the effects of depth variation and exposure duration on the combustion characterization of the Maple wood species (Acer platanoides L.) and Walnut (Juglans regia L.) according to ISO 5660–1 in case of exposing the specimens to a constant heating rate 50 kWm−2. The delivered experimental data by cone calorimeter apparatus is used to train, test, and validate the optimized cascade forward artificial neural network with topology 2–8–8–12–2. This structure is simulated to predict the target parameters: the heat release rate (HRR) and the mass burning rate (MBR). With real systems, it is possible to achieve a reasonable performance and the closest approximations for the cascade model. The experimental combustion parameters: time of flame out, average specific mass burning rate, total heat release, maximum average rate of heat emission, and fire growth index are considered to make a systematic analysis and assessment with change depth. Three regions are considered for investigation of output target curves, thermally thin (d ≤ 1.1 cm), thermally medium (1.1 cm < d< 1.5 cm), thermally thick (d≥ 1.5cm). The findings demonstrate that independent of exposure period, an increase in depth change causes a sizable reduction in the HRR and MBR. Beyond 1.5 cm of depth in thermally thick regions, there is no discernible effect of time instant on changes in target parameters. In contrast, HRR and MBR gradients across depth in thermally thin regions are striking.

The effect of repeated washings on thermal protective performances of one most used structural firefighting turnout gear in the Gauteng Province in South Africa

Fire performance measurements of one of the most used firefighting protective ensembles (also called turnout gears), in terms of thermal and smoke hazards, were determined with the cone calorimeter, that of thermal stability were determined with thermogravimetric analyzer, the physical inspection (physical degradation) of the surface done with the scanning electron microscopy, and energy dispersive spectroscopy measurements determined the elemental compositions of the detergent used in washing and the residual elements in the turnout gears. The cone calorimeter results indicated that the values of the thermal performance parameters, namely: peak heat release rate, maximum average rate of heat emission, and fire growth rate index, all decrease with increasing number of washing cycles, while the smoke parameters: peak smoke production rate, smoke growth rate index, total smoke release, and related sustained flaming values, all increase with increasing number of washing cycles. From the thermogravimetric analyzer measurements, the thermal stability of the turnout gears decrease with increasing number of washings.

Enhancing flame and electrical surface discharge resistance in silicone rubber composite insulation through aluminium hydroxide, clay, and glass fibre additives

Silicone rubber (SR) is a leading polymer used in electrical outdoor insulation applications due to its superior hydrophobic characteristics. However, the low flame and electrical surface discharge resistance of SR limit its broad viability and challenge its integrity in severe outdoor working conditions. This work attempts to explore the flame retardancy and surface discharge characteristics of SR co-filled with aluminium hydroxide (ATH), nanoclay montmorillonite (MMT), and chopped glass fibre (GF). Results indicate that the incorporation of ATH/MMT/GF could assist in improving the fire and surface discharge resistance of the SR material. It is noted that the maximum average rate of heat emission (MARHE) and total smoke production (TSP) are measured at 24.93 kW/m2 and 0.48 m2 in SRE, relative to 61.29 kW/m2 and 6.02 m2 in SRB. Using finite element analysis (FEA), the maximum electric field strength is computed at 4.66 × 106 V/m in the air gap coupled with a high-voltage (HV) plate and sample. SRE exhibits a higher partial discharge inception voltage (PDIV) value of 2.32 kVrms than its counterparts, while the maximum discharge magnitude (Qmax) is computed at 7095 pC, relative to 7746 pC in SRB. SRE emerges as a preferable SR composite to be used in electrical insulation applications with excellent flame and surface discharge resistance characteristics.

Burning Properties of Combined Glued Laminated Timber

This study delved into the combustion properties of combined glulam bonded using polyurethane (PUR) and resorcinol-phenol-formaldehyde (RPF) adhesives. The experiment involved three distinct wood species, namely, spruce, alder, and beech, which were combined in homogeneous, non-homogeneous symmetrical, and non-homogeneous asymmetrical arrangements. These species were selected to represent a spectrum, namely, softwood (spruce), low-density hardwood (alder), and high-density hardwood (beech). The varying combinations of wood species illustrate potential compositions within structural elements, aiming to optimize mechanical bending resistance. Various parameters were measured during combustion, namely, the heat release rate (HRR), peak heat release rate (pHRR), mass loss rate (MLR), average rate of heat emission (ARHE), peak average rate of heat emission (MARHE), time to ignition (TTI), and effective heat of combustion (EHC). The findings indicate that incorporating beech wood into the composite glulam resulted in an increase in heat release, significantly altering the burning characteristics, which was particularly evident at the second peak. Conversely, the use of spruce wood exhibited the lowest heat release rate. Alder wood, when subjected to heat flux at the glued joint, displayed the highest heat emission, aligning with the results for EHC and MARHE. This observation suggests that wood species prone to early thermal decomposition emit more heat within a shorter duration. The time to ignition (TTI) was consistent, occurring between the first and second minute across all tested wood species and combinations. Notably, when subjected to heat flux, the glulam samples bonded with PUR adhesive experienced complete delamination of the initial two glued joints, whereas those bonded with RPF adhesive exhibited only partial delamination.

Benign design of intumescent fire protection coatings for steel structures containing biomass humic acid as carbon source

The application of biomass materials in engineering has received a great deal of attention. In this work, a new eco-friendly biomass-based intumescent coating, composed of natural and sustainable biomass humic acid (HA), ammonium polyphosphate (APP), melamine (MEL), and zinc borate (ZB), was developed to endow steel structures with excellent fire resistance and fire retardancy. When exposed to a butane torch, the intumescent coating (1.5 mm thickness) reduced the maximum temperature observed on the backside of a 3 mm thick steel plate by over 350 °C. Moreover, the cone calorimeter results showed that thanks to the formation of an extremely intumescent and dense char layer, the peak heat release rate (pHRR) and total heat release (THR) of intumescent coatings (S5) were reduced by 86 % and 61 %, respectively, as compared to that of the control epoxy coating, meanwhile, significant reductions in fire growth rate (FIGRA, −89 %) and maximum average rate of heat emission (MARHE, −86 %) were also observed, suggesting that 2 wt% ZB loading is required to achieve optimal level of fire resistance and fire retardancy. Furthermore, the mechanism of action was elucidated by SEM-EDX, FTIR, Raman, and XRD analyses. Results revealed that the combination of APP, MEL, HA, and ZB promoted the formation of a continuous and cohesive graphitized intumescent char layer on the surface of the steel plate, reinforced by borophosphate and zinc-containing species, which effectively prevents the transfer of heat and fuel, thereby enhancing the fire resistance and fire retardancy of the intumescent coating. This eco-friendly intumescent coating provides a strategy for developing new green fire protection systems using widely available, low-cost biomass materials without using hazardous ingredients.

Bismaleimide resin co‐modified by allyl ether of resveratrol and allyl ether of eugenol‐grafted polysiloxane with enhanced toughness, heat resistance, and flame retardancy

AbstractModifying bismaleimide (BMI) resin to improve its toughness and flame retardancy without sacrificing the glass transition temperature (Tg) and thermal decomposition stability is still a challenge. In this study, we employed the allyl ether of resveratrol (AER) and eugenol allyl ether grafted polysiloxane (PMES‐Allyl) to co‐modify BMI resin. For the BMI/AER/PMES‐Allyl (BAPA) resin, the content of PMES‐Allyl was 15 wt%, and the molar ratio of maleimide and allyl groups was controlled as 1:0.8. Compared to commercial 2,2′‐diallyl bisphenol A modified BMI (BD) resin, the BAPA resin exhibited superior thermal properties after curing, due to the role of AER in improving the crosslinking density and chain rigidity of the network. The cured BAPA resin had a Tg more than 380°C, and its initial thermal decomposition temperature (Td5%) and char yield (Y800°C) reached 424.8°C and 46.4%, respectively. Meanwhile, PMES‐Allyl as a rubber phase could effectively improve the toughness of the cured resin. The impact strength of the cured BAPA resin was 15.2 kJ/m2. Moreover, the two modifiers both helped to improve the flame retardancy of the material. Compared with the cured BD resin, the cured BAPA resin showed a decrease of peak heat release rate (PHRR), total heat release (THR), and maximum average rate of heat emission (MARHE) by 25.5%, 35.5%, and 31.5%, respectively. Its total smoke production (TSP) was only 35.6% of that of the cured BD resin. In addition, the cured BAPA resin also displayed a lowered water absorption and improved thermal aging resistance. Therefore, it is suggested to be a promising and high‐performance thermosetting resin for cutting‐edge applications.

Fire behavior of pressure‐sensitive adhesive tapes and bonded materials

AbstractPressure‐sensitive adhesive tapes are used in several industrial applications such as construction, railway vehicles and the automotive sector, where the burning behavior is of crucial importance. Flame retarded adhesive tapes are developed and provided, however, often without considering the interaction of adhesive tapes and the bonded materials during burning nor the contribution of the tapes to fire protection goal of the bonded components in distinct fire tests. This publication delivers an empirical comprehensive knowledge how adhesive tapes and their flame retardancy effect the burning behavior of bonded materials. With a special focus on the interaction between the single components, one flame retarded tape and one tape without flame retardant are examined in scenarios of emerging and developing fires, along with their bonds with the common materials wood, zinc‐plated steel, mineral wool, polycarbonate, and polymethylmethacrylate. The flame retardant significantly improved the flame retardancy of the tape as a free‐standing object and yielded a V‐2 rating in UL 94 vertical test and raised the Oxygen Index by 5 vol.%. In bonds, or rather laminates, the investigations prove that the choice of carrier and substrates are the factors with the greatest impact on the fire properties and can change the peak of heat release rate and the maximum average rate of heat emission up to 25%. This research yielded a good empirical overall understanding of the fire behavior of adhesive tapes and bonded materials. Thus, it serves as a guide for tape manufacturers and applicants to develop tapes and bonds more substrate specific.

Improving Flame Retardant Properties of Aliphatic Polyketone (POK)-Based Composites.

The effect of zinc borate (ZB) and high-molecular-weight siloxane (SIL) on flame retardancy, mechanical, and thermal properties of aliphatic polyketone (POK)-containing aluminum diethyl phosphinate (OF) was investigated in this study. Ten wt % OF is sufficient to obtain V0 rating according to the UL94 test. As the weight fraction of OF was increased, the flame retardancy properties and LOI values improved, while the tensile and impact properties decreased. To avoid the degradation in mechanical and impact properties as much as possible and obtain the same and better flame retardancy properties, synergists such as SIL and ZB were used. Flame retardancy of POK-based composites was determined by the limiting oxygen index (LOI) test, UL94 measurement, and cone calorimeter test. The additions of 1 wt % SIL and ZB have not led to a considerable decrease in the tensile strength and impact properties of POK-10OF. While ZB and SIL are very efficient in decreasing the smoke density, ZB is more efficient than SIL in increasing the LOI value of the composite. The addition of 1, 2, and 4 wt % ZB and SIL synergists did not lower their UL94 ratings. Moreover, it can be added that ZB is more efficient than SIL in decreasing the fire growth rate (FIGRA) and maximum average rate of heat emission (MARHE) values. Using OF (10 wt %) and ZB (4 wt %), LOI values higher than 32% and smoke density values lower than 150 were obtained.

Solid‐state NMR characterization of multi‐component intumescent flame retardant polybutylene succinate formulations

AbstractIn this work, a series of multi‐component intumescent PBS formulations were elaborated by the combination of intumescent flame retardant (IFR) system (consisting of ethylenediamine phosphate and melamine poly(aluminum phosphate), 7:3, wt:wt) and synergists. Three boron/zinc‐containing compounds (i.e., melamine borate, zinc oxide, zinc carbonate) were examined as potential synergists to improve the fire behavior and fire retardancy of PBS. The MLC results showed that the incorporation of all of these compounds enhanced the fire retardancy of PBS to some extent. Among them, zinc oxide exhibited the best fire retardant performances in terms of reduction of the peak heat release rate (pHRR, −61%), fire growth rate index (FIGRA, −19%), maximum average rate of heat emission (MARHE, −55%), and increase of the time to pHRR (+370 s) and to flameout (+650 s) as compared to PBS/IFR10%. Furthermore, the effect of zinc oxide loading on the fire retardancy of PBS was also investigated, the results showed that 2 wt.% loading exhibited the best performances. Solid‐state NMR characterization indicated that the presence of ZnO resulted in the formation of a crack‐free and dense intumescent char layer reinforced by complex aluminum‐zinc‐phosphates glassy species. The intumescent char layer provided a protective physical barrier with improved flexibility and cohesion, which effectively limits the heat and mass transfer between condensed and gas phases and hence, improving the fire retardancy of PBS.

Making polycarbonate flame retardant: Flame retardant selection and calorimetric analyses

Polycarbonate (PC) has been widely applied in aerospace and railway industries, and it is imperative to improve its fire safety related properties, especially heat release properties. Particularly, the MARHE value (maximum average rate of heat emission) directly obtained from the cone calorimeter (CONE) test is a comprehensive property that is presented in the EN45545-2 standard developed by the EU. In order to study the effect of flame retardants on the MARHE of polycarbonate, four flame retardants with different flame retardant mechanisms were used to prepare low heat release PC. CONE was used to characterize the heat release performance of PC, focusing on exploring the factors affecting MARHE and the method of preparing low heat release materials. The flame-retardant mechanism of PC was studied by SEM and TG/DTG. Meanwhile, the flame retardant index (FRI) is calculated as a reference for the flame retardant performance of PC. Results show the MARHE of HPCTP/PC is reduced by 31.12%, and it is confirmed that MARHE is influenced by time to ignition (TTI), peak heat release rate (PHRR), total heat release rate (THR), and the shape of the peak. Mica-RDP/PC materials were prepared based on the conclusions of MARHE derivation. RDP and Mica play a typical synergistic flame-retardant mechanism, with MARHE reductions from 20.31% to 20.00% of the single-component systems to 31.39%. All FRI values of PC materials are in the range of Good flame retardancy. This study provides a feasible way for the deep understanding and wide application of MARHE and the improvement of the fire safety performance of PC.

Enhanced fire retardancy with excellent electrical breakdown voltage, mechanical and hydrophobicity of silicone rubber/aluminium trihydroxide composites by milled glass fibres and graphene nanoplatelets

The integrity of polydimethylsiloxane (PDMS) based silicone rubber (SR) is highly critical in the electrical insulation industry during a wildfire event. In this work, SR composites are prepared with milled glass fires (MGFs) and graphene nanoplatelets (GNPs) to study the limiting oxygen index (LOI), cone calorimeter parameters, electrical breakdown voltage, mechanical and hydrophobic properties of solely aluminium trihydroxide (ATH) filled PDMS. Results exhibit that ATH could help in improving the aforementioned characteristics of pristine SR whereas, the MGFs and GNPs impart a pronounced impact on further improving the properties of solely ATH-filled SR. It is noticed that LOI improves to 35% and 36% whilst the maximum average rate of heat emission (MARHE) reduces to 78.6 kW/m2, and 69.6 kW/m2 in SR4 and SR5. In addition, the electrical breakdown voltage is slightly reduced at 24.65 kV/mm and 25.78 kV/mm in SR4 and SR5 relative to 27.47 kV/mm in SR1. GNPs and MGFs mutually render a positive impact on improving the tensile strength of SR2. Furthermore, SR composites are found with excellent hydrophobicity. The static contact angle marginally decreases in SR2 relative to SR1 whilst it is measured comparatively high at ∼115° in MGFs and GNPs-filled SR composites. SR4 and SR5 seem propitious composites comparatively with improved LOI, excellent fire retardancy, better mechanical strength and hydrophobicity whilst retaining the electrical breakdown strength.

Combination effect of zinc borate in intumescent polybutylene succinate systems: Study of the carbonaceous structures using solid-state NMR

Inspired by the concept of intumescence, this research proposed and exemplified a strategy for reinforcing the carbonaceous structures to improve the fire retardancy of intumescent polybutylene succinate (PBS). Herein, intumescent PBS formulations were fabricated by incorporating ethylenediamine phosphate (EDAP) and melamine (MEL) or melamine cyanurate (MCA) as well as zinc borate (ZnB) into PBS at a relatively low loading (10 wt%). The reaction to fire of PBS formulations were assessed by mass loss calorimeter (MLC) and the reinforcement mechanism of the condensed phase was investigated by solid-state NMR technique. Compared to PBS/EDAP&MEL(5:1,10%) and PBS/EDAP&MCA(5:1,10%), the synergistic combination of ZnB and EDAP&MEL (or EDAP&MCA) significantly reduced the peak of heat release rate (pHRR) of PBS/EDAP&MEL(5:1,8%)/ZnB(2%) and PBS/EDAP&MCA (5:1,8%)/ZnB(2%) by 61% and 53%, respectively, exhibiting high degrees of intumescence. Meanwhile, the fire growth rate index (FIGRA) were reduced by 48.8% and 39.5%, respectively, and the maximum average rate of heat emission (MARHE) decreased by 47.9% and 53.3%, respectively. Moreover, the flameout time increased by 428 s (from 507 to 935 s) and 444 s (from 509 to 954 s), respectively. Those phenomena suggested a synergistic flame retardant effect of ZnB and intumescent additives on PBS. Solid-state NMR of 11B, 13C and 31P of the top and bottom of chars after MLC test demonstrated the strengthening of the protective char by the formation of borophosphate and other phosphate glasses, limiting cracking and increasing the char cohesion.

Thermal Insulating Rigid Polyurethane Foams with Bio-Polyol from Rapeseed Oil Modified by Phosphorus Additive and Reactive Flame Retardants.

In this article, rigid polyurethane foams obtained with the addition of a bio-polyol from rapeseed oil, were modified with the dimethyl propane phosphonate as additive flame retardant and two reactive flame retardants diethyl (hydroxymethyl)phosphonate and diethyl bis-(2-hydroxyethyl)-aminomethylphosphonate. The influence of used flame retardants on the foaming process and characteristic processing times of tested polyurethane systems were determined. The obtained foams were tested in terms of cell structure, physical and mechanical properties, as well as flammability. Modified foams had worse mechanical and thermal insulation properties, caused by lower cellular density and higher anisotropy coefficient in the cross-section parallel to the foam rise direction, compared to unmodified foam. However, the thermal conductivity of all tested foam materials was lower than 25.82 mW/m∙K. The applied modifiers effectively reduced the flammability of rigid polyurethane foams, among others, increasing the oxygen index above 21.4 vol.%, reducing the total heat released by about 41–51% and the rate of heat release by about 2–52%. A correlation between the limiting oxygen index values and both total heat released parameters from the pyrolysis combustion flow calorimetry and cone calorimetry was observed. The correlation was also visible between the value of the heat release capacity (HRC) parameter obtained from the pyrolysis combustion flow calorimetry and the maximum average rate of heat emission (MARHE) from the cone calorimeter test.

A phosphaphenanthrene-benzimidazole derivative for enhancing fire safety of epoxy resins

In this work, a P/N-derived flame retardant (DOPO-BNM) was synthesized using 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 2-aminobenzimidazole, and 3-nitrobenzaldehyde as raw materials. The effects of DOPO-BNM on the flame retardancy, and thermal and mechanical performances of epoxy resin (EP) were comprehensively investigated. With the introduction of 8 wt% DOPO-BNM, the EP/8% DOPO-BNM sample passed a V-0 classification in vertical burning (UL-94) test, and its limiting oxygen index (LOI) increased to 32.5%. In comparison to the EP sample, the EP/8% DOPO-BNM sample exhibited 13.0%, 28.8%, 17.5%, 47.9% and 34.5% reductions in the peak heat release rate (PHRR), total heat release (THR), maximum average rate of heat emission (MARHE), total smoke production (TSP) and average effective heat of combustion (AEHC), demonstrating its enhanced fire safety. Furthermore, the char residue of EP/8% DOPO-BNM sample was increased by 41.2% relative to that of EP sample in the cone calorimetry test. During burning, DOPO-BNM mainly reduced the burning degree of volatiles, and also promoted the char formation. Additionally, DOPO-BNM slightly decreased the glass-transition temperature (Tg) of EP thermoset, while it remained the mechanical performances. In summary, the addition of DOPO-BNM not only effectively enhanced the fire safety of epoxy thermoset, but also maintained the thermal and mechanical properties.

Thermal degradation, visco-elastic and fire-retardant behavior of hybrid Cyrtostachys Renda/kenaf fiber-reinforced MWCNT-modified phenolic composites.

Natural fibers have emerged as a potential alternate to synthetic fibers, because of their excellent performance, biodegradability, renewability and sustainability. This research has focused on investigating the thermal, visco-elastic and fire-retardant properties of different hybrid Cytostachys Renda (CR)/kenaf fiber (K) (50/0; 35/ 15, 25/25, 15/ 35, 0/50)-reinforced MWCNT (multi-walled carbon nanotubes)-modified phenolic composites. The mass% of MWCNT-modified phenolic resin was maintained 50 mass% including 0.5 mass% of MWCNT. In order to achieve homogeneous dispersion ball milling process was employed to incorporate the MWCNT into phenolic resin (powder). Thermal results from thermogravimetric analysis and differential scanning calorimetric analysis revealed that the hybrid composites (35/15; 35 mass% CR and 15 mass% K) showed higher thermal stability among the composite samples. Visco-elastic results revealed that kenaf fiber-based MWCNT-modified composites (0/50; 0 mass% CR and 50 mass% K) exhibited higher storage and loss modulus due to high modulus kenaf fiber. Fire-retardant analysis (UL-94) showed that all the composite samples met H-B self-extinguishing rating and exhibited slow burning rate according to limiting oxygen index (LOI) test. However, (15/35; 15 mass% CR and 35 mass% K) hybrid composites showed the highest time to ignition, highest fire performance index, lowest total heat release rate, average mass loss rate, average fire growth rate index and maximum average rate of heat emission. Moreover, the smoke density of all hybrid composites was found to be less than 200 which meets the federal aviation regulations (FAR) 25.853d standard. Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was carried out to select an optimal composite sample considering the thermal, visco-elastic and fire-retardant behaviors. Through TOPSIS analysis, the hybrid (15/35; 15 mass% CR and 35 mass% K) composite sample has been selected as an optimal composite which can be used for high-temperature aircraft and automotive applications.

Assessment of the explosion risk during lithium-ion battery fires

Lithium-ion batteries are widely used for renewable energy storage and to deliver mobile power because of their high energy densities and electromotive forces. However, such batteries can catch fire and explode, potentially causing casualties and property damage. Here, we used a cone calorimeter to investigate the fire risk and assess the associated heat release rate (HRR). Standard cylindrical battery fires feature two combustion stages, the first of which is characterized by diffusion-like flames and the second by partially premixed flames with a higher peak HRR and a violent explosion. The overall combustion properties depend principally on the state of charge (SOC). A higher SOC battery is associated with a higher maximum HRR, a shorter HRR peak-to-peak time, larger CO and CO2 emissions, and a greater instantaneous mass loss. The average rate of heat emission based on the measured combustion properties is introduced and its maximum value is expected to predict reactivity and explosiveness comprehensively in the event of fire.

Improvement of Flame Retardancy and Antidripping Properties of Intumescent Polybutylene Succinate Combining Piperazine Pyrophosphate and Zinc Borate

Developing flame-retarded polybutylene succinate (PBS) is a challenging task owing to its high flammability, noncharring, and melt-dripping during burning. In this work, based on the synergistic combination between piperazine pyrophosphate (PAPP) and zinc borate (ZnB), a promising intumescent PBS system was developed as an efficient strategy to impart PBS with improved flame retardancy and antidripping properties. The results showed that PBS/PAPP15%/ZnB5% passed V-0 rating in the UL-94 vertical burning test (3 mm), while only a V-2 rating was achieved for PBS/PAPP20%. Compared to PBS/PAPP20%, the combination of PAPP and zinc borate (ratio of 15:5) led to significant reductions in the peak heat release rate (pHRR, −55%), fire growth rate index (FIGRA, −40%), and maximum average rate of heat emission (MARHE, −47%) evaluated by mass loss cone calorimetry. Meanwhile, the flame retardancy index of PBS/PAPP15%/ZnB5% reached up to 5.18 and the flameout time significantly increased to 1049 s. Fourier transform infrared and solid-state nuclear magnetic resonance analyses were employed to gain insight into the reaction-to-fire mechanism in the condensed phase. The results confirmed the fact that the formation of a crack-free protective intumescent char layer, reinforced by thermally stable inorganic species (boron–zinc phosphates), effectively restricted the heat and fuel transfer between condensed and gas phases, hence resulting in the excellent enhancement in flame retardancy.

A highly efficient intumescent polybutylene succinate: Flame retardancy and mechanistic aspects

A new strategy was developed for the fabrication of intumescent flame retardant system to improve the fire performance of polybutylene succinate (PBS) based on the synergistic effect of ethylenediamine phosphate (EDAP) and melamine poly(aluminum phosphate) (MPAlP) as well as zinc borate (ZnB). Cone calorimetry results exhibited that, with only 10 wt.% total loading of additives, the peak heat release rate (pHRR) and total heat release (THR) of PBS/EDAP&MPAlP(7:3, 8%)/ZnB(2%) were significantly reduced by 63% and 13%, respectively, in comparison to PBS. Meanwhile, the fire growth rate index (FIGRA) and maximum average rate of heat emission (MARHE) were decreased by 43% and 48% respectively, and its flameout time reached up to 840 s from 493 s for neat PBS. It should be noted that solid-state MAS NMR (11B, 13C, 27Al, and 31P) technique provided information to determine chemistry in the condensed phase during combustion. It was evidenced that the combination of EDAP/MPAlP and ZnB led to the formation of a protective intumescent char embedded with highly thermally stable phosphate species (e.g., boron phosphate and zinc phosphate). They improved the cohesion (crack-free) and stability as well as the resistance of the char, thus improving the fire retardancy of PBS. Additionally, PBS/EDAP&MPAlP(7:3,8%)/ZnB(2%) showed low smoke emission and good thermal/mechanical properties, thanks to the introduction of zinc borate. As a result, this work provides a new perspective for the development of new intumescent flame retardant systems toward PBS.

Impact of crumb rubber reinforcement on the properties of wood–plastic composites

ABSTRACT The use of crumb rubber is one form of recycling scrap tires that can aid in addressing the environmental concerns of tire disposal. In the present investigation, reinforced wood–plastic composites (WPCs) were manufactured incorporating crumb rubber. The bulk density of crumb rubber-reinforced WPC was found to be 19% higher than the baseline materials. This indicated that crumb rubber assisted in the consolidation process. Both baseline and crumb rubber-reinforced WPC materials were mechanically characterized according to ASTM D 1037. Compression modulus of crumb rubber-reinforced WPC showed an increase of 200% as compared to baseline WPC. Cone calorimetry demonstrated that the peak heat release rate, the maximum average rate of heat emission (MARHE), effective heat of combustion, and fuel load of crumb rubber-reinforced WPC were lower than the baseline WPC. Nonetheless, it was observed that the amount of CO and CO2 produced were more in the case of crumb rubber-reinforced WPC.

Burning Behaviour of Rigid Polyurethane Foams with Histidine and Modified Graphene Oxide.

Since rigid polyurethane (PU) foams are one of the most effective thermal insulation materials with widespread application, it is an urgent requirement to improve its fire retardancy and reduce the smoke emission. The current work assessed the fire behavior of PU foam with non-halogen fire retardants system, containing histidine (H) and modified graphene oxide (GOA). For investigated system, three loadings (10, 20, and 30 wt.%) were used. The Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis, cone calorimetry (CC) and smoke density chamber tests as well as pre- and post-burning morphological evaluation using scanning electron microscope (SEM) were performed. Moreover, TGA combined with FT-IR was conducted to determine the substances, which could be evolved during the thermal decomposition of the PU with fire retardant system. The results indicated a reduction in heat release rate (HRR), maximum average rate of heat emission (MAHRE), the total heat release (THR) as well as the total smoke release (TSR), and maximum specific optical density (Dsmax) compared to the polyurethane with commercial fire retardant, namely ammonium polyphosphate (APP). A significantly improvement, especially in smoke suppression, suggested that HGOA system may be a candidate as a fire retardant to reduce the flammability of PU foams.