Intumescent Flame Retardant Poly Research Articles

Water Hyacinth Fiber as a Bio-Based Carbon Source for Intumescent Flame-Retardant Poly (Butylene Succinate) Composites.

In this study, flame-retardant poly (butylene succinate) (PBS) composites were developed utilizing a bio-based intumescent flame retardant (IFR) system. Water hyacinth fiber (WHF) was used as a bio-based carbon source, while ammonium polyphosphate (APP) served as both an acid source and a blowing agent. Effects of WHF:APP weight ratio and total IFR content on the thermal stability and flammability of WHF/APP/PBS composites were investigated. The results demonstrated that the 15WHF/30APP/PBS composite with a WHF to APP ratio of 1:2 and a total IFR content of 45 wt% had a maximum limiting oxygen index (LOI) value of 28.8% and acquired good flame retardancy, with a UL-94 V-0 rating without polymer-melt dripping. Additionally, its peak heat release rate (pHRR) and total heat release (THR) were, respectively, 53% and 42% lower than those of the neat PBS. Char residue analysis revealed that the optimal WHF:APP ratio and total IFR content promoted the formation of a high graphitized intumescent char with a continuous and dense structure. In comparison to the neat PBS, the tensile modulus of the 15WHF/30APP/PBS composite increased by 163%. Findings suggested the possibility of employing WHF, a natural fiber, as an alternative carbon source for intumescent flame-retardant PBS composites.

High-efficient flame retardant ethylene-vinyl acetate composites by incorporating monomolecular IFR and its pyrolysis behavior

Highly efficient flame retardant and excellent mechanical performance was critical for the application of ethylene vinyl acetate copolymer (EVA) composites. Herein, a monomolecular intumescent flame retardant poly(piperazine methylphosphonic acid pentaerythritol ester) defined as PPMPPE was incorporated into the EVA matrix, and the flame retardancy, mechanical performance of EVA composites were investigated. When 21 wt% PPMPPE was incorporated, the limiting oxygen index (LOI) of 1.6 mm EVA/PPMPPE composites was increased from 18.2 % for neat EVA to 27.5 %, and it achieved UL-94 V-0 grate during vertical burning tests. Meanwhile, the cone calorimetry tests indicated that the peak value of heat release rate and total heat release of FR-EVA composites were obviously reduced by 41.1 % and 27 % compared to neat EVA. The analysis of flame-retarded mechanism for EVA/PPMPPE indicated that PPMPPE facilitated the decomposition of EVA and formed an expanding char layer, and it possessed barrier effect in condensed phase. In addition, the PPMPPE could exert free radicals quenching effect and in gaseous phase. Therefore, the PPMPPE endowed the EVA matrix with good flame-retardant efficiency. Meanwhile, the mechanical performance of EVA/21 wt% PPMPPE composites was well maintained, and its tensile strength and elongation at break decreased by 21.9 % and 14.4 %, respectively. This research work provided a feasibility approach for producing EVA composites with excellent flame-retardant and mechanical performance.

Mechanical properties and flame retardancy of PLA composites containing zinc oxide and chain extender

AbstractA micro‐cross‐linked structure had been constructed by the addition of zinc oxide with nanometer‐scale particle size (nano ZnO) and chain extender (ADR) into intumescent flame retardant poly (lactic acid) (FRPLA). Flame retardant properties, mechanical properties and thermal stabilities were studied. Limited oxygen index of the FRPLA composite with 1% nano ZnO and 0.8% ADR (FRPLA/0.8ADR/1ZnO) was a maximum (39.4%).Tmaxand residue at 800°C of FRPLA/0.8ADR/1ZnO was the highest in air. Tensile strength, elongation at break and impact strength of FRPLA/0.8ADR/1ZnO was significantly higher than that which resulted with the addition of either individual filler, indicating that the synergistic effect between nano ZnO and ADR regulated the comprehensive performance of FRPLA. The synergetic effect between nano ZnO and ADR were further illustrated.

Synergistic effect of MXene on the flame retardancy and thermal degradation of intumescent flame retardant biodegradable poly (lactic acid) composites

The effect of Ti3C2 MXene nanosheets on the intumescent flame retardant (IFR) poly (lactic acid) (PLA) composites was investigated among a series of PLA/IFR/MXene, which were prepared by melt blending 0–2.0 wt% MXene, 10.0 wt%– 12.0 wt% IFR and PLA together. The results of limiting oxygen index (LOI) and vertical burning (UL-94) discover that the combination of 0.5 wt% MXene and 11.5 wt% IFR synergistically improves the fire safety of PLA to reach UL-94 V-0 rating with LOI value of 33.0%. The PLA/IFR/MXene composites perform an obvious reduction in peak of heat release rate (HRR) in cone calorimeter tests (CCTs). Furthermore, the carbon residues after CCTs were characterized by scanning electron microscope (SEM), laser Raman spectroscopy (LRS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is demonstrated that both the titanium composition of the MXene structure and the characteristics of the two-dimensional material enhance the PLA/IFR/MXene composite materials' ability to produce a dense barrier layer to resist burnout during thermal degradation.

Design, synthesis and application of a highly efficient mono-component intumescent flame retardant for non-charring polyethylene composites

A novel hyperbranched mono-component intumescent flame retardant poly(piperazine methylphosphonic acid pentaerythritol ester) defined as PPMPPE was synthesized, and its chemical structure was characterized. The individual PPMPPE was incorporated into polyethylene (PE), and the fire resistance, thermal properties and flame retardant mechanism of PE composites were investigated in detail. The 1.6-mm PE/PPMPPE sheets fulfilled UL-94 V-0 level during vertical burning tests, and the limiting oxygen index was 25.3% when the loading amount of PPMPPE was 22 wt%. PPMPPE was completely melted, and the expanded char layer was generated on heating. The addition of PPMPPE stimulated the degradation and charring of PE composites in advance and improved the residual mass and thermal stability of FR-PE at high temperature. The cone calorimeter tests verified that the heat release rate and total heat release of PE/PPMPPE composites were obviously declined. PPMPPE exerted shielding effect in condensed phased and quenching active free radicals in the gas phase. The flame was constrained and even extinguished. Thus, PE composites fulfilled superior flame retardant properties.

Enhancing flame retardancy and promoting initial combustion carbonization via incorporating electrostatically surface-functionalized carbon nanotube synergist into intumescent flame-retardant poly(butylene succinate)

Fire safety is becoming more stringent in the use of polymers. In spite of introducing intumescent flame retardants (IFRs), poly(butylene succinate) (PBS) still presents fast fire growth and continuous combustion. Based on the contribution of the one-dimensional synergist to melting-dripping suppression and flame retardancy enhancement, aminated multi-walled carbon nanotube was first electrostatically attached by ammonium polyphosphate (APP), and hence promote carbonization in the char mass of 65.7% during combustion for the IFR system of PBS/APP/pentaerythritol (PER). Furthermore, total heat release (THR) and average mass loss rate (AMLR) reduced by 79.6% and 93.8%, respectively. The flame retardancy mechanism was mainly ascribed to highly thermal stability of char during initial fire growth and simultaneous formation of continuous char layer thereof. So it is inspired that flammable feature of polymers might be rationally utilized to promote flame retardancy.

Preparation of Intumescent Flame Retardant Poly(butylene succinate) Using Urea Intercalated Kaolinite as Synergistic Agent

Urea (U) was successfully intercalated into Kaolinite (Kaol) and the product K-U was introduced into poly(butylene succinate) (PBS)/intumescent flame retardants (IFR) by melt blending. The structure of K-U was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The flame retardancy, thermal degradation, and combustion behavior of PBS composites were characterized by limiting oxygen index (LOI), vertical burning test to get UL-94 rating, thermogravimetricanalysis (TGA), and cone calorimeter test (Cone). With the introduction of K-U and IFR into PBS, the LOI obviously increased from 21.9 % for neat PBS to 40.1 % for composite containing 20 wt% IFR/5 wt% K-U; PBS cannot pass any UL-94 rating but the composite passed UL-94 V-0 rating. Similarly, the peak heat release rate (PHRR) in cone test decreased from 576 kW/m2 to 292 kW/m2. SEM results showed the char of the composite became more compact and smooth.

The influence of nano ZnO coated by phosphazene/triazine bi-group molecular on the flame retardant property and mechanical property of intumescent flame retardant poly (lactic acid) composites

Nano zinc oxide (nano ZnO) and phosphazene/triazine bi-group flame retardant in situ doping nano zinc oxide (A4-d-ZnO) were used as synergists in intumescent flame retardant poly (lactic acid) (PLA) composites, respectively. The results showed that nano ZnO endowed flame retardant PLA excellent flame retardant properties, such as the higher LOI value, the lower pk-HRR, av-HRR, THR, mass loss rate, TSR and more final mass than A4-d-ZnO. It was because that nano ZnO catalyzed PLA decomposed into low molecular segments, which acted as a char-forming agent. However, it destroyed the mechanical properties seriously. By contrast, although the flame retardant properties of PLA/IFR/A4-d-ZnO was not better than PLA/IFR/nano ZnO, owing to the weakened catalytic effect of A4-d-ZnO coated by the phosphazene/triazine bi-group flame retardant, A4-d-ZnO improved the flame retardant properties, the thermal stability and the mechanical properties at the same time, which was important and necessary for application.

The synergistic effects of a novel intumescent flame-retardant poly-(4-nitrophenoxy)-phosphazene and ammonium polyphosphate on ABS systems

Novel intumescent flame retardancy acrylonitrile–butadiene–styrene (ABS) composites were prepared by adding poly-(4-nitrophenoxy)-phosphazene (DPP) as charring and inflate agent, and ammonium polyphosphate (APP) as acid and inflate agent. The flame-retardant properties of samples were studied by LOI, UL-94 and microscale combustion calorimeter (MCC), when the ratio of APP and DPP was 1:1 with 30 mass% additive amount, the LOI was 27%, and the UL-94 reached V-0 rating. To further study the synergistic effects of DPP and APP, the charring-forming capability and thermal behavior of ABS composites were extensively studied by thermogravimetric analysis (TGA) under nitrogen and air, respectively. Also the binary system of APP and DPP was investigated by TGA measurements to identify their reaction and the synergistic mechanisms. The char residues were studied by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) analysis and Fourier transform infrared (FTIR). Meanwhile, the gaseous products generated in degradation process were detected by thermogravimetric analysis coupled Fourier transform infrared (TGA/FTIR).

Synthesis of a novel mono-component intumescent flame retardant and its high efficiency for flame retardant polyethylene

A novel polymeric mono-component intumescent flame retardant poly(piperazine methylphosphonic acid neopentylglycol ester) (PPMPNG) was synthesized from methylphosphonic acid, piperazine and neopentyl glycol. Its chemical structure was detailed characterized by Fourier transform infrared spectroscopy (FTIR), 13C and 31P solid-state nuclear magnetic resonance. PPMPNG was incorporated into polyethylene (PE) and the flame retardancy, thermal properties and flame retardant mechanism of materials were investigated. The samples with the thickness of 1.6 mm passed UL-94 V-0 rating during vertical burning tests and the limiting oxygen index was 25.6% when 23 wt% PPMPNG was introduced. The results of thermogravimetric analysis (TGA) showed that the addition of PPMPNG promoted the degradation and carbonization of materials at the beginning and improved the char residue amount and thermal stability of FR-PE at high temperature. Cone calorimeter tests indicated that the peak value of heat release rate was considerably reduced with the incorporation of PPMPNG. The flame retardant mechanism showed PPMPNG exerted isolation effect in condensed phased and quenched active free radical effect in gas phase. The combustion intensity was reduced and the flame was suppressed and even extinguished, thus a high efficiency for PE matrix was achieved.

Intercalation of phosphotungstic acid into layered double hydroxides by reconstruction method and its application in intumescent flame retardant poly (lactic acid) composites

Phosphotungstic acid is a typical kind of superior catalysts, and it is hardly to intercalate into the layered double hydroxides (LDH) by ion-exchange process because of its low negative charge. In this work, a phosphotungstic acid intercalated MgAl-LDH (PWA-LDH) was prepared by reconstruction method, and it was then introduced into poly (lactic acid) (PLA) resin in association with intumescent flame retardant (IFR) by melt blending to prepare a flame-retardant biodegradable PLA composite. The effects of PWA-LDH on the flame retardancy of PLA composites were characterized by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter test. The results showed that the composite sample containing 18.0 wt% IFR and 2.0 wt% PWA-LDH achieved the maximal LOI value of 48.3%, passed the UL-94 V-0 rating, and significantly decreased the peak heat release rate from 306.3 kW/m2 of neat PLA to 40.1 kW/m2. Thermogravimetric analysis showed that both the thermal stability and the char formation were enhanced. The char morphology observation revealed that PWA-LDH was beneficial to form dense and compact char layers. It was demonstrated that there existed a synergistic effect between IFR and PWA-LDH in promoting the char formation and enhancing the fire resistance.

Synergistic effect of halloysite nanotubes on flame resistance of intumescent flame retardant poly(butylene succinate) composites

A novel intumescent flame retardant poly(butylene succinate) (IFR‐PBS) with antidripping property was prepared using halloysite nanotubes (HNTs) as the synergistic agent. Ammonium polyphosphate (APP), melamine (MA), pentaerythritol (PER), and halloysite nanotubes (HNTs) were added in PBS via melt blending. The effects of HNTs as the synergistic agent on the flame retardancy property, thermal property, and mechanical property of IFR‐PBS composites were investigated. Cone calorimetry revealed that partial substitution of IFR by HNTs (1.5 wt%) substantially improved the flame retardancy of IFR‐PBS with a reduction of heat release rate (HRR), total heat release (THR), and total smoke production (TSP). In addition, the limiting oxygen index value was increased from 42.1 to 58.2 with only 1.5 wt% addition of HNTs. The incorporation of HNTs also enhanced the thermal stability of the IFR‐PBS composites and reinforced the composites. Scanning electron microscopy (SEM) results showed that the composite containing HNTs had a tighter protective char layer after cone calorimeter test, which protected the underlying polymer from the external heating. Overall, the results indicated that suitable amounts of HNTs had a noticeable synergistic effect on the flame retardancy property of IFR‐PBS composites. POLYM. COMPOS., 40:202–209, 2019. © 2017 Society of Plastics Engineers

Intumescent flame-retardant poly(1, 4-butylene terephthalate) with ammonium polyphosphate and a hyperbranched triazine charring-foaming agent: Flame retardancy performance and mechanisms

Intumescent flame-retardant poly(1, 4-butylene terephthalate) composites with ammonium polyphosphate and a hyperbranched triazine charring-foaming agent were prepared through melt blending. The flame retardancy, pyrolysis behavior, and flame-retardant mechanism of flame-retardant poly(1, 4-butylene terephthalate) were investigated using flammability tests, cone calorimeter measurements, thermogravimetric analysis including evolved gas analysis, and residue analysis (Fourier transform infrared and scanning electron microscopy). The results showed that the intumescent flame retardant with the appropriate ammonium polyphosphate/hyperbranched triazine charring-foaming agent mass ratio (4/1) could significantly improve the flame retardancy of poly(1, 4-butylene terephthalate), and the highest Limiting Oxygen Index value and UL-94 V-0 rating was reached. The peak heat release rate and total heat evolved remarkably decreased, respectively, by 84% and 76% corresponding to poly(1, 4-butylene terephthalate). Thermogravimetric analysis results showed the synergistic effect between ammonium polyphosphate and hyperbranched triazine charring-foaming agent could enhance the char formation ability of composites. The results of gaseous products and residue char structure analysis indicated intumescent flame retardant influenced the decomposition behavior and promoted the formation and accumulation of phosphorous/azotic and polyaromatic char possessing high graphitization degree, which exerted a condensed-phase flame-retardant effect on the flame-retardant composites.

Synthesis of novel intumescent flame retardant containing phosphorus, nitrogen and boron and its application in polyethylene

A novel intumescent flame retardant poly(phenyl phosphamide spirocyclic diethanolamine borate) (PPSDB) containing phosphorus, nitrogen and boron elements was synthesized successfully with diethanolamine borate and phenylphosphonic dichloride. The structure of PPSDB was characterized by infrared spectroscopy with Fourier transformation and nuclear magnetic resonance. As a new intumescent flame retardant, flame-retardant polyethylene (PE) composites were prepared by filling PPSDB with different fractions. The thermal stability of PPSDB and PE/PPSDB composites was investigated by thermogravimetric analysis. The results showed that the thermal stability of PPSDB was fit for processing PE composites, the initial decomposition temperatures of PE/PPSDB composites would decrease and the char residue would increase with an increase in the PPSDB fraction. The PE/PPSDB composite with 30 wt% PPSDB had the best combination properties; the limited oxygen index value was 29.2, and vertical burning reached UL-94 V-0 rating, and the tensile strength and notched impact strength were 18.6 MPa and 12.5 kJ m−2 respectively. The morphologies of char residue showed a lot of protruding structures consisting of smaller protuberances, which prevented the combustion of composite and enhanced anti-dripping property effectively.

Preparation and study of intumescent flame retardant poly(butylene succinate) using MgAlZnFe‐CO3 layered double hydroxide as a synergistic agent

ABSTRACTIntumescent flame retardant consisting of ammonium polyphosphate and melamine, and MgAlZnFe‐CO3 layered double hydroxides (LDHs) prepared by the constant pH coprecipitation method, were added to poly(butylene succinate) (PBS) via melt blending to obtain novel intumescent flame retardant poly(butylene succinate) (IFR‐PBS) composites. A study on the effect of MgAlZnFe‐CO3 LDHs on the mechanical, thermal, and flame retardancy properties of IFR‐PBS composites was investigated. It was revealed that IFR‐PBS composites exhibited both excellent flame retardancy and antidripping properties when the content of MgAlZnFe‐CO3 LDHs was 1% (the total loading of flame retardant was 20%), for a goal of vertical flammability (UL‐94) V‐0 rate and a limiting oxygen index value of 35. The results showed that a suitable amount of MgAlZnFe‐CO3 LDHs had a noticeable synergistic effect on IFR‐PBS composites. Importantly, tensile strength and flexural strength were improved by the presence of MgAlZnFe‐CO3 LDHs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40736.

Combination effects of graphene and layered double hydroxides on intumescent flame-retardant poly(methyl methacrylate) nanocomposites

A novel intumescent flame-retardant poly(methyl methacrylate) (PMMA) nanocomposite has been prepared via in situ polymerization by incorporating intumescent flame retardants (IFRs), graphene and layered double hydroxides (LDHs). Results from X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicate that a fine dispersion of IFR particles, intercalated LDHs and exfoliated graphene is achieved in the PMMA matrix. Thermal and flammability properties of PMMA nanocomposite were investigated using thermogravimetry, cone calorimetry, limiting oxygen index (LOI) and vertical burning (UL-94). The use of IFRs in combination with graphene and LDHs in the PMMA matrix improves greatly the thermal stability and flame retardant properties of the nanocomposites. The PMMA/IFR/RGO/LDH nanocomposites, filled with 10wt.% IFRs, 1wt.% graphene and 5wt.% LDHs, achieve the LOI value of 28.2% and UL-94 V1 grade. Compared with neat PMMA, the PHRR of PMMA/IFRs/RGO/LDHs is reduced by about 45%, while the mechanical properties of PMMA/IFR/RGO/LDH nanocomposites exhibit almost no deterioration. The results from scanning electronic microscopy (SEM) confirm that the compact and dense intumescent char enhanced with LDHs and graphene nanosheets is formed for the PMMA/IFR/RGO/LDH nanocomposites during combustion, which inhibits the transmission of heat and mass when exposed to flame or heat source, and thus improves the flame retardant properties of the nanocomposites.

Functionalized carbon nanotubes with oligomeric intumescent flame retardant for reducing the agglomeration and flammability of poly(ethylene vinyl acetate) nanocomposites

AbstractA novel oligomeric phosphorous–nitrogen‐containing intumescent flame retardant poly (2,6‐diaminopyridine spirocyclic pentaerythritol bisphosphonate) (PDSPB) is synthesized, and subsequently multiwalled carbon nanotube (MWNT)‐grafted oligomeric intumescent flame retardant, MWNT‐g‐PDSPB, is fabricated via chemical grafting reaction and characterized. The grafting reaction was characterized by FTIR, NMR, and XPS. After high‐density PDSPB (88 wt%) were attached to the MWNTs, core‐shell nanostructures with MWNTs as the hard core and PDSPB as the soft shell were formed. The resultant MWNT‐g‐PDSPB was soluble and stable in polar solvents, such as DMF and DMSO. MWNT‐g‐PDSPB has excellent thermal stability and charring ability. The TEM results showed that the functionalized MWNTs could achieve better dispersion in poly(ethylene vinyl acetate) (EVA) matrix. The residue char of MWNT‐g‐PDSPB is as high as 70 wt%, and the grafting of intumescent flame retardant of PDSPB can improve both the dispersion of MWNTs in polymer matrix and flame retardancy of the nanocomposites. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers

Preparation of lignin–silica hybrids and its application in intumescent flame-retardant poly(lactic acid) system

Lignin–silica hybrids (LSHs) were prepared by sol–gel method and characterized by Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). LSH and ammonium polyphosphate (APP) were added into poly(lactic acid) (PLA) as a novel intumescent flame-retardant (IFR) system to improve the flame retardancy of PLA. The flame-retardant effect of APP and LSH in PLA was studied using limiting oxygen index (LOI), vertical burning (UL-94) tests and cone calorimeter. The thermal stability of PLA/APP/LSH composites was evaluated by thermogravimetric analysis (TGA). Additionally, the morphology and components of char residues of the IFR-PLA composites were investigated by SEM and XPS. With the addition of APP/LSH to PLA system, the morphology of the char residue has obviously changed. Compared with PLA/APP and PLA/APP/lignin, a continuous and dense intumescent charring layer with more phosphor in PLA composites is formed, which exhibits better flame retardancy. All the results show that the combination of APP and LSH can improve the flame-retardant property and increase the thermal stability of PLA composites greatly.

The effect of different organic modified montmorillonites (OMMTs) on the thermal properties and flammability of PLA/MCAPP/lignin systems

AbstractThe effect of different organic modified montmorillonites (DK1, DK2, and DK4) based on a novel intumescent flame retardant (IFR) poly(lactic acid) (PLA) system is reported. The IFR system was composed of microencapsulated ammonium polyphosphate and lignin. The morphological characterization of PLA/OMMT nanocomposites was conducted by X‐ray diffractometry and transmission electron microscopy. The flame retardant and thermal properties of the composites were evaluated by limiting oxygen index (LOI), vertical burning test (UL‐94), and cone calorimeter. From the results, it could be seen that the sample containing DK2 possessed the best flame retardance, such as lower peak heat release rate (pHRR) and higher LOI value. The thermal degradation and gas products of the samples were monitored by thermogravimetric analysis and thermogravimetric analysis infrared spectrometry. Scanning electron microscopy was used to explore the surface morphology of the char residues. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013

Study on the Synthesis and Characterization of a Novel Phosphorus-Nitrogen Containing Intumescent Flame Retardant

In this study, a novel phosphorus-nitrogen containing intumescent flame retardant (P-N IFR) poly(melamine 2-carboxyethyl(phenyl) phosphate)(PMCEP) was prepared via the reaction of 2-carboxyethyl (phenyl) phosphinic acid (CEPPA) and melamine (MEL) in two-steps. Meanwhile, the molecular structure of the chemical compound was determined by FTIR,1H-NMR and elemental analysis; and the thermal properties was investigated by means of TGA. Combustion studies revealed high limiting oxygen index (LOI) indicative of better flame-retardancy properties for PBT resin.