Flammability Of Poly Research Articles

Flammability analysis of poly(ethylene terephthalate) and recycled PET with pyrolyzed filler

The future is the recovery of the filler and its reuse in hybrid materials. It is important that as a result of recycling, the filler does not lose its properties, but acquires new ones. The aim of this research work was to investigate the effect of filler recovered by pyrolysis on the flammability of poly(ethylene terephthalate) and recycled PET. It was important to obtain a flammability class higher or equal to the pure PET and RPET matrix. Flammability tests carried out using the UL94, LOI, and PCFC methods allowed perform a first characterization of the properties of materials during their combustion. These studies show that it becomes possible to give specific functional properties to recycled fillers.

Synthesis of Novel Polymeric Acrylate-Based Flame Retardants Containing Two Phosphorus Groups in Different Chemical Environments and Their Influence on the Flammability of Poly (Lactic Acid).

Novel polymeric acrylate-based flame retardants (FR 1–4) containing two phosphorus groups in different chemical environments were synthesized in three steps and characterized via nuclear magnetic resonance (NMR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and mass spectrometry (MS). Polylactic acid (PLA) formulations with the synthesized compounds were investigated to evaluate the efficiency of these flame retardants and their mode of action by using TGA, UL94, and cone calorimetry. In order to compare the results a flame retardant polyester containing only one phosphorus group (ItaP) was also investigated in PLA regarding its flame inhibiting effect. Since the fire behavior depends not only on the mode of action of the flame retardants but also strongly on physical phenomena like melt dripping, the flame retardants were also incorporated into PLA with higher viscosity. In the UL94 vertical burning test setup, 10% of the novel flame retardants (FR 1–4) is sufficient to reach a V-0 rating in both PLA types, while a loading of 15% of ItaP is not enough to reach the same classification. Despite their different structure, TGA and cone calorimetry results confirmed a gas phase mechanism mainly responsible for the highly efficient flame retardancy for all compounds. Finally, cone calorimetry tests of the flame retardant PLA with two heat fluxes showed different flame inhibiting efficiencies for different fire scenarios.

Green Approach to Improving the Strength and Flame Retardancy of Poly(vinyl alcohol)/Clay Aerogels: Incorporating Biobased Gelatin.

Biobased gelatins were used to improve the compressive properties and flammability of poly(vinyl alcohol)/montmorillonite (PVA/MMT) aerogels, fabricated using a simple and environmentally friendly freeze-drying method. Because of the excellent compatibility and strong interfacial adhesion between PVA and gelatin, the compressive moduli of aerogels were enhanced dramatically with the incorporation of gelatin. PVA/MMT/porcine-gelatin aerogels exhibit compressive modulus values as much as 12.4 MPa, nearly 300% that of the control PVA/MMT aerogel. The microstructure of the PVA/MMT/gelatin aerogels shows a three-dimensional co-continuous network. Combustion testing demonstrated that with the addition of gelatin, the self-extinguishing time of the aerogel was cut by half and the limiting-oxygen-index values increased to 28.5%. The peak heat-release rate, obtained from cone calorimetry, also decreased with the incorporation of gelatin. Thermogravimetric analysis demonstrated that the gelatins slowed the sharp decomposition of the PVA matrix polymer and increased the thermal stability of the aerogels at the major decomposition stage of the composite aerogels. These results indicate that as a green, biobased material, gelatin could simultaneously improve the mechanical properties and the properties of flame retardancy.

The influence of melamine phosphate modified MoS2 on the thermal and flammability of poly(butylene succinate) composites

This work reported a facile fabrication method to modify molybdenum disulfide (MoS2) nanosheets with common flame retardant melamine phosphate (MAP) and then were incorporated into poly(butylene succinate) by melt blending method with the purpose of improving the thermal and flame retardancy properties. MAP modified MoS2 nanosheets dispersed well in poly(butylene succinate) composites with intercalated structure. The incorporation of MAP modified MoS2 nanosheets led to an increase of thermal degradation temperature and char formation as well as reduction of the peak heat release rate. Copyright © 2016 John Wiley & Sons, Ltd.

Investigation of thermal stability and flammability of poly(methyl methacrylate) composites by combination of APP with ZrO2, sepiolite or MMT

The thermal degradation and flame retardancy of poly(methyl methacrylate) containing three mineral fillers, with different geometry, MMT: plate-like, sepiolite: fibrilar and zirconium oxide ZrO2: spherical, in combination with ammonium polyphosphate (APP) were studied. The flame behavior of composites was investigated using pyrolysis-combustion flow calorimeter, cone calorimeter and LOI tests. The results revealed that the composites containing APP and sepiolite present the best fire behavior. A rheological study was performed on composites to establish a relationship between viscosity and flammability. The residues of samples after cone calorimeter test were studied using X-ray diffraction and micro-tomography in order to investigate their chemical composition and also repartition of fillers. A better repartition of sepiolite during combustion could be the origin of the best results obtained for sample containing this filler.

The Effect of a Novel Intumescent Flame Retardant-Functionalized Montmorillonite on the Thermal Stability and Flammability of Eva

A novel intumescent flame retardant-functionalized montmorillonite (PAB-MMT) was prepared by modification of sodium montmorillonite (Na-MMT) with an intumescent flame retardant (PAB) containing phosphorus-nitrogen structure. The results of X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) analysis indicated that PAB had intercalated into Na-MMT. The applications of this fact for improving the thermal stability and flammability of poly(ethylene-co-vinyl acetate) were investigated by thermogravimetric analysis (TGA), and microscale combustion calorimetry (MCC). Scanning electron microscopy (SEM) was carried out to learn the morphology of the char residue. The results showed that the addition of PAB-MMT into EVA could improve the flame retardancy of the EVA matrix. The peak heat release rate (PHRR) and total heat release (THR) were significantly reduced in comparison with those of other EVA composites. The TGA data showed higher char residue than other composites, which was the reason for the improved flame retardancy.

Thermal performance and flammability of poly(ethylene terephthalate) fabrics grafted with different monomers followed by electron beam irradiation

Electron beam irradiation grafting of acrylic acid (AAc), acrylamide (AAm), and dimethyl vinylphosphonate (DMVP) onto poly(ethylene terephthalate) (PET) fabrics was performed using a high-energy electron accelerator. Parameters affecting the graft polymerization of PET fabrics, including absorbed dose and monomer concentration, were investigated. Fourier transform infrared spectroscopy analysis confirmed that the monomers were grafted onto the PET fabrics. The thermal behavior of the grafted PET fabrics was investigated with thermogravimetric analysis. Findings showed that grafting with AAm could improve the thermal stability of PET. The limiting oxygen index values and vertical flammability test results showed that PET fabric graft-polymerized with AAc could improve the flammability and prevent melt dripping. Grafting with AAm and DMVP could improve the flame retardation property of PET fabric. Scanning electron micrographs showed that the surface morphology of the PET fabric samples was significantly influenced by graft polymerization, and that grafting with AAc could promote the formation of residual char and impart an anti-dripping quality to PET fabrics.

Preparation and flammability of poly(vinyl alcohol) composite aerogels.

Poly(vinyl alcohol) (PVOH)-based aerogel composites with nanoscale silica, halloysite, montmorillonite (MMT), and laponite were prepared via a freeze-drying method. The PVOH/MMT and PVOH/laponite composites exhibit higher compressive moduli than the PVOH/SiO2 or PVOH/halloysite samples. Layered microstructures were observed for the samples except with PVOH/laponite, which showed irregular network morphologies. Thermogravimetric analysis of the aerogel samples showed increased thermal stability with the addition of nanofillers. The heat release measured by cone calorimetry, smoke release, and carbon monoxide production of the aerogel composites are all significantly decreased with the addition of nanofillers; these values are much lower than those for commercial expanded polystyrene foam. The fillers did not lead to obvious increases in the limiting oxygen index values, and the corresponding time to ignition values decrease. The ability to adjust the nanofiller levels in these foamlike aerogel composites allows for specific tuning of these products for fire safety.

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

Thermal Properties and Combustion Behaviors of Chitosan Based Flame Retardant Combining Phosphorus and Nickel

A renewable carbonization agent based compound nickel chitosan phosphate (NiPCS) has been prepared, which was the combination of flame retardant and synergist. Its effect on thermal properties and flammability of poly(vinyl alcohol) (PVA) has been investigated. Microscale combustion calorimetry (MCC) test proved that NiPCS can decrease the intensities of heat release rate (PHRR) and total heat release rate (THR) greatly. Thermogravimetric analysis (TGA) results indicated that NiPCS possessed a high formation of char. With the increase of the flame retardant, the thermal stability of materials enhanced in high temperature. Real time Fourier transform infrared (RT-IR) data confirmed that the flame retardant can promote the dehydration effect as well as accelerate the char forming. The volatilized products and the synergistic effect of nickel on thermal properties were both investigated with thermogravimetric analysis/infrared spectrometry (TGA-IR) and laser Raman spectroscopy (LRS). The results revealed that nickel restrained the thermal degradation of materials as well as improved the structural organization level of char.

Effect of clay loading on flammability of poly(methyl methacrylate)/clay nanocomposites

The present study is related to the investigation of flammability properties of poly(methyl methacrylate) (PMMA) after incorporation of clay. PMMA/layered silicate (nanoclay) nanocomposites with 5% loading of nanofiller were prepared using melt intercalation technique. Commercially modified nanoclays such as Cloisite 30B, Cloisite 93A and in-house modified nanoclay (Quaternary ammonium salt modified Na-MMT i.e. OTAB-Na-MMT have been used as organoclays for the preparation of nanocomposites. Thermal characterization of the above prepared nanocomposites was carried out by thermal conductivity, horizontal burning test (UL94HB) and cone calorimeter experiments. The morphological behavior of nanocomposites was characterized by wide angle x-ray diffraction technique. The morphology of charred material obtained after burning was investigated using scanning electron microscopic analysis.

Effect of aminobisphosphonated copolymer on the thermal stability and flammability of poly(methyl methacrylate)

AbstractMethyl methacrylate was copolymerized with propyl N,N‐tetramethylbis(phosphonate)‐bis(methylene)aminemethyl methacrylate (MAC3NP2). The thermal degradation and flammability of this modified poly(methyl methacrylate) (PMMA) were compared with those of pure PMMA using thermogravimetric analysis (TGA) and pyrolysis combustion flow calorimetry (PCFC). The morphology of char was investigated using scanning electron microscopy and the yield of phosphorus using energy‐dispersive X‐ray analysis. The gases evolved during degradation in TGA were analysed using Fourier transform infrared spectroscopy. The total heat release and heat release capacity of the reactively modified PMMA are reduced, as compared to pure PMMA. The modified PMMA presents a better thermal stability (above 290 °C) than pure PMMA and leads to an important char formation. A comparison among TGA, PCFC and the amount of phosphorus in the condensed phase gives useful information about the role of phosphorus in the flame retardancy of the copolymer. The result reveals the effect of phosphorus not only in the condensed phase but also in the vapour phase. Copyright © 2011 Society of Chemical Industry

A comparison of the role of boehmite (AlOOH) and alumina (Al 2O 3) in the thermal stability and flammability of poly(methyl methacrylate)

In this paper, a comparison of the role of boehmite (AlOOH) and alumina (Al 2O 3) in the thermal stability and flame retardant behaviour of poly(methyl methacrylate) (PMMA) is presented. PMMA–AlOOH and PMMA–Al 2O 3 nanocomposites were prepared by melt blending with different filler contents. These nanocomposites were studied by thermogravimetric analysis (TGA) and cone calorimetry. In the presence of the filler (alumina or boehmite), the thermal stability of the polymer appeared to be significantly improved. An increase of the decomposition temperature of between about 19 and 35 °C was demonstrated by TGA. Cone calorimeter measurements showed that the peak of heat release rate is lowered in the presence of AlOOH or Al 2O 3 in comparison to pure PMMA and that this decrease is higher when the filler content increases. When loading rate is higher (15 wt%), a significant improvement in fire resistance of PMMA was observed in both systems but with two different modes of action.

Influence of covalently bound phosphorus-containing groups on the flammability of poly(vinyl alcohol), poly(ethylene- co-vinyl alcohol) and low-density polyethylene

Poly(vinyl alcohol) and ethylene-vinyl alcohol copolymers have been phosphorylated with H 3PO 4 and H 3PO 3. The phosphorylated samples possess pendent phosphate and phosphite groups and are significantly more flame retardant than the unmodified materials. The flame retardance arises in part from a condensed-phase mechanism involving dehydration, crosslinking and intumescent char formation, similar to that observed when certain phosphorus-based additives are used with poly(vinyl alcohol), cellulose and other highly hydroxylated polymers, and in part from a vapour-phase mechanism. Low-density polyethylene can also be rendered flame retardant to a certain extent by phosphonylation.

Aromatic polyamides. III. Mechanistic studies on the role of substituent chlorine in flame retarding aromatic polyamides

AbstractThe flammability of poly(1,3‐phenylene isophthalamide) and poly(chloro‐2,4‐phenylene isophthalamide) was measured by the oxygen index method. The chloro polyamide had reduced flammability shown by a 10–15 higher oxygen index. Analysis of the chars of the two polymers at 700°C by thermogravimetry (TGA) and elemental analysis showed that the chlorine caused a significant increase in the retention of C, H, N, and O in the pyrolysis residue. Most of the chlorine in the chloro polyamide, however, was lost by 700°C. Based on these results, we have suggested that the chlorine imparts flame retardancy by a combination of vapor‐ and condensed‐phase mechanisms. The origin of condensed‐phase activity is discussed.

The effect of red phosphorus on the flammability of poly(ethylene terephthalate)

AbstractAddition of red phosphorus in concentrations of about 4% to poly(ethylene terephthalate) (PET) reduces the flammability of that polymer. The rates of flame propagation and the ignitability are reduced, while the oxygen index (O.I.) is increased. The surface temperature of burning PET amounts to TS ≈ 380°C; addition of 4% red phosphorus raises this value to TS ≈ 450°C. An increase of the environmental temperature TE enhances the flammability of PET and PET + phosphorus samples; the O.I. decreases and the rate of flame propagation increases with temperature. The flame‐retardant effectiveness of red phosphorus is reduced if the sample is burned in a N2O atmosphere. This indicates that part of the flame retardancy imparted by phosphorus involves gas‐phase inhibition. The major flame‐retardant action does, however, occur in the condensed phase, since the rate of pyrolysis of PET is affected by the presence of red phosphorus.