Showing papers on "Fire retardant published in 2012"

Effect of flame retardants on mechanical properties, flammability and foamability of PP/wood–fiber composites

Abstract: The mechanical properties, flame retardancy, thermal degradation and foaming properties of wood–fiber/PP composites have been investigated. Ammonium polyphosphate (APP) and silica were used as flame retardants. The limiting oxygen index (LOI), thermal gravimetric analysis (TGA) and cone colorimeter (CONE) were employed for the study of fire retardance. At the same time, wood–fiber/PP composite foams were produced with the batch foaming technique using CO 2 as blowing agent. The effects of APP and silica content, pressure and temperature on the final cell structure were investigated. According to LOI, TGA and cone calorimeter results obtained from the experiments, APP and silica are effective flame retardants for wood–fiber/PP composites, and silica was shown to have a flame retardant synergistic effect with APP in wood–fiber/PP composite. The mechanical properties of the composites decreased with addition of flame retardants, except for the tensile strength of small amount of silica filled wood–fiber/PP composite. The results also revealed that the cellular morphologies of the foamed wood–fiber/PP composites are a strong function of the content of APP and silica as well as foaming conditions.

Halogen-Free Flame-Retardant Flexible Polyurethane Foam with a Novel Nitrogen–Phosphorus Flame Retardant

Abstract: A novel nitrogen–phosphorus flame retardant, 2-carboxyethyl(phenyl)phosphinic acid melamine salt (CMA), was synthesized by the reaction of 2-carboxyethyl(phenyl)phosphinic acid with melamine in aqueous solution, and it was characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), inductively coupled plasma-atomic emission spectrometry (ICP-AES), elemental analysis, and thermogravimetric analysis (TGA). Halogen-free flame-retardant flexible polyurethane foams (FPUF) were prepared successfully by using CMA as a flame retardant. The effects of CMA content on the mechanical, thermal, and flame-retardant properties of FPUF were investigated by tensile test, TGA, limiting oxygen index (LOI), flame propagation test (Cal T.B. 117A-Part I standard), and cone calorimeter. The foam morphology of FPUF was studied via scanning electron microscopy (SEM). The results showed that CMA endowed FPUF with good flame-retardant properties. FPUF containing only 12 wt % CMA can pass Cal ...

Fire retardancy and morphology of layered double hydroxide nanocomposites: a review

Abstract: One of the methods to reduce the flammability of polymeric materials is the incorporation of layered double hydroxides (LDHs) into the polymer matrix. Dispersing LDH into the polymer matrix results in the formation of nanocomposites with significantly improved thermal and fire retardant properties. In this review the focus is mainly on the dispersion of LDH within the polymer matrix and how the dispersion affects the fire retardant properties of polymer–LDH nanocomposites.

Functionalized graphene oxide for fire safety applications of polymers: a combination of condensed phase flame retardant strategies

Abstract: Graphene is promising for the fire safety applications of polymers, but the ease of burn out limits further developments. A novel strategy based on functionalized graphene oxide (FGO) is developed to overcome this challenge. Graphene oxide is functionalized with char-catalyzing agents and reactive compounds and incorporated into polystyrene. When FGO–polystyrene composites are degraded or burned, FGO catalyzes the char formation from polystyrene (Char A). Char A protects FGO from burning out and then FGO acts as a graphitic char (Char B). Because of the combination of Char A, Char B, the physical barrier effects of FGO, and the strong interfacial interactions of FGO and polymers, the fire safety properties of the FGO–polystyrene composites are improved, including decreased peak CO release rate (66% decrease), decreased peak CO2 release rate (54% decrease), decreased peak heat release rate (53% decrease), decreased thermal degradation rate (30% decrease), decreased total heat release (38% decrease), and increased char formation (7 times), etc. This strategy combines several condensed phase flame retardant strategies such as the nanocomposite technique, intumescent flame retardant systems and phosphorus–nitrogen synergism systems, and hence results in more significant improvements as compared with prior work.

Thermal Degradation and Flame Retardance of Biobased Polylactide Composites Based on Aluminum Hypophosphite

Abstract: A series of flame retardant polylactide composites (FR-PLA) based on aluminum hypophosphite (AHP) were facilely prepared by melt blending method. The thermal behavior, flammability, and mechanical properties of FR-PLA composites were investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), the UL-94 vertical burning test, limiting oxygen index (LOI), cone calorimeter testing, microscale combustion calorimetry, mechanical testing, and dynamic mechanical analysis (DMA). TGA results showed that the FR-PLA composites presented higher char residue and reduced mass loss rate than neat PLA. The FR-PLA composite showed excellent fire resistance, from no rating of neat PLA to a V0 rating of FR-PLA containing 20 wt % aluminum hypophosphite in the UL-94 test. The microscale combustion calorimetry test showed that the heat release capacity, the peak of heat release and the total heat release of FR-PLA composites were significantly decreased with the increase of AHP content. The cone ...

Modification of lignin and its application as char agent in intumescent flame‐retardant poly(lactic acid)

Abstract: Urea-modified lignin was prepared according to the Mannich reaction and well characterized by Fourier transform infrared spectrometer, elemental ananlyses, and scanning electron microscopy (SEM). Ammonium polyphosphate (APP) and urea-modified lignin were added into poly(lactic acid) (PLA) as a novel intumescent flame-retardant (IFR) system to improve flame retardancy of PLA. The flammability of IFR–PLA composites was studied using limiting oxygen index, UL-94 vertical burning method and cone calorimeter test, and their thermal stability was evaluated by thermogravimetric analysis. The results showed that the urea-modified lignin combined with APP exhibited much better flame retardancy and thermal stability than that of the combination of virgin lignin and APP. The improvement may be attributed to the better char morphology with more phosphoric char evidenced by SEM and X-ray photoelectron spectroscopy. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

Investigation of fire behavior of rigid polyurethane foams containing fly ash and intumescent flame retardant by using a cone calorimeter

Abstract: Cone calorimeter is one of the most useful bench-scale equipment which can simulate real-world fire conditions. Therefore, cone calorimeter tests have been the most important and widely used tests for research and development of fire behavior of polymeric materials. In this study, fire behavior of rigid polyurethane foams containing fly ash (up to 5 wt %) and intumescent flame retardant (up to 5 wt %) composed of ammonium polyphosphate/pentaerythritol was investigated by using a cone calorimeter. In addition, thermogravimetric analysis of the additives and the foams were also carried out to explain the effects of fly ash and intumescent flame retardant on fire behavior of the foams. Experimental results indicated that rigid polyurethane foam containing fly ash and the intumescent flame retardant in comparison with pure rigid polyurethane foam shows significantly enhanced fire resistance and thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Structural characteristics and flammability of fire retarding EPDM/layered double hydroxide (LDH) nanocomposites

Abstract: A high performance elastomeric flame retardant nanocomposite was prepared which was based on maleic anhydride grafted ethylene-propylene-diene terpolymer (mEPDM), a one-step synthesised organo-layered double hydroxide (LDH), and an intumescent flame retardant (FR) comprised of pentaerythritol (PER), ammonium polyphosphate (APP) and methyl cyanoacetate (MCA). The morphology, fire behavior and mechanical properties of the flame-retarded mEPDM/LDH nanocomposite have been studied in detail. Wide angle X-ray scattering (WAXS), small angle X-ray scattering (SAXS) and TEM observation confirmed an exfoliated structure of LDH in a particular composite containing 2 phr (parts per hundred) LDH and 38 phr FR. As an effective flame retardant synergistic agent, MgAl–LDH shows a significant decrease in the heat release rate (HRR), low mass loss (ML) and low fire growth rate (FIGRA) of the nanocomposite. The flame retardant mechanism has been proposed, which is mainly due to the condensed phase flame retardant mechanism to form reinforced char layers during combustion, leading to the low volatiles produced. Moreover, as far as the mechanical properties of the vulcanizates are concerned, in all cases of flame retardant mEPDM and flame retarded mEPDM/LDH nanocomposites, they exhibit superior values compared to the gum compound.

Phosphorus-containing compounds useful for making halogen-free, ignition-resistant polymers

Abstract: Phosphorus-containing compounds useful for flame retardant epoxy resins are disclosed. The flame retardant epoxy resins may be used to make electrical laminates. This invention is particularly useful in end use applications in which a low bromine or low halogen content is required or desired.

Iron-montmorillonite and zinc borate as synergistic agents in flame-retardant glass fiber reinforced polyamide 6 composites in combination with melamine polyphosphate

Abstract: This paper presents a preliminary investigation on the effects of organically modified iron-montmorillonite (Fe-OMT) and zinc borate (ZnB) on thermal degradation behaviors and flame retardancy of melamine polyphosphate (MPP) flame-retarded glass fiber reinforced polyamide 6 (GFPA6). The samples were characterized using limiting oxygen index (LOI), UL-94 tests, thermogravimetric analysis (TGA), Fourier transform infrared coupled with the thermogravimetric analyzer (TG-FTIR) and Microscale Combustion Calorimeter (MCC) measurements. The residue after LOI test was also analyzed by Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and Raman spectroscopy. A substitution of a certain fraction of MPP with ZnB or Fe-OMT can significantly improve the UL-94 rating of GFPA6/MPP composites from no rating to V0 rating, exhibiting excellent flame retardacny. Based on the investigations, different flame retardant mechanisms were proposed for the two effective flame-retardant formulations.

Functionalization of Cotton with UV-Cured Flame Retardant Coatings

Abstract: A novel phosphorus monomer (PDHA) was synthesized and incorporated onto the surface of cotton fabric via UV-induced graft polymerization to improve flame retardancy and thermal stability. The structure of PDHA was characterized by 1H nuclear magnetic resonance (1H NMR), 31P NMR, and Fourier transform infrared spectra (FTIR) and the grafting processes were followed by IR (ATR) spectroscopy and scanning electron microscopy (SEM). The thermal stability and flame retardancy of the treated fabrics were studied by thermogravimetric analysis (TGA), thermogravimetric analysis/infrared spectrometry (TGA-IR), and microscale combustion colorimeter (MCC). Test performed on real time FTIR analysis for treated cotton showed that the coatings containing phosphorus could catalyze the dehydration and char formation of cotton textiles at a lower temperature. The enhanced flame retardant action may be caused by the thermal decomposition of phosphate acrylate producing acidic intermediates, which could react with fabrics to ...

Synthesis of novel triazine charring agent and its effect in intumescent flame-retardant polypropylene

Abstract: A novel charring agent (CNCA-DA) containing triazine and benzene ring, using cyanuric chloride, aniline, and ethylenediamine as raw materials, was synthesized and characterized. The effects of CNCA-DA on flame retardancy, thermal degradation, and flammability properties of polypropylene (PP) were investigated by limited oxygen index (LOI), vertical burning test (UL-94), thermogravimetric analysis (TGA), and cone calorimeter test (CCT). The TGA results showed that CNCA-DA had a good char forming ability, and a high initial temperature of thermal degradation; the char residue of CNCA-DA reached 18.5% at 800°C; Ammonium polyphosphate (APP) could improve the char residue of APP/CNCA-DA system, the char residue reached 31.6% at 800°C. The results from LOI and UL-94 showed that the intumescent flame retardant (IFR) containing CNCA-DA and APP was very effective in flame retardancy of PP. When the mass ratio of APP and CNCA-DA was 2 : 1, and the IFR loading was 30%, the IFR showed the best effect; the LOI value reached 35.6%. It was also found that when the IFR loading was only 20%, the flame retardancy of PP/IFR can still pass V-0 rating in UL-94 tests, and its LOI value reached 27.1%. The CCT results demonstrated that IFR could clearly change the decomposition behavior of PP and form a char layer on the surface of the composites, consequently resulting in efficient reduction of the flammability parameters, such as heat release rate (HRR), total heat release (THR), smoke production rate (SPR), total smoke production (TSP), and mass loss (ML). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012