scholarly journals Synergistic Action of Montmorillonite with an Intumescent Formulation: The Impact of the Nature and the Strength of Acidic Sites on the Flame-Retardant Properties of Polypropylene Composites

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2781
Author(s):  
Raíssa Carvalho Martins ◽  
Michelle Jakeline Cunha Rezende ◽  
Marco Antonio Chaer Nascimento ◽  
Regina Sandra Veiga Nascimento ◽  
Simone Pereira da Silva Ribeiro
Keyword(s):  
Flame Retardant ◽  
Nitrogen Adsorption ◽  
Synergistic Action ◽  
Limit Oxygen Index ◽  
Esterification Reaction ◽  
X Ray ◽  
Polypropylene Composites ◽  
Acidic Sites ◽  
Flame Retardant Properties ◽  
The Impact

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.

scholarly journals Synthesis and Application of H-ZSM-5 Zeolites with Different Levels of Acidity as Synergistic Agents in Flame Retardant Polymeric Materials

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2110 ◽  
Author(s):  
Felipe Reis Bernardes ◽  
Michelle Jakeline Cunha Rezende ◽  
Victor de Oliveira Rodrigues ◽  
Regina Sandra Veiga Nascimento ◽  
Simone Pereira da Silva Ribeiro
Keyword(s):  
Flame Retardant ◽  
Polymeric Materials ◽  
Nitrogen Adsorption ◽  
Acid Sites ◽  
Synergistic Action ◽  
Ammonium Polyphosphate ◽  
Limiting Oxygen Index ◽  
Adsorption Analysis ◽  
Flame Retardant Properties ◽  
Temperature Programmed

Several studies show a synergistic effect between intumescent formulations and aluminosilicates, such as zeolites and clays, but little is known about the effect of acidity of these additives on the synergistic action. In this work, H-ZSM-5 zeolite was submitted to desilication treatments for 30 min and for 2 h, and silicalite-1 was synthesized. The objective was to obtain samples of equivalent crystalline structure, but with different amounts of acid sites, in order to evaluate the effect of acid concentration of H-ZSM-5 zeolites on the synergistic action with an intumescent formulation composed by ammonium polyphosphate and pentaerythritol in polypropylene. H-ZSM-5 zeolites and silicalite were characterized by X-ray diffraction, nitrogen adsorption analysis and temperature-programmed desorption of ammonia. The desilication produced H-ZSM-5 zeolites with similar volumes of mesopores in both treatments, but the zeolite resulting from 2 h of desilication presented a higher concentration of acid sites than the zeolite from 30 min. The flame-retardant properties were evaluated by UL-94 classification, limiting oxygen index, glow-wire, thermogravimetric analysis and heating microscopy. The results showed that increasing the concentration and accessibility of the acid sites of H-ZSM-5 zeolites the flame-retardant properties of the studied composites improved. It is suggested that the increase of acid site concentration positively influences the catalysis of the reaction between ammonium polyphosphate and pentaerythritol, favoring the production of the precursors of the intumescent layer.

scholarly journals Study of the Synergistic Effect of Nanoporous Nickel Phosphates on Novel Intumescent Flame Retardant Polypropylene Composites

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Shibin Nie ◽  
Chi Zhang ◽  
Chao Peng ◽  
De-yi Wang ◽  
Daowei Ding ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Intumescent Flame Retardant ◽  
The Novel ◽  
Polypropylene Composites ◽  
Pp Composites ◽  
Flame Retardant Properties ◽  
Microencapsulated Ammonium Polyphosphate ◽  
Thermal Stability Of ◽  
Nickel Phosphates ◽  
Limited Oxygen

A char forming agent (CFA) and silica-gel microencapsulated ammonium polyphosphate (Si-MCAPP) were selected to form novel intumescent flame retardant system to prepare flame retardant polypropylene (PP) composites, and then the influences of nanoporous nickel phosphates (NiP) on the thermal and flame retardant properties of flame retardant PP composites were studied by the real time FTIR (RTFTIR) spectra, limited oxygen index (LOI) test, and the scanning electron microscopy. RTFTIR shows the addition of NiP can improve the thermal stability of flame retardant PP composites. LOI test shows LOI value is increased with the increase of the content of NiP, and the optimized concentration of NiP is 1.0%. Furthermore, smoke toxicity of the novel flame retardant PP composites was studied by mice experiment. The upper limit of the no death smoke concentration of the composite is 12.37 mg/L.

scholarly journals Preparation of β-Cyclodextrin Inclusion Complex and Its Application as an Intumescent Flame Retardant for Epoxy

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 71 ◽  
Author(s):  
Xueying Shan ◽  
Kuanyu Jiang ◽  
Jinchun Li ◽  
Yan Song ◽  
Ji Han ◽  
...  
Keyword(s):  
Carbon Source ◽  
Inclusion Complex ◽  
Flame Retardant ◽  
1H Nmr ◽  
Intumescent Flame Retardant ◽  
Molar Ratio ◽  
Gravimetric Analysis ◽  
X Ray ◽  
Cone Calorimeter Test ◽  
The Impact

A new P-N containing the flame retardant, which was namely N,N′-dibutyl-phosphate diamide (DBPDA), was synthesized and it was assembled into the cavity of β-cyclodextrin (β-CD) to form an inclusion complex (IC). The structure and properties of IC were characterized by Fourier transform infraredspectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), 1H nuclear magnetic resonance (1H NMR), scanning electron microscopy with X-ray microanalysis (SEM-EDS), differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). 1H NMR and SEM-EDS were also used to identify the molar ratio of β-CD/DBPDA in IC and the results from the analyses indicated that their molar ratio was 1:1. In order to test the flame retardant effect of IC, it was added to epoxy (EP). IC was proposed to be able to act as an intumescent flame retardant (IFR) system in EP through a combination of β-CD and DBPDA properties during the combustion process. β-CD is a biomass carbon source, which has the advantages of environmental protection and low cost. Furthermore, DBPDA is both a source of acid and gas. When IC was heated, IC had the advantage of acting as both a carbon source and foam forming agent, while the DBPDA component were able to directly generate phosphoric acid and NH3 in situ. The impact of IC in low additive amounts on flame retardancy of EP was studied by the cone calorimeter test. When only 3 wt % IC was incorporated, the peak values of heat release rate (pHRR) and smoke production rate (pSPR) of EP were reduced by 22.9% and 33.3% respectively, which suggested that IC could suppress the heat and smoke release efficiently.

The intercalation of ammonium sulfamate into kaolinite and its effect on the fire performance of polypropylene

2017 ◽  
Vol 31 (10) ◽  
pp. 1352-1370 ◽  
Author(s):  
Wufei Tang ◽  
Hongfei Li ◽  
Sheng Zhang ◽  
Jun Sun ◽  
Xiaoyu Gu
Keyword(s):  
Flame Retardant ◽  
Oxygen Index ◽  
Potassium Acetate ◽  
Limit Oxygen Index ◽  
Fire Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Heat Release Rate ◽  
Ammonium Sulfamate ◽  
Xrd Patterns

Kaolinite has often been intercalated before being introduced into polymers to improve its dispersibility; however, the conventional intercalation usually reduces the flame retardancy of the composite. This work reports our recent efforts on improving both the flame retardant efficiency and dispersibility of kaolinite in polypropylene (PP) by intercalating with ammonium sulfamate (AS). The intercalation had been performed through three steps: dimethyl sulfoxide was firstly introduced into kaolinite layers under supersonic wave, then it was replaced by potassium acetate-aqueous (KAc), and finally the intercalated KAc was replaced by AS to obtain AS-intercalated kaolinite. The structure of intercalated kaolinite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, and thermogravimetric analysis (TGA). The flammability evaluation by limit oxygen index, vertical burning test (UL-94), cone calorimeters test (CONE), and TGA indicated that the fire resistance, thermal stability, and physical properties of PP can be effectively enhanced by the introduction of AS-intercalated kaolinite. The peak heat release rate (pHRR) value of PP composite containing only 1.5 wt% intercalated kaolinite (1169 kW m−2) had been reduced 13.2% compared with that of the sample containing 1.5 wt% raw kaolinite (1346 kW m−2). The morphology analysis from scanning electron microscope images and XRD patterns demonstrated that the compatibility and dispersibility of kaolinite in PP had been significantly improved by intercalation. The flame retardant mechanism of AS-intercalated kaolinite in PP was proposed.

SOLID SULFONIC ACID CATALYSTS BASED ON POROUS CARBONS AND CARBON–SILICA COMPOSITES

2011 ◽  
Vol 18 (06) ◽  
pp. 229-239 ◽  
Author(s):  
XIAO NING TIAN ◽  
LIJUAN LUO ◽  
ZHONGQING JIANG ◽  
X. S. ZHAO
Keyword(s):  
Acetic Acid ◽  
Electron Microscope ◽  
Photoelectron Spectroscopy ◽  
Nitrogen Adsorption ◽  
Esterification Reaction ◽  
Mesoporous Carbons ◽  
Templating Method ◽  
X Ray ◽  
Transmission Electron ◽  
Silica Template

Mesoporous carbons prepared using a templating method under different carbonization temperatures are sulfonated with concentrated H2SO4 . Without the moving of silica template carbon–silica composites were prepared, which can maintain the pore structure well during sulfonation reaction process. The resultant samples are characterized using nitrogen adsorption, transmission electron microscope, field-emission scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, and elemental analysis techniques. The catalytic performances of the sulfonated carbons and composites are evaluated by esterification reaction of methanol with acetic acid. The results show that a low-temperature carbonization process is favorable for improving the reaction conversion of acetic acid. In addition, the sulfonated carbon–silica composites show a higher acetic acid conversion than the sulfonated mesoporous carbons.

Synergistic effects of intumescent flame retardant and nano-CaCO3 on foamability and flame-retardant property of polypropylene composites foams

2017 ◽  
Vol 54 (3) ◽  
pp. 615-631 ◽  
Author(s):  
Li Depeng ◽  
Li Chixiang ◽  
Jiang Xiulei ◽  
Liu Tao ◽  
Zhao Ling
Keyword(s):  
Mechanical Properties ◽  
Stress Concentration ◽  
Flame Retardant ◽  
Synergistic Effects ◽  
Crystallization Rate ◽  
Intumescent Flame Retardant ◽  
Limit Oxygen Index ◽  
Scanning Calorimetry ◽  
Polypropylene Composites ◽  
Flame Retardant Property

Synergistic effects of intumescent flame retardant and nano-CaCO3 on foamability and flame retardant property of polypropylene composites and their foams were carefully investigated. The differential scanning calorimetry results showed that the intumescent flame retardant played a plasticizing effect on the polypropylene/intumescent flame-retardant composites and accelerated the crystallization rate. The rheological properties and supercritical CO2-assisted molding foaming behaviors of the polypropylene/intumescent flame retardant/nano-CaCO3 composites showed that the nano-CaCO3 could enhance their foamability. Scanning electron microscopy pictures and mechanical properties of the polypropylene/intumescent flame-retardant composites foams indicated that the agglomeration of intumescent flame retardant would reduce the cell uniformity and even cause the cell collapse. Furthermore, the stress concentration, caused by the agglomeration, could reduce the mechanical properties of the PP composites foams. The synergistic effect of the nano-CaCO3 could improve the cell uniformity and reduce the stress concentration so that the mechanical properties of the polypropylene/intumescent flame retardant /nano-CaCO3 composites foams were improved. Moreover, the polypropylene/intumescent flame retardant/nano-CaCO3 composites foams had the higher limit oxygen index values than the polypropylene/intumescent flame-retardant foams. TGA results also showed that the nano-CaCO3 could improve the thermal stability of the polypropylene composites foams by forming compact carbon layer. The experimental results indicated that the foamability of the polypropylene composites and the flame-retardant property of their foams could be improved by the synergistic effects of intumescent flame retardant and nano-CaCO3.

scholarly journals Enhancing Flame Resistance of Cellulosic Fibers Using an Ecofriendly Coating

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 179
Author(s):  
Riadh Zouari ◽  
Sondes Gargoubi
Keyword(s):  
Acrylic Acid ◽  
Flame Retardant ◽  
Advanced Materials ◽  
Attenuated Total Reflectance ◽  
Flame Resistance ◽  
X Ray ◽  
Cellulosic Fibers ◽  
Flame Retardant Properties ◽  
Cellulosic Textiles ◽  
Textile Coating

Among the various advanced materials, flame-retardant cellulosic textiles are important as they directly relate to human health and hazards. The use of environmentally friendly flame-retardant coatings is currently one of the major concerns in the textile coating industry. In this work, acrylic acid was grafted onto the surface of cotton using plasma technology to enhance the attachment of acrylate phosphate monomer. Surface analyses, such as scanning electron microscopy (SEM), energy dispersive x-ray (EDX) and attenuated total reflectance Fourier-transform infrared (ATR-FTIR), were carried out to characterize the coating. Textile properties such as wettability and mechanical properties of untreated and treated cotton samples were investigated. A laundering test was also performed to predict the durability of the finishing. The outcomes revealed that acrylic acid-grafted samples treated with acrylate phosphate monomer have good flame-retardant properties.

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