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

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.

Buildings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 24
Author(s):  
Jonathan Almirón ◽  
María Vargas ◽  
Danny Tupayachy-Quispe ◽  
Sophie Duquesne ◽  
Francine Roudet ◽  
...  

In this research, the influence of natural zeolites obtained from the volcanic ash of the Ubinas volcano has been studied as synergistic agents in a flame-retardant system (composed of ammonium polyphosphate, pentaerythritol, and polypropylene). Four zeolites were synthesized from volcanic ash, including those that had been calcined and those that had not. These were then placed in an alkaline solution at three synthesis temperatures. Zeolites were characterized through X-ray diffraction, specific surface area by nitrogen adsorption analysis (Brunauer–Emmett–Teller) and scanning electron microscopy. Polypropylene matrix composites were prepared with ammonium polyphosphate, pentaerythritol and zeolites at 1, 5 and 9%. Its thermal stability and fire resistance were evaluated by thermogravimetric analysis, limiting oxygen index, vertical burning test and cone calorimeter and its morphological structure by scanning electron microscopy. It was determined that the synthesis temperature and the use of calcined and without calcined volcanic ash have an influence on the characteristics of the zeolites and on its synergistic action.


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

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.


2015 ◽  
Vol 1115 ◽  
pp. 406-409 ◽  
Author(s):  
Fatimah A’thiyah Sabaruddin ◽  
Noorasikin Samat ◽  
A.I.H Dayang Habibah

It is known that polymeric materials are easily to get on fire due to their chemical structures. Thus the flame retardant material such as aluminium hydroxide (ATH) is used to improve the flame retardancy property of polymers. Polypropylene (PP) with various amount of nanosized ATH particles of (5, 10, 20, 30, 40 wt%) were compounded with an extruder machine. The effects of two different type of coupling agent (3-Aminopropyltriethoxysilane (APS) and Maleic anhydride grafted polypropylene (MAPP)) on the flame retardant properties were compared. All samples were characterized with two flame tests; the limiting oxygen index (LOI) and UL94 horizontal burning test (UL94 HB). It is found that both tests showed improvement on the flame resistance properties of the nanocomposites, mainly at high ATH loadings. Type of coupling agents affects the flame retardancy properties of PP/ATH nanocomposites.


2019 ◽  
Vol 37 (4-6) ◽  
pp. 434-451 ◽  
Author(s):  
Jonathan Almirón ◽  
Francine Roudet ◽  
Sophie Duquesne

This research determines whether the materials of volcanic ash (CV), rice husk ash (CR), and thermally treated solid waste (RS-T), coming from the pyrolysis of plastics, have some flame-retardant effect when added to polypropylene flame-retardant additives (such as ammonium polyphosphate and pentaerythritol). These materials were characterized by specific surface area by nitrogen adsorption analysis (Brunauer–Emmett–Teller) and X-ray fluorescence and X-ray diffraction methods. It was determined that SiO2 and Al2O3 are considered as flame-retardant minerals. Composites composed of polypropylene, ammonium polyphosphate, pentaerythritol, and these materials at several concentrations, from 1% to 9%, were prepared. The thermal stability and flame retardancy of the composites synthesized were investigated based on the limiting oxygen index, thermogravimetric analysis, and cone calorimetry. It was determined that these materials have a synergistic action with flame-retardant additives by increasing the fireproof properties of polypropylene. Mechanical properties were determined by tensile tests.


2015 ◽  
Vol 30 (6) ◽  
pp. 816-826 ◽  
Author(s):  
Yiren Huang ◽  
Jianwei Yang ◽  
Zhengzhou Wang

Flame-retardant properties of ammonium polyphosphate (APP) and its two microcapsules, APP with a shell of melamine–formaldehyde (MF) resin (MFAPP) and APP with a shell of epoxy resin (EPAPP), were studied in styrene–butadiene–styrene (SBS). The results indicate that APP after the microencapsulation leads to an increase in limiting oxygen index in SBS compared with APP. When dipentaerythritol is incorporated into the SBS composites containing the APP microcapsules, a further improvement in flame retardancy of the composites is observed. The microencapsulation does not result in much improvement of mechanical properties. Moreover, the effect of a compatibilizer (SBS grafted with maleic anhydride) on flame-retardant and mechanical properties of SBS/APP composites was investigated.


e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 235-243 ◽  
Author(s):  
Lin Liu ◽  
Rui Lv

AbstractA DOPO (9,10-dihydro-9-oxa-10-phosphaphen-anthrene-10-oxide)-based halogen-free flame retardant (ODOPM-CYC) was synthesized and incorporated in rigid polyurethane foam (RPUF). The structure of ODOPM-CYC was characterized by Fourier transform infrared spectra (FTIR), 1H NMR and 31P NMR. The effects of ODOPM-CYC on the flame resistance, mechanical performances, thermal properties and cell structure of RPUF were also investigated. The results showed that the incorporation of ODOPM-CYC strikingly enhanced flame retardant properties of RPUF. The flame retarded RPUF acquired a limiting oxygen index (LOI) value of 26% and achieved UL-94 V-0 rating with the phosphorus content of 3 wt%. The smoke production rate (SPR) also showed an obvious decrease and total smoke release (TSR) was 39.8% lower than that of neat RPUF. Besides, the results demonstrated that the incorporation of ODOPM-CYC provided RPUF better thermal stability but did not show any obvious influence on its thermal conductivity.


Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4123 ◽  
Author(s):  
Kata Decsov ◽  
Katalin Bocz ◽  
Beáta Szolnoki ◽  
Serge Bourbigot ◽  
Gaëlle Fontaine ◽  
...  

Ammonium-polyphosphate (APP) was modified by microencapsulation with a bio-based sorbitol polyglycidyl ether (SPE)-type epoxy resin and used as a flame retardant additive in polylactic acid (PLA) matrix. The bioresin-encapsulated APP (MCAPP) particles were characterized using Fourier transform infrared (FTIR) spectroscopy and Raman mapping, particle size distribution was determined by processing of scanning electron microscopic (SEM) images. Interaction between the APP core and the bioresin shell was revealed by combined thermogravimetric analysis (TGA)‑FTIR spectroscopy. The APP to SPE mass ratio of 10 to 2 was found to be optimal in terms of thermal, flammability, and mechanical properties of 15 wt% additive containing biocomposites. The bioresin shell effectively promotes the charring of the APP-loaded PLA composites, as found using TGA and cone calorimetry, and eliminates the flammable dripping of the specimens during the UL-94 vertical burning tests. Thus, the V-0 rating, the increased limiting oxygen index, and the 20% reduced peak of the heat release rate was reached compared to the effects of neat APP. Furthermore, better interfacial interaction of the MCAPP with PLA was indicated by differential scanning calorimetry and SEM observation. The stiff interphase resulted in increased modulus of these composites. Besides, microencapsulation provided improved water resistance to the flame retardant biopolymer system.


2019 ◽  
Vol 14 ◽  
pp. 155892501987030
Author(s):  
Yinchun Fang ◽  
Xinhua Liu ◽  
Cuie Wang

Layer-by-layer assembly is a simple and effective method which has been widely studied to improve the flame retardancy of textiles in recent years. In this article, flame-retardant and anti-dripping polyethylene terephthalate fabrics were successfully prepared by layer-by-layer assembly branched polyethylenimine and ammonium polyphosphate on their surface. The results of limiting oxygen index values and vertical burning test revealed that the flame retardancy and anti-dripping performance of polyethylene terephthalate fabrics were improved after the layer-by-layer assembly treatment; especially, the dripping phenomenon was eliminated when the number of branched polyethylenimine/ammonium polyphosphate bilayers was over 10. The influence of alkali treatment of polyethylene terephthalate fabrics before layer-by-layer assembly was also investigated. The results showed that alkali treatment of the polyethylene terephthalate fabrics would promote the combination of polyethylene terephthalate fabrics and the charged flame retardants indicating better flame retardancy. The results of thermogravimetric analysis revealed that layer-by-layer assembly treatment of polyethylene terephthalate fabrics would promote char formation both under the nitrogen atmosphere and under the air atmosphere which may act through condensed phase action. The scanning electron microscopy images of the char residues revealed that the layer-by-layer assembly treatment of polyethylene terephthalate fabrics would promote the formation of a compact and intact char residue, which was beneficial for the improvement of flame retardancy and anti-dripping performance. This research would provide the experimental basis for the effective flame retardancy and anti-dripping performance of polyethylene terephthalate fabric.


Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1708 ◽  
Author(s):  
Wang ◽  
Teng ◽  
Yang ◽  
You ◽  
Zhang ◽  
...  

In this article, the intumescent flame-retardant microsphere (KC-IFR) was prepared by inverse emulsion polymerizations, with the use of k-carrageenan (KC) as carbon source, ammonium polyphosphate (APP) as acid source, and melamine (MEL) as gas source. Meanwhile, benzoic acid functionalized graphene (BFG) was synthetized as a synergist. A “four-source flame-retardant system” (KC-IFR/BFG) was constructed with KC-IFR and BFG. KC-IFR/BFG was blended with waterborne epoxy resin (EP) to prepare flame-retardant coatings. The effects of different ratios of KC-IFR and BFG on the flame-retardant properties of EP were investigated. The results showed that the limiting oxygen index (LOI) values increased from 19.7% for the waterborne epoxy resin to 28.7% for the EP1 with 20 wt% KC-IFR. The addition of BFG further improved the LOI values of the composites. The LOI value reached 29.8% for the EP5 sample with 18 wt% KC-IFR and 2 wt% BFG and meanwhile, UL-94 test reached the V-0 level. In addition, the peak heat release (pHRR) and smoke release rate (SPR) of EP5 decreased by 63.5% and 65.4% comparing with EP0, respectively. This indicated the good flame-retardant and smoke suppression property of EP composites coating.


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