Synergism between Intumescent Flame Retardant and Organo-Montmorillonite in Polypropylene Nanocomposites

2013 ◽  
Vol 785-786 ◽  
pp. 502-507 ◽  
Author(s):  
Ya Jun Chen ◽  
Chao Wang ◽  
Chun Zhuang Yang

A simple method of melt blending was used to prepare PP, PP/IFR and PP/IFR/OMMT composites. The Flammability and mechanical property of the composites were investigated. Limiting oxygen index (LOI) tests and cone calorimetry results indicate that there are synergisms between IFR and OMMT. Incorporation of OMMT led to a further increase in LOI value of intumescent retarded PP samples when the addition amounts of OMMT are less than 2%. Cone calorimeter measurements demonstrate that the peak heat release rate (PHRR), average mass loss rates (AMLR) and fire growth rate index (FIGRA) of PP/IFR/OMMT composites are all less than that of PP/IFR30 when OMMT contents are less than 1.5% (including 1.5%).Char residues after cone calorimeter tests were investigated. Unlike the expansion char residue of PP/IFR, the char residues of PP/IFR/OMMT display a lower height and compact morphology, which are due to the barrier effect of OMMT. The presence of less than 1.5% OMMT can somewhat enhance the tensile strength and Izod impact strength of PP/IFR/OMMT composites. Larger OMMT amounts decrease the above mechanical properties.

2018 ◽  
Vol 38 (2) ◽  
pp. 62-73 ◽  
Author(s):  
Andrea Dorigato ◽  
Giulia Fredi ◽  
Luca Fambri ◽  
José-Marie Lopez-Cuesta ◽  
Alessandro Pegoretti

This work aims to investigate the fire performance of novel polyethylene-based single polymer composites. Fumed silica nanoparticles and magnesium hydroxide microfiller were added at an optimized concentration to a linear low-density polyethylene matrix, which was then reinforced with ultra-high molecular weight polyethylene fibers. Through the optimization of the production process, it was possible to limit the porosity inside the single polymer composites, thus retaining the pristine mechanical properties of the fibers. The addition of SiO2 and magnesium hydroxide determined an increase in the elastic modulus in both the longitudinal and transversal direction, but it concurrently led to a reduction in ductility, especially in the transversal direction. The fillers were proved to bring interesting improvements of the thermal degradation resistance and of the flame behaviour. Thermogravimetric analysis tests highlighted an increase in the onset degradation temperature and in the temperature associated to the maximum degradation rate. Moreover, both the oxidation onset temperature and limiting oxygen index were considerably improved. Cone calorimetry tests evidenced that filled single polymer composites were characterized by lower peak heat release rate and total heat released with respect to neat single polymer composites.


Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 48 ◽  
Author(s):  
Muhammad Maqsood ◽  
Gunnar Seide

Starch, being a polyhydric compound with its natural charring ability, is an ideal candidate to serve as a carbonization agent in an intumescent system. This charring ability of starch, if accompanied by an acidic source, can generate an effective intumescent flame retardant (IFR) system, but the performance of starch-based composites in an IFR system has not been tested in detail. Here, we describe a PLA-based IFR system consisting of ammonium polyphosphate (APP) as acidic source and cornstarch as carbon source. We prepared different formulations by melt compounding followed by molding into sheets by hot pressing. The thermal behavior and surface morphology of the composites was investigated by thermogravimetric analysis and scanning electron microscopy respectively. We also conducted limiting oxygen index (LOI), UL-94, and cone calorimetry tests to characterize the flame-retardant properties. Cone calorimetry revealed a 66% reduction in the peak heat release rate of the IFR composites compared to pure PLA and indicated the development of an intumescent structure by leaving a residual mass of 43% relative to the initial mass of the sample. A mechanism of char formation has also been discussed in detail.


2021 ◽  
Vol 8 (3) ◽  
pp. 33-39
Author(s):  
Chen Chen ◽  
Shuai Wang ◽  
Zheng Zhang ◽  
Dongdong Wei ◽  
Jian Liu ◽  
...  

Poly[tetra(tetramethylcyclosiloxyl-piperazin)-phosphinic acid methyl ether) (PNCTSi) was successfully synthesized, and its chemical structure was investigated by Fourier transform infrared spectra (FTIR) and nuclear magnetic resonance (1H-NMR and 13C-NMR) spectroscopy. The flammability and thermal decomposition behaviors of cotton fabrics treated with PNCTSi were systematically evaluated by limiting oxygen index (LOI), vertical burning test (UL-94), thermogravimetric analysis (TGA), and cone calorimetry. As a result, the LOI value reached 30.1% and the char length decreased to 10.3 cm when cotton fabrics were treated in 300 g/L of PNCTSi solution for 30 min. According to TGA results, the residual rate of treated cotton fabrics at 800 °C increased to 16.4%. The peak heat release rate (PHRR) and CO2/CO ratio significantly decreased.


Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1801
Author(s):  
Rafał Oliwa ◽  
Joanna Ryszkowska ◽  
Mariusz Oleksy ◽  
Monika Auguścik-Królikowska ◽  
Małgorzata Gzik ◽  
...  

We investigated the effect of the type and amount of expandable graphite (EG) and blackcurrant pomace (BCP) on the flammability, thermal stability, mechanical properties, physical, and chemical structure of viscoelastic polyurethane foams (VEF). For this purpose, the polyurethane foams containing EG, BCP, and EG with BCP were obtained. The content of EG varied in the range of 3–15 per hundred polyols (php), while the BCP content was 30 php. Based on the obtained results, it was found that the additional introduction of BCPs into EG-containing composites allows for an additive effect in improving the functional properties of viscoelastic polyurethane foams. As a result, the composite containing 30 php of BCP and 15 php of EG with the largest particle size and expanded volume shows the largest change in the studied parameters (hardness (H) = 2.65 kPa (+16.2%), limiting oxygen index (LOI) = 26% (+44.4%), and peak heat release rate (pHRR) = 15.5 kW/m2 (−87.4%)). In addition, this composite was characterized by the highest char yield (m600 = 17.9% (+44.1%)). In turn, the change in mechanical properties is related to a change in the physical and chemical structure of the foams as indicated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis.


2017 ◽  
Vol 31 (4) ◽  
pp. 514-534 ◽  
Author(s):  
Li Dang ◽  
Xueying Nai ◽  
Xin Liu ◽  
Donghai Zhu ◽  
Yaping Dong ◽  
...  

Isotactic polypropylene (iPP) composites containing magnesium oxysulfate whisker (MOSw) or lauric acid-modified MOSw (LA-MOSw) were prepared via melt mixing in a torque rheometer. Scanning electron microscopy pictures showed that the interface between MOSw and iPP matrix was defined, whereas a vague interface was seen in the iPP–LA-MOSw composites. Mechanical properties of these two groups of composites were investigated in terms of tensile, notched impact, and flexural behavior aspects for the purposes of studying toughening effect of MOSw and LA-MOSw. Tensile results showed that yield strength of composites further reduced with the presence of LA, indicating the decrease in interfacial interaction bewteen iPP matrix and MOSw. As such, LA-MOSw performed better than MOSw in toughening of iPP matrix. Flexural strength and modulus of iPP–MOSw composites increased sharply with the increase in MOSw content, while less dependence on the LA-MOSw content indicated that MOSw was deemed beneficial to increase the stiffness. In addition, flammability properties were investigated by cone calorimetry experiment. The results showed that the peak heat release rate apparently reduced with addition of MOSw or LA-MOSw. Besides, iPP–LA-MOSw composites showed higher specific extinction area values than iPP–MOSw composites, which meant the weaker smoke suppression effect of LA-MOSw. It was chiefly because of the incomplete combustion caused by the continuous and complete charred (MgO) shield. The presence of LA was another possible reason.


2013 ◽  
Vol 820 ◽  
pp. 84-87
Author(s):  
Zheng Zhou Wang ◽  
Charles A. Wilkie

Cadmin sulfate nanoparticles, hollow sphere (CdS-HS) and rode (CdS-NR) were synthesized by ultrasonic and solvothermal process, respectively. The effect of the two kinds of nanoparticles on flammability of polystyrene was investigated using cone calorimeter (Cone) and microscale combustion calorimeter (MCC). Cone data indicate that the incorporation of 1% CdS nanoparticles leads to a about 20% reduction in the peak heat release rate (PHRR) compared to the pure PS; CdS-NR is more efficient in reducing the PHRR proved by both Cone and MCC results. The TG results show that the addition of the nanoparticles mainly increases thermal stability of PS at high temepratures.


2020 ◽  
Vol 842 ◽  
pp. 16-21
Author(s):  
Wei Ying Gao

In our previous work, ammonium polyphosphate (APP) microcapsule with the shell of boron modified phenolic resin (BPF) was prepared, recorded as BPFAPP. However, the compatibility and the flame retardancy of BPFAPP in thermoplastic polyurethane elastomer (TPU) are still not very good due to the brittle and hard shell wall. To improve the brittleness of microcapsules shell and the property reinforcements of APP in TPU, APP was encapsulated with the tung oil and boron modified phenolic resin (TBPF) in this paper, recorded as TBPFAPP. The property reinforcements of TBPFAPP in TPU were studied. The thermogravimetry, limiting oxygen index and cone calorimetry analysis showed that TPU/TBPFAPP composite had higher char yield and better flame resistance. The tensile strength and elongation at break showed that the mechanical properties were also significantly improved due to the introduction of α-Eleostearate.


2019 ◽  
Vol 2 (1) ◽  
pp. 30-48
Author(s):  
Giulia Fredi ◽  
Andrea Dorigato ◽  
Luca Fambri ◽  
José-Marie Lopez-Cuesta ◽  
Alessandro Pegoretti

AbstractThis work aims to study the synergistic effect of aluminum/magnesium hydroxide microfillers and organomodified fumed silica nanoparticles as flame retardants (FRs) for linear low-density polyethylene (LLDPE), and to select the best composition to produce a fire-resistant polyethylene-based single-polymer composite. The fillers were added to LLDPE at different concentrations, and the prepared composites were characterized to investigate the individual and combined effects of the fillers on the thermo-oxidation resistance and the fire performance, as well as the microstructural, physical, thermal and mechanical properties. Both filler types were homogeneously distributed in the matrix, with the formation of a network of silica nanoparticles at elevated loadings. Melt flow index (MFI) tests revealed that the fluidity of the material was not considerably impaired upon metal hydroxide introduction, while a heavy reduction of the MFI was detected for silica contents higher than 5 wt%. FRs introduction promoted a noticeable enhancement of the thermo-oxidative stability of the materials, as shown by thermogravimetric analysis (TGA) and onset oxidation temperature (OOT) tests, and superior thermal properties were measured on the samples combining micro- and nanofillers, thus evidencing synergistic effects. Tensile tests showed that the stiffening effect due to a high content of metal hydroxide microparticles was accompanied by a decrease in the strain at break, but nanosilica at low concentration contributed to preserve the ultimate mechanical properties of the neat polymer. The fire performance of the samples with optimized compositions, evaluated through limiting oxygen index (LOI) and cone calorimetry tests, was strongly enhanced with respect to that of the neat LLDPE, and also these tests highlighted the synergistic effect between micro- and nanofillers, as well as an interesting correlation between fire parameters and viscosity.


2005 ◽  
Vol 13 (8) ◽  
pp. 795-805 ◽  
Author(s):  
M.U. Wahit ◽  
A. Hassan ◽  
Z.A. Mohd Ishak ◽  
A. Abu Bakar

Rubber-toughened nanocomposites (RTNC) consisting of ternary blends of polyamide 6 (PA6), polypropylene (PP) and polyethylene-octene elastomer (POE) containing 4 wt% of organophilic modified montmorillonite were produced by melt compounding followed by injection moulding. The blend composition was kept constant (PA6/PP=70/30 parts by weight) while the POE content was varied between 5 and 20 wt%. Maleated PP (PP-g-MA) was used as compatibilizer. The morphology of the RTNC was studied by scanning electron microscopy and X-ray diffraction (XRD). The mechanical properties of RTNC were studied through tensile, flexural, Izod impact and fracture toughness properties. While the tensile and flexural properties were found to decrease with the increasing concentration of POE, the toughness was significantly enhanced as compared to the neat PA6/PP blends. In general, the blends containing 10-15 wt% of POE had the best balance of stiffness, strength and toughness. The addition of 30 wt% of PP in the PA6 matrix improved the compatibility between PA6 and the rubber phase. XRD established that the organoclay was well dispersed (exfoliated) and preferentially embedded in the PA6 phase.


2018 ◽  
Vol 913 ◽  
pp. 729-737
Author(s):  
Hui Ling Xu ◽  
Hong Kun Bao ◽  
Chao Sheng Wang ◽  
Hua Ping Wang

Poly(ethylene terephthalate) (PET) fiber with excellent flame retardant property was prepared with introducing a containing phosphorus flame retardant 10-(2’,5’-dihydroxyphenyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (ODOPB) into PET by melt blending method. The intrinsic viscosity of the modified PET was decreased after melt blending, indicated that ODOPB could promote the degradation of PET. The addition of ODOPB can increase the amount of carbon residue of PET, which can effectively reduce the heat transfer. The movement and regularity of PET molecular chain are affected by ODOPB, resulting in the reducing of the crystallization of PET. The Raman curves indicate that the addition of ODOPB can improve the regularity of carbon layer, which is conducive to achieve the effect of flame retardant. When the mass fraction of P is 0.7 %, the limiting oxygen index of sample reaches 32.4% and UL-94 vertical reaches V-2, the fiber fracture strength is 2.6 cN/dtex, which has excellent flame retardant and mechanical properties.


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