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1.
The natural basalt fiber (BF) was incorporated into EVA composites with environmental‐friendly nickel alginate‐brucite based flame retardant (NiFR), to further improve the flame‐retardant effect and mechanical properties. The flame retardancy of EVA composites were characterized by LOI, UL 94, and cone test. With 55 wt% loading, 3BF/52NiFR had the highest LOI value of 31.9 vol.% in all fiber reinforced composites and pass UL 94V‐0 ratting. And comparing to 55B composite with untreated brucite, 3BF/52NiFR decreased peak of heat release rate by 47.8%, total heat release by 21.9%, and total smoke production by 35.5% and kept more residue 54.0% during cone test. Moreover, 3BF/52NiFR also enhanced the mechanical properties of composites by better compatibility with EVA matrix. BF/NiFR exert synergistic flame‐retardant effect major in promoting charring effect in condensed phase during combustion. The fire‐resisted and rigid BF into the char layer reinforced the intensity of protective barrier which prolonged the residence time of pyrolysis carbonaceous groups degraded from EVA matrix, resulting in less heat and smoke release.  相似文献   

2.
A novel EVA/unmodified nano-magnesium hydroxide(NMH)/silicone rubber ternary nanocomposite was prepared by using a special compound flame retardant of NMH and silicone rubber(CFR).The flammability of the ternary composite was studied by cone calorimeter test(CCT).Synergistic effect on flame retardancy was found between silicone rubber and NMH.EVA/CFR ternary nanocomposite showed the lowest peak heat release rate(PHRR)and mass loss rate (MLR)among the samples of virgin EVA,EVA composites.The synergistic flame retardancy of silicone rubber and NMH in EVA system is attributed to the enhanced char layers in the condensed phase that prevents the heat and mass transfer in the fire.  相似文献   

3.
A new flame retardant system with organic modified boron nitride (m‐BN) and intumescent flame retardant (IFR) was used in this paper, and the synergistic flame retardancy of m‐BN and IFR on natural rubber (NR) was studied. NR/IFR/m‐BN composites were characterized by X‐ray photoelectron spectroscopy(XPS), Fourier transform infrared spectrometry (FTIR), thermogravimetric analysis, UL‐94, limiting oxygen index (LOI), tensile testing, cone calorimeter testing, and thermal conductivity testing. When 4 wt% m‐BN was added, the flame retardancy and mechanical properties of the composites were improved. The LOI value of NR/IFR/4 phr m‐BN reached 26.8%, and suppressed fire spread in a UL‐94 test. Compared with pure NR, the peak heat release rate (pHRR) was reduced by 52.2%, the total heat release (THR) was reduced by 27.6%, and CO yields were reduced by 51.4%. As a key aspect of fire safety, the ignition time is effectively delayed to 23 seconds due to the increased thermal conductivity of NR/IFR/m‐BN. Since the synergistic effect of m‐BN effectively improves the flame retardancy of NR, it provides a feasible method for improving the fire safety of polymers.  相似文献   

4.
In this work, Fe‐montmorillonite (Fe‐MMT) is synthesized and used as a synergistic agent in ethylene vinyl acetate/magnesium hydroxide (EVA/MH) flame retardant formulations. The synergistic effect of Fe‐MMT with magnesium hydroxide (MH) as the halogen‐free flame retardant for ethylene vinyl acetate (EVA) is studied by thermogravimetric analysis (TGA), limiting the oxygen index (LOI), UL‐94, and cone calorimetry test. Compared with that of Na‐MMT, it indicates that the synergistic effects of Fe‐MMT enhance the LOI value of EVA/MH polymer and improve the thermal stability and reduce the heat release rate (HRR). The structure and morphology of nanocomposites are studied by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The mechanical properties of the EVA composites have also been studied here, indicating that the use of Fe‐MMT reduces the amount of inorganic fillers. MH hence enhances the mechanical properties of the EVA composite while keeping the UL‐94 V‐0 rating. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

5.
《先进技术聚合物》2018,29(6):1804-1814
Urea formaldehyde microsphere (UFM) was prepared and used with organic montmorillonite (OMMT) to modify the flame retardant efficiency of ethylene vinyl acetate copolymer (EVA)/intumescent flame retardant (IFR) composites. The results show that single IFR may modify the flame retardancy of EVA, but its efficiency is not good enough. The EVA composite containing 21 wt% IFR is just classified the UL_94 V2 and has a limiting oxygen index (LOI) 24.7 vol%. Combining UFM with IFR does not improve the flame retardancy of EVA/IFR composites, and blending OMMT with IFR only improves its LOI. Adding 2 wt% UFM, 2 wt% OMMT, and 17 wt% IFR into EVA, it obtains the UL_94 V0 without melt dripping and a LOI 29.0 vol%. Also, the peak heat release rate and total heat release decrease a lot. Good synergistic effects among IFR, UFM, and OMMT improve the char residues and modify the char micromorphology of EVA composites, which provide better protect for the underlying resin.  相似文献   

6.
Conferring the flame retardant performance and thermal conductivity simultaneously for epoxy resin (EP) thermosets was significant for fire safety and thermal management applications of electrical and electronic devices. Herein, the graphitic carbon nitride (g‐C3N4) with desired amount was assembled on the surface of ammonium polyphosphate (APP), and the obtained APP/g‐C3N4 (CN‐APP) was characterized and confirmed by X‐ray diffraction, Fourier transform infrared spectroscopy tests, scanning electron microscopy, and transmission electron microscopy. CN‐APP was incorporated into EP and then cured with m‐phenylenediamine. The thermal conductive value of EP/CN‐APP thermosets achieved 1.09 W·mK?1, and the samples achieved UL‐94 V‐0 grade during vertical burning tests with the limiting oxygen index of 30.1% when 7 wt% CN‐APP with the mass fraction of APP/g‐C3N4 of 9/1 was incorporated. For comparative investigation, equal amount of individual g‐C3N4 was introduced into EP thermosets, and the thermal conductivity was only 0.4 W·mK?1. Compared with pure EP, the addition of CN‐APP enhanced the glass transition temperature of EP/CN‐APP thermosets and promoted the generation of more expanded, coherent, and compact char layer during combustion. Consequently, the heat release and smoke production of EP/CN‐APP thermosets were greatly suppressed and led to the improvement of fire safety of materials. It was an alternative and promising approach for preparing high‐performance polymeric materials especially used in integrated electronic devices.  相似文献   

7.
The combination of catalyzing carbonization and free‐radical quenching mechanism is proposed to be a promising strategy for the preparation of high‐efficiency flame‐retardant polypropylene (PP). Herein, a novel functionalized zirconium phosphate (RQZrP) nanosheet with free‐radical quenching capability was fabricated by decorating macromolecular N‐alkoxy hindered amine (MNOR) onto the surface of ZrP. It was combined with an intumescent flame retardant (IFR) to flame‐retard PP. The results showed that there was a good synergism between RQZrP and IFR, which effectively improved the fire safety of PP. When the content of RQZrP was 2 wt% and IFR was 23 wt%, the limiting oxygen index (LOI) of PP increased from 19.0% to 33.0%, and it achieved a UL‐94 V‐0 rating. Meanwhile, the peak heat release rate (PHRR), total heat release (THR), carbon monoxide production (COP), and carbon dioxide production (CO2P) were significantly decreased. It revealed that nitroxyl radicals generated by RQZrP could capture alkyl radicals and peroxy radicals that produced during the degradation and combustion of PP. Meanwhile, RQZrP acted as a solid acid that catalyzed PP chains rapidly cross‐linking to form char on its surface, and it also played as a supporting skeleton to enhance the strength and compactness of the char layer, thus effectively preventing the transmission of heat, oxygen, and combustible gases.  相似文献   

8.
The aim of this study was to investigate and compare the flame retardant properties of boron compounds with respect to aluminum trihydroxide (ATH) in an epoxy system based on bisphenol A epichlorohydrin‐based epoxy resin and cycloaliphatic polyamine‐based hardener. Six different boron compounds including colemanite (C), ulexite (U), boric acid (BA), boric oxide (BO), melamine borate (MB) and guanidinium nonaborate (GB) were used as flame retardant additive. The flame retardant properties of epoxy‐based composites were investigated using limiting oxygen index (LOI), UL 94 standards both in vertical and horizontal position, thermogravimetric analysis, cone calorimeter and scanning electron microscopy. According to flammability test results, boron compounds except for C and U showed better performance than ATH. According to the LOI results, 40% BA containing sample had the highest LOI value of 28.5, while 30% MB, 35% GB and 40% BA containing samples had the highest UL 94V rating (V0). According to the cone calorimeter test results, all boron containing samples had better fire performances than ATH containing sample; 40 wt% BO containing sample showed the lowest peak heat release rate, average heat release rate and total heat release values. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

9.
The flame‐retardant microcapsules were successfully fabricated with an aluminum hypophosphite (AHP) core. Fourier transform infrared (FTIR) and X‐ray photoelectron spectroscopy (XPS) were used to verify that AHP was encapsulated in the microcapsules, and thermogravimetry analysis showed that microencapsulated AHP (MAHP) possessed higher thermal stability than that of AHP. Then, a flame‐retardant and smoke suppression system for silicone foams (SiFs) was obtained through a synergistic effect of MAHP and zinc borate (2ZnO·3B2O3·3.5H2O). The mechanical properties, flame retardance, and smoke suppression of SiFs with MAHP and zinc borate were tested using the tensile test, limiting oxygen index (LOI) test, UL‐94 test, and cone calorimeter test. The mechanical properties indicated that the tensile strength and elongation at break of SiFs could evidently improve with the incorporation of MAHP. Compared with pure SiF, SiF8 with 4.5‐wt% MAHP and 1.5‐wt% zinc borate could achieve an LOI value of 30.7 vol% and an UL‐94 V‐0 rating, the time to ignition amplified almost six times, the peak heat release rate and total heat release were 51.10% and 46.00% less than that of pure SiF, respectively, the fire performance index increased nearly 13 times, and the fire growth index value was only 13.18% of pure SiF. Moreover, the partial substitution of zinc borate imparted a substantial improvement in both flame retardancy and smoke suppression. Especially, the peak smoke production rate and total smoke production of SiF8 were merely 38.46% and 38.84% of pure SiF.  相似文献   

10.
α-Zr phosphate (hereafter referred to as ZrP) based composites were prepared by melt blending in order to improve the flame retardancy properties of polyamide 6 (PA6), polyethylene terephthalate (PET), polypropylene (PP) and ethylene vinyl acetate copolymer (EVA). Different morphologies are distinguishable by electron microscopy: PA6-ZrP seems to be a nanocomposite by Transmission Electron Microscopy (TEM) whereas PET-, PP- and EVA-ZrP blends appear micro-composites by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses. ZrP acts as flame retardant in PA6 reducing the total heat evolved and consequently the heat release rate during the combustion measured by cone calorimetry. Moreover, ZrP reduces the flammability of PET and EVA acting in synergistic effect with phosphorous based flame retardants. Indeed, it is showed that it is possible to reduce the amount of phosphorous flame retardant adding ZrP to reach UL94 classification V0 for both polymers.  相似文献   

11.
The ferrocene‐based polymer (PDPFDE) accompanied with traditional intumescent flame retardant (IFR) system (ammonium polyphosphate (APP)/pentaerythritol (PER) = 3/1, mass ratio) has been used as additive flame retardant in polypropylene (PP), aiming to lower the total loading amount. The thermal stability and fire retardant properties were investigated by thermogravimetric analysis (TGA), limiting oxygen index (LOI), vertical combustion (UL‐94), and cone calorimetry (CONE). The fire retardant mechanism was studied by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. The results showed that the PP1 with 25 wt% IFR only passed the UL‐94 V‐1 rating, but the PP6 loaded by 0.5 wt% PDPFDE and 22.5 wt% IFR possessed an LOI value of 28.5% and passed the UL‐94 V‐0 rating; the peak heat release rate (pHRR) and total heat release (THR) are decreased by 63% and 43%, respectively, compared with pure PP. In addition, the char residue of PP6 manifested a very compact and smooth surface, indicating a more effective barrier layer. Meanwhile, it was interesting that the addition of PDPFDE evidently improved the impact strength and elongation at break of PP/IFR composites.  相似文献   

12.
The photoinitiated crosslinking of halogen‐free flame retarded linear low density polyethylene/poly(ethylene‐co‐vinyl acetate) blends (LLDPE/EVA) with the intumescent flame retardant (IFR) of phosphorous‐nitrogen compound (NP) in the presence of photoinitiator and crosslinker and their characterization of related properties have been investigated by gel determination, heat extension test, cone calorimeter test (CCT), thermogravimetric analysis (TGA), Fourier transfer infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), mechanical properties measurements, limiting oxygen index (LOI), UL‐94, and water resistance test. The data from the gel content and heat extension rate (HER) show that the LLDPE/EVA/IFR blends filled with NP are readily crosslinked to a gel content of above 75% and the HER values reach about 50% by UV‐irradiation of 5 sec under suitable amount of photoinitiator and crosslinker. The data obtained from the CCT and LOI indicate that photocrosslinking can considerably decrease the heat release rates (HRR) by 10–15%, prolongate the combustion time, and increase two LOI values for the LLDPE/EVA/NP blends UV irradiated for 5 sec. The results from TGA and the dynamic FTIR spectra give the evidence that the photocrosslinked LLDPE/EVA/NP samples show slower thermal degradation rate and higher thermo‐oxidative degradation temperature than the uncrosslinked LLDPE/EVA/NP samples. The morphological structures of charred residues observed by SEM give the positive evidence that the compact charred layers formed from the photocrosslinked LLDPE/EVA/NP samples play an important role in the enhancement of flame retardant and thermal properties. The data from the mechanical tests and water‐resistant measurements show that photocrosslinking can considerably improve the mechanical and water‐resistant properties of LLDPE/EVA/NP samples. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

13.
In this work, the flame‐retardant high‐density polyethylene/ethylene vinyl‐acetate copolymer (HDPE/EVA) composites have been prepared by using expandable graphite (EG) as a flame retardant combined with ammonium polyphosphate (APP) and red phosphorus masterbatch (RPM) as synergists. The synergistic effects of these additives on the flammability behaviors of the filled composites have been investigated by limiting oxygen index, UL‐94 test, cone calorimeter test, thermogravimetric analysis (TGA), Fourier‐transform infrared (FTIR), and scanning electron microscopy. The results show that APP and RPM are good synergists for improving the flame retardancy of EG‐filled HDPE/EVA composites. The data from TGA and FTIR spectra also indicate the synergistic effects of APP and RPM with EG considerably enhance the thermal degradation temperatures but decrease the charred residues of the HDPE/EVA/EG composites because the flame‐retardant mechanism has changed. The morphological observations present positive evidences that the synergistic effects take place in APP and RPM with EG in flame‐retardant EG‐filled HDPE/EVA/EG composites. The formation of stable and compact charred residues promoted by APP and RPM with EG acts as effective heat barriers and thermal insulations, which improves the flame‐retardant performances and prevents the underlying polymer materials from burning. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

14.
In this work, a new type of leaf‐shaped cobalt‐zeolitic imidazolate framework–modified graphene (Co‐ZIF‐L@RGO) hybrid was successfully prepared and blended with an intumescent flame retardant (IFR). It was added into thermoplastic polyurethane (TPU) to study the effect of its combination with IFR on the thermal conductivity and flame retardant performance of TPU. The morphology and structure of the Co‐ZIF‐L@RGO hybrid were characterized by scanning electron microscope (SEM), Fourier transform infrared and X‐ray diffraction (XRD). The results showed that Co‐ZIF‐L were uniformly loaded on the surface of graphene. Furthermore, compared with pure TPU, the limiting oxygen index values of the composite material with 3 wt% Co‐ZIF‐L and 27 wt% IFR increased to 32.6%. Their UL‐94 rating reached V‐0 rating. Their peak heat release rate, total heat release, peak smoke production rate and total smoke production were also greatly reduced by 84.4%, 70.1%, 60.3% and 62.5%, respectively. The thermogravimetric‐infrared test results showed that the amount of toxic gas emissions was effectively suppressed. The residual carbon was analyzed by SEM, laser Raman spectroscopy and XRD, and flame retardant mechanism was further investigated. Besides, the addition of this hybrid improved the thermal conductivity of TPU.  相似文献   

15.
This article introduces a newly innovative idea for preparation of superconductive ternary polymeric composites of polyamide 6 (PA6), conductive carbon black (CCB), and multiwalled carbon nanotubes (MWCNTs) with different weight ratios by a melt‐mixing technique. The complementary effects of CCB and MWCNTs at different compositions on rheological, physical, morphological, thermal, and dynamic mechanical and electrical properties of the ternary composites have been examined systematically. We have used a novel formulation to produce high‐weight fraction ternary polymer composites that show extremely higher conductivity when compared with their corresponding binary polymer composites at the same carbon loading. For example, with an addition of 10 wt % MWCNTs into the CCB/PA6 composite preloaded with 10 wt % CCB, the electrical conductivity of these ternary composites was about 5 S/m, which was 10 times that of the CCB/PA6 binary composite (0.5 S/m) and 125 times that of the MWCNT/PA6 binary composite (0.04 S/m) at 20 wt % carbon loading. The incorporation of the MWCNTs effectively enhanced the thermal stability and crystallization of the PA6 matrix in the CCB/PA6 composites through heterogeneous nucleation. The MWCNTs appeared to significantly affect the mechanical and rheological properties of the PA6 in the CCB/PA6 composites, a way notably dependent on the MWCNT contents. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1203–1212, 2010  相似文献   

16.
This study investigates the influence of nylon‐6 (PA‐6) and ethylene‐vinyl acetate copolymer (EVA) alloy/clay nanocomposites on the properties of the flame‐retardant (FR) poly(propylene). Cone calorimetry and scanning electron microscopy (SEM) techniques were used to investigate the effect of PA‐6 and EVA alloy nanocomposites on the fire properties and dispersion of intumescent flame‐retardants (IFRs). The experimental results show that PA‐6 and EVA alloy nanocomposites improve the fire and mechanical properties of the FR poly(propylene). It is also shown that the improvement of the properties mainly depends on the weight ratio of PA‐6 and EVA in the alloys. The probable mechanisms are discussed in this paper. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

17.
A novel phosphorus‐containing silicone flame retardant (PDPSI) was prepared by Mannish reaction, and a series of PDPSI/PET composites were prepared by melt blending method. The nuclear magnetic resonance (1H NMR), Fourier transformation infrared (FTIR), and the thermogravimetric analyzer (TGA) results indicated that PDPSI showed network structure and owned good thermal stability, with the char residue of 62.2% at 800°C. The flame retardancy of PDPSI/PET composites was characterized by limiting oxygen index (LOI), vertical burning tests (UL‐94), and cone calorimeter (CCT). The results revealed that the addition amount of PDPSI was 5%, the LOI value of PDPSI/PET composites increased to 27.3%, and UL‐94 test passed V‐0 rating. When the PDPSI loading was 3%, PET composites showed excellent flame retardancy and smoke suppression, with a decrease in the peak heat release rate (PHRR) by 71.19% and the total smoke release (TSP) reduced from 14.4 to 11.1m2. The scanning electron microscopy (SEM) and FTIR results of char residue demonstrated that the flame‐retardant mechanism of PDPSI was solid phase flame retardant. PDPSI catalyzed the aromatization reaction of PET to promote the formation of a dense and continuous carbon layer, finally improving the flame retardancy and smoke suppression properties of PET.  相似文献   

18.
Unsaturated polyester resins (UPRs) are usually used in the field of automotive and electronic appliances, but their natural flammability severely constrain their wide application. In this research, a mono‐component intumescent flame retardant piperazine pyrophosphate (PPAP) was incorporated into the UPR matrix and the fire retardancy, thermal properties, combustion performance, and flame‐retarded mechanisms of UPR/PPAP were comprehensively investigated. With as low as 18 wt% PPAP introduced, UPR/18 wt% PPAP thermosets fulfilled UL‐94 V‐0 grade during vertical burning tests and the limiting oxygen index value reached 29.8%. Cone calorimeter tests shown that the peak of heat release and CO production were prominently declined with the decrease of 60.9% and 70.2% compared with those of UPR. The incorporation of PPAP efficaciously enhanced the fire safety of UPR thermosets. The investigation of flame‐retarded mechanisms for UPR/PPAP thermosets indicated that PPAP stimulated UPR thermosets to form sufficient, compact, partially graphitized, and expanded char layer on thermosets surface in advance and the char layer effectively exerted shielding effect in condensed phase. Thus, the total amount of heat of UPR/PPAP was suppressed with the reduction of 42.5% compared with that of UPR. Overall, the excellent fire safety performance promised the flame‐retardant UPR/PPAP thermosets crucial application values in some key areas.  相似文献   

19.
In this work, a novel multifunctional organic‐inorganic hybrid flame agent (AM‐MEL) was prepared from magnesium hydroxide nanosheets decorated by nitrilotrimethylene triphosphonic acid and melamine. Then, an intrinsic flame‐retardant epoxy resin (EP) was prepared by covalently incorporating AM‐MEL nanoparticles. Meanwhile, ammonium polyphosphate (APP) was added into EP to form an intumescent flame retardant system with AM‐MEL. The chemical structure of AM‐MEL was characterized by Fourier transform infrared spectra, X‐ray photoelectron spectroscopy, and scanning electron microscopy. With the incorporation of 5 wt% AM‐MEL and 15 wt% APP, EP/AM‐MEL/APP could reach a limiting oxygen index value of 32.0% and achieve UL‐94 V‐0 rating, along with 88.0%, 70.0%, 81.5%, and 87.3% decrease in the peak heat release rate, total heat release, total smoke production, and the peak CO production rate, respectively, with respect to that of pure EP. The mechanisms of its flame retardant and smoke suppression were investigated.  相似文献   

20.
A novel organic-inorganic hybrid flame retardant consisting of a brucite core and a dodecylamine polyphosphate shell was synthesized by a facile nanoengineering route. The flammability characterization and synergistic flame retardant mechanism of the core/shell flame retardant (CFR) in ethylene-vinyl acetate (EVA) blends had been compared with EVA/physical mixture (PM, with the given proportion of brucite and dodecylamine polyphosphate as well as CFR) and EVA/brucite blends. With the same loading amount (40 wt%) of fillers in EVA, the peak heat release rate and smoke production rate of EVA/CFR blends were significantly reduced to 49% and 48% of that of EVA/PM blends, respectively. Meanwhile, the limiting oxygen index (LOI) was increased up to 32 (14.3% higher than that of EVA/PM blends) and the UL-94 test could achieve the V-0 rating. These remarkable properties were obtained just by nanoengineeing the core/shell structured brucite@polyphosphate@amine hybrid system, facilitating the formation of intact and compact residue with fence structure in process of polymer composite burning.  相似文献   

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