Synergistic effects of hydroxy silicone oil on intumescent flame retardant polypropylene system

The effects of hydroxy silicone oil as a synergistic agent on the flame retardancy of intumescent flame retardant polypropylene composites (IFR-PP) were studied, and the IFR system mainly consisted of the ammonium polyphosphate (APP), melamine (MEL) and pentaerythritol (PER). The UL 94 rating, thermogravimetric analysis (TGA), cone calorimeter (CONE) and digital photograph were used to evaluate the synergistic effects of hydroxy silicone oil (HSO). It has been found that the PP composite containing only APP, MEL and PER does not show good flame retardancy at 30% additive level. The cone calorimeter results show that the heat release rate, mass loss rate, mass, total heat release, carbon monoxide and carbon dioxide of PP/APP/MEL/PER/HSO composites decrease in comparison with the PP/APP/MEL/PER composite. The digital photographs demonstrated that HSO could promote to form the homogenous and compact intumescent char layer. Thus, a suitable amount of HSO plays a synergistic effect in the flame retardancy.     

新型低烟无卤阻燃电缆料的制备及表征

研究了以磷酸三甲苯酯(TCP)、水滑石(LDHs)、氢氧化铝(ATH)复配得到的复合阻燃剂对乙烯-醋酸乙烯酯共聚物(EVM:AV含量大于40%)性能的影响。分别通过氧指数、水平燃烧和拉伸性能测试考察了TCP/LDHs/ATH/EVM复合材料的阻燃性能和力学性能。结果表明,当TCP/LDHs/ATH/EVA为20/35/35/100(质量份数)时,复合材料的极限氧指数(LOI)达到35.2,阻燃级别为FH-1;断裂伸长率达到280%,拉伸强度达到11.0MPa。此复合材料可用于制造阻燃电缆。     

Influence of red phosphorus on the flame-retardant properties of ethylene vinyl acetate/layered double hydroxides composites

Mg?CAl?CFe ternary layered double hydroxides (LDHs) were synthesized based on Bayer red mud by a calcination?Crehydration method, and characterized using powder X-ray diffraction and thermogravimetric analysis techniques. The synergistic flame-retardant effects of red phosphorus (RP) in ethylene vinyl acetate (EVA)/LDHs composites were studied with the limiting oxygen index (LOI), the UL 94 test, the cone calorimeter test (CCT), and the smoke density test (SDT). And, the thermal degradation behavior of the composites was examined by thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR) analysis. Results showed that the LOI values of the composites with RP were basically higher than those of the pure EVA sample and composites containing LDHs only. And the addition of a suitable amount of RP in EVA/LDHs/RP composites can apparently favor UL 94 test. In the UL 94 test there was a V-1 rating and dripping phenomena for the composites containing 50?% LDHs. However, the composites containing 47.5?% LDHs and 2.5?% red phosphorus did not drip. The CCT results indicated that the heat release rate (HRR) of the EVA/LDHs/RP composites with a suitable amount of RP decreased in comparison with that of the EVA/LDHs composites. The SDT showed that RP was helpful to smoke suppression. TG-FTIR data showed that the EVA/LDHs/RP composites show a higher thermal stability than the EVA/LDHs composites. A suitable amount of RP in EVA/LDHs/RP composites resulted in an increase in LOI values, a decrease in the HRR, the achievement of the UL 94 V-1 rating with no dripping phenomenon, a good smoke suppression character, and a high thermal stability.     

Synergistic flame retardant effects of ammonium polyphosphate in ethylene‐vinyl acetate/layered double hydroxides composites

Mg–Al–Fe ternary layered double hydroxides (LDH) were synthesized based on bayer red mud by calcination‐rehydration method, and characterized using X‐ray diffraction and thermogravimetric analysis (TGA). The synergistic flame retardant effects of ammonium polyphosphate (APP) with LDH in ethylene‐vinyl acetate (EVA) composites were studied using limiting oxygen index (LOI), UL 94 test, cone calorimeter test (CCT), and smoke density test (SDT). The thermal degradation behavior of EVA/LDH/APP composites was examined by thermal gravimetric analysis‐fourier transform infrared spectrometry (TG‐FTIR). The results showed that LOI values decreased by incorporation of APP together with LDH; and, a suitable amount of APP in EVA/LDH composites can apparently improve UL 94 rating. The CCT results indicated that heat release rate (HRR) of the EVA/LDH/APP composites with APP decreased in comparison with that of the EVA/LDH composites. The SDT results showed that APP was helpful to suppress smoke. The TG‐FTIR data showed that the composites with APP had a higher thermal stability than the EVA/LDH composites at high temperature. POLYM. ENG. SCI., 54:766–776, 2014. © 2013 Society of Plastics Engineers     

Synergistic effects of 4A zeolite on the flame‐retardant properties and thermal stability of an efficient halogen‐free flame‐retardant EVA composite

The synergistic effects of 4A zeolite (4A) on the thermal degradation, flame retardancy, and char formation of an efficient halogen‐free flame‐retardant ethylene‐vinyl acetate copolymer composite (EVA/IFR) were investigated by limited oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter test (CCT), digital photography, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), laser Raman spectroscopy (LRS) and thermogravimetric analytical (TGA) methods. It was found that a small amount of 4A clearly improved the LOI value of the EVA/IFR composite and reinforced the fire retardant performance with a great reduction in the combustion parameters of the EVA/IFR system from the CCT test. The entire composites passed the UL‐94 V‐0 rating test. The TGA and integral procedure decomposition temperature (IDPT) results showed that 4A enhanced the thermal stability of the EVA/IFR system and increased the char residue content effectively. The morphological structures observed by digital and SEM imaging revealed that 4A could promote EVA/IFR to form a more continuous and compact intumescent char layer. The LRS and EDS results demonstrated that by introduction of 4A into the EVA/IFR system, a more graphite structure was formed with increase phosphorus content in the char residue. POLYM. ENG. SCI., 56:380–387, 2016. © 2016 Society of Plastics Engineers     

Synergistic flame retardant effects of Fe-OMMT with LDH in EVA/LDH composites

Abstract

The synergistic effects of Fe organic modified montmorillonite (Fe-OMMT) with layered double hydroxides (LDHs) in ethylene vinyl acetate copolymer/LDH (EVA/LDH) composites have been studied using thermal analysis [thermogravimetric analysis (TGA)], limiting oxygen index (LOI), UL-94 test and cone calorimeter test (CCT). The results showed that the addition of a given amount of Fe-OMMT apparently increased the LOI value and the rating in the UL-94 test. The results from the LOI and UL-94 tests show that Fe-OMMT can act as flame retardant synergistic agents in EVA/LDH composites. The CCT data indicated that the addition of Fe-OMMT in the EVA/LDH system can greatly reduce the heat release rate. The TGA data show that Fe-OMMT, as an excellent flame retardant synergist of LDH, cannot increase the thermal degradation temperature and the charred residues.     

Flame retardant synergism of rubber and Mg(OH)2 in EVA composites

A synergistic effect on flame retardancy was found when acrylonitrile butadiene ultra-fine fully vulcanized powdered rubber (NB-UFPR) was incorporated into ethylene vinyl acetate/nano-magnesium hydroxide (EVA/nano-MH) composite by a new process. The fire performance of EVA and EVA composites was compared in this communication by cone calorimeter test (CCT). The CCT data indicated that the addition of NB-UFPR in EVA/nano-MH system not only reduced the heat release rate, but also prolonged the ignition time of the composite, which is contrary to the effect of NB-UFPR when it was added alone in EVA polymer. Thermogravimetric analysis revealed that nano-MH accelerated the loss of acetic acid, but NB-UFPR assisted to reduce nano-MH's accelerating effect. FTIR spectra showed a new absorption at 3374 cm⁻¹ in the blends of EVA/NB-UFPR and EVA/NB-UFPR/nano-MH.     

Combustion characteristics and synergistic effects of red phosphorus masterbatch with expandable graphite in the flame retardant HDPE/EVA composites

In this work, the flammability behaviors and synergistic effects of red phosphorus masterbatch (RPM) with expandable graphite (EG) in flame‐retardant high‐density polyethylene/ethylene vinyl‐acetate copolymer (HDPE/EVA) composites have been investigated by limiting oxygen index (LOI), UL‐94 test, cone calorimeter test (CCT), thermogravimetric analysis (TGA), Fourier‐transform infrared (FTIR) and scanning electron microscopy (SEM). The data obtained from LOI, UL‐94 test and CCT showed that suitable amount of RPM had synergistic effects with EG in the HDPE/EVA/EG/RPM composites. The addition of RPM greatly increased the LOI values by 3.4%, obtained UL‐94 V‐0 rating, decreased the heat release rates and total heat release, and prolongated the ignition time when 6.7 phr RPM substituted for EG in the HDPE/EVA/EG/RPM composites. The data from TGA and FTIR spectra also indicated the synergistic effects of RPM with EG considerably enhanced the thermal degradation temperatures. The morphological observations after UL‐94, CCT, and SEM images presented positive evidences that the synergistic effects took place for RPM with EG, and the flame‐retardant mechanism has been changed in flame‐retardant HDPE/EVA/EG/RPM composites. The formation of stable and compact charred residues promoted by RPM acted as effective heat barriers and thermal insulations, which improved the flame‐retardant performances and prevented the underlying polymer materials from burning. POLYM. ENG. SCI., 55:2884–2892, 2015. © 2015 Society of Plastics Engineers     

ZnO/MoO3/Al(OH)3阻燃聚丙烯材料的制备及性能

采用水热法制备了一维材料ZnO和MoO_3纳米线(nanowires,NWs),并通过SEM和XRD对纳米线的形貌和结构进行了表征。将一维纳米线和纳米氢氧化铝(ATH)与聚丙烯(PP)熔融共混制备了ZnO/MoO_3/Al(OH)_3/PP复合材料(NWs/ATH/PP)。利用TGA、极限氧指数(LOI)测定仪和锥形量热仪(CCT)表征了复合材料的热稳定性和燃烧性能,利用万能材料试验机测试了复合材料的力学性能。结果表明:当添加质量分数3.75%ZnO纳米线、质量分数3.25%MoO_3纳米线和质量分数21.00%纳米ATH时,NWs/ATH/PP复合材料的初始分解温度较纯PP增加了17.8℃,残重率为24.6%,峰值热释放速率(PHRR)和总热释放量(THR)分别下降了54.3%和25.7%,LOI提高7.1%。SEM结果显示:NWs/ATH/PP的残炭表面致密、连续且平整。     

Preparation and flame retardancy of a novel flame‐retardant poly(ethylene‐co‐vinyl acetate)/aluminum hydroxide composites containing phosphorus

A novel flame‐retardant (SPDH) containing phosphorus was synthesized through the reaction of 10‐(2,5‐dihydroxyphenyl)‐9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide and synthesized intermediate product 3,9‐dichloro‐2,4,8,10‐tetraoxa‐3,9‐diphosphaspiro[5.5] undecane‐3,9‐dioxide, which was used for optimizing the flame retardancy of ethylene‐vinyl acetate copolymer (EVM) rubber/aluminum hydroxide (ATH) composites. The microstructure of SPDH was characterized and determined by Fourier transform infrared and nuclear magnetic resonance spectroscopy. Thermogravimetric analysis (TGA) showed that SPDH had good charring effect at high temperature (600°C). The flame retardancy of the optimized EVM/ATH composites by SPDH was investigated by limiting oxygen index (LOI), cone calorimeter, and UL‐94 vertical burning tests. A higher LOI value (29.8%) and better UL‐94 rating (V‐0) can be achieved for the optimized EVM/ATH composite (EVM‐7) than EVM/ATH composite without SPDH (EVM‐3) with the total loading of additives. The heat release rate decreased and residual mass increased gradually as the loading of SPDH increased for the optimized EVM/ATH composites. There existed distinct synergistic flame‐retardant effect between SPDH and ATH in EVM matrix. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

PGS@P-N阻燃剂的制备及增强EVA复合材料的 阻燃性能的研究

利用坡缕石表面的羟基，采用化学方法首先将坡缕石（PGS）用磷酸进行了改性，随后通过酸碱中和的方法，将十二胺接枝到磷酸分子上，得到改性的含P、N型复合阻燃剂PGS@P-N。通过SEM、 XRD、 FTIR等方法对所合成阻燃剂PGS@P-N的形貌和结构进行了表征，利用氧指数法(LOI)、垂直燃烧法(UL-94)和锥形量热法(CCT)对复合材料的阻燃性能进行了测试，并对复合材料的力学性能和相容性进行了考察。结果表明：当向EVA中加入质量分数为30%的PGS@P-N/EG后，EVA/PGS@P-N/EG(可膨胀石墨)复合材料的氧指数达到了36.3%，与EVA/PGS/EG比较，接入烷基链后，EVA/PGS@P-N/EG复合材料的断裂伸长率提高了40%。     

Intumescent Flame Retardation of EVA Using Microencapsulated Ammonium Polyphosphate and Pentaerythritols

With a melamine-formaldehyde (MF) resin coating layer, microencapsulated ammonium polyphosphate (MCAPP) is prepared by in situ polymerization and is characterized by XPS and water leaching test. The microencapsulation of APP with the MF resin leads to a decrease in the particle's water leaching rate. The flame-retardant action of MCAPP and APP in EVA are studied using LOI and UL 94 test, and their thermal stability is evaluated by thermogravimetric analysis (TGA). The LOI value of the EVA/MCAPP composite at the same loading is higher than the value of the EVA/APP composite. In comparison with the EVA/MCAPP composites, it is found that the LOI values of the EVA/MCAPP/PER and EVA/MCAPP/DPER ternary composites at the same additive loading increase, and UL 94 ratings of most ternary composites are raised to V-0. The water-resistant properties of the EVA composites are studied, and the results of the composites containing with APP and MCAPP are compared. Moreover, the peroxide cross-linking of the EVA composites is investigated, and the mechanical properties and thermal stability of the composites increase after the cross-linking.     

Study on char reinforcing of different inorganic fillers for expandable fire resistance silicone rubber

Sodium silicate monohydrate (NSH), glass frits (GF) and aluminum hydroxide (ATH) were incorporated into room temperature vulcanized (RTV) silicone rubber (SR) as char reinforcing materials to improve the fire resistance of intumescent flame retardant silicone rubber. SR composites containing only intumescent flame retardant such as phosphorus nitrogen composite flame retardant (NH₂-C) and expandable graphite (EG) were used as comparison samples. Limiting oxygen index (LOI) test, vertical burning test (UL-94), flame resistance test, scanning electron microscopy (SEM) and X-ray diffraction spectroscopy tests, as well as volume variation and compression strength of char residues were used to discuss the effects of the above-mentioned fillers on the fire resistance, char residue strength and char integrity of SR composites. The results showed that SR composite filled with only intumescent flame retardants EG and NH₂-C had excellent flame retardancy. After adding ATH, the char residue was relatively dense and had good compressive strength, but its thermal insulation performance was reduced. GF or NSH reduced the flame retardancy of SR composites, but it obviously played a role in binding combustion residues, forming new crystals and improving the stability of char residues.     

电子束辐照和氢氧化铝对LLDPE/EVA共混物凝胶含量和力学性能的影响

研究了电子束辐照剂量和氢氧化铝(ATH)的含量对线性低密度聚乙烯(LLDPE)/乙烯-醋酸乙烯酯(EVA)共混物凝胶含量和力学性能的影响。辐照剂量是影响LLDPE/EVA/ATH阻燃体系凝胶含量的主要因素,而ATH对其凝胶含量的影响较小。随着ATH含量的增加,LLDPE/EVA共混物的拉伸强度逐步增加,断裂伸长率迅速下降。所有阻燃体系的拉伸强度均是随着辐照剂量的增加而逐步增大,但辐照剂量对这些阻燃体系的断裂伸长率的影响却比较复杂。     

Synergistic effects between red phosphorus and alumina trihydrate in flame retardant silicone rubber composites

Abstract

The synergistic flame retardant effects between red phosphorus (RP) and alumina trihydrate (ATH) in silicone rubber (SR) composites were evaluated using limiting oxygen index, UL 94 rating, cone calorimeter, thermogravimetric analysis and digital photographs. It has been found that the SR composite containing only ATH does not show good flame retardancy at 39·0 wt-% loading. The cone calorimeter results showed that the heat release rate, mass loss rate, mass and total heat release of SR/ATH/RP composites decrease greatly in comparison with the SR/ATH composites. The digital photographs demonstrated that 1·0 wt-%RP could promote the formation of the homogenous and compact char layer. Thus, a suitable amount of RP has a synergistic effect with ATH in the flame retardant SR composite system.     

A facile method for preparation of PGS@ZB‐N and gas‐sol alternating synergistic effect for fire resistance of EVA

Through the simple precipitation of palygorskite (PGS) by zinc borate (ZB) (to make PGS@ZB) and the decoration of PGS@ZB by dodecylamine (N), a novel organic‐inorganic@inorganic hybrid flame retardant of PGS@ZB‐N was prepared and was incorporated with ethylene vinyl acetate copolymer (EVA) to improve its flame retardance. The structure and morphology of PGS@ZB‐N were characterized by Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), and scanning electron microscopy (SEM), and it was confirmed that the PGS@ZB‐N hybrid had been successfully prepared. The flame retardancy and burning behavior of EVA/PGS@ZB‐N/EG (EG = expandable graphite) composite were studied through thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL‐94 (by the vertical burning test), and cone calorimeter test (CCT) characterizations. The prepared EVA/PGS@ZB‐N/EG composite obtained an LOI value of 41.2% with the addition of 30 wt% PGS@ZB‐N/EG. It was found that EVA/PGS@ZB‐N/EG was protected through a gas phase and condensed phase alternating synergistic effect mechanism.     

Synthesis of a magnesium/aluminum/iron layered double hydroxide and its flammability characteristics in halogen‐free,flame‐retardant ethylene/vinyl acetate copolymer composites

Mg–Al–Fe ternary hydrotalcites were synthesized by a coprecipitation method and characterized with powder X‐ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The flame‐retardant effects of Mg/Al–CO₃ layered double hydroxides (LDHs) and Mg/Al/Fe–CO₃ LDHs in an ethylene/vinyl acetate copolymer (EVA) were studied with the limited oxygen index (LOI), the UL‐94 test, and the cone calorimeter test (CCT), and the thermal degradation behavior of the composites was examined by thermogravimetric analysis. The results showed that the LOI values of the EVA/(Mg/Al/Fe–CO₃ LDH) composites were basically higher than those of the EVA/(Mg/Al–CO₃ LDH) composites at the same additive level. In the UL‐94 test, there was no rating for the EVA/(Mg/Al–CO₃ LDH) composite at the 50% additive level, and a dripping phenomenon occurred. However, the EVA/(Mg/Al/Fe–CO₃ LDH) composites at the same loading level of LDHs containing a suitable amount of Fe³⁺ ion reached the V‐0 rating, the dripping phenomenon disappearing. The CCTs indicated that the heat release rate (HRR) of the EVA composites with Mg/Al/Fe–CO₃ LDHs containing a suitable amount of Fe³⁺ decreased greatly in comparison with that of the composites with Mg/Al–CO₃ LDHs. The introduction of a given amount of Fe³⁺ ion into Mg/Al–CO₃ LDHs resulted in an increase in the LOI, a decrease in the HRR, and the achievement of the UL‐94 V‐0 rating. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Combustion Behavior and Thermal Oxidative Degradation of EVA Containing Intumescent Flame Retardant

Microencapsulated ammonium polyphosphate (VAPP) with poly(vinyl alcohol)- melamine-formaldehyde (VMF) shell was introduced in ethylene vinyl acetate copolymer (EVA) to improve its flame retardancy. Due to the presence of VMF shell, VAPP shows better compatibility, flame retardancy and water resistance compared with ammonium polyphosphate (APP) in EVA. The flammability of EVA and its flame-retarded composites was studied by LOI, UL-94 and cone calorimeter. The composite containing 40 wt% VAPP can pass V-0 in UL-94 test, and hot water treatment shows few effects on its LOI value and UL-94 rating. The cone results indicated that the use of VAPP in EVA can significantly decrease heat release rate and total heat release compared with APP. To understand the mechanism of action of VAPP, dynamic FTIR experiments were carried out on EVA and EVA/VAPP composites. Based on above studies, the flame retardant mechanism of VAPP in EVA composite is discussed.     

Preparation of expandable graphite with silicate assistant intercalation and its effect on flame retardancy of ethylene vinyl acetate composite

A halogen‐free intumescent flame retardant expandable graphite composite (EG), with an initial expansion temperature of 202°C and expansion volume of 517 mL g⁻¹, was successfully prepared via a facile two‐step intercalation method, i.e. using KMnO₄ as oxidant and H₂SO₄, Na₂SiO₃·9H₂O as intercalators. The prepared EG flame retardant was characterized by field emission scanning electron microscope, X‐ray diffraction spectroscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. Furthermore, flame retardancy and thermal property of various ethylene vinyl acetate copolymer (EVA) composites, including EVA/EG and EVA/EG/APP (ammonium polyphosphate) specimens, were studied through limiting oxygen index instrument (LOI), vertical combustion UL‐94 rating, thermal gravimetric and differential thermal analysis. The results indicate that the EVA/EG and EVA/EG/APP composites exhibit a better flame retardancy. Addition of EG at a mass fraction of 30% leads LOI of 70EVA/30EG composite improved to 28.7%. Even more, the synergistic effect between EG and APP improves the LOI of 70EVA/10APP /20EG composite to 30.7%. This synergistic efficiency is attributed to the formation of compact and stable layer‐structure, and the prepared EG can make EVA composite reach the UL‐94 level of V‐0. POLYM. COMPOS., 36:1407–1416, 2015. © 2014 Society of Plastics Engineers     

Effects of silicon additive as synergists of Mg(OH)2 on the flammability of ethylene vinyl acetate copolymer

The present work dealt with the effects of nine kinds of silicon additives on flame retardancy of ethylene‐vinyl acetate copolymer (EVA)/magnesium hydroxide [Mg(OH)₂] composites, as well as mechanical properties. The limiting oxygen index (LOI) test, horizontal fire test, vertical fire test, and cone calorimeter test were employed to evaluate flame retardancy of the composites. It was found that different silicon additives had different synergistic effects with Mg(OH)₂ on flame retardancy of the EVA matrix and exerted different influences on mechanical properties of the composites. The incorporation of organic montmorillonite (MMT) clay or silicone rubber not only made the composite reach FH‐1 rating in the horizontal fire test and FV‐1 rating in the vertical fire test, respectively, but also dramatically reduced the peak rate of heat release (Peak RHR) and increased the fire performance index (FPI) and ignition time (IT). The composites filled with precipitated SiO₂ exhibited the longest IT, the highest FPI, and FV‐1 rating. However, only the composites filled with silicone rubber could attain a balance between mechanical properties and flame retardancy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006