1 可以金属氧化物
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Received: Revised: Accepted: Published:
Lei Wang,†,‡,§ Wei Yang,†,‡,§ Bibo Wang,† Yu Wu,† Yuan Hu,†,§,* Lei Song,†,* and Richard K. K. Yuen‡
†
State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People's Republic of China ‡ Department of Building and Construction, City University of Hong Kong and USTC-CityU Joint Advanced Research Centre, Suzhou, People's Republic of China § Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute of University of Science and Technology of China, Suzhou, People's Republic of China ABSTRACT: The objective of this work was to compare the flame retardancy of intumescent flame retardant ethylene−vinyl acetate (EVA/IFR) composites containing different metal oxides including lanthanide oxide, iron oxide, the mixture of iron oxide and lanthanide oxide, and lanthanum ferrite nanocrystalline (LaFeO3). A novel compound containing iron and lanthanum, LaFeO3 was successfully prepared. The EVA/IFR composites with these different coadditives were then fabricated through a melt blending process. Thermogravimetric analysis data showed that these different coadditives could increase the char residue formation. Cone calorimeter results revealed that these different coadditives and IFR could clearly change the decomposition behavior of EVA and form a char layer on the surface of the composites, consequently resulting in efficient reduction of the flammability parameters, such as heat release rate, total heat release, average mass loss rate, average smoke extinction area, and so on. Moreover, significant improvements were obtained in limited oxygen index and Underwriters Laboratories 94 ratings. Among all of the samples, the fire risk of EVA/IFR/LaFeO3 system was the lowest. The residue characterization demonstrated that LaFeO3 could promote the formation of the homogeneous and compact intumescent char layer.
© 2012 American Chemical Society
enhance the efficiency of IFRs. Many compounds have been used as coadditives, such as fumed silica, zeolite, lanthanum oxide, iron compounds, α-zirconium phosphate, and so on. It has been reported that Fe2O3 and La2O3 can improve the efficiency of intumescent systems.14−16 The promotive effect of lanthanum oxide on intumescent flame-retardant polypropylene-based formulations has been investigated. The results demonstrated that La2O3 could significantly improve the thermal stability and flame retardancy of intumescent flameretardant polypropylene.14 Polypropylene/novel intumescent flame retardant in combination with lanthanum oxide was fabricated. It was found that a suitable amount of La2O3 played a promotive effect in the flame retardancy and smoke suppression of IFR composites.15 It has been also reported that Fe2O3 was an effective modifier to improve the thermal stability of the APP-PER-MEL coating.16 Inspired by the effectiveness of Fe2O3 and La2O3, a novel compound containing iron and lanthanum (LaFeO3) was prepared and used as a coadditive to improve the flame retardancy of an EVA/IFR composite. First, LaFeO3 was synthesized and characterized. In order to understand the impact of LaFeO3 on the combustion chacteristics of the EVA/ IFR composite, the effect of lanthanide oxide, iron oxide, the
1. INTRODUCTION Ethylene−vinyl acetate copolymer (EVA) is widely used as insulating materials in the wire and cable industry due to its good mechanical and physical properties.1 However, the development and application are greatly limited by its high flammability. In past decades, the halogenated compounds were commonly used as fillers to improve the fire retardancy of EVA.2 Unfortunately, their fire retardant action is accompanied by negative effects, such as the generation of corrosive, obscuring, toxic smoke. In addition, the manufacture and application of some halogen-containing flame retardants are restricted by new regulations, such as the European Directives on WEEE (Waste of Electric and Electronic Equipment, became European Law in February 2003), RHS (Restrictions of Hazardous Substances, became European Law in February 2003), and REACH (Registration, Evaluation, Authorization, and Restriction of Chemicals, entered into force on 1 June 2007). Therefore, there is a growing demand for new, halogenfree flame retardants.3−5 In recent years, intumescent flameretardant (IFR) additives have been widely utilized in the flame retardation of flammable polymers,6−11 because of their low toxicity and low propensity for smoke generation. A typical and widely studied IFR system is composed of ammonium polyphosphate, pentaerythritol, and melamine (APP/PER/ MEL). But adding only IFRs usually requires high content to achieve a good flame retardant rating. A small amount of coadditives often brings significant improvements in thermal stability and flame retardant properties, implying that they can
பைடு நூலகம்Article pubs.acs.org/IECR
The Impact of Metal Oxides on the Combustion Behavior of Ethylene−Vinyl Acetate Coploymers Containing an Intumenscent Flame Retardant
Lei Wang,†,‡,§ Wei Yang,†,‡,§ Bibo Wang,† Yu Wu,† Yuan Hu,†,§,* Lei Song,†,* and Richard K. K. Yuen‡
†
State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People's Republic of China ‡ Department of Building and Construction, City University of Hong Kong and USTC-CityU Joint Advanced Research Centre, Suzhou, People's Republic of China § Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute of University of Science and Technology of China, Suzhou, People's Republic of China ABSTRACT: The objective of this work was to compare the flame retardancy of intumescent flame retardant ethylene−vinyl acetate (EVA/IFR) composites containing different metal oxides including lanthanide oxide, iron oxide, the mixture of iron oxide and lanthanide oxide, and lanthanum ferrite nanocrystalline (LaFeO3). A novel compound containing iron and lanthanum, LaFeO3 was successfully prepared. The EVA/IFR composites with these different coadditives were then fabricated through a melt blending process. Thermogravimetric analysis data showed that these different coadditives could increase the char residue formation. Cone calorimeter results revealed that these different coadditives and IFR could clearly change the decomposition behavior of EVA and form a char layer on the surface of the composites, consequently resulting in efficient reduction of the flammability parameters, such as heat release rate, total heat release, average mass loss rate, average smoke extinction area, and so on. Moreover, significant improvements were obtained in limited oxygen index and Underwriters Laboratories 94 ratings. Among all of the samples, the fire risk of EVA/IFR/LaFeO3 system was the lowest. The residue characterization demonstrated that LaFeO3 could promote the formation of the homogeneous and compact intumescent char layer.
© 2012 American Chemical Society
enhance the efficiency of IFRs. Many compounds have been used as coadditives, such as fumed silica, zeolite, lanthanum oxide, iron compounds, α-zirconium phosphate, and so on. It has been reported that Fe2O3 and La2O3 can improve the efficiency of intumescent systems.14−16 The promotive effect of lanthanum oxide on intumescent flame-retardant polypropylene-based formulations has been investigated. The results demonstrated that La2O3 could significantly improve the thermal stability and flame retardancy of intumescent flameretardant polypropylene.14 Polypropylene/novel intumescent flame retardant in combination with lanthanum oxide was fabricated. It was found that a suitable amount of La2O3 played a promotive effect in the flame retardancy and smoke suppression of IFR composites.15 It has been also reported that Fe2O3 was an effective modifier to improve the thermal stability of the APP-PER-MEL coating.16 Inspired by the effectiveness of Fe2O3 and La2O3, a novel compound containing iron and lanthanum (LaFeO3) was prepared and used as a coadditive to improve the flame retardancy of an EVA/IFR composite. First, LaFeO3 was synthesized and characterized. In order to understand the impact of LaFeO3 on the combustion chacteristics of the EVA/ IFR composite, the effect of lanthanide oxide, iron oxide, the
1. INTRODUCTION Ethylene−vinyl acetate copolymer (EVA) is widely used as insulating materials in the wire and cable industry due to its good mechanical and physical properties.1 However, the development and application are greatly limited by its high flammability. In past decades, the halogenated compounds were commonly used as fillers to improve the fire retardancy of EVA.2 Unfortunately, their fire retardant action is accompanied by negative effects, such as the generation of corrosive, obscuring, toxic smoke. In addition, the manufacture and application of some halogen-containing flame retardants are restricted by new regulations, such as the European Directives on WEEE (Waste of Electric and Electronic Equipment, became European Law in February 2003), RHS (Restrictions of Hazardous Substances, became European Law in February 2003), and REACH (Registration, Evaluation, Authorization, and Restriction of Chemicals, entered into force on 1 June 2007). Therefore, there is a growing demand for new, halogenfree flame retardants.3−5 In recent years, intumescent flameretardant (IFR) additives have been widely utilized in the flame retardation of flammable polymers,6−11 because of their low toxicity and low propensity for smoke generation. A typical and widely studied IFR system is composed of ammonium polyphosphate, pentaerythritol, and melamine (APP/PER/ MEL). But adding only IFRs usually requires high content to achieve a good flame retardant rating. A small amount of coadditives often brings significant improvements in thermal stability and flame retardant properties, implying that they can
பைடு நூலகம்Article pubs.acs.org/IECR
The Impact of Metal Oxides on the Combustion Behavior of Ethylene−Vinyl Acetate Coploymers Containing an Intumenscent Flame Retardant