Advancements in traditional and nanosized flame retardants for polymers—A review (original) (raw)
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Journal of the Textile Institute, 2003
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Polypropylene (PP) and Polyamide 6 (PA6) samples, with and without fire retardants (FR) (ammonium polyphosphate in PP, and a mixture of organic aluminium phosphinate and melamine polyphosphate (OP 1311) in PA 6) and nanofillers (NC) were burned under different fire conditions in order to compare their toxic product yields. Fire effluents (CO, smoke and hydrocarbons) were generated using a steady state tube furnace (BS 7900, ISO TS 19700) for the separate materials and fire retarded and nanocomposite modifications of these materials under flaming conditions. Under well-ventilated conditions yields of carbon monoxide (CO) for all PP samples are similar, whereas for PA6 samples much higher yields of CO for PA6 þ FR and PA6 þ NC are observed. The highest yields of CO occur for both pure polymers in underventilated fire conditions when fire retardant and nanoclay are combined together. For PP the smoke is fairly independent of fire condition, but the PP þ FR þ NC shows less agglomeration. For PA6 the sample containing OP 1311 shows consistently higher smoke yields. For hydrocarbon yields similar effects are observed for both PP and PA6 polymers; the highest yields are for PA6 þ NC, except under-ventilated fires where PA6 þ FR produce the most; for PA6 þ FR þ NC samples the lowest yields are observed, compared to either NC or FR formulations.
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In this work, an efficient approach to improving the fire retardancy and smoke suppression for intumescent flame-retardant polypropylene (PP) composites is developed via incorporating functionalized sepiolite (organo-modified sepiolite [ONSep]). The PP composites with different amounts of intumescent flame retardants and ONSep were prepared by melt compounding. The morphology, thermal behavior, fire retardancy, smoke suppression, and mechanical property of flame-retardant PP composites were studied. The results indicate an appropriate amount of ONSep in the flame-retardant PP composites can increase thermal degradation temperature and char formation as well as a reduction of the peak heat release rate and total heat release; moreover, the addition of ONSep significantly decreases the CO production, total smoke production, smoke production rate, and smoke temperature. Simultaneously, the impact strength of intumescent flame-retardant PP composite is also maintained by introducing an appropriate amount of ONSep as compared with that without ONSep. KEYWORDS flame/fire retardancy, mechanical properties, nanoparticles, polymer-matrix composites 1 | INTRODUCTION Polypropylene (PP) is widely used in a variety of applications, including transportation, construction, electronic appliances, and general household materials for its excellent physical and mechanical properties, low density, ease of processing, good chemical resistance, etc. 1,2 Nevertheless, the flammability characteristics of PP is one of the main drawbacks limiting its wide application. 3,4 In order to expand its application, significant work has been performed to improve fire safety of PP. Halogen-containing flame retardants have been widely applied to PP because of their high efficiency as radical scavengers during combustion, even in low loading levels. However, this kind of additive releases significant amounts of toxic gases and corrosive smoke during combustion. 5,6 Thus, advanced halogen-free and low-smoke flame retardant systems are one of the most popular topics in current polymer materials research and development, such as metal hydroxides and intumescent flame retardants (IFRs). Metal hydroxides like aluminum trihydroxide (ATH) or magnesium dihydroxide (MDH) can decompose during heating, releasing water and forming a char layer that reduces the temperature and decomposition rate of the polymer substrate. 7,8 However, very high concentrations greater than 50 wt% of these additives must be used to achieve good flame retardancy, and the physical and mechanical properties of PP are negatively impacted. Recently, IFR is considered to be one of the most promising flame retardants to replace halogen-containing flame retardants because of its environmentally friendly, high-efficiency, anti-dripping, and low
Fire and Materials, 2013
1 Low-melting glass has been synthesized in the system PbO-ZnO-B 2 O 3 and Na 2 O-P 2 O 5 -MoO3 and its composition has been developed. The effect of the glass chemical composition on the softening temperature and the change of appearance during the heating have been established. Polypropylene-based composite with different content of glass powder as a filler was obtained. Thermophysical properties of the composites were determined. Introduction of glass powder to the polypropylene composition damaged the material structure homogeneity. Using DTA method it was established that the developed filler shifts the temperature of polymer complete combustion toward higher temperature by above 40 K.