聚酰胺6/黏土纳米复合材料阻燃性能的研究进展

对聚酰胺6/黏土纳米复合材料的阻燃性能研究进展进行了综述.阐述了聚酰胺6/黏土纳米复合材料的阻燃机理,结合相关的实验结果分析了各种因素对聚酰胺6/黏土纳米复合材料阻燃性能的影响;结合聚酰胺6/黏土纳米复合材料的研究现状,展望了未来的研究趋势.     

高聚物/黏土纳米复合材料阻燃性能的研究进展

综述了近几年来高聚物／黏土纳米复合材料阻燃性能的研究进展，介绍了其结构、制备、阻燃机理及表征方法，并与常规阻燃剂进行了阻燃性能比较，发现在机械、加工、环保等方面，高聚物／黏土纳米复合材料均优于常规阻燃剂，同时对其研究与应用做了展望。     

Flame retardancy of nanocomposites

Nishizawa Technical Institute (NTI) and Kyoto Institute of Technology (KIT) have developed EVA‐clay nanocomposites with excellent mechanical and flame retardant properties by a reactive process and have succeeded in a novel method to synthesize an aluminium hydroxide nanoparticle, which has the effect of improving the flame retardancy of nanocomposites with EVA. About the EVA‐clay nanocomposites, the peak heat release rate (HRR) of sample MM2 (EVA‐clay partially processed nanocomposites) and sample MM3 (EVA‐clay completely processed nanocomposites) was reduced from 1/3 (one third) to 1/4 (one fourth) compared with EVA only. Sample AL‐1 (EVA‐aluminium nanocomposites) showed a more effective reduction of HRR than sample AL‐2 (EVA‐normal aluminium hydroxide). Beside these experiments, the orientation of the nanofiller MMT (montmorillonite) by a 2‐axis extruder equipped a special novel kneading roll head and the flame retardancy of silica nanocomposite coating materials (Sol‐Gel process) is discussed. Copyright © 2004 John Wiley & Sons, Ltd.     

Fire behaviour of polyester–clay nanocomposites

The aim of this study was on the one hand, to compare the fire behaviour of polyester/clay nanocomposites with that of the neat polymers added with the conventional flame retardant melamine isocyanurate (MIC) and on the other hand, to study the effect of the flame retardant added to the nanocomposites. Polyester/clay nanocomposites were prepared by using polybutylene terephthalate (PBT) and a co‐polyester elastomer as polymeric matrices and a commercial organoclay as filler. As verified by X‐ray diffractometry (XRD) and transmission electron microscopy (TEM) intercalated structures were obtained by mixing the molten polymer with the layered silicate in a corotating twin screw extruder. The fire behaviour of these materials was investigated by means of an oxygen consumption calorimetry (Cone Calorimeter). Peak heat release rate of 3‐mm thick samples measured at 50 kW/m² external heat flux was reduced by a factor of 2–3 by the addition of organically modified montmorillonite to the polymers. The further addition of MIC did not give a significant improvement in the behaviour of the materials. Copyright © 2005 John Wiley & Sons, Ltd.     

Tensile and flammability properties of polypropylene‐based RTPO/clay nanocomposites for cable insulating material

Nanocomposites of polypropylene‐based RTPO with organically modified clays were prepared by melt compounding of three components, that is, polypropylene‐based RTPO, maleic anhydride‐grafted polypropylene oligomer (PPgMA), and organically modified clay. Their morphologies, tensile behaviors, and flammability properties were investigated. In the clay nanocomposites, the silicate layers were dispersed at the nanometer level, which was confirmed by X‐ray diffraction and transmission electron microscopy. The tensile yield strength of nanocomposites containing 10 wt % clay exhibited 2.8 times higher value compared with that of neat resin. The combustion behavior of the nanocomposites was evaluated by measuring the heat release rate (HRR) using cone calorimetry. The peak HRR was lowered greatly and the char yield was very high compared with those of neat resin. However, these flame retardant properties of clay are not sufficient as a flame retardant used alone in cable applications. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2375–2381, 2005     

A polymeric flame retardant and surfactant‐free montmorillonite nanocomposites: Preparation and exfoliation mechanism discussion

A polymeric flame retardant (PDEPD) and various amounts of sodium montmorillonite (Na‐MMT) nanocomposites with exfoliation structure were prepared via one‐step polycondensation, attempting to prepare flame‐retardant nanocomposites. The nanocomposites exhibited high thermal stability at high temperature. Based on several comparative studies, we investigated and proposed the possible exfoliation mechanism of Na‐MMT in PDEPD substrate. The microscale combustion calorimeter and cone calorimeter results showed the PDEPD/Na‐MMT nanocomposites could significantly improve the flame retardancy of polystyrene and polyurethane elastomer (TPU), especially the TPU matrix. This study provides new viewpoint for preparing flame‐retardant nanocomposites without surfactants. POLYM. COMPOS., 35:167–173, 2014. © 2013 Society of Plastics Engineers     

Roles of graphite oxide, clay and POSS during the combustion of polyamide 6

Two contrasting approaches have been adopted in the current study to obtain environmental benign and superior flame retardant polymer nanocomposites. In the first approach, polyhedral oligomeric silsesquioxane (POSS) is incorporated as an additional filler in polyamide 6/clay nanocomposite to improve the homogeneity of the ‘physical’ barrier, since POSS transforms to a glassy material upon fire and enhances the coupling of silicate layers to each other. In the second approach, fire response of an intumescent system, polyamide 6/graphite oxide (GO), is compared to polyamide 6/clay systems. The intention of using GO as a flame retardant is to benefit from its layered structure (‘physical’ barrier mechanism) and intumescent/blowing effect (‘chemical’ mechanism). Considerable insight and physical knowledge on the roles of different fillers in the combustion process have been obtained, which would provide useful guidance for the development of a new generation of nanocomposites. Besides the obvious contrasting differences in the flame properties of different materials, the incorporation of various fillers, depending on their nature, has both advantages and disadvantages from the viewpoint of flame retardancy.     

Preparation and Combustion Properties of Flame Retardant Nylon 6/Montmorillonite Nanocomposite

Flame retardant Nylon 6 (PA6)/montmorillonite (MMT) nanocomposites have been prepared using direct melt intercalation technique by blending PA6, organophilic clay and conventional fire retardants, such as the melamine cyanurate (MCA) and the combination of decabromodiphenyl oxide (DB) and antimony oxide (AO). Their morphology and combustion properties are characterized by XRD, transmission electron microscopy (TEM), UL‐94 test and Cone Calorimeter experiments. The flame retardant nanocomposites with MCA or DB and AO show lower heat release rate (HRR) peak compared to that of conventional flame retardant PA6. Meanwhile, the synergetic effect was studied between clay and DB‐AO.

TEM of PA‐n nanocomposite.     

Morphology,microhardness, and flammability of compatibilized polyethylene/clay nanocomposites

Morphology, thermal properties, and microhardness of ethylene‐glycidyl methacrylate copolymer (EGMA)/clay and ethylene‐acrylic ester‐glycidyl methacrylate terpolymer (EAGMA)/clay nanocomposites with different clay concentrations have been studied. The results have shown that EGMA and EAGMA are highly compatible with the organoclays Cloisite®20A (Cl20A) and Cloisite®30B (Cl30B). Intercalated structures are formed in the whole range of Cl20A loadings investigated, whereas partial degradation of the Cl30B organoclay was observed. The thermal characteristics and microhardness of EGMA/clay nanocomposites suggest that the filler dispersion deteriorates at high concentration. The concentrated EGMA/Cl20A nanocomposites have been used as masterbatches to prepare ternary high density polyethylene (HDPE)/Cl20A and low density polyethylene (LDPE)/Cl20A nanocomposites. Diffractometric characterization and scanning electron microscopy observations of these materials have shown that the intercalated structure of the starting EGMA/Cl20A masterbatches is preserved after dilution with the polyolefins. The results suggest that the silicate platelets remain localized within the EGMA droplets in the diluted nanocomposites. The latter display improved microhardness, whereas the mechanical properties, including elongation at break, are comparable with those of the neat polyolefins. Considerable enhancement of the flame retardant properties has been observed for the ternary nanocomposites. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

Synergistic effect of organo‐montmorillonite on intumescent flame retardant ethylene‐octene copolymer

Nanocomposite of thermoplastic elastomer ethylene‐octene copolymer/maleated ethylene‐octene (POE/POE‐g‐MAH) with organo‐montmorillonite (OMMT, 11 wt %) as masterbatch have been obtained by melt blending and it has been characterized by transmission electron microscopy (TEM). Flame retardant POE/POE‐g‐MAH/OMMT/ammonium polyphosphate‐pentaerythritol (APP‐PER) (an intumescent flame retardant with 75 wt % ammonium polyphosphate and 25 wt % pentaerythritol) composites were prepared by using melting processing to study their structures, flame‐retardancy, thermal, and mechanical properties. TEM showed exfoliated structures throughout POE/POE‐g‐MAH/OMMT masterbatch and POE/POE‐g‐MAH/OMMT/APP‐PER nanocomposites. Synergistic effect was observed between OMMT and APP‐PER resulting in significant improvements on thermal stability, flame‐retardancy and mechanical properties in the POE/POE‐g‐MAH/OMMT/APP‐PER nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Flame retardant nanocomposites of polyamide 6/clay/silicone rubber with high toughness and good flowability

A novel flame retardant, silicone elastomeric nanoparticle (S-ENP) with T_g of −120 °C and particle size of ∼100 nm has been developed and used as a modifier for polyamide 6 (nylon-6). It has been found that S-ENP can not only increase the toughness and improve the flame retardancy of nylon-6 but also helps unmodified clay exfoliate in nylon-6 matrix. It has been also found that the S-ENP and exfoliated clay platelet in nylon-6 have a synergistic flame retardant effect on nylon-6. A novel flame retardant nanocomposite of nylon-6/unmodified clay/S-ENP with high toughness, high heat resistance, high stiffness and good flowability has been prepared and a mechanism of synergistic flame retardancy has also been proposed.     

Synergistic effects of exfoliated LDH with some halogen‐free flame retardants in LDPE/EVA/HFMH/LDH nanocomposites

The synergistic effects of exfoliated layered double hydroxides (LDH) with some halogen‐free flame retardant (HFFR) additives, such as hyperfine magnesium hydroxide (HFMH), microencapsulated red phosphorus (MRP), and expandable graphite (EG), in the low‐density polyethylene/ethylene vinyl acetate copolymer/LDH (LDPE/EVA/LDH) nanocomposites have been studied by X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermal analysis (TGA and DTG), mechanical properties, limiting oxygen index (LOI), and UL‐94 tests. The XRD results show that EVA as an excellent compatilizer can promote the exfoliation of LDH and homogeneous dispersion of HFMH in the LDPE/EVA/HFMH/LDH nanocomposites prepared by melt‐intercalation method. The TEM images demonstrate that the exfoliated LDH layers can act as synergistic compatilizer and dispersant to make the HFMH particles dispersed homogeneously in the LDPE matrix. The results from the mechanical, LOI, and UL‐94 tests show that the exfoliated LDH layers can also act as the nano‐enhanced and flame retardant synergistic agents and thus increase the tensile strength, LOI values, and UL‐94 rating of the nanocomposites. The morphological structures of charred residues observed by SEM give the positive evidence that the compact charred layers formed from the LDPE/EVA/HFMH/LDH nanocomposites with the exfoliated LDH layers play an important role in the enhancement of flame retardant and mechanical properties. The TGA and DTG data show that the exfoliated LDH layers as excellent flame retardant synergist of MRP or EG can apparently increase the thermal degradation temperature and the charred residues after burning. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Thermal stability,aging properties,and flame resistance of NR‐based nanocomposite

Polymer/clay nanocomposites have some unique properties due to combination of flame resistance and improved mechanical and thermal stability properties which are important to enhance the material quality and performance. The objective of this work was to investigate the effect of organically modified montmorillonite (org‐MMT) on the thermal and flame retardant as well as hardness and mechanical properties of the nanocomposites based on the natural rubber (NR). It was shown that by the addition of 3 wt % of org‐MMT to NR, its aging hardness rise was decreased more than 55% and the ignition time was delayed about 150%. The reduction in heat release rate peak value was equal to 54% compared to the pristine NR. Addition of org‐MMT improved the thermal stability of the NR. Furthermore, nanocomposites which were calendared before curing showed much more thermal stability and fire resistance than those which contained similar amount of organoclay. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and thermal analysis of cotton–clay nanocomposites

Nanocomposites were produced from cotton with montmorillonite clay used as the nanofiller material. Three exfoliation and intercalation methods with different solvents and clay pretreatment techniques were tested for the production of these organic–inorganic hybrids. The method that resulted in superior clay–cotton nanocomposites used a clay pretreatment with 4‐methylmorpholine‐N‐oxide as the cotton solvent. The nanocomposites showed significant improvements in the thermal properties in comparison with unbleached cotton and cotton processed under the conditions for nanocomposite preparation. The degradation temperature of the nanocomposites increased by 45°C, and the char yields for some compositions were twice those of unbleached cotton. The crystalline melt of the materials decreased by 15°C. Future research will include the development of textiles based on these cotton–clay materials and testing for flame‐retardant properties and product strength. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2125–2131, 2004     

Polystyrene-based composites and nanocomposites with reduced brominated-flame retardant

Polystyrene was melt blended with a halogen-based flame retardant (FR), hexabromocyclododecane, and a non-halogenated FR, triphenyl phosphate (TPP), in a twin-screw extruder. An organically modified montmorillonite (Cloisite 15A) was used to prepare FR polystyrene nanocomposites. The flammability properties and thermal stability of FR polystyrene composites and nanocomposites were investigated. X-ray diffraction analysis showed that the exfoliation structure of organically modified montmorillonite in polystyrene nanocomposites may be achieved by melt-compounding in a twin-screw extruder. Furthermore, a good dispersion of FRs and nanoparticles of organically modified montmorillonite was observed by energy dispersive X-ray analysis. Thermogravimetric analysis demonstrated that the thermal stability of FR nanocomposites enhanced in the presence of clay nanoparticles and antioxidant. The aim of this study was to reduce the FR level, especially in the brominated FRs. The good results obtained by the limiting oxygen index test showed high-performance flammability properties in the composites containing hexabromocyclododecane and TPP, resulted from the synergy effects between these two FRs. However, in spite of producing high thermal performance polystyrene nanocomposites and dispersing clay nanoparticles efficiently into the polystyrene matrix, the flame retardancy properties were deteriorated in the presence of clay nanoparticles. Therefore, the organically modified clay (Cloisite 15A) was not a good synergic compound to improve the flame retardancy of polystyrene nanocomposites.     

Synthesis and Thermal Characterization of Polyurethane/Clay Nanocomposites Based on Palm Oil Polyol

Polyurethanes (PUs) are very versatile polymeric materials with a wide range of physical and chemical properties. PUs also have desirable properties, such as high abrasion resistance, tear strength, shock absorption, flexibility, and elasticity. Although they have poor thermal stability, it can be improved by using treated clay.

The objective of the present work is to study the thermal stability of polyurethane, polyurethane/montmorillonite (PU CTAB-mont 3% wt), and polyurethane/montmorillonite containing moca (PU Moca CTAB-mont 3% wt) nanocomposites based on palm oil polyol.

The interest of investigating the synthesis of polyurethane/clay nanocomposites based on palm oil polyol is to explore the use of palm oil polyol to partially replace petrochemical-based polyol.

Polyurethane/clay nanocomposites were prepared by a pre-polymer method and evaluated by Fourier Transform Infrared Spectra (FTIR) to determine micro-domain structures of segmented PU, PU CTAB-mont 3% wt, and PU Moca CTAB-mont 3% wt. The morphology of the nanocomposites was characterized by X-ray diffraction (X-RD), and flame retardant was investigated with thermogravimetric analysis (TGA). The result showed that in comparison with the virgin polyurethane, adding clay and moca demonstrated better thermal stability.     

Influence of the degree of exfoliation of an organoclay on the flame‐retardant properties of cross‐linked ethylene‐co‐Propylene‐co‐diene monomer‐g‐Maleic anhydride‐based composites

Layered montmorillonite was synthesized by hydrothermal method, progressively modified by an alkylammonium and thoroughly characterized by elemental, thermal, and X‐ray diffraction (XRD) analysis. Pristine and modified clays were introduced in maleic anhydride‐modified ethylene‐co‐propylene‐co‐diene monomer matrix. XRD and transmission electron microscopy investigations showed microcomposite as well as intercalated or exfoliated nanocomposites morphologies depending on the organic content of the clay. The inhibitor character of the pristine clay on peroxides as crosslinking agent for rubbers was then demonstrated and overcome by using electron beam irradiation for specimens containing unmodified clay. Dynamic mechanical analyses and swelling measurements showed that it is possible to obtain the same degree of crosslinking of the polymer matrix by electron beam irradiation of the composites based on pristine clay specimens and conventional peroxide curing of modified‐clay‐based ones. Finally, flame‐retardant properties of different clays‐based composites showed a direct dependence on the degree of exfoliation. It was observed that the better the exfoliation, the higher is the flame retardancy. POLYM. COMPOS., 38:966–973, 2017. © 2015 Society of Plastics Engineers     

PVAc/OMMT纳米复合物的制备及其在阻燃PP中的应用

通过原位乳液插层法制备了有机蒙脱土(OMMT)含量较高的聚醋酸乙烯酯/有机蒙脱土(PVAc/OMMT)纳米复合物,并将其作为阻燃母料与氢氧化镁(MH)复配,与聚丙烯(PP)熔融共混制备了性能良好的无卤阻燃PP,用X射线衍射(XRD)、锥形量热分析(CONE)等对材料进行了表征。结果表明:当OMMT和MH的用量分别为3%和40%时,阻燃PP的热释放速率峰值(PHRR)相比于基体树脂从929.0kW/m2降低至193.7kW/m2,总释放热(THR)从165.2MJ/m2降低到73.6MJ/m2。     

EVA/MWNTs复合材料的阻燃性能

综述了近几年来乙烯-乙酸乙烯酯共聚物/多壁碳纳米管（EVA/MWNTs）纳米复合材料的研究进展,介绍了其制备方法,详述了其热解行为及阻燃性能（包括热释放速率、引燃时间、成炭性）,并对其阻燃机理进行了深入的讨论。比较了MWNTs、有机黏土、层状双氢氧化物等不同纳米填料的阻燃性能,分析了对MWNTs进行不同处理（包括纯化、使用高密度聚乙烯进行表面涂覆改性、研磨）对相应纳米复合材料的热稳定性及可燃性的影响。     

Carbon-family materials for flame retardant polymeric materials

As an abundant and attractive element, the emergence of new carbon-based materials brings revolutionary development in material science and technology. Carbon-based materials have spawned considerable interest for fabricating polymer composites/nanocomposites with greatly improved mechanical, thermal, gas barrier, conductivity, and flame retardant performance. In this review, the importance of carbon-based materials and the necessity of fire resistance for polymeric materials are initially introduced. Then, the fundamental flame retardant mechanisms and experimental analytical techniques are described to understand the relationship between structures and flame retardant properties. The main section is dedicated to the preparation and properties of multifunctional polymer composites/nanocomposites with carbon-based materials, with special emphasis on the flame retardant properties of these materials. A wide variety of carbon-based materials are discussed for use in flame retardant polymer nanocomposite, including graphite, graphene, carbon nanotubes, fullerenes as well as some new emerging carbon forms (carbon nitride, carbon aerogels, etc). Finally, a brief outlook at the developments in carbon-based materials for flame retardant polymeric composites is given by discussing the major progress, opportunities, and challenges.