Nanocarbon-Based Flame Retardant Polymer Nanocomposites

In recent years, nanocarbon materials have attracted the interest of researchers due to their excellent properties. Nanocarbon-based flame retardant polymer composites have enhanced thermal stability and mechanical properties compared with traditional flame retardant composites. In this article, the unique structural features of nanocarbon-based materials and their use in flame retardant polymeric materials are initially introduced. Afterwards, the flame retardant mechanism of nanocarbon materials is described. The main discussions include material components such as graphene, carbon nanotubes, fullerene (in preparing resins), elastomers, plastics, foams, fabrics, and film–matrix materials. Furthermore, the flame retardant properties of carbon nanomaterials and their modified products are summarized. Carbon nanomaterials not only play the role of a flame retardant in composites, but also play an important role in many aspects such as mechanical reinforcement. Finally, the opportunities and challenges for future development of carbon nanomaterials in flame-retardant polymeric materials are briefly discussed.     

(Photo)oxidative degradation and stabilization of flame retarded polymers

Flame retarded polymer formulations are mainly used in long-term applications whereas antioxidants, light stabilizers and co-additives provide the requested lifetime of plastic materials. However many flame retardants influence the oxidative and photooxidative stability of polymers often in a negative way resulting in early failure and loss in value. Moreover insufficient (photo)oxidative stability of the flame retardant itself may reduce the flame retardance performance over time. Therefore, there is a need to develop adjusted stabilizer systems considering the type of flame retardant, the polymer substrate and the intended application. Therefore, the influence of flame retardants on the (photo)oxidative stability of selected polymers is reviewed and strategies to extend the lifetime of flame retarded polymers are provided. In addition, the specific requirements of the stabilization of nanocomposites as potential flame retardant components are covered.     

Combustion and thermal properties of paper honeycomb

The honeycomb structure has superior compressive strength so that it is being utilized in various fields. In addition, the paper honeycomb has excellent economic feasibility because of its low production cost and has an environment-friendly advantage because its recycling is possible. Securing of flame retardant performance is essential to use it as interior materials of buildings and fireproof doors using the advantage like this. The present research has evaluated combustion and thermal properties according to flame retardant treatment in terms of two kinds of specimens when flame retardant film is attached to paper honeycomb, and when paper honeycomb is impregnated to flame retardant agents. As a result of evaluating flame retardant performance utilizing a cone calorimeter, the case impregnated into flame retardant agents showed the most superior flame retardant performance. Through this result, it was confirmed that the paper honeycomb can be utilized as interior materials of buildings though improvement of flame retardant performance.     

使用裂解气相色谱对几种阻燃聚丙烯材料热稳定性及阻燃机理的探讨

用裂解气相色谱（PyGC)考察了经三种类型阻燃剂（含磷、含溴、含溴和磷）改性的聚丙烯的热稳定性。利用PyGC-MS法分析不同样品的高温裂角产物,以此来推测阻燃材料受热分解时气相以及凝聚相所发生的反应,推断阻燃机理,分析影响阻燃效果的因素,为阻燃剂的开发提供有益参考。结果证实,它们都影响聚丙烯的热降解。溴系阻燃剂和磷系阻燃剂是分别从气相阻断、凝固相加速成炭实现阻止燃烧的,而磷-溴型阻燃剂同时具备单纯含磷或者含溴阻燃能力。     

硅橡胶复合材料阻燃研究进展

将功能填料引进到硅橡胶及其复合材料中可以获得特定功能的硅橡胶复合材料,已经成为近些年研究热点。目前阻燃剂种类繁多,但是性能比较单一,这已经不能满足人们的需要。人们在关注硅橡胶复合材料阻燃性能的同时,也考虑与其它性能兼备以及成本等问题。因此,本文综述了铂化合物、磷系阻燃剂、阻燃涂层、阻燃填料和微胶囊化阻燃剂等阻燃体系下硅橡胶复合材料的阻燃研究现状,总结了不同阻燃剂的阻燃机理,并且给出了其今后的改进方法,最后对硅橡胶复合材料阻燃研究的发展做了展望。     

石墨烯在聚合物阻燃材料中的应用及作用机理

本文从聚合物基底的阻燃复合材料类别角度出发,详细介绍了石墨烯在不同种类聚合物阻燃材料中的应用现状与作用机理。 包括有:石墨烯/聚乙烯、石墨烯/聚丙烯、石墨烯/聚苯乙烯、石墨烯/环氧树脂、石墨烯/聚氨酯、石墨烯/聚乙烯醇等多种石墨烯/聚合物复合阻燃材料。 同时还介绍了石墨烯基材料在其中所发挥的作用,该综述为发展出新型的石墨烯基/聚合物复合阻燃材料提供了很好的理论支持。     

Kinetics of tetrabromobisphenol A pyrolysis. Comparison between correlation and mechanistic models

Brominated flame retardants are well recognized as being highly effective flame retardants. 4-4′-Isopropylidenebis(2,6-dibromophenol), commonly known as tetrabromobisphenol A, is the brominated flame retardant with the largest production volume and is used to improve fire safety, mainly of laminates in electrical and electronic equipment. A kinetic study of the pyrolysis of TBBA has been carried out to obtain decomposition parameters under different operating conditions and taking into account that TBBA is a compound with a high boiling point and that vaporization occurs simultaneously to decomposition. Dynamic runs and dynamic + isothermal run at different heating rates and using different masses of sample were correlated simultaneously. All TG runs were fitted with a unique set of kinetic parameters that is able to explain all the experiments. Moreover, a simplified detailed kinetic model has been developed and the kinetic parameters obtained satisfactorily reproduce the thermal decomposition of TBBA.     

聚乳酸阻燃性能的研究进展

聚乳酸作为一种资源与环境友好材料已得到了广泛深入的研究。如果能够提高聚乳酸的阻燃性能,则能进一步扩大其应用范围。目前对聚乳酸的阻燃改性主要采用添加阻燃剂的方法,并以磷系、氮系、硅系、金属化合物阻燃剂以及多种阻燃成分的复配为主,而聚乳酸的反应型阻燃也在不断研究发展中。本文在介绍阻燃作用机理的基础上,综述了聚乳酸阻燃研究发展现状,并对聚乳酸的阻燃提出展望。     

A facile strategy to fabricate intumescent fire-retardant and smoke suppression protective coatings for natural rubber

As flammable natural rubber (NR) becomes more ubiquitous in industrial fields, there is a growing need for safe and effective flame retardant treatments through efficient techniques. Remarkably, our developed highly efficient natural tannic acid (TA)-based intumescent flame-retardant system (AGT) has the unique function in the rubber flame retardant aspect. Meanwhile, the developed coating method through polyurethane elastomer (PU) both as adhesive medium and a carbonforming agent can not only minimize the influence of flame retardant on the desirable intrinsic properties of base polymer and also maximize the efficiency of flame retardant. The flame-retardant coating (AGT/PU) exhibits highly efficient flame retardant performances reflected by a 31.9% reduction in peak heat release rate and a 27.3% reduction in total heat release and a 26.2% reduction in total smoke production with 50 wt% loading in 1 mm thick coating due to synergistic flame retardant effects. More importantly, the excellent flame retardancy performance are obtained by the PU@AGT10, as reflected in flame retardancy index (FRI) value of 11.88 makes it as excellent flame retardancy performance. While many physically mixed flame retardants are usually seriously detrimental to mechanical properties of NR, the influence of AGT/PU coating on mechanical properties of NR decreases obviously because fire retardant just directly impacts on PU adhesive layer rather than NR matrix, and the reinforcement function of graphene is also much significant. Moreover, the coating method requires just less flame retardant to achieve high flame retardant effect for NR. These findings suggest that significant opportunities for flame retardant polymer materials in industry.     

磷系阻燃剂阻燃聚碳酸酯研究进展*

磷系阻燃剂具有阻燃效率高、低烟、低毒、与基质材料相容性好等优点,在阻燃高分子材料领域得到广泛应用。本文介绍了磷系阻燃剂的分类及阻燃机理,综述了近年来磷酸酯阻燃剂、膦酸酯阻燃剂、DOPO磷杂菲类阻燃剂、磷腈类阻燃剂和无机磷阻燃剂在阻燃聚碳酸酯领域的研究进展,为新型磷系阻燃剂的研发提供参考。     

聚合法制备无卤阻燃尼龙的研究进展

在全球阻燃材料无卤化的推进过程中,氮系、磷系、硅系等阻燃剂以及其复配物受到各国研究人员的广泛关注。利用聚合法(原位聚合法和共聚法)制备阻燃尼龙,可有效解决共混法中常存在的阻燃剂在基体中分散不均匀而导致的材料性能下降的问题。原位聚合法和共聚法是根据阻燃成分在基体中的存在方式而区分的,通常前者以物理均匀分散为主,后者多以化学键结合。本文在不同制备方法的背景下,根据阻燃剂类别进一步细分,综述了用原位聚合法和共聚法制备无卤阻燃尼龙的相关研究,并探讨了该领域中亟待解决的问题及未来发展方向。     

Determination of a polymeric hindered amine light stabilizer in polypropylene formulated with magnesium hydroxide flame retardant by reactive thermal desorption-gas chromatography.

A polymeric hindered amine light stabilizer (HALS), Tinuvin 622 (MW [symbol: see text] 4000), in PP materials formulated with a magnesium hydroxide flame retardant was determined by reactive thermal desorption (RTD) gas chromatography (GC). Two kinds of the HALS components that were formed through the RTD in the presence of tetramethylammonium hydroxide [(CH3)4NOH, TMAH] were clearly observed in the chromatograms of the PP samples, with negligible interference from the other additives and the PP substrate. Here, the coexisting flame retardant was proved to affect significantly the RTD process of the occluded HALS. As a result, the recovery of the HALS components in the RTD-GC chromatograms of the PP samples increased with increase in the content of the flame retardant. This enhancement of the HALS recovery is attributed mainly to the preferential exposure of the HALS on the surface of the ground PP sample through the interaction between the polymeric HALS and the flame retardant in the molten PP during kneading. In spite of such a considerable action of the flame retardant, the observed intensities of the characteristic peaks of HALS by RTD-GC showed a good linear relationship with the HALS content in the PP samples with constant content of the flame retardant (50 phr); this relationship could be used as the calibration line for the determination of the polymeric HALS in the PP materials containing the flame retardant.     

Composition of a wood combustion inhibitor based on a magnesium complex containing phosphorus and nitrogen

A flame retardant for wood impregnation based on a magnesium complex containing phosphorus and nitrogen was developed. It considerably reduces the wood loss in fire tests. Application of the flame retardant in an amount of 300 g m^–2 allows preparation of materials with the fire performance corresponding to group I of materials. The mechanism of the fireproofing action of the flame retardant on wood and the thermal degradation of the impregnated wood were studied.     

Nanocomposites and Blends of Biocatalytically Synthesized Organosilicone Co-Polymers for Flame Retardant Applications

The great synthetic flexibility of organosilicone polymers, their ease of processing, low cost, and nontoxic nature present an attractive alternative solution over current flame retardant materials. Novozyme-435 catalyzed amidation reaction with silicone-based oligomer was carried out to scale up the synthesis of co-polymer which was fully characterized from its detailed spectroscopic studies. Synthesized co-polymer was compounded in polyolefins for flame retardant applications. Nanoclay [Cloisite 20A, 2C₁₈ MMT (dimethylditallowammonium-/dimethyldioctadecylammonium-modified montmorillonite)] was used as a potential additive in co-polymer, which was then blended with polyolefins to improve their thermal as well as flame retardant properties. The present work provides an initial exciting basis for the enzymatic synthesis of silicon based co-polymers in bulk and their flame retardant applications.     

Catalytic action of phospho-tungstic acid in the synthesis of melamine salts of pentaerythritol phosphate and their synergistic effects in flame retarded polypropylene

A solid acid, phospho-tungstic acid (PTA), has been used to catalyze the pentaerythritol-melamine phosphate (PER-MP) reaction to synthesize intumescent flame retardant, melamine salt of pentaerythritol phosphate (MPP) used in flame retardant polypropylene (PP). This novel and environmentally friendly synthesis technology well solves the problems of conventional preparation methods. PTA plays a double-role: on one hand, it remarkably enhances the conversion of the above reaction and decreases the reaction temperature; on the other hand, it acts as an effective synergist with MPP and greatly improves the flame retardancy; accordingly, no additional process is needed to remove PTA after the reaction, and the products of the catalyzed reaction were directly incorporated with PP to prepare high-performance flame retardant materials. The catalytic and synergistic effects of PTA, as well as the flame retardancy and mechanical properties of the corresponding flame retardant PP were investigated.     

含环三磷腈衍生物的辐照交联聚乙烯基复合材料的制备及阻燃性能

将具有阻燃剂和辐照敏化剂双重功能的含烯丙基环三磷腈（CP-Allyl）,通过熔融共混的方式引入到由低密度聚乙烯和乙烯-醋酸乙烯共聚物组成的基体中,制备了一系列基于有机-无机阻燃复配剂的新型无卤阻燃聚乙烯基复合绝缘材料。进一步通过100～190 kGy剂量下的电子束辐照,实现了复合材料的辐照交联,并建立了辐照剂量与交联度以及材料性能的关系。研究结果表明,含有功能性环三磷腈衍生物的辐照交联复合材料具有优良的力学强度、阻燃性和电绝缘性能。力学强度在14.5 MPa以上,极限氧指数为28.2%～32.4%,电阻达到2.47×1012Ω以上,因而有希望在电线电缆领域获得应用。     

Characterisation of the dispersion in polymer flame retarded nanocomposites

Flame retardant nanocomposites have attracted many research efforts because they combine the advantages of a conventional flame retardant polymer with that of polymer nanocomposite. However the properties obtained depend on the dispersion of the nanoparticles. In this study, three types of polymer flame retarded nanocomposites based on different matrices (polypropylene (PP), polybutadiene terephtalate (PBT) and polyamide 6 (PA6)) have been prepared by extrusion. In order to investigate the dispersion of nanoparticles in the polymer containing flame retardant, conventional methods used to characterise the morphology of composites have been applied to FR composites containing nanoclays. XRD, TEM and melt rheology give useful information to describe the dispersion of the nanofiller in the flame retarded nanocomposite. In the PA6-OP1311 (phosphorus based flame retardant) materials, the clay is well dispersed unlike in PBT and PP materials where microcomposites are obtained with some intercalation. The poor dispersion is also highlighted by NMR measurements but the presence of flame retardant particles interferes in the quantitative evaluation of nanoclay dispersion and underestimations are made.     

反应性挤出加工制备无卤阻燃高分子材料

聚合物反应性加工集聚合物加工与化学反应为一体,以聚合物加工装置为反应器,通过聚合物加工过程中的化学反应形成新物质和新结构,实现高分子材料的高性能化和功能化,是高分子材料科学的研究前沿之一.本文简要介绍了我们研究小组近年来采用反应性挤出加工制备高性能无卤阻燃高分子材料方面的研究进展.利用反应性挤出加工剪切力强、温度可控以及易于传质传热的特点实现了常规方法难以合成的高黏阻燃剂三聚氰胺磷酸盐季戊四醇酯（MPP）和三聚氰胺氰尿酸（MCA）的高效合成,制备了综合性能优良的聚丙烯/MPP、尼龙6/MCA等无卤阻燃高分子材料.研究所涉及的化学和物理方法,为聚合物无卤阻燃提供了高效、经济、环保和易于工业化的新技术,并拓宽了聚合物反应性加工的应用领域.     

A review on flame retardant technology in China. Part I: development of flame retardants

This paper provides an insight into some developments in flame retardants for different polymeric materials in China, primarily based on the publications that have appeared in the last 15 years. It focuses on the following aspects: halogen‐containing flame retardants, inorganic flame retardants (e.g. metal oxides and hydroxides, silicon‐containing materials, ammonium polyphosphate, red phosphorus, and expandable graphite), and organic flame retardants (e.g. aliphatic and aromatic phosphonates, nitrogen‐containing organics, and multi‐element organics). The inherently flame‐retardant polymer systems are also reviewed. The exploration of the novel flame retardants and flame‐retardant systems provides a powerful basis for the construction of flame‐retardant technologies and industrial applications in China. Copyright © 2009 John Wiley & Sons, Ltd.     

Combination effect of nanoparticles with flame retardants on the flammability of nanocomposites

Polystyrene based nanocomposites (PNCs) with and without flame retardant additives were successfully prepared through a single-screw extrusion technique. The combination effect of nanoparticles and flame retardants was investigated with nanosilica and attapulgite clay as nanofillers, and with a NASA formulated SINK flame retardant. A comprehensive study was done by Cone Calorimetry, UL94 and TGA.The addition of nanoparticles to polystyrene generally improved the OI of polystyrene. The horizontal burning tests suggested that nanofiller types have different impacts on the flammability of nanocomposites. According to the vertical burning tests and oxygen indices, it was found that polystyrene/silica and polystyrene/attapulgite clay PNCs alone are not flame retardant. In fact, the materials burned faster. However, the combination of nanocomposites with the SINK flame retardant significantly altered the thermal stability, and flammability of the materials. A remarkable reduction in heat release rates of polystyrene was achieved for both silica and attapulgite with flame retardant nanocomposites. For instance, the introduction of 20% SINK into PS reduced the PHRR of PS from 1212 to 838 (−31%); 10% silica reduced it from 1212 to 1060 (−13%), while the combination of silica and SINK reduced it to 530 (−56%), which clearly shows interaction between nanosilica and SINK.