苯并噁嗪树脂/丁腈橡胶复合材料双网络结构及其耐烧蚀和绝热性能

考察了苯并噁嗪树脂（PBR）对丁腈橡胶（NBR）耐烧蚀和绝热性能的影响。结果表明,随着PBR用量的增加,PBR/NBR复合材料的线性烧蚀率和热导率下降,这主要是由于燃烧表面的炭化物和基质之间的强烈相互作用及PBR在整个NBR基体中形成的树脂网络结构阻止了外部热流的侵入,此外PBR还能生成不可燃气体阻止了基质的进一步燃烧。当PBR用量为60份（质量）时,PBR/NBR复合材料的线性烧蚀率和热导率分别达到0.023 mm/s和0.169 W/（m·K）。     

Ablation properties of aluminum silicate ceramic fibers and calcium carbonate filled silicone rubber composites

The ablative performance of aluminum silicate ceramic fiber (ASF) and calcium carbonate (CaCO₃) filled silicone rubber composites prepared through a two‐roll mill was examined. The properties of the composites were investigated by thermogravimetry, thermal conductivity measurements, and oxyacetylene torch testing. After the material was burnt, the structure and composition of the char were analyzed by Fourier transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy (SEM). The results of the ablation test showed that the ablation resistance improved greatly in an appropriate filler scope. Combined with SEM, it was proven that a firm, dense, and thermal insulation layer, which formed on the composites surface during the oxyacetylene torch test, was a critical factor in determining the ablation properties. Thermogravimetric analysis revealed that the thermal stability of the composites was enhanced by the incorporation of ASF and CaCO₃. The thermal conductivity measurements showed that the silicone rubber composites had a very low thermal conductivity ranging from 0.206 to 0.442 W m^?1 K^?1; this significantly prevented heat from transferring into the inner matrix at the beginning of the burning process. The proportion of 20/40 phr (ASF/CaCO₃) was optimum for improving the ablation resistance of the silicone rubber composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41619.     

阻燃抑烟型聚乳酸/竹粉复合材料性能研究

采用模压成型法制备了氢氧化铝（ATH）、聚磷酸铵（APP）及APP+ATH阻燃型聚乳酸/竹粉(PLA/BF)复合材料,通过扫描电子显微镜考察了复合材料拉伸断面和燃烧后炭层的微观结构,并对其力学性能、热稳定性能和燃烧性能进行了测试。结果表明,阻燃剂的引入均降低了复合材料的力学性能,但显著提高了热稳定性,600 ℃时复合材料的残炭率分别达到了20.3 %、27.9 %和26.3 %;ATH对复合材料具有显著的抑烟效果,但抑热作用较APP要差,而ATH与APP复合阻燃剂使复合材料兼具较好的抑热作用和抑烟效果。     

Tensile,thermal, flammability and morphological properties of sepiolite filled ethylene propylene diene monomer (EDPM) rubber composites

The effect of sepiolite loading content on the curing characteristics, tensile mechanical, thermal, swelling, flammability and morphological properties of sepiolite-filled ethylene propylene diene monomer (EPDM) composites was investigated. The composites were prepared with sepiolite loadings of 0–70 part per hundred (phr) of rubber using a two-roll mill. The results highlighted the improvement in the tensile properties and cross-link density values peaked at 60 phr of sepiolite loading. The scorch time, curing time, swelling percentage, and linear burning rate of the composites decreased with an increase in sepiolite loading. Thermogravimetric analysis showed an increasing trend with increase in sepiolite loading. The temperatures corresponding to 5, 25 and 50% weight loss (T_5wt%, T_25wt% and T_50wt%) and the percentage of char residue gradually increased with increase in sepiolite loading. The homogenous dispersion of the sepiolite particles in the EPDM matrix and the formation of zigzag structures, especially at 60 phr, were the main reasons of the improvement of mechanical properties which were confirmed by the morphological studies. The formation of a protective layer, which acted as a barrier against heat transfer into the deeper layers, enhanced the flammability resistance of the composites. Notably, the EPDM filled with 60 phr sepiolite exhibited excellent performance in the aspects of mechanical, thermal stability and flammability properties and resistance towards swelling.     

Ablation properties of zinc borate and aluminum hypophosphite filled silicone rubber composites

The ablative properties of epoxy modified silicone rubber composites filled with zinc borate (ZB) and aluminum hypophosphite (AHP) were studied. The decomposition of the added fillers and covering connection of residual on the substrate contribute to the improvement of heat insulation. The ablation test shows that the formation of a dense char layer with certain strength is key to improving the ablative properties. The optimal ablative performance is achieved when the concentration of ZB and AHP is 10 and 5 phr, respectively. Under such circumstances, the linear ablation rate is as low as 0.032 mm/s, which is about 61% lower than the pure silicone rubber. Furthermore, the structure and composition of the formed char layer were analyzed using X-ray diffraction analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy.     

Influence of ammonium polyphosphate modified with 3‐(methylacryloxyl) propyltrimethoxy silane on mechanical and thermal properties of wood flour–polypropylene composites

In this article, the influence of ammonium polyphosphate (APP) and ammonium polyphosphate modified with 3‐(Methylacryloxyl) propyltrimethoxy silane (M‐APP) on mechanical properties, flame retardancy, and thermal degradation of wood flour–polypropylene composites (WF/PP composites) have been investigated. Polypropylene grafted with m‐isopropenyl‐α,α‐dimethylbenzyl‐isocyanate (m‐TMI‐g‐PP) was used to improve the adhesion of WF/PP composites. APP and M‐APP were used as flame retardants. The experimental results demonstrated that addition of M‐APP obviously enhanced mechanical properties of WF/PP composites. According to cone calorimetry results, M‐APP is also an effective flame retardant for WF/PP composites, compared to that of APP. It was also found that M‐APP decreased the 1% weight loss temperature and increased char residue. The thermal degradation of wood flour based upon the first peak temperature of wood decreased from 329.3 to 322.9°C and the thermal degradation of PP based upon the second peak temperature of PP improve from 518.0 to 519.6°C, when M‐APP was added to the WF/PP composites. From SEM results the char layer of the 25% M‐APP systems is much more intumescent than that of the 25% APP systems, indicating that 3‐(Methylacryloxyl) propyltrimethoxy silane can improve the char‐forming ability of WF/PP composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Thermal stability and ablation properties study of aluminum silicate ceramic fiber and acicular wollastonite filled silicone rubber composite

The thermal stability and ablation properties of silicone rubber filled with silica (SiO₂), aluminum silicate ceramic fiber (ASF), and acicular wollastonite (AW) were studied in this article. The morphology, composition, and ablation properties of the composite were analyzed after oxyacetylene torch tests. There were three different ceramic layers found in the ablated composite. In the porous ceramic layer, the rubber was decomposed, producing trimers, tetramers, and SiO₂. ASF and part of AW still remained and formed a dense layer. The SiO₂/SiC filaments in the ceramic layer reduced the permeability of oxygen, improving the ablation properties of the composites. The resultant ceramic layer was the densest, which acted as effective oxygen and heat barriers, and the achieved line ablation rate of the silicone composite were optimum at the proportion of 20 phr/40 phr (ASF/AW). Thermogravimetric analysis (TGA) confirmed that thermal stability of the composites was enhanced by the incorporation of ASF and AW. The formation of the ceramic layer was considered to be responsible for the enhancement of thermal stability and ablation properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39700.     

膨胀石墨在聚乙烯中阻燃协效作用的研究

以膨胀石墨(EG)与聚磷酸铵(APP)复配组成膨胀型阻燃剂，应用于高密度聚乙烯(PE-HD)中。热分析表明APP／FG的添加使得PE-HD材料的热稳定性增强，降解过程变缓，剩炭率增加。氧指数(LOI)结果表明APP／EG具有良好的阻燃协同作用。扫描电镜(SEM)显示APP／EG的加入可使得PE-HD样品生成连续致密的炭层。同时力学性能研究表明APP／EG对材料的力学性能的影响比其它膨胀型阻燃剂要小。     

有机蒙脱土对EVA/IFR复合材料阻燃性能的影响

以聚磷酸铵（APP）和季戊四醇（PER）为膨胀型阻燃剂（IFR）制备了含有蒙脱土的无卤阻燃乙烯 醋酸乙烯共聚物（EVA）复合材料。通过极限氧指数、热失重分析、锥形量热分析等手段研究了有机蒙脱土(OMMT)的存在对EVA阻燃性能和热降解性能的影响,并通过扫描电子显微镜对复合材料残炭表面形貌进行了观察和分析。结果表明,加入有机蒙脱土可以促进复合材料成炭、改善炭层质量,从而起到了良好的隔热、抑烟作用;OMMT的最佳添加量为3份（质量份数,下同）,复合材料的极限氧指数可达到29.4 %,垂直燃烧可达V 0级。     

Effect of hybrid cross-linked polyphosphazene microspheres on ablative and mechanical properties of ethylene propylene diene monomer

Polymeric ablative materials (PAMs) are widely used in spacecraft currently for thermal insulation. However, it is challenging to find a single filler that can improve both ablative and mechanical properties of PAMs. In this study, a new type of hybrid cross-linked polyphosphazene microspheres (PHC) is added to ethylene propylene diene monomer (EPDM) composites as a filler for the first time and its influence on the ablation, mechanical, and thermal properties of EPDM is investigated. The results show that the addition of 3 phr PHC increases the ablation performance by about 10% and enhances the mechanical properties by 20% approximately. In addition, the ablation mechanism is studied in accordance with SEM, FTIR, and Raman spectroscopy. On the one hand, PHC has the effect of catalyzing carbonization, thus increasing the rate of residual carbon; on the other hand, PHC changes the morphology of the char layer, forming a cross-linked structure containing P─O─Si bonds on the surface. The findings regarding catalyzing carbonization and the special char layer structure could guide the design of ablative materials.     

PE基木塑复合材料的阻燃研究

采用无卤阻燃剂聚磷酸铵(APP)以及阻燃协效剂硼酸锌(ZB)、硅藻土,制备具有良好阻燃性能的木塑复合材料。结果表明:APP在改善木塑复合材料阻燃性能的同时,可提高材料的热稳定性,当其用量为20份时,复合材料垂直燃烧达到UL94V-0级,此时,体系的力学性能变化不大;ZB、硅藻土对木塑复合材料的协效阻燃规律不同于对塑料的阻燃规律,添加2份硅藻土的阻燃体系形成的炭层最致密,可有效地隔热隔氧。     

Effect of borax on the thermal and mechanical properties of ethylene‐propylene‐diene terpolymer rubber‐based heat insulator

The effect of Borax on the mechanical and ablation properties of three different ethylene‐propylene‐diene terpolymer (EPDM) compounds containing 20 phr carbon fiber, 20 phr Kevlar or 10 phr/ 10 phr carbon fiber/ Kevlar was investigated. All formulations contained 30 phr fumed silica powder and 10 phr paraffinic oil. It was found that adding Borax to the composite samples containing carbon fiber or Kevlar fiber or their mixture with an equal ratio can increase the tensile strength, elastic modulus and hardness with a slightly decrease in the elongation at break of the rubber samples. The results of thermogravimetry analysis (TGA) on the various samples showed significant increase in the char yield at 670°C by adding Borax to the rubber compounds. Moreover, ablation resistance of samples was also improved by increasing Borax content. Meanwhile, density and thermal conductivity of the insulator were also reduced up to about 10% when the carbon fiber was replaced with the Borax. The results indicated that composites containing Kevlar have high storage modulus and produce compact and stable char. EPDM rubber composite containing Borax (20 phr), carbon fiber (10 phr), and Kevlar (10 phr) showed thermal and ablative properties comparable with those of the asbestos‐ filled EPDM. The thermal conductivity and ablation rate of the above‐ mentioned sample were 0.287 W/m/K and 0.13 mm/s respectively. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41936.     

Flame retardation of dibromoneopentyl glycol on intumescent flame‐retardant/low‐density polyethylene composites

On the basis of ammonium polyphosphate (APP) microencapsulated with pentaerythritol/dibromoneopentyl glycol (DBNPG) mixed phosphate melamine salt as an intumescent flame retardant (IFR), the influence of DBNPG on the flame retardancy of IFR/low‐density polyethylene was investigated. The results prove that DBNPG could influence the combustion heat and the thermal barrier properties of the char layer in combustion. The intumescent degree (ID), compactness, and closure were the determinants of the thermal barrier properties of the char layer. A greater ID below 500°C and then a more compact and closed char layer above 500°C contributed to the better thermal barrier properties. An appropriate DBNPG reduced the combustion heat and promoted the formation of a compact and closed char layer by increasing of the melting viscosity of the composites. However, excessive DBNPG destroyed the closure of the char layer and increased the combustion heat because of a decrease in the melting viscosity of the composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41244.     

二溴新戊二醇在膨胀型阻燃PE-LLD中的作用

以二溴新戊二醇(DBNPG)作为碳源代替部分季戊四醇(PER), 以PER/DBNPG混合磷酸酯三聚氰胺甲醛树脂(MFR)微胶囊化聚磷酸铵(APP)合成膨胀型阻燃剂(IFR), 用于线形低密度聚乙烯(PE-LLD)阻燃。结果表明,适量的DBNPG可增强IFR与PE-LLD之间的相容性,改善材料的拉伸性能,提高材料熔体黏度,形成封闭的膨胀炭层;但DBNPG过量,IFR的软化温度降低,导致熔体黏度下降,破坏炭层的封闭性,恶化阻燃性能;当PER/DBNPG的质量比为70.0/115.5, 且PE-LLD/IFR的配比为70/30时,复合材料的阻燃性能达到最佳。     

APP/层状硅酸盐填充UPR包覆层的耐烧蚀机理

将有机填料聚磷酸铵(APP)分别与层状硅酸盐类填料有机改性蒙脱土、滑石粉复配后填充UPR绝热包覆材料,通过氧乙炔烧蚀试验考察了复合材料的烧蚀性能.采用TG-DTG、SEM等研究有机-无机复配填料改性UPR包覆材料耐烧蚀性能的作用机理.结果表明,当APP与蒙脱土的质量比为20∶5,APP与滑石粉质量比为20∶30时,复合材料的耐烧蚀性能最佳,线烧蚀速率分别为0.317、0.363 mm/s.热分解试验600℃时,APP/有机改性蒙脱土/UPR的实际残留量比计算残留量增加8.2%,APP/滑石粉/UPR增加3.9%.烧蚀试验后APP/有机改性蒙脱土/UPR形成片层状残炭结构;APP/滑石粉/UPR生成较为松散的残炭.     

Effects of two kinds of THEIC‐based charring agents on flame‐retardant properties of polylactide

Two charring agents tris (2‐hydrooxyethyl) isocyanurate terephthalic acid ester, (dimer/trimer mixture TT23, and tetramer TT4) were synthesized by using tris (2‐hydrooxyethyl) isocyanurate (THEIC) and terephthalic acid (TPA) as raw materials. These two charring agents were combined with ammonium polyphosphate (APP) to form intumescent flame retardants (IFR) for polylactide (PLA). The thermal stability of IFRs were tested by TGA, it is found that APP/TT4 mixture has a higher thermal stability and a better char forming ability than that of APP/TT23 mixture. The combustion properties and thermal stability of PLA/APP/TT23 and PLA/APP/TT4 composites were evaluated by UL‐94 burning tests, limiting oxygen index (LOI), cone calorimeter tests and TGA, the chemical structure of char residues were analyzed by FTIR and XPS. It can be concluded that PLA with 30 wt % of APP/TT4 (weight ratio 5 : 1) achieved the greatest flame retardancy. Moreover, the continuous and expansionary char layer observed from SEM images proved better char forming ability of TT4 than that of TT23. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42086.     

Effects of zirconium carbide content on thermal stability and ablation properties of carbon/phenolic composites

Ceramic particles were utilized to improve thermal stability and ablation properties of carbon/phenolic (C/Ph) composites. In this study, zirconium carbide (ZrC) modified C/Ph composites were fabricated by vacuum impregnation method, and effects of ZrC content on thermal stability and ablation properties were investigated by thermogravimetry analysis and plasma wind tunnel test. Moreover, morphological characterization was carried out using X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. Experimental results showed that increasing ZrC content could lead to an evident increase in char yield, but an observable reduction in linear ablation rates and back-face temperatures because of the formation of ZrO₂ layer on the ablation surface. The work provided an effective way to improve thermal stability and ablation properties of C/Ph composites.     

Sepiolite hybridized commercial fillers,and their effects on curing process,mechanical properties,thermal stability,and flammability of ethylene propylene diene monomer rubber composites

Ethylene propylene diene monomer rubber (EPDM)-based composites containing sepiolite (sep) hybridized with calcium carbonate (CaCO₃), silica (Sil) or carbon black (CB) were prepared on a two-roll mill. The influence of fillers’ contents on the curing, mechanical, thermal and flammability of the composites was investigated. In comparison with EPDM/sep at 30 parts per hundred rubbers (phr) as a control composite, EPDM/sep/CB composites exhibited an outstanding improvement in tensile strength followed by EPDM/sep/Sil and EPDM/sep/CaCO₃ composites. EPDM/sep/CB displayed the highest thermal stability and also improved flammability resistance. In addition, a higher amount of carbon black gave higher tensile strength. The results were influenced by the ability of CB to disperse well and form protective layers acting as mass transport barriers in the matrix. The field emission scanning electron microscopy analyses proved better dispersion of CB in the matrix. The presence of protective layers on the surface of samples consequently improved the thermal properties of the EPDM composites. The mechanism of formation of char protective layer in hybrid EPDM composites was also investigated based on morphological observations of char residues. According to this work, Sil and CB were able to hybrid with sep, while sep could be a potential substitution of CaCO₃ in the EPDM composites.     

Synergistic effect of THEIC‐Based charring agent on flame retardant properties of polylactide

A novel charring agent tris(2‐hydrooxyethyl) isocyanurate terephthalic acid ester, tetramer (TT4) was synthesized using tris(2‐hydrooxyethyl) isocyanurate and terephthalic acid as raw materials, and it was characterized by Fourier transformed infrared spectrometry and ¹H‐NMR spectrum. It was combined with ammonium polyphosphate (APP) to form intumescent flame retardants for polylactide (PLA). The combustion properties and thermal stability of PLA/APP/TT4 composites were evaluated by UL‐94 burning tests, limiting oxygen index (LOI), and thermogravimetric analyses (TGA). It was found PLA with 30 wt % of APP/TT4 (5 : 1) achieved UL‐94 V‐0 rating and a 40.6 LOI value. Results from TGA demonstrated that APP/TT4 composites could retard the degradation of PLA above 410°C. The char residue at 500°C is higher than 24%, showing a good char forming ability. Moreover, the continuous and expansionary char layer observed from the SEM images proved good charring forming ability of TT4. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41218.     

聚磷酸铵对聚乳酸/麦秸秆复合材料阻燃和力学性能的影响

用聚磷酸铵(APP)对聚乳酸(PLA)/秸秆粉复合材料进行阻燃处理,对复合材料的阻燃性能、力学性能和热降解行为进行了分析。结果表明,APP添加量达到20份时,极限氧指数提高了33 %,成炭率提高了330 %,而且达到UL 94 V-0级,表现出显著的阻燃作用;APP的加入降低了复合材料的冲击性能,但能改善其刚性,对弯曲强度和密度影响不大;此外APP的添加还改变了复合材料的热降解行为,使其分解温度提前,稳定了PLA基体;材料燃烧后膨胀成多孔炭层,起到了隔热和阻氧的作用。