SEBS/蒙脱土纳米复合材料结构和性能研究

采用溶液混合方法制备了氢化苯乙烯/丁二烯三元嵌段共聚物(SEBS)/有机蒙脱土(OM-MT)纳米复合材料(NC)。对SEBS/OMMT NC的插层结构和物理力学、动态力学、耐热等性能进行了研究。结果表明,与SEBS复合,OMMT层间距明显增大,制备出具有插层型结构的NC。加入OMMT可明显提高SEBS的拉伸断裂强度、300%定伸强度和断裂伸长率,但永久变形也增大。DMA研究表明,SEBS/OMMT NC的储能模量和损耗模量比纯SEBS显著提高,PEB链段的tanδ降低,而PS链段增加。SEBS/OMMT NC比SEBS的热稳定性明显提高。     

聚合物/蒙脱土纳米复合材料研究进展

文章简要介绍了蒙脱土的结构,概述了聚合物/蒙脱土纳米蒙脱土材料的结构及性能,详细介绍了聚丙烯(PP)/蒙脱土、聚乙烯(PE)/蒙脱土、环氧树脂(EP)/蒙脱土纳米复合材料国内外最新的研究进展,叙述了聚合物/蒙脱土纳米复合材料优良的力学性能和热学性能。最后对聚合物/蒙脱土纳米复合材料的未来发展做了预测。     

SBS／蒙脱土纳米复合材料的流变行为

用毛细管流变仪测定并研究了热塑性丁苯三嵌段共聚物（SBS）／蒙脱土纳米复合材料的熔体的稳态剪切流变行为，研究结果表明：温度和压力一定的条件下，加入一定量的改性蒙脱土可以降低熔体的粘度；在较低的剪切速率下，即出现剪切变稀现象；在高剪切速率下，粘度对剪切速率的敏感性是降低的，改性蒙脱土加入量对熔体的剪切粘度影响较小，主要是由基体材料所决定的；随温度的升高熔体粘度对剪切速率的敏感性是降低的。采用转矩流变仪对材料的加工性能进行研究，发现复合材料的加工性能基本上保持了纯SBS的加工性能。     

蒙脱土/EPDM纳米复合材料燃烧性能的研究

采用熔融插层法制备了蒙脱土/EPDM纳米复合材料,并研究了燃烧性能。结果表明,EPDM大分子不能与未有机化的钠基蒙脱土(Na+-MMT)插层复合,但能有效插入有机蒙脱土(OMMT)片层之间,形成OMMT/EPDM插层纳米复合材料。Na+-MMT对改善蒙脱土/EPDM纳米复合材料的阻燃和抑烟效果不明显;OMMT/EPDM纳米复合材料的热释放速率、总生烟量及烟密度等参数均明显降低;随OMMT用量的增大,阻燃性和抑烟性变得越来越好,最后趋于稳定。     

蒙脱土/SBR纳米复合材料阻燃性能的研究

采用熔融插层法制备蒙脱土／SBR纳米复合材料，并研究其阻燃性能。结果表明，SBR大分子不能有效插入钠基蒙脱土（Na—MMT）片层间，而能有效插入有机蒙脱土（OMMT）片层间，形成插层型纳米复合材料；将OMMT与高抗冲聚苯乙烯（HIPS）制成阻燃母粒能进一步提高SBR的插层效果。OMMT可以明显改善复合材料的阻燃和抑烟性能，随着OMMT用量的增大，复合材料的热释放速率、峰值热释放速率、平均热释放速率、总热释放和总生烟量先明显降低然后趋于稳定；HIPS-OMMT阻燃母粒可以明显改善复合材料阻燃性能，但对抑烟性能的改善效果不如OMMT。     

聚氨酯/蒙脱土纳米复合材料

综述了聚氨酯／蒙脱土纳米复合材料的制备、结构表征和热力学性能，对制备过程进行了热力学分析，并对其发展前景进行了讨论。聚氨酯／蒙脱土纳米复合材料是一种新型的有机／无机纳米复合材料。在无机材料含量远低于常规填充量的情况下复合材料就可以具有较好的力学性能、阻隔性，热稳定性能也显著提高。     

TDE-85/蒙脱土纳米复合材料固化动力学及耐热性能研究

采用插层聚合法将有机蒙脱土(OMMT)引入TDE-85/3,3'-二乙基-4,4'-二氨基二苯甲烷(DED-DM)固化体系中,通过示差扫描量热法(DSC)研究了OMMT改性前后固化体系的非等温固化动力学,采用Ozawa和Crane公式计算了体系的反应活化能和反应级数,确定了固化工艺;研究了OMMT含量对固化物插层效果、玻璃化转变温度、热失重过程及冲击性能的影响。结果表明:OMMT的加入使体系固化反应活化能和反应级数略有升高,这说明OMMT对体系的固化反应有一定的阻碍作用,但不改变固化反应机理。质量分数为1%～3%的OMMT在树脂基体中分散良好,实现纳米复合,材料的玻璃化转变温度明显提高。     

聚合物/蒙脱土纳米复合材料的研究进展

简要概述了聚合物/蒙脱土纳米复合材料的结构及性能,详细介绍了聚酰胺/蒙脱土、聚烯烃/蒙脱土和热固性树脂/蒙脱土纳米复合材料的研究进展。并总结了复合材料的各种优异性能,分析了蒙脱土提高复合材料性能的机理。     

聚丙烯/蒙脱土纳米复合材料研究

本文综述了聚丙烯／蒙脱土纳米复合材料的特点、制备方法,并对复合材料的结构表征方法作了介绍。     

尼龙/蒙脱土纳米复合材料研究进展

介绍了尼龙／蒙脱土纳米复合材料的制备方法，并对国内外关于尼龙／蒙脱土纳米复合材料热性能、力学性能、流变性能、结晶性能以及插层动力学研究进展进行了综述。结果认为，尼龙／蒙脱土纳米复合材料是一种新型的复合材料，蒙脱土的加入，改进了尼龙的力学性能，提高了复合材料的热变形温度。     

The effects of metallic derivatives released from montmorillonite on the thermal stability of poly(ethylene terephthalate)/montmorillonite nanocomposites

By in situ polycondensation, poly(ethylene terephthalate) (PET)/montmorillonite (MMT) nanocomposites was prepared, which were characterized via X‐ray diffraction and transmission electron microscope. The processing stability of these nanocomposites was investigated by the change of number–average molecular weight and carboxyl terminal group content during injection molding, and the thermal stability of the nanocomposites was investigated via thermogravimetric analysis. It was found that some metallic derivatives released from MMT during polycondensation had a great influence on the processing and thermal stabilities of the nanocomposites. The quantity of these metallic derivatives was determined by inductively coupled plasma. The stabilization effect of phosphorous compounds generated from MMT modified with phosphonium was observed. Processing stability and thermal stability of these nanocomposites exhibited similar trend because of almost the same causes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1692–1699, 2006     

Study of polypropylene/montmorillonite nanocomposites prepared by solid‐state shear compounding (S3C) using pan‐mill equipment: the morphology of montmorillonite and thermal properties of the nanocomposites

In this paper, polypropylene (PP)/organophilic montmorillonite (OMMT) nanocomposites were successfully prepared without any compatibilizers by solid‐state shear compounding (S³C) using pan‐mill equipment. X‐ray diffraction (XRD) patterns show that the OMMT characteristic (001) peak at 2θ equal to 4.59 degrees disappeared for the milled OMMT and corresponding composites. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) photographs show that the thickness of pan‐milled OMMT decreased from ca 100–200 nm to ca 30–50 nm, and OMMT was partly exfoliated in the PP matrix because the pan‐type mill can exert fairly strong squeezing force in the normal direction and shearing force in both radial and tangential directions on milled materials. PP/OMMT nanocomposites at low OMMT loading have higher melting point, crystallization temperature, thermal degradation temperature and heat distortion temperature than those of neat PP. Moreover, addition of OMMT accelerates crystallization of PP significantly. S³C is a novel approach to prepare polymer/layered silicate nanocomposites with high performances at low filler loading. Copyright © 2004 Society of Chemical Industry     

Viscoelasticity and thermal stability of poly(arylene ether nitrile) nanocomposites with various functionalized carbon nanotubes

Poly(arylene ether nitrile) (PEN) nanocomposites containing various functionalized multi‐walled carbon nanotubes (MWCNTs) were prepared through a solution‐casting method. The as‐prepared PEN nanocomposites were investigated using parallel‐plate rheometry and thermogravimetric analysis, aimed at examining the effect of surface functionalization on the dispersion of MWCNTs from the viscoelastic and thermal properties. The linear viscoelasticy results indicated that 4‐aminophenoxyphthalonitrile‐grafted MWCNTs presented better dispersion in the PEN matrix than purified and carboxylic MWCNTs because the corresponding composite showed the lowest rheological percolation threshold, which was further confirmed from scanning electron microscopy, dissolution experiments and solution rheological experiments. The thermogravimetric analysis results revealed that the presence of 4‐aminophenoxyphthalonitrile‐grafted and carboxylic MWCNTs retarded the depolymerization compared with purified MWCNTs, showing a marked increase in the temperature corresponding to a loss of 5 wt% (increased by 14–22 °C) and maximum rate of decomposition (increased by 4–8 °C). Both the state of dispersion and the surface functionalization of MWCNTs are very important to the thermal stability of the PEN matrix. Copyright © 2011 Society of Chemical Industry     

聚酯热稳定性的研究

在合成聚酯试验之后,利用聚合试验装置搅拌器扭矩变化来表征聚酯加工过程中的热稳定性,比热失重法更接近聚酯加工过程,比粘度降法减少了干扰因素。研究结果表明:稳定剂种类、添加量和调配方式等均影响聚酯的热稳定性。     

Study of the thermal stabilization mechanism of biodegradable poly(L‐lactide)/silica nanocomposites

Biodegradable poly(L ‐lactide) (PLA)/silica (SiO₂) nanocomposites were prepared by melt compounding to investigate the effect of spherical nanofillers on the thermal stability of PLA. The nanocomposites displayed improved thermal stability both under nitrogen and in air. The stabilization mechanism was attributed mainly to the barrier effect of the network formed, which was demonstrated by the improved barrier properties and rheological performance. The dispersion of nanofiller and matrix‐nanoparticle interactions were investigated to evaluate the dependence of the network on SiO₂ loadings. Fourier transform infrared spectroscopy and thermogravimetric analysis indicated that hydroxyl groups on SiO₂ surfaces and PLA chain‐ends reacted during melt processing. The resulting grafted SiO₂ and entangled PLA chains formed a dense network, which hindered the diffusion of oxygen and volatile decomposition products. Furthermore, the improvement in thermal stability resulted from the restraining effect on the mobility of active hydroxyl end‐groups, so that some related thermal decomposition reactions were inhibited, which was confirmed from gel permeation chromatography measurements. Copyright © 2010 Society of Chemical Industry     

PTT树脂热分解稳定性研究

研究了不同相对分子质量PTT树脂在氮气和空气 2种气氛中的热分解稳定性。结果表明 ,在氮气中 ,PTT树脂只有 1个热失重台阶 ,相对分子质量对于PTT热分解参数影响不大 ,相应的热分解温度分别为θdi为 3 82 .2～ 3 83℃ ,θmax为 3 99.3～40 3 .4℃ ,θdf为 418.1～ 419.0℃ ,总失重为 88.4%～ 88.7% ,这可以作为PTT热分解稳定性的表征。在空气中 ,PTT树脂存在2个热失重台阶 ,在第 1失重台阶中 ,θdi为 3 70 .9～ 3 75 .2℃ ,θmax为 40 3 .9～ 40 5 .5℃ ,θdf为 414 .7～ 416.0℃ ,样品的总失重为88.9%～ 89.8% ,可以作为PTT热氧化分解稳定性的表征 ;而在第 2失重台阶中 ,θdi为 461.8～ 472 .2℃ ,θmax为 473 .9～ 487.8℃ ,θdf为 480 .5～ 494.1℃ ,样品的总失重为 8.6%～ 9.7% ,第 2失重台阶是残留物进一步氧化燃烧过程的体现。在 2 60℃下 ,PTT在氮气和空气气氛中受热 60min后分别有 1.4%和 4.8%的热失重。说明PTT的热氧化分解稳定性较其热分解稳定性要差 ,但两者相差不大。     

Structural and thermal stabilization of isotactic polypropylene/organo-montmorillonite/poly(ethylene-co-octene) nanocomposites by an elastomer component

Rheological and thermal properties of isotactic polypropylene (iPP)/organo-montmorillonite (OMMT)/poly(ethylene-co-octene) (PEOc) ternary nanocomposites and iPP/OMMT binary nanocomposites were studied by X-ray diffraction (XRD), rheometry, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) in this paper. The clay layers were mainly intercalated and partially exfoliated and well dispersed in these nanocomposites with the help of maleic anhydride modified polypropylene (PPgMA). Clay layers were mainly localized close to/inside the PEOc-rich phase from the direct observation of morphological study. A compact and stable network structure was formed in ternary composites when clay content was 2 phr (parts per hundred parts of iPP/PPgMA) or higher, which resulted in the lower stress relaxation rate and a pseudo-solid like behavior in low frequency region. Compared with iPP/OMMT composites, iPP/OMMT/PEOc composites had a much stronger ability to resist thermal decomposition. In another word, combining with the filler network, PEOc greatly improved the structural and thermal stabilities of iPP/OMMT nanocomposites.     

Effect of organophilic montmorillonite on polyurethane/montmorillonite nanocomposites

Different kinds of organophilic montmorillonite cotreated by cetyltrimethyl ammonium bromide (CTAB) and aminoundecanoic acid (AUA) were synthesized and applied to prepare polyurethane/montmorillonite nanocomposites via solution intercalation. The results of wide‐angle X‐ray diffraction (WAXD) and transmission electron microscopy showed that, for the montmorillonite modified with CTAB and CTAB/AUA (molar ratio of 1/2), an ordered intercalated nanostructure was derived, while for the montmorillonite treated with AUA, a disordered nanostructure was derived. The tensile properties of the polyurethane (PU) nanocomposites showed higher enhancement relative to PU matrix. TG showed that there is some enhancement in degradation behavior between the nanocomposites and PU matrix. DMTA results showed that nanocomposites from some organophilic montmorillonites showed a much higher storage modulus below and above glass transition temperature, while the nanocomposites from montmorillonite treated by AUA show an even lower storage modulus. The loss curves showed that the main glass transition temperature of PU was improved to some extent for the nanocomposites. The water absorption of PU and nanocomposites was also studied and the difference in reduction was thoroughly analyzed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2536–2542, 2004