MC尼龙蒙脱土纳米复合材料的制备与表征

在超声条件下以KH550硅烷偶联剂插层蒙脱土,采用阴离子聚合反应制备MC尼龙蒙脱土纳米复合材料(MMT/PA),并对改性蒙脱土和纳米复合材料的结构进行表征与性能测试。结果表明,在超声分散条件下KH-550硅烷偶联剂进入蒙脱土的片层间,增大层间距;聚合过程中己内酰胺进入蒙脱土的片层间,实现蒙脱土与己内酰胺的键性结合,并使得最终尼龙分子插层进入蒙脱土的片层间形成纳米复合材料。蒙脱土以部分剥离的多片层聚集体均匀地分散在尼龙基体中,起到增强增韧作用,当蒙脱土含量在3%左右时纳米复合材料的力学性能达到最优。     

原位聚合法制备尼龙66/蒙脱土纳米复合材料及其性能

采用原位聚合法制备了尼龙66/有机蒙脱土纳米复合材料,利用TEM观察了复合材料的微观结构,测试了其力学性能、热稳定性和阻燃性能,探讨了复合材料结构与性能之间的关系。研究结果表明:蒙脱土以纳米尺度均匀分散在尼龙66基体中,蒙脱土的加入改善了材料的力学性能、热稳定性和阻燃性能。     

原位聚合尼龙6／蒙脱土纳米复合材料的结晶行为

本文用原位聚合的方法制备了尼龙6／蒙脱土纳米复合材料,通过高速离心沉降实验和XRD表征了蒙脱土在复合材料中的剥离程度和分散状态;采用解偏振光强度法研究了复舍材料的等温结晶过程,并用偏光显微镜观察了其结晶形态;通过DSC研究了复舍材料的非等温结晶动力学,并用Kissinger法计算了复舍材料的结晶活化能。结果表明,蒙脱土在复合材料中完全剥离,以纳米片层的形式均匀分散在基体尼龙6中,蒙脱土的纳米片层对基体的结晶过程起异相成核作用;在蒙脱土的含量较低时,复合材料的结晶速率明显提高,但当蒙脱土的含量较高时,由于蒙脱土纳米片层对结晶生长的阻碍作用占主导地位,复舍材料的结晶速率有所下降,复合材料的结晶活化能也表现出类似的行为。     

超声波原位插层制备硅树脂/蒙脱土纳米复合材料

采用超声波技术,原位插层聚合法制备了甲基苯基硅树脂/有机蒙脱土(OMMT)纳米复合材料。利用X射线衍射(XRD),透射电镜(TEM)研究了复合材料内部结构以及超声波时间对蒙脱土分散性影响。结果表明,蒙脱土片层间距随着超声波时间延长而增加,当超声波时间短于20min时,有机蒙脱土片层以有序的插层型存在,形成插层型的聚合物/蒙脱土纳米复合材料(PLSN);超声波时间长于30min时,有机蒙脱土片层被剥离,无序地分散在硅树脂基体中,形成剥离型的聚合物/蒙脱土纳米复合材料。     

低密度聚乙烯/蒙脱土复合材料的制备及隔声性能

以有机改性蒙脱土(OMMT)作为纳米隔声填料,分别通过熔融共混法和溶液共混法制备了LDPE/OMMT复合材料,研究了蒙脱土含量和制备方法对复合材料的隔声性能的影响。采用多级拉伸共挤出装置改善蒙脱土在基体中的分散,研究不同力场大小作用下蒙脱土分散形态及复合材料的隔声性能。结果表明,少量蒙脱土的加入可以大幅度改善LDPE的隔声性能,但是随着蒙脱土含量的增加,蒙脱土团聚严重,复合材料的隔声性能变差,与熔融共混相比,由于溶液共混法更能使蒙脱土在基体中分散,制备的复合材料的隔声性能更好。随着分割叠加单元个数的增加,蒙脱土在LDPE基体中分散改善,当分割-变形-叠加单元(LME)个数达到8个时,蒙脱土纳米级分散在基体中,复合材料的隔声性能最佳。     

微波辅助原位熔融缩聚法制备聚乳酸/有机蒙脱土纳米复合材料

以微波为热源替代传统加热方式,采用原位熔融缩聚法制备出聚乳酸/有机蒙脱土纳米复合材料。有机蒙脱土的加入有利于聚乳酸分子链进入蒙脱土片层,当蒙脱土用量为1.5%时,微波辐射60 min所制得的聚乳酸/有机蒙脱土纳米复合材料与纯聚乳酸相比,拉伸强度提高近2倍,热失重中心温度提高7.3℃,对紫外线的屏蔽波段扩展了50nm以上。透射电镜(TEM)结果表明,有机蒙脱土以剥离态均匀分散于聚乳酸基体中。     

PMAA/MMT及PMAA/MMT/SiO_2纳米复合材料的结构与性能研究

采用原位插层聚合法制备了聚甲基丙烯酸/蒙脱土(PMAA/MMT)纳米复合材料和聚甲基丙烯酸/蒙脱土/二氧化硅(PMAA/MMT/SiO2)纳米复合材料,并比较两种纳米复合材料的结构与性能。研究结果表明,PMAA/MMT纳米复合材料属于插层与剥离共存型纳米复合材料。PMAA/MMT/SiO2纳米复合材料中蒙脱土的特征衍射峰已经消失,蒙脱土与二氧化硅均匀分散在聚合物基体中。PMAA/MMT及PMAA/MMT/SiO2纳米复合材料均有一定的鞣制性能,但相对而言PMAA/MMT/SiO2纳米复合材料的鞣制效果较好。     

LLDPE/HDPE/MMT纳米复合材料的制备及性能研究

以线性低密度聚乙烯(LLDPE)、高密度聚乙烯(HDPE)、有机改性的蒙脱土(MMT)为主要原料,选用乙烯-醋酸乙烯酯接枝马来酸酐(EVA-g-MAH)作为增容剂,采用熔融插层法制备了线性低密度聚乙烯/高密度聚乙烯/蒙脱土(LLDPE/HDPE/MMT)纳米复合材料。通过X射线衍射(XRD)分析蒙脱土在聚乙烯基体中的分散情况,并研究蒙脱土的含量对其在基体中分散效果的影响。TG实验结果表明,蒙脱土的加入使LLDPE/HDPE/MMT纳米复合材料的热稳定性得到很大的提高。由DSC曲线可以得出,加入蒙脱土的复合材料相比于纯聚合物,其熔点和热分解温度都有很大的提高,提高程度与蒙脱土的含量有关。     

聚乙烯和纳米蒙脱土与淀粉共混改性研究进展

综述了近年来纳米蒙脱土和聚乙烯与淀粉共混改性制备可降解复合材料的方法和加工工艺。此外,还综述了淀粉的表面改性和相容剂加入、纳米蒙脱土的剥离和在基体树脂中的分散对共混复合材料的力学性能、热性能、耐水性能及材料的微观结构的影响。     

聚丙烯/蒙脱土纳米复合包装材料的制备与力学性能研究

采用熔融插层法在双螺杆挤出机中制备了聚丙烯(PP)/蒙脱土(MMT)纳米复合材料,纳米复合材料机械性能测试结果表明,当有机蒙脱土(MMT)质量比为2%时,复合材料的综合力学性能明显优于聚丙烯(PP).扫描电镜观测不到纳米复合材料中明显的有机-无机相畴,表明蒙脱土(MMT)片层分散均匀,分散尺度已基本达到纳米级.     

石墨烯微片/天然橡胶纳米复合材料的研究

目的 研究石墨烯微片的添量对石墨烯微片/天然橡胶纳米复合材料性能的影响,并对机械共混法和胶乳共混法进行比较。方法 探索复合材料的制备工艺,利用扫描电镜(SEM)、透射电镜(TEM)、拉曼光谱(RDS)、万能力学试验机等对石墨烯微片和石墨烯微片/天然橡胶纳米复合材料的形貌、结构以及性能进行分析和研究。结果 测试结果表明,石墨烯微片作为填料添加到复合材料中,使复合材料的性能得到了增强。相比纯橡胶而言,石墨烯微片(10 phr)/天然橡胶复合材料的拉伸强度增加了41.5%,热导率增加了153.3%。结论 石墨烯微片可以大幅度提高复合材料的性能,并且胶乳共混法制备的复合材料的性能要优于机械共混法制备的复合材料的性能。     

Dispersion of nanoplatelets of graphite on PMMA matrix by in situ polymerisation technique

Poly(methyl methacrylate)/expanded graphite (PMMA/EG) composites were prepared by the incorporation of EG in various proportions (1%, 2%, 3%, 4% and 5%) with PMMA by in situ polymerisation technique. The polymer composites were characterised by ultraviolet–visible (UV–vis) and Fourier transform infra-red spectroscopies. The structural property of PMMA/EG nanocomposites was studied by X-ray diffraction. The scanning electron microscopy and transmission electron microscopy of synthesised composites were taken in order to study their morphological properties. The conductivity of composites was measured as function of EG concentration. It was found that conductivity of composites gradually increased with the increase in EG loading. Oxygen permeability of PMMA/EG nanocomposites was calculated and it was found that the property was reduced substantially with rise of EG proportion. The thermal stability of PMMA/EG nanocomposites was improved by dispersion of EG with PMMA matrix.     

可分散性纳米SiO_2改性尼龙1010的制备和性能

采用表面经硅烷偶联剂原位修饰的纳米二氧化硅(SiO2)通过熔融共混的方法制备了纳米SiO2/尼龙l010复合材料,测试了材料的力学性能,并通过扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、热失重(TGA)等分析手段考察了纳米SiO2在聚合物基体中的分散情况、热稳定性能及聚合物的结晶形态。实验结果表明,通过熔融共混方法制得的复合物,其力学性能较尼龙1010有较大提高,纳米SiO2在聚合物中达到了均匀分散,SiO2的加入使尼龙1010的热稳定性能稍有提高;同时起异相成核作用,使晶体尺寸减小,γ晶型有所增加。     

纳米Al2O3对尼龙6结晶性能的影响

采用硅烷偶联剂KH-560对纳米氧化铝(nano-Al2O3)进行表面处理后与尼龙6(PA6)熔融共混制备PA6/nano-Al2O3复合材料,用扫描电镜(SEM)观察了材料断面形貌,借助差示扫描量热仪(DSC)研究了原料配比及降温速率对PA6/nano-Al2O3复合材料结晶性能影响。结果表明,nano-Al2O3在PA6结晶过程中起异相成核作用,限制了PA6分子链运动,使复合材料玻璃化转变温度及结晶度提高,非等温结晶过冷度降低,结晶速率加快;材料结晶温度、结晶焓、结晶度随降温速率增加而下降。     

Microstructure of AA2024-SiC nanostructured metal matrix composites

Nanostructured metal matrix composites (NMMCs) in large-dimension billets were fabricated by hot isostatic pressing (HIPing) of cryomilled powders consisting of AA2024 alloy reinforced by 25 wt.% SiC particles. Microstructure of the bulk nanostructured composites and cryomilled powders was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). In addition, mechanical properties of the bulk nanocomposites were also addressed.     

Synthesis and characterization of polyamide-6/graphite oxide nanocomposites

Polyamide-6/graphite oxide (PA6/GO) nanocomposites were synthesized using delamination/absorption method. The morphologies of the composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Both XRD and TEM showed that the GO sheets were completely exfoliated and distributed uniformly in PA6 matrix. Differential scanning calorimetry results revealed that the crystallization temperatures of the composites increased compared to that of pristine PA6, which was due to the heterogeneous nucleating effect of GO. However, the half-time of crystallization of the composites were evidently longer than that of pristine PA6, indicating an apparent decrease in the crystallization rate when GO was loaded into the polymer matrix. This was due to the constraining effect of layered GO on PA6 chains. The temperature of maximum decomposition rate was increased by 53 °C only by adding 5 wt% GO, and the maximum decomposition rate of the nanocomposites reduced greatly. The storage modulus (G′) and loss modulus (G″) curves shifted to higher modulus upon addition of 1–5 wt% of GO. With increasing GO loading, the shear viscosity of the nanocomposites gradually increased compared with pure PA6.     

Effect of pyrene-modified multiwalled carbon nanotubes on the properties of epoxy composites

The block polymer of poly(styrene-b-pyrene) (PS-b-PAH) containing pyrene units was successfully applied on the surface of multiwalled carbon nanotubes (MWNTs) and the properties of nanocomposites were enhanced. The morphology of the modified MWNTs was characterized by transmission electron microscopy (TEM), and the results showed that PS-b-PAH helped effectively the MWNTs to disperse well in epoxy matrices, and these dispersed MWNTs were stabilized by the pyrene modifier. The mechanical properties of the composites, such as impact toughness and flexural strength, and the electrical conductivity of the nanocomposites, are improved significantly after the treatment of the MWNTs using PS-b-PAH. The results show that the mechanical and electrical properties of the modified MWNTs/epoxy composites with PS-b-PAH are obviously superior to those of pristine MWNTs/epoxy composites. The enhanced interfacial interactions lead to good dispersion of MWNTs in epoxy matrices, thus enhancing the mechanical and electrical properties of the nanocomposites.     

Al/CNT nanocomposite fabrication on the different property of raw material using a planetary ball mill

In recent years, significant research has been focused on the development of carbon nanotube (CNT) reinforced aluminum nanocomposites, which are quickly emerging because of their lightweight, high strength and other mechanical properties. The potential applications of these composites include the automotive and aerospace industries. In this study, powder metallurgy techniques are employed to fabricate aluminum (Al)/CNT nanocomposites with different raw material properties with optimized conditions. We successfully fabricated three different samples, including un-milled Al, un-milled Al with CNT and milled Al with CNT nanocomposites, in the presence of additional CNTs with various experimental conditions using a planetary ball mill. Scanning electron microscopy and field emission scanning electron microscopy are used to evaluate the particle morphology and CNT dispersion. The CNTs are well dispersed on the surface of the fabricated milled Al with CNT nanocomposites than un-milled Al with CNT nanocomposites for milling. The fabricated Al/CNT nanocomposites are processed by a compacting, sintering and rolling process. Vickers hardness measurements are used to characterize the mechanical properties. The hardness of the Al/CNT nanocomposites are improved milled Al with CNT nanocomposite compared other fabricated composites.     

Carbon black–clay hybrid nanocomposites based upon EPDM elastomer

The present study explored the effect of nanoclay on the properties of the ethylene–propylene–diene rubber (EPDM)/carbon black (CB) composites. The nanocomposites were prepared with 40 wt% loading of fillers, where the nanoclay percentage was kept constant at 3 wt%. As the modified nanoclay contains the polar groups and the EPDM matrix is nonpolar, a polar rubber oil extended carboxylated styrene butadiene rubber (XSBR), was used during the preparation of nanocomposites to improve the compatibility. Primarily the nanoclay was dispersed in XSBR by solution mixing followed by ultrasonication. After that EPDM-based, CB–clay hybrid nanocomposites, were prepared in a laboratory scale two roll mill. The dispersion of the different nanoclay in the EPDM matrix was observed by wide-angle X-ray diffraction (WAXD) and high resolution transmission electron microscopy. It was found that the mechanical properties of the hybrid nanocomposites were highly influenced by the dispersion and exfoliation of the nanoclays in the EPDM matrix. Thermo gravimetric analysis, scanning electron microscopy and dynamic mechanical thermal analysis was carried out for each nanocomposite. Among all the nanocomposites studied, the thermal and mechanical properties of Cloisite 30B filled EPDM/CB nanocomposite were found to be highest.     

聚氯乙烯/极性单体改性蒙脱土纳米复合材料的制备及性能

用甲基丙烯酸甲酯,丙烯酸等极性小分子对钠基蒙脱土（Na^＋-MMT）进行处理,得到改性的有机蒙脱土（OMMT）,用熔融复合法制备了聚氯乙烯/蒙脱土纳米复合材料.力学性能测试发现,复合材料的拉伸及冲击性能较纯PVC都得到提高.通过XRD、TEM等方法对材料的微观结构进行表征,发现所得材料为剥离型复合材料.并用DSC测试了复合材料的玻璃化转变温度（Tg）.