剥离型(苯乙烯/马来酸酐)共聚物/蒙脱土纳米复合材料的制备

研究了制备剥离型(苯乙烯/马来酸酐)共聚物(SMAH)蒙/脱土(MMT)纳米复合材料的方法。研究表明,通过原位插层及熔融插层只能制备出插层型的SMAH/MMT纳米复合材料。为了制备剥离型的SMAH/MMT纳米复合材料,先将尼龙6(PA6)与MMT熔融插层制备出PA6/MMT纳米复合材料,再用抽提的方法将PA6/MMT复合材料中的部分PA6除去,得到含有少量PA6的剥离型MMT,然后将剥离型MMT与SMAH共混,从而制备出剥离型的SMAH/MMT纳米复合材料。该复合材料的粘度低于SMAH,且具有较好的加工性能。     

Comparison of the influence of different compatibilizers on the structure and properties of ethylene vinyl acetate copolymer/modified clay nanocomposites

Nanocomposites of an ethylene vinyl acetate copolymer and clay were prepared by melt blending and extrusion. Two different compatibilizers, ethylene glycidyl methacrylate (EGMA) and maleic anhydride grafted polypropylene (MAPP), were used in these nanocomposites. The structural properties of the composites were characterized with X‐ray diffraction and transmission electron microscopy. The surface morphology was characterized with polarized optical microscopy. The tensile and permeability properties were studied. The thermal stability of the nanocomposites was characterized through thermogravimetric analysis. MAPP‐compatibilized nanocomposites had intercalated and partially exfoliated structures, whereas EGMA‐compatibilized nanocomposites had completely exfoliated structures. The EGMA‐compatibilized nanocomposites were thermally more stable than the MAPP‐compatibilized nanocomposites. The mechanical and permeability properties of the EGMA‐compatibilized nanocomposites were better than those of the MAPP‐compatibilized nanocomposites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Electrical properties of low density polyethylene/ZnO nanocomposites: The effect of thermal treatments

Low density polyethylene (LDPE)/ZnO nanocomposites were prepared by melt compounding followed by annealing or quenching treatment. Electrical properties of the thermally treated nanocomposites were investigated. The results showed that thermal treatments exerted a pronounced effect on the electrical properties of LDPE/ZnO nanocomposites. The dielectric constant of annealed LDPE/ZnO nanocomposites at various ZnO contents was higher than that of quenched nanocomposites. In sharp contrast, the resistivity of annealed LDPE/ZnO nanocomposites was considerably lower than that of quenched samples. The frequency dependence of dielectric constant was much pronounced for both the annealed and quenched LDPE/ZnO nanocomposites associated with the formation of ZnO network as the ZnO volume content reached 52 vol %. The structure–property relationship of the nanocomposites is discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1436–1444, 2006     

聚丙烯纳米复合材料的研究进展

对聚丙烯纳米复合材料的国内外研究进展进行了综述,重点讨论了聚丙烯／层状硅酸盐和聚丙烯／无机刚性粒子这两类纳米复合材料的增强增韧机理、制备方法与性能。     

Fatigue and hysteresis behavior of halloysite nanotubes‐filled natural rubber (SMR L and ENR 50) nanocomposites

The effect of various halloysite nanotubes (HNTs) loading on fatigue life, stress–strain behavior, and hysteresis of HNTs/Standard Malaysian Rubber (SMR) L and HNTs/epoxidized natural rubber (ENR) 50 nanocomposites were studied. The addition of HNTs caused decrement in fatigue life for both nanocomposites at any extension ratio. Generally, HNTs/SMR L nanocomposites showed higher fatigue life than ENR 50 nanocomposites. Addition of more HNTs caused decrement of stress for HNTs/SMR L nanocomposites, whereas HNTs/ENR 50 nanocomposites showed vice versa at any strain. This result was supported by the graph of accumulated strain energy against extension ratio. Hysteresis values increased with addition of HNTs in both nanocomposites where of HNTs/ENR 50 nanocomposites exhibited higher hysteresis than HNTs/SMR L nanocomposites at any HNTs loading. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

聚乙烯(PE)/OMMT纳米复合材料的结构、形态和性能

选择一种新型的有机改性蒙脱土(OMMT),在不加任何相容剂的条件下,利用熔融挤出法分别制备出了剥离型高密度聚乙烯/蒙脱土纳米复合材料、插层型线型低密度聚乙烯/蒙脱土和低密度聚乙烯/蒙脱土纳米复合材料。利用透射电子显微镜观察制备的复合材料的亚微观分散形态,确定了制备出的纳米复合材料的类型,并对不同亚微观结构形态进行了分析讨论,得出了不同分子结构影响纳米复合材料形成不同分散形态的结论;对于3种纳米复合材料的物理性能测试结果表明,不同亚微观分散形态的纳米复合材料的纳米效应不同,对物理性能的影响各有不同,对于聚合物/蒙脱土纳米复合材料的深入研究具有重大意义,同时分散均匀的纳米复合材料结构对于进一步研究聚乙烯纳米膜的气体阻隔性等性能奠定了良好的基础。     

有机蒙脱土对天然橡胶/丁苯橡胶的补强及增容作用

采用机械混炼法制备了天然橡胶(NR)/丁苯橡胶(SBR)/有机蒙脱土(OMMT)纳米复合材料,采用TEM和XRD对复合材料的亚微观结构进行了表征,并对复合材料的表观交联密度、静态力学性能、动态力学性能和硫化热效应进行了研究。结果表明,复合材料为剥离型纳米复合材料;OMMT能够明显提高纳米复合材料的交联密度和静态力学性能;OMMT导致NR/SBR共混胶动态损耗因子降低,并且能够促使NR和SBR玻璃化转变温度更为接近,起到了增容作用;OMMT实现了NR和SBR两相的同步硫化。     

Role of free volume characteristics of polymer matrix in bulk physical properties of polymer nanocomposites: A review of positron annihilation lifetime studies

Polymer nanocomposites which have one or more nano-dimensional phases dispersed in polymer matrix show enhancement in bulk physical properties. In order to achieve the desired properties, a large number of polymer nanocomposites have been prepared by choosing different polymers and nanofillers. These studies showed that interfacial interaction between polymer molecules and nanofillers is the most important factor to achieve the synergistic effect towards enhancement in the bulk physical properties. The strong interfacial interaction also promotes the fine dispersion of nanofillers in a polymer matrix which consequently enables the preparation of polymer nanocomposites with higher loading of nanofillers. The polymer matrix constitutes a large volume fraction of polymer nanocomposites and hence the molecular packing of the polymer matrix itself plays a deterministic role in governing the physical properties of the nanocomposites. The strong interfacial interaction brings severe changes in the original molecular packing. In order to establish the structure-property relationships for polymer nanocomposites, characterization of molecular packing of polymer matrix in its nanocomposites is essential. In this aspect positron annihilation lifetime spectroscopy (PALS) is a highly suitable technique for characterization of free volume holes in polymers or polymer nanocomposites. The present review briefly describes the positron annihilation lifetime spectroscopy technique and relevant models for calculations of free volume hole’s size, density and their size distribution in polymer nanocomposites. We present a summary of the recent studies focussed on investigation of free volume structure (molecular packing) of polymer nanocomposites using PALS and its impact on transport, thermal and mechanical properties of the nanocomposites.     

Study on thermoplastic polyurethane/montmorillonite nanocomposites

The thermoplastic polyurethane/montmorillonite (TPU/MMT) nanocomposites were prepared by melt intercalation. The structure and property of the TPU/MMT nanocomposites were studied by XRD, TEM, TG, Molau test, and mechanical property measurement. The interlayer spacing between the MMT platelets in TPU/MMT nanocomposites blended for 10 and 15 min was the same. The silicate platelets were dispersed in TPU matrix on 5–15 nm scale for TPU/MMT nanocomposites. The interface interaction between the silicate layers and TPU matrix for TPU/MMT nanocomposites was strong. Compared to those of pure TPU, the tensile strength and tear strength of the TPU/MMT nanocomposites increased. The tensile strength and tear strength of the TPU/MMT nanocomposites decreased with increasing blending time because of the degradation of the TPU matrix. The thermal stability of the TPU/MMT nanocomposites was lower than that of the pure TPU in the first step, whereas in the second step, the TPU/MMT nanocomposites showed higher thermal stability. POLYM. COMPOS., 2008. © 2007 Society of Plastics Engineers     

Thermal stability and molecular interaction of polyurethane nanocomposites prepared by in situ polymerization with functionalized multiwalled carbon nanotubes

Polyurethane (PU) nanocomposites were prepared through conventional and in situ methods with multiwalled carbon nanotubes (MWNTs) functionalized with poly(ϵ-caprolactone). The thermal degradation and stability of PU–MWNT nanocomposites were investigated with nonisothermal thermogravimetry and were explained in terms of the interaction between MWNTs and PU molecules with Fourier transform infrared spectroscopy. The difference in thermal stability between the conventional and in situ nanocomposites was also compared. The thermal degradation of all the nanocomposite samples took place in two stages and followed a first-order reaction. The degradation temperature of the in situ nanocomposites was higher than that of the conventional nanocomposites with the same loading of MWNTs. The activation energy at 10% degradation and the half-life period were also higher in the in situ nanocomposites compared to the conventional nanocomposites. Such higher thermal stability of the in situ nanocomposites was ascribed to covalent bond formation between MWNTs and PU chains, which could result in better dispersion of MWNTs in the PU matrix for the in situ nanocomposites than for the conventional nanocomposites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Biodegradable polyaniline/dextrin conductive nanocomposites: synthesis,characterization, and study of antioxidant activity and sorption of heavy metal ions

Conductive nanocomposites based on polyaniline/dextrin were synthesized by in situ polymerization of aniline in presence of dextrin. The nanocomposites were characterized by field emission scanning electron microcopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, X-ray diffraction and conductivity measurements. It was observed that the conductivity values increased with the increase of aniline content in nanocomposites. The obtained nanocomposites have been analyzed for the antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl assay. The results showed that the antioxidant activity of the nanocomposites was enhanced by increasing the aniline content. Polyaniline/dextrin nanocomposites were used as sorbent materials for the removal of heavy metals from aqueous solutions. The sorption data indicated that the novel polyaniline/dextrin nanocomposites have high tendency for the removal of heavy metal ions such as Cu(II), Cd(II) and Pb(II) from aqueous solutions. In addition, the in vitro biodegradability of polyaniline/dextrin nanocomposites with different weight ratios was studied by soil burial tests. The result demonstrated that the nanocomposites are biodegradable under soil environment by degradation range between 30.18 and 74.52 %. The observed physical properties of the polyaniline/dextrin nanocomposites open interesting possibilities for novel applications of electrically conducting polysaccharide-based composites, particularly those that may exploit the antioxidant activity and heavy metal ions sorption of the polyaniline/dextrin nanocomposites.     

Study on Polyurethane/MDI-Modified-Organic Montmorillonite Nanocomposites

Polyurethane (PU)/MDI-modified-organic montmorillonite (MOMMT) nanocomposites were prepared by in situ polymerization and intercalation technology. Compared with that of organic montmorillonite (OMMT), the interlayer spacing of MOMMT was increased from 1.50 nm to 2.05 nm because MDI was grafted on the surface of the silicate layers through reaction between MDI and -OH. The dispersion of silicate layers in PU/MOMMT nanocomposites was better than that of silicate layers in PU/OMMT nanocomposites. Compared with those of PU/OMMT nanocomposites, the tensile strength and tear strength of PU/MOMMT nanocomposites were increased, and the MOMMT showed a higher stiffened effect. Because of the improvement of the dispersion and interfacial interaction, the temperature of initial weight loss of PU/MOMMT nanocomposites was higher than that of PU/OMMT nanocomposites, so PU/MOMMT nanocomposites had better thermal stability.     

A comparison of the temperature dependence of the modulus, yield stress and ductility of nanocomposites based on high and low MW PA6 and PA66

Nanocomposites with both organically modified and unmodified silicate have been prepared by an extrusion process using low and high molecular weight grades of PA6 and a low MW grade of PA66. Mechanical properties have been tested at temperatures ranging from 20 to 120 °C. The modulus increase in all nanocomposites with organically modified nanocomposites is similar: at room temperature an increase in the modulus of approximately 10% for each wt% of silicate is found. PA66 nanocomposites display an identical normalized modulus increase as PA6 nanocomposites, while unmodified silicate nanocomposites show a smaller increase in the modulus. The yield stress also increases with the addition of layered silicate. Low MW PA6 and PA66 nanocomposites show brittle fracture behaviour at room temperature, while high MW PA6 nanocomposites are ductile. With increasing temperature all nanocomposites become ductile at a certain temperature.     

聚氨酯/石墨烯纳米复合材料的研究进展

石墨烯以其独特的结构和优异的性质,使其聚氨酯纳米复合材料成为重要的研究领域。介绍了石墨烯/聚氨酯纳米复合材料的制备方法。讨论了石墨烯/聚氨酯纳米复合材料的结构与性能。综述了石墨烯/聚氨酯纳米复合材料的主要应用。     

Single‐walled nanotube bucky paper and nanocomposite

A new processing method for the fabrication of single‐walled nanotube (SWNT)‐reinforced nanocomposites was developed to achieve uniform dispersion and high composition of the nanotubes in the nanocomposites. In this method, SWNTs were preformed as bucky paper by multi‐step dispersion and micro‐filtration of a suspension of nanotubes. The nanocomposites were then fabricated by infiltration of diluted epoxy resin through the bucky paper and hot pressing. The wetting of the nanocomposites was examined using scanning electron microscopy and atomic force microscopy. The results showed that the epoxy resin completely penetrated the bucky paper through the nanoporous structures. The results of dynamic mechanical analysis of the nanocomposites showed that the storage moduli of the nanocomposites increased by 200–250%. The tan δ curves indicated that the nanotubes had a strong influence on the damping properties of the nanocomposites. This processing technique is an effective method for fabricating nanocomposites with uniform dispersion and high composition of SWNTs. Copyright © 2006 Society of Chemical Industry     

Preparation and flame resistance properties of revolutionary self-extinguishing epoxy nanocomposites based on layered double hydroxides

Layered double hydroxides/epoxy (LDHs/EP) nanocomposites were prepared from organo-modified LDHs, a diglycidyl ether of bisphenol A monomer (DGEBA) and amine curing agents. The organo-modified LDHs were obtained by ionic exchange of a magnesium-aluminum carbonate LDH in an acid medium. X-ray diffraction and transmission electron microscopy showed a dispersion of the layers at a nanometer scale, indicating the formation of LDH/EP nanocomposites. The thermal degradation and flame resistance properties of LDH/EP nanocomposites, montmorillonite-epoxy (MMT/EP) nanocomposites, LDH/EP microcomposites and aluminum hydroxide-epoxy microcomposites were compared by thermogravimetrical analyses, simultaneous thermal analyses, UL94 and cone calorimeter tests. Only LDH/EP nanocomposites showed self-extinguishing behavior in the horizontal UL94 test; LDH/EP microcomposites and MMT/EP nanocomposites samples burned completely showing that the unique flame resistance of LDH/EP nanocomposites is related to both the level of dispersion and the intrinsic properties of LDH clay. Furthermore, cone calorimeter revealed intumescent behavior for LDH/EP nanocomposites and a higher reduction in the peak heat release rate compared to MMT/EP nanocomposites.     

Recent advance in research on halloysite nanotubes-polymer nanocomposite

Halloysite nanotubes (HNTs) are novel 1D natural nanomaterials with predominantly hollow tubular nanostructures and high aspect ratios. Due to their high mechanical strength, thermal stability, biocompatibility, and abundance, HNTs have a number of exciting potential applications in polymer nanocomposites. In this article, we review the recent progress toward the development of HNTs-polymer nanocomposites, while paying particular attention to interfacial interactions of the nanocomposites. The characteristics of the HNTs relative to the formation of the polymer nanocomposites are summarized first. The covalent or non-covalent functionalization methods for HNTs and various fabrication approaches for HNTs-polymer nanocomposites are introduced afterward. Polymer nanocomposites reinforced with HNTs possess highly increased tensile and flexural strength, elastic moduli, and improved toughness. HNTs-polymer nanocomposites also exhibit elevated thermal resistance, flame retardance and unique crystallization behavior. Due to the tubular microstructure and the biocompatibility of HNTs, HNTs-polymer nanocomposites have demonstrated good drug encapsulation and sustained release abilities, gaining them extensive use as tissue engineering scaffolds and drug carriers. Finally, we summarize the characteristics of HNTs-polymer nanocomposites and predict for the development of the potential applications in high-performance composites for aircraft/automobile industries, environmental protection, and biomaterials.     

悬浮聚合聚甲基丙烯酸甲酯／蒙脱土纳米复合材料的制备及表征

采用悬浮聚合法制备了聚甲基丙烯酸甲酯／蒙脱土（PMMA/MMT）纳米复合材料，利用X射线衍射仪、透射电子显微镜和傅里叶变换红外光谱等手段表征了复合材料的结构，研究了不同改性剂对复合材料结构的影响。通过热重分析考察了复合材料的热性能。结果表明，通过悬浮聚合可以成功制备剥离型纳米复合材料，PMMA基体与MMT可以产生较强的相互作用。MMT的加入可以显著提高复合材料的热稳定性。当MMT含量为10％（质量分数，下同）时，PMMA的最大分解温度提高了15℃。     

纳米复合材料研究进展

综述了无机纳米复合材料、有机 /无机纳米复合材料、聚合物 /聚合物纳米复合材料的制备 ,新进展及应用。     

Studies on physico-mechanical properties and thermal characteristics of polypropylene/layered silicate nanocomposites

Polypropylene/layered silicate nanocomposites were prepared from base polymer (10 MFI) and octadecylamine modified montmorillonite (1.30P nanomer), melt compounded with and without compatibilizer, i.e., maleic anhydride grafted polypropylene (Epolene-G3015). Physico-mechanical properties of the virgin PP and nanocomposites with different nanomer percentages and compatibilizer loadings were studied and compared. Thermal characteristics of nanocomposites were also compared with those of the virgin polymer. TEM analysis of the nanocomposites was carried out to study the dispersion of nanomer in the resulting hybrids. The nanocomposites showed improved mechanical properties over those of the virgin polymer with a marginal increase in specific gravity. Addition of compatibilizer further enhanced the mechanical properties of nanocomposites because of the compatibilization of the clay and host polymer interface. The uncompatibilized nanocomposites showed an increase in thermal stability and a higher melting point. However, the compatibilized nanocomposites showed delayed crystallization due to the presence of an oligomeric fraction of the added Epolene. Polym. Compos. 25:646–652, 2004. © 2004 Society of Plastics Engineers.