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1.
Nanocomposites based on diglycidyl ether of bisphenol A (DGEBA) epoxy reinforced with 1–10 wt% I.30E nanoclay were fabricated using high shear mixing technique and characterized to determine the effects of clay loading on their mechanical, thermal, and water uptake properties. The XRD and TEM analyses revealed that the structures of the resultant nanocomposites were a combination of disordered intercalated and exfoliated morphologies. Tensile strength increased for nanocomposite containing 1 % clay loading and decreased for higher nanoclay loading. Unlike strength, the stiffness increased almost linearly with clay loading, showing 46 % improvement in modulus of elasticity for nanocomposites containing 5 % of nanoclay. Water uptake measurements indicated enhancement in the barrier properties of epoxy matrix as nanoclay loading increased from 1 up to 5 wt%. 相似文献
2.
Polylactide-layered silicate nanocomposites with and without a chain extender were prepared by melt mixing using a twin-screw extruder. An organo-modified clay, Cloisite® 30B, and a chain extender Joncryl®-ADR 4368F were employed in this study. The effect of the chain extender and processing conditions on the properties of the PLA-clay nanocomposites were investigated for different strategies of mixing. The resulting nanocomposites were characterized by X-ray diffraction (XRD), while their morphology was observed by SEM and TEM. The incorporation of the chain extender could enhance the degree of clay dispersion provided that it is judiciously added to the nanocomposite. The corresponding results revealed that the Joncryl-based nanocomposites, where nanoclay platelets were well-dispersed, exhibited a significantly reduced permeability as compared to others. The mechanical properties of the neat PLA, the PLA and Joncryl-based nanocomposites were also examined. The increased molecular weight in Joncryl-based nanocomposites caused a significant increase in the modulus, drawability and toughness of the samples. 相似文献
3.
Yibing Cai Yuan Hu Shanyong Xuan Yi Zhang Huaxia Deng Xinglong Gong Zuyao Chen Weicheng Fan 《Journal of Materials Science》2007,42(14):5524-5533
Poly (styrene-acrylonitrile) (SAN)/clay nanocomposites have been prepared by melt intercalation method from pristine montmorillonite
(MMT), using hexadecyl trimethyl ammonium bromide (C16) and hexadecyl triphenyl phosphonium bromide (P16) as the reactive
compatibilizers between polymer and clay. The influence of the reactive compatibilizers proportion relative to the clay on
the structure and properties of the SAN/clay nanocomposites is investigated by X-ray diffraction (XRD) and transmission electron
microscopy (TEM), high-resolution electron microscopy (HREM), thermogravimetric analysis (TGA) and dynamic mechanical analysis
(DMA). The effects of the two different clays (MMT and organic modified MMT) on the nanocomposites formation, morphology and
property are also studied. The results indicate that the SAN cannot intercalate into the interlayers of the MMT and results
in microcomposites. In the presence of the reactive compatibilizers, the dispersion of clay in SAN is rather facile and the
SAN/clay nanocomposites reveal an intermediate morphology, an intercalated structure with some exfoliation and the presence
of small tactoids. The appropriate proportion with 3 wt% reactive compatibilizers to 5 wt% MMT induces well-dispersed morphology
and properties in the SAN matrix. The TGA analyses show that the thermal stability properties of the SAN/clay nanocomposites
have been improved compared with those of the pristine SAN. The DMA results show that the storage modulus and glass transition
temperature (Tg) of the SAN/clay nanocomposites have remarkably enhancements compared with the pristine SAN. At last the intercalation
mechanism of the technology is discussed. 相似文献
4.
《Composites Part A》2007,38(1):192-197
To improve the performance/cost ratio of epoxy/clay nanocomposites, epoxy resin was reinforced with crude clay with the help of a silane modifier. The epoxy/crude clay nanocomposites were produced through a recently developed “slurry compounding” approach. The microstructure of the nanocomposites was characterized with X-ray diffraction (XRD), optical microscopy and transmission electron microscopy (TEM). The thermal mechanical properties were studied with dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). It has been shown that only 5 wt% of silane modifier is required to facilitate the dispersion and exfoliation of crude clay in epoxy matrix. The storage moduli and thermal stability were improved with the addition of crude clay. 相似文献
5.
Torsional and tensile behaviour of acrylonitrile–butadiene–styrene (ABS)-clay nano-composites have been investigated and correlated with morphological and rheological characterisations. Nano-composites of ABS are prepared by melt compounding with different loading levels of nanoclay (Cloisite 30B) in a twin screw extruder and have been characterised in terms of torsional, axial and impact behaviour for their application in external orthotic devices. Tensile stress strain curve of nanocomposites are investigated to quantify resilience, toughness and ductility. Torque values of the nanocomposites are observed under torsion (10°–90°) and compared with that of neat ABS. Performance of ABS under torsional load improved by addition of nanoclay. Both modulus of elasticity and rigidity are found to improve in presence of nanoclay. State of dispersion in nano-composites is investigated using conventional methods such as transmission electron microscopy (TEM), X-ray diffraction (XRD), as well as by parallel plate rheometry. Addition of clay exhibits shear thinning effect and results in increase in storage modulus as well as complex viscosity of the nanocomposites. Zero shear viscosity rises tenfold with 1–2% addition of nanoclay, indicating the formation of structural network. It is found that state of dispersion of nanoclay governs the torsional and mechanical properties in ABS-clay nanocomposites. 相似文献
6.
采用原位插层聚合法制备了尼龙6/蒙脱土剥离型纳米复合材料,讨论了超分散有机蒙脱土的用量对复合材料性能的影响,用动态力学分析(DMA)、X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)等手段研究了纳米复合材料的结构和性能。结果表明,有机蒙脱土加入量为3%(质量分数,下同)时,复合材料综合性能最佳;有机蒙脱土的加入大大提高了尼龙6的综合性能,并提高了尼龙6的储能模量和玻璃化温度。有机蒙脱土在尼龙6基体中有良好的分散性和相容性,蒙脱土片层被完全剥离,在尼龙6基体中实现了纳米级分散。 相似文献
7.
Thermoplastic starch/poly(vinyl alcohol) (PVOH)/clay nanocomposites, exhibiting the intercalated and exfoliated structures, were prepared via melt extrusion method. The effects of clay cation, water, PVOH and clay contents on clay intercalation and mechanical properties of nanocomposites were investigated. The experiments were carried out according to the Taguchi experimental design method. Montmorillonite (MMT) with three types of cation or modifier (Na+, alkyl ammonium ion, and citric acid) was examined. The prepared nanocomposites with modified montmorillonite indicated a mechanical improvement in the properties in comparison with pristine MMT. It was also observed that increases in tensile strength and modulus would be attained for nanocomposite samples with 10%, 5% and 4% (by weight) of water, PVOH and clay loading, respectively. The clay intercalation was examined by X-ray diffraction (XRD) patterns. The chemical structure and morphology of the optimum sample was also probed by FTIR spectroscopy and transmission electron microscopy (TEM). 相似文献
8.
Polymer–clay nanocomposites have attracted considerable interest over recent years due to their dramatic improved mechanical properties. In the present study, compatibility of Acrylonitrile Butadiene Styrene (ABS) and organically modified montmorillonite nanoclay (Cloisite 30B) and composition capability of them are investigated. Polymethylmethacrylate (PMMA) in varying amount (0, 2, and 4 wt%) is used as the compatibilizer. In order to produce nanocomposite parts, the material is first compounded using a twin-screw extruder and then injected into a mold. The effect of the nanoclay percentage and processing parameters on the tensile strength and hardness of nanocomposite parts is also explored using Taguchi Design of Experiments method. Nanoclay content (in three levels: 0, 2 and 4 wt%), melt temperature (in three levels: 190, 200 and 210 °C), holding pressure (in three levels: 80, 105 and 130 MPa) and holding pressure time (in three levels: 1, 2.5 and 4 s) are considered as the variable parameters. Moreover, distribution of nanoclay layers is analyzed using Wide Angle X-ray Diffraction (XRD) test. XRD results displayed that with the presence of PMMA, nanoclay in ABS matrix is compounded in more exfoliated and less intercalated dispersion mode. Adding PMMA also leads to a remarkable increase in the fluidity of the melt during injection molding process. Results also illustrated that nanocomposites with medium loading level (i.e. 2%) of nanoclay have the highest tensile strength, while the highest hardness number belongs to nanocomposites with 4 wt% nanoclay. Obtained results also indicated that injection temperature has the most important effect on tensile strength and hardness of ABS–clay nanocomposites. 相似文献
9.
Polyethylene/organo-montmorillonite clay (org-MMT) nanocomposites were prepared utilizing PP-g-MA as a compatibilizer by melt
intercalation method. In order to increase the miscibility of polyethylene (PE) with nanoparticle surface at firs, a primary
masterbatch consist of compatibilizer and org-MMT was prepared then, this compound was melt intercalated with PE to synthesis
the PE/org-MMT nanocomposites. In this study, the presence of commercial low density polyethylene in Nanocomposites structure
and also the effect of process parameters such as: amount of nanoparticles, mixing rate and mixing time on nanocomposite structure
and properties have been investigated. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results showed
that the interlayer distance of nanoparticle layers increased and a partially intercalated structure was prepared by melt
intercalation method. Interaction between polyethylene chains and nanoparticle layers could be improved if the control of
above parameters causes to penetrate the chains into nanoclay layers; by an optimization, this effect could improve the physical
and mechanical properties. The DSC data revealed that melting temperature has slowly increased and crystalinity has lightly
decreased. Consequently we can claim the thermal properties of LDPE/clay nanocomposite did not considerably change with clay
content. A rise in the mechanical properties such as yield stress and modulus was observed by tension test; by addition of
5% clay content the tensile strength increased about 7%, the tensile modulus enhanced about 60% and the yield stress increased
about 16% in comparison with the pure LDPE. 相似文献
10.
11.
Barbosa R Araújo EM Melo TJ Ito EN Hage EJ 《Journal of nanoscience and nanotechnology》2008,8(4):1937-1941
High density polyethylene/Brazilian clay nanocomposites were prepared by the melt intercalation technique. A montmorillonite sample from Boa Vista/PB, Northeast of Brazil, was organically modified with esthearildimethylammonium chloride (Praepagen WB) quaternary ammonium salt. The unmodified and modified clays with the quaternary ammonium salt were introduced in 1, 2, 3 and 5 wt% in a PE polymer matrix. The dispersion analysis and the interlayer distance of the clay particles were obtained by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The mechanical properties of tensile and the flammability of the nanocomposites were studied. In general, the mechanical properties of the systems presented superior values compared to the matrix. The systems showed a reduction on the burning rate, indicating that the flammability resistance of nanocomposites was improved. 相似文献
12.
Achmad Chafidz Mohammad Al-haj Ali Rabeh Elleithy 《Journal of Materials Science》2011,46(18):6075-6086
A commercial homopolymer polypropylene was melt blended with commercial nanoclay masterbatch at different concentrations of
nanoclay using twin screw extruder (TSE). The influence of three different concentrations (5, 10, and 15 wt%) of the nanoclay
on the morphological, thermal, rheological, and mechanical properties was investigated. The morphology of the nanocomposites
was characterized using Scanning Electron Microscope (SEM), whereas, the thermal behavior (e.g., melting and crystallization)
was characterized using Differential Scanning Calorimetry (DSC). The melt rheology and dynamic mechanical properties were
analyzed using a torsional rheometer. Additionally, the tensile properties were characterized as well. The morphological analysis
showed that the nanoclay was well distributed in the PP matrix as indicated by the SEM micrographs. The DSC results showed
that the presence of nanoclay in the PP matrix increased the degree of crystallinity of PP-nanoclay composites, which reached
a maximum at 5 wt% of nanoclay concentration. However, the melting temperature of the PP-nanoclay composites was not affected
by the presence of nanoclay particles. In addition, rheological analysis showed that the melt response gradually changed from
pseudo-liquid like to pseudo-solid like as the nanoclay concentration increased. Moreover, the storage modulus (G′) increased by increasing nanoclay content. Furthermore, tensile test results showed that the addition of nanoclay leads to
a significant enhancement in the mechanical properties of the PP nanocomposites. 相似文献
13.
《Journal of Experimental Nanoscience》2013,8(4):480-492
Intercalated/exfoliated nanocomposites of thermoplastic polyolefin (TPO) blended nanoclay (Cloisite 20?A and Cloisite 30B) were fabricated using melt extrusion process. Polypropylene grafted maleic anhydride (PP-g-MA) was used as a compatibiliser to improve the dispersibility of clay. TPO/nanoclay composites were prepared with different percentages of clay loading (3, 5 and 7?wt%) by adding PP-g-MA as a compatibiliser. The nanocomposites having 5?wt%C20A/5?wt% compatibiliser exhibited a remarkable improvement in mechanical (tensile modulus, flexural modulus and impact strength) and thermal (heat distortion temperature, HDT) properties. The thermal measurements have been carried out by differential scanning calorimetry, thermogravimetric analysis and HDT methods. Dynamic mechanical analysis studies indicated that PP macromolecules were intercalated or exfoliated between the interlayer of silicates. The morphology of nanocomposites was characterised by scanning electron microscopy (SEM) and X-ray diffraction (XRD) was used to find out the arrangement of crystals in the nanocomposites. The SEM and XRD clearly demonstrated the progressive break up of particles and results in decreased particle size with the optimised combination. 相似文献
14.
Nanostructure and mechanical properties of aromatic polyamide and reactive organoclay nanocomposites
Muhammad Usman Alvi Sonia Zulfiqar Cafer T. Yavuz Hee-Seok Kweon Muhammad Ilyas Sarwar 《Materials Chemistry and Physics》2014
Aromatic polyamide/organoclay nanocomposites were synthesized using the solution blending technique. Treatment of montmorillonite clay with p-phenylenediamine produced reactive organophilic clay for good compatibility with the matrix. Polyamide chains were prepared by condensing a mixture of 1,4-phenylenediamine and 4-4′-oxydianiline with isophthaloyl chloride under anhydrous conditions. These chains were end capped with carbonyl chloride using 1% extra acid chloride near the end of reaction to develop the interactions with organoclay. The dispersion and structure–property relationship were monitored using FTIR, XRD, FE-SEM, TEM, DSC and tensile testing of the thin films. The structural investigations confirmed the formation of delaminated and disordered intercalated morphology with nanoclay loadings. This morphology of the nanocomposites resulted in their enhanced mechanical properties. The tensile behavior and glass transition temperature significantly augmented with increasing organoclay content showing a greater interaction between the two disparate phases. 相似文献
15.
In recent times, polymer-layered silicate nanocomposites have drawn a great deal of attention because they often exhibit tremendous
improvements in material properties compared with virgin polymers or conventional micro- or macro-composites. In the present
study, nanocomposites were developed from organically modified clay and poly(ethylene-co-vinyl acetate-co-carbon monoxide) by melt mixing. FTIR spectroscopy reveals that the interaction between the organoclay and EVACO is thermodynamically
favored. High resolution wide angle X-ray diffraction and transmission electron microscopy were used to study the morphology
of the nanocomposites. Elemental mapping by scanning electron microscopy indicates good dispersion and distribution of the
nanoclay in EVACO matrix. The mechanical properties of the nanocomposites are optimum at a clay loading of 3%. 相似文献
16.
17.
This article deals with the functionalization of a triblock copolymer, poly-(styrene-ethylene-co-butylene)-styrene (SEBS),
at the mid-block by means of chemical grafting by two polar moieties—acrylic acid and maleic anhydride and subsequent novel
synthesis of nanocomposites based on hydrophilic montmorillonite clay (MT) at very low loadings. The mid-block was grafted
with 3 and 6 wt% acrylic acid through solution grafting and 2 and 4 wt% maleic anhydride through melt grafting reactions which
were confirmed by spectroscopic techniques. The nanocomposites derived from the grafted SEBS and hydrophilic MT clay conferred
dramatically better mechanical, dynamic mechanical, and thermal properties as compared to those of the original SEBS and its
clay-based nanocomposites. Different phase separated morphologies could be observed from transmission electron microscopy
(TEM) and atomic force microscopy (AFM) studies for grafted SEBS. X-ray diffraction (XRD), AFM, and TEM studies revealed better
interaction and dispersion of MT clays with the grafted SEBS matrix, resulting in better transparency of these nanocomposite
films. Superlative enhancement of thermal degradation properties was achieved with maleated and acrylated SEBS–MT nanocomposites.
Thermodynamic calculations and interfacial tension measurements indicated possible ways of favorable intercalation-exfoliation
mechanism of maleated and acrylated SEBS–MT nanocomposites. 相似文献
18.
Xiang GAO Lixin MAO Ming TIAN Liqun ZHANG Riguang JIN 《材料科学技术学报》2006,22(1):87-92
Polycarbonate (pc)/polypropylene (pp)/silicate attapulgite (AT) ternary nanocomposites were first prepared via the two-step melt blending process. Phase structure of the ternary composites was characterized by transmission electron microscopy (TEM) and dynamic mechanical analysis (DMA), in which the morphology of encapsulation of AT by PP in the PC matrix were observed. The mechanical properties of the ternary composites were investigated using the tensile tester and Izod impact tester. The results show that encapsulation of AT by PP in PC enhances the toughness of the matrix effectively and give the best tensile and impact strength. 相似文献
19.
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. 相似文献
20.
Epoxy nanocomposites reinforced with recycled cellulose fibres (RCFs) and organoclay platelets (30B) have been fabricated and investigated in terms of WAXS, TEM, mechanical properties and TGA. Results indicated that mechanical properties generally increased as a result of the addition of nanoclay into the epoxy matrix. The presence of RCF significantly enhanced flexural strength, fracture toughness, impact strength and impact toughness of the composites. However, the inclusion of 1 wt.% clay into RCF/epoxy composites considerably increased the impact strength and toughness. The presence of either nanoclay or RCF accelerated the thermal degradation of neat epoxy, but at high temperature, thermal stability was enhanced with increased char residue over neat resin. The failure micromechanisms and energy dissipative processes in these nanocomposites were discussed in terms of microstructural observations. 相似文献