In this article, we address in situ synthesis of polyethylene terephthalate (PET) nanocomposites using the bis (2‐hydroxyethyl) phthalate monomer and inorganic layered materials (sulfanilic acid salt‐modified magnesium aluminum‐layered double hydroxides [MgAl LDH‐SAS] and Dimethyloctadecyl [3‐(trimethoxysilyl) propyl] ammonium chloride [DTSACl] and tetraethyl orthosilicate [TEOS]‐ modified clay [CL120‐DT]). The dispersion morphology of the synthesized nanocomposites was evaluated using XRD and TEM, from these results, it was confirmed that 0.5 wt% loaded PET/MgAl LDH‐SAS and PET/CL120‐DT nanocomposites have flocculated and intercalated morphologies, respectively. Thermomechanical analyses were performed by thermogravimetric analysis, dynamic mechanical analysis, and differential scanning calorimetry, respectively. Moreover, the water vapor transmission rate (WVTR) values of a pure PET, PET/CL120‐DT 0.5 wt%, and PET/MgAl LDH‐SAS 0.5 wt% nanocomposites were found to be 49, 45, and 46 g·m?2·day?1, respectively. Furthermore, the gas barrier properties of PET composite films containing various amounts of inorganic nanoparticles were investigated using Gas permeability analysis (GPA). 相似文献
An organo‐modified MgAl‐layered double hydroxide (OMgAl‐LDH) was successfully exfoliated in the xylene solution of polyethylene‐grafted‐maleic anhydride (PE‐g‐MA) under re‐fluxing condition. A PE‐g‐MA/MgAl‐LDH exfoliation nanocomposite was formed after the precipitation of PE‐g‐MA from the dispersion system. The structure and thermal property of the PE‐g‐MA/MgAl‐LDH exfoliation nanocomposite were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetry analysis (TGA). The disappearance of d001 XRD peak of OMgAl‐LDH at 20 = 3.2° suggests that the MgAl hydroxide sheets are exfoliated in the nanocomposite. The TEM image shows that the MgAl hydroxide sheets of less than 70 nm in length or width are exfoliated and dispersed disorderly in PE‐g‐MA matrix. TGA profiles indicate that the PE‐g‐MA/MgAl‐LDH nanocomposite with 5 wt% OMgAl‐LDH loading shows a faster charring process in temperature range from 210 to 390 °C and a greater thermal stability beyond 390 °C than PE‐g‐MA does. The decomposition temperature of the nanocomposite is 25 °C higher than that of PE‐g‐MA as measured at 50% weight loss. The PE‐g‐MA/MgAl‐LDH nanocomposite is promising for application of flame‐retardant polymeric materials. 相似文献
Layered double hydroxides are a type of layered stacked compound, which can be intercalated with organic‐molecule modifiers. An ion‐exchange process for layered double hydroxide (LDH) was used to intercalate water‐soluble sulfanilic acid salt (SAS) and dimethyl 5‐sulfoisopthalate (DMSI) into lithium aluminum layered double hydroxides (LiAl LDHs). In this work, a hydrothermal process was used to modify LiAl LDHs, and the modified LiAl LDHs were treated with either SAS or DMSI through an ion‐exchange process and were then intercalated using bis‐hydroxyethylene terephthalate (BHET). The results indicate that the modified LiAl LDHs improved the interlayer compatibility between the PET and LiAl LDH layers; thus, enabling the oligomer molecules to more easily enter the gallery of the LiAl LDH layers so that polymer chains could be included between the LDH layers during polymerization of the matrix. The better barrier, mechanical properties, and thermal stability of these new types of PET nanocomposites are discussed. 相似文献
The interlayer surface of MgAl layered double hydroxide (MgAl-LDH) was modified by exchanging about half of the interlayer nitrate anions by dodecyl sulfate anions (DS) to get MgAl(H-DS) LDH, and then the MgAl(H-DS) was melt intercalated by LLDPE to get the LLDPE/MgAl-LDH exfoliation nanocomposites. The samples were characterized by Fourier transform infrared (PTIR) spectroscopy, X-ray diffraction (XRD), ion chromatography, transmission electron microscopy (TEM), and thermogravimetry analysis (TGA). The nanoscale dispersion of MgAl-LDH layers in the LLDPE matrix was verified by the disappearance of (001) XRD reflection of the modified MgAl-LDH and by the TEM observation. The TGA profiles of LLDPE/MgAl-LDH nanocomposites show a faster charring process between 210 and 370 ℃ and a higher thermal stability above 370 ℃than LLDPE. The decomposition temperature of the nanocomposites with 10 wt% MgAl(H-DS) can be 42 ℃ higher than that of LLDPE at 40% weight loss. 相似文献
Exfoliated polystyrene (PS)/ZnAl layered double hydroxide (LDH) nanocomposites have been synthesized via emulsion polymerization in the presence of N-lauroyl-glutamate surfactants and long-chain n-hexadecane. The samples were characterized using elemental analysis, Fourier transform infrared (FTIR) spectrum, X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The XRD and TEM results demonstrate that the exfoliated ZnAl-LDH layers of 50-70 nm width and about 1 nm thickness were well dispersed at molecular level in the PS matrix. And the completely exfoliated PS/LDH nanocomposites can be obtained even at the 10 wt% LDH loading. When the 50% weight loss was selected as a comparison point, the decomposition temperature of exfoliated PS/LDH sample with 5 wt% LDH was ca. 28 degrees C higher than that of pure PS. 相似文献
Thermally stable modifier were used to modify clay or lithium aluminum layered double hydroxides (LiAl LDH) nanoparticles for preparation of poly (ethylene terephthalate)/clay or LiAl LDH nanocomposites. The effect of modify agent, studied by microcompouding process. The PET nanocomposites which were made by twin‐screw microcompounder dispersion morphology of inorganic layered materials in nanocomposites could be explained by wide‐angle X‐ray diffraction (WXRD), and transmission electron microscopy (TEM). Nanocomposite also formed the better mechanical, UV resistance, and gas barrier properties. Optical properties and crystallization behaviour of these new types of nanocomposites are investigated in this paper. 相似文献
The nylon 6/MgAl layered double hydroxide (MgAl-LDH) nanocomposites have been prepared by melt intercalation of nylon 6 into the part organic dodecyl sulfate (DS) anion-modified MgAl(H-DS) interlayers. The structures and properties of MgAl(H-DS) and corresponding nanocomposites were characterized by ion chromotography, X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), and cone calorimeter test (CCT). The nanoscale dispersion of MgAl(H-DS) layers in the nylon 6 matrix has been verified by the disappearance of d001 XRD diffraction peak of MgAl(H-DS) and the observation of TEM image. DSC tests evince that these exfoliated MgAl(H-DS) layers play the role of nucleating agents with strong heterogeneous nucleation effect on the crystallization of nylon 6 and increase its crystallization temperature over 12 °C with only 5 wt% MgAl(H-DS). TGA tests show that the effect of alkaline catalysis degradation from LDH on nylon 6 decreases the thermal stability of nylon 6/MgAl-LDH nanocomposites. The data from the cone calorimeter tests show that the HRR and MLR values of the sample with 5 wt% MgAl(H-DS) decrease considerably to 664 kW/m2 and 0.161 g/m2 s from 1064 kW/m2 and 0.252 g/m2 s of pure nylon 6, respectively. This kind of exfoliated nanocomposite is promising for the application of flame-retardant polymeric materials. 相似文献
A modified nano‐hydrotalcite was used as inorganic flame‐retardant fillers for poly(ethylene terephthalate) (PET) polymers. A flame‐retardant compound was obtained from layered hydrotalcite (LDH) dispersed in brominated polystyrene (PBS) solution and then solvent evaporation from the dissolved PBS samples. The compound of PBS/LDH was characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) and was found to have high aspect ratio LDH dispersed in the PBS matrix. Flame‐retardant PET composite was prepared by melt‐compounding the flame‐retardant compound of PBS/LDH and PET. Improvement in the fire retardancy of the nano‐flame‐retardant PET composite obtained was found by measuring the oxygen index. The nanostructure of flame‐retardant PET composite was chirecterized by scanning electron microscopy (SEM) of flame‐retardant PET composite. The mechanical properties of the flame‐retardant PET nano‐composite were also characterized. 相似文献
Layered materials (MMT,LDH) were successfully modified by chain end functionalized polyethylene via an ion exchange method.The samples were characterized by using elemental analysis,Fourier transform infrared (FTIR) spectrum,X-ray diffraction (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and thermogravimetric analysis (TGA).The XRD results demonstrated that MMT was successfully exfoliated with the disappearance of [001] peak.For the LDH,the peak [003] moved to a low angle and greatly weakened,indicating that LDH was successfully functionalized and completely intercalated or exfoliated.HDPE/layered nanocomposites were obtained between HDPE and different content of functional layered materials.The SEM and TEM results of nanocomposites showed the layered materials were well dispersed in the HDPE matrix,with a particle size of 100-200 nm. 相似文献
This article addresses the synthesis of organically tailored Ni-Al layered double hydroxide (ONi-Al LDH) and its use in the fabrication of exfoliated poly(methyl methacrylate) (PMMA) nanocomposites. The pristine Ni-Al LDH was initially synthesized by co-precipitation method and subsequently modified using sodium dodecyl sulfate to obtain ONi-Al LDH. Nanocomposites of PMMA containing various amounts of modified Ni-Al LDH (3 wt%-7 wt%) were synthesized via solvent blending method to investigate the influence of LDH content on the properties of PMMA matrix. Several characterization methods such as X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), rheological analysis, differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA), were employed to examine the structural, viscoelastic and thermal properties of PMMA/OLDH nanocomposites. The results of XRD and TEM examination confirm the formation of partially exfoliated PMMA/OLDH nanocomposites. The FTIR results elucidate that the characteristic bands for both pure PMMA and modified LDH are present in the spectra of PMMA/OLDH nanocomposites. Rheological analyses were carried out to examine the adhesion between polymer matrix and fillers present in the nanocomposite sample. The TGA data indicate that the PMMA nanocomposites exhibit higher thermal stability when compared to pure PMMA. The thermal decomposition temperature of PMMA/OLDH nanocomposites increases by 28 K compared to that of pure PMMA at 15% weight loss as a point of reference. In comparison with pure PMMA, the PMMA nanocomposite containing 7 wt% LDH demonstrates improved glass transition temperature (Tg) of around 3 K. The activation energy (Ea), reaction orders (n) and reaction mechanism of thermal degradation of PMMA/OLDH nanocomposites were evaluated using different kinetic models. Water uptake capacity of the PMMA/OLDH nanocomposites is less than that of the pure PMMA. 相似文献
Latexes of poly(n‐butyl acrylate‐co‐methyl methacrylate) [P(BA‐co‐MMA)] filled with magnesium–aluminum layered double hydroxides (MgAl‐LDHs) are synthesized using miniemulsion polymerization. Three commercial LDHs organically modified with different types of anions are used as fillers (Perkalite F100S, Perkalite A100, and Perkalite AF50) and three different types of surfactants are tested to stabilize the miniemulsions including a cationic, an anionic, and a nonionic one. Stable LDH‐containing miniemulsions are prepared with a mixture of sodium dodecyl sulfate and Triton X‐405 and the polymerizable co‐stabilizer octadecyl acrylate. They are then polymerized to yield nanocomposite latexes. Depending on the type of LDH used, the presence of the inorganic material in the reaction medium affects the polymerization kinetics. X‐ray diffraction analysis of the resulting nanocomposite films suggests exfoliation of the inorganic material. The glass transition temperature of the nanocomposites is not affected by the LDHs and the decomposition temperature of the nanocomposites determined by thermogravimetric analysis is greater than that of the pure polymer. 相似文献
Poly(L ‐lactide)/layered aluminosilicate nanocomposites were synthesized in bulk by ring‐opening polymerization in the presence of two organo‐modified montmorillonites. When the organo‐modifier consisted of an ammonium cation bearing primary hydroxyl groups, polymerization was initiated by the alcohol functions after adequate activation. The growing polymer chains were directly “grafted” onto the clay surface through the hydroxyl‐functionalized ammonium cations yielding exfoliated nanocomposites with enhanced thermal stability.
TEM image of a fully exfoliated Cloisite®30B‐based nanocomposite, showing delamination of the silicate layers. 相似文献