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1.
Ethylenediamine (EDA) covalently functionalized graphene sheets (GS‐EDA) and acidized carbon nanotubes (MWNTs‐COOH) were first prepared, followed by synthesizing l ‐aspartic acid functionalized GS‐EDA/MWNTs‐COOH (LGC) hybrid nanomaterials by using l ‐aspartic acid as a bridging agent. Then nanocomposites of high density polyethylene‐g ‐maleic anhydride (HDPE‐g ‐MAH) synergistic strengthening–toughening using LGC hybrids were prepared via melt compounding method. The surface structure of filler was characterized by using infrared (FTIR) and Raman spectrum. The synergistic strengthening–toughening effects of LGC hybrids on the HDPE‐g ‐MAH were investigated by scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), thermal gravimetric analysis (TGA), tensile, and impact tests. FTIR showed that EDA has been grafted on the graphene sheets, and ? COOH group has been introduced into MWNTs. The l ‐aspartic acid connected GS‐EDA and MWNTs‐COOH through chemical bonds. SEM observations showed that LGC hybrids were homogeneously dispersed in HDPE‐g ‐MAH nanocomposites. Tensile and impact tests indicated that the mechanical properties of nanocomposites were improved obviously when LGC hybrid nanomaterials were incorporated simultaneously. DMA analysis indicated that the storage modulus of composites was higher than that of pure HDPE‐g ‐MAH matrix. TGA results revealed that the maximum decomposition temperature of HDPE‐g ‐MAH composites containing 0.75 wt % of LGC showed 11.5 °C higher than that of HDPE‐g ‐MAH matrix. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45055.  相似文献   

2.
Dodecyl amine (DA) functionalized graphene oxide(DA‐GO) and dodecyl amine functionalized reduced graphene oxide (DA‐RGO) were produced by using amidation reaction and chemical reduction, then two kinds of well dispersed DA‐GO/high‐density polyethylene (HDPE) and DA‐RGO/HDPE nanocomposites were prepared by solution mixing method and hot‐pressing process. Thermogravimetric, X‐ray photoelectron spectroscopy, Fourier transforms infrared spectroscopy, X‐ray diffractions, and Raman spectroscopy analyses showed that DA was successfully grafted onto the graphene oxide surface by uncleophilic substitution and the amidation reaction, which increased the intragallery spacing of graphite oxide, resulting in the uniform dispersion of DA‐GO and DA‐RGO in the nonpolar xylene solvent. Morphological analysis of nanocomposites showed that both DA‐GO and DA‐RGO were homogeneously dispersed in HDPE matrix and formed strong interfacial interaction. Although the crystallinity, dynamic mechanical, gas barrier, and thermal stability properties of HDPE were significantly improved by addition of small amount of DA‐GO or DA‐RGO, the performance comparison of DA‐GO/HDPE and DA‐RGO/HDPE nanocomposites indicated that the reduction of DA‐GO was not necessary because the interfacial adhesion and aspect ratio of graphene sheets had hardly changed after reduction, which resulting in almost the same properties between DA‐GO/HDPE and DA‐RGO/HDPE nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39803.  相似文献   

3.
This research investigates the effect of exfoliated graphene nanoplatelets (GNP) on the crystallization behavior, thermal conductivity, and electrical conductivity of high‐density polyethylene (HDPE)/GNP nanocomposites. HDPE/GNP nanocomposites were fabricated by melt blending followed with injection molding. Results indicate that GNP is a good nucleating agent at low loading levels and as a result can significantly increase crystallization temperature and crystallinity of HDPE. At high GNP loadings, however, the close proximity of GNP particles retards the crystallization process. The thermal stability and thermal conductivity of HDPE/GNP nanocomposites were found to be significantly enhanced as a function of GNP concentration owing to the excellent thermal properties of GNP. Finally, the high percolation threshold of HDPE/GNP nanocomposites (∼10–15 vol%), prepared by melt blending and injection molding was successfully reduced to around 5 vol% of GNP loading by employing a novel compounding method, solid‐state ball milling. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers  相似文献   

4.
Graphene nanoplatelets coated by polyaniline (GNP@PANI) and ethylene–vinyl acetate (EVA) copolymer–high‐density polyethylene (HDPE) were used for the first time to prepare high‐performance antistatic composites through an effective method that combined solution mixing and melt blending. GNP@PANI nanocomposites were fabricated by in situ polymerization to improve the dispersion of graphene nanoplatelets (GNPs) in the EVA–HDPE matrix and the compatibility between the GNPs and the EVA–HDPE matrix. The GNP@PANI nanocomposites and EVA were first prepared as a premix through solution mixing, and then, the premix and HDPE were prepared as highly antistatic composites through melt blending. The dispersion of the GNPs in the EVA–HDPE matrix and the compatibility between the GNPs and the EVA–HDPE matrix were confirmed by field emission scanning electron microscopy and transmission electron microscopy observations. The GNP@PANI–EVA–HDPE composites met the requirements for antistatic materials when the content of the GNP@PANI nanocomposites was 5 wt % with only about 1 wt % GNPs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45303.  相似文献   

5.
Nanocomposites based on high density polyethylene (HDPE)/linear low density polyethylene (LLDPE) blend were prepared by melt compounding in a twin‐screw extruder using organoclay (montmorillonite) as nano‐filler and a 50/50 wt% mixture of maleic anhydride functionalized high density polyethylene (HDPE‐g‐MA) and linear low density polyethylene (LLDPE‐g‐MA) as the compatibilizing system. The addition of a maleated polyethylene‐based compatibilizing system was required to improve the organoclay dispersion in the HDPE/LLDPE blend‐based nanocomposite. In this work, the relationships between thermal properties, gas transport properties, and morphology were correlated. The compatibilized nanocomposite exhibited an intercalated morphology with a small number of individual platelets dispersed in the HDPE/LLDPE matrix, leading to an significant decrease in the oxygen permeation coefficient of the nanocomposites. A decrease in the carbon dioxide permeability and oxygen permeability with increase of nanoclay was observed for the compatibilized nanocomposites. The carbon dioxide permeability of the compatibilized nanocomposites was lower than the carbon dioxide permeability of the uncompatibilized nanocomposites even with the low intrinsic barrier properties of the compatibilizer. These effects were attributed to a good dispersion of the inorganic filler, good wettability of the filler by the polymer matrix, and strong interactions at the interface that increased the tortuous path for diffusion. Theoretical permeability models were used to estimate the final aspect ratio of nanoclay in the nanocomposite and showed good agreement with the aspect ratio obtained directly from TEM images. POLYM. ENG. SCI., 56:765–775, 2016. © 2016 Society of Plastics Engineers  相似文献   

6.
Graphene, consisted of a single layer of carbon atom in a two‐dimensional lattice, has superior electrical and physical properties that promise many exciting applications. In this study, graphenes were prepared from graphite powder by chemical method and their images were investigated by TEM and SEM. To develop high performance epoxy nanocomposites with good dispersion of graphenes and strong epoxy‐graphene interfacial bonding, graphenes were amine‐functionalized and the effects of the amine‐functionalization on the curing behavior and physical properties of epoxy/graphene nanocomposites were studied. FTIR spectra confirmed the amine‐functionalization. The physical properties of the nanocomposites were investigated by DSC, DMA, TMA, and impact tester. Fracture surfaces were investigated by SEM. The physical properties of the nanocomposites could be improved considerably by the amine‐functionalization of graphenes. POLYM. ENG. SCI., 54:985–991, 2014. © 2012 Society of Plastics Engineers  相似文献   

7.
Cellulose acetate (CA)‐based nanocomposites with various contents of neat multiwalled carbon nanotube (MWCNT) or acid‐treated one (MWCNT‐COOH) are prepared via melt‐compounding method and investigated their morphology, thermal stability, mechanical, and electrical properties. SEM microphotographs reveal that MWCNT‐COOHs are dispersed uniformly in the CA matrix, compared with neat MWCNTs. FTIR spectra support that there exists a specific interaction between carboxyl groups of MWCNT‐COOHs and ester groups of CA, indicating good interfacial adhesion between MWCNT‐COOHs and CA matrix. Accordingly, thermal stability and dynamic mechanical properties of CA/MWCNT‐COOH nanocomposites were higher than those of CA/MWCNT composites. On the contrary, electrical volume resistivities of CA/MWCNT‐COOH nanocomposites are found to be somewhat higher than those of CA/MWCNT composites, which is because of the deterioration of graphene structures for MWCNT‐COOHs and the good dispersion of MWCNT‐COOHs in the CA matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

8.
Polymer nanocomposites filled with low volume fractions of carbon nanofibers (CNFs) were prepared by melt‐compounding. Three types of polymers with different crystallization behavior, i.e., weakly‐crystallized low density polyethylene (LDPE), strongly crystallized high density polyethylene (HDPE) and amorphous polystyrene (PS), were selected as matrices for the nanocomposites. The effects of polymer crystallization on the dispersion of CNFs were examined. Optical and electron microscopic examinations revealed that the dispersion of CNFs in the nanocomposite matrices was strongly depended on the crystallization behavior of polymer matrices. The CNFs were found to disperse uniformly in weakly crystallized LDPE and amorphous PS matrices, but agglomerated in HDPE due to its strong crystallization tendency. Such a distinct dispersion behavior of CNFs in polymers had a profound effect on the electrical properties of the nanocomposites investigated. The PS/CNF nanocomposites exhibited the lowest percolation threshold. The HDPE/CNF nanocomposites showed the largest percolation threshold due to the CNF agglomeration within the amorphous phase of HDPE. POLYM. ENG. SCI., 48:177–183, 2008. © 2007 Society of Plastics Engineers  相似文献   

9.
The objective of this work is to modify graphene and study the effect of modification of graphene in thermal and electrical properties of graphene/polypyrrole and graphene/polyaniline nanocomposites. The amine functionalization of graphene was confirmed by Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The nanocomposites were prepared by insitu oxidative polymerization method using ammonium persulfate as oxidant. Field emission scanning electron microscopy and high‐resolution transmission electron microscopy were used to study the morphology of the nanocomposites which indicates toward the better dispersion of modified graphene within the polymer matrices as compared to unmodified composites. The modification of graphene played an important role in the noticeable improvements in electrical conductivity of the prepared composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

10.
Nanocomposites of polypropylene impact copolymer and organoclays were prepared using different compatibilizers (polypropylene‐graft‐(maleic anhydride) (PPMA), polyethylene‐graft‐(maleic anhydride) (PEMA) and their mixture) and varying percentages of clay (3 and 6%) in an attempt to obtain balanced mechanical properties. The nanocomposites were prepared by melt compounding and test specimens were prepared by injection molding. Mechanical properties such as tensile, flexural and Izod impact strength are reported. The clay dispersion was investigated using wide‐angle X‐ray diffraction while the phase morphology was characterized using scanning electron microscopy. It is shown that the mechanical properties of the system with mixed PPMA and PEMA compatibilizers showed the best balance of mechanical properties among the nanocomposites explored. Copyright © 2006 Society of Chemical Industry  相似文献   

11.
In this article, we describe the fabrication by melt mixing of graphene‐polypropylene nanocomposites and present the effect of graphene addition on some selected properties of polypropylene (PP). The graphene nanosheets (GNs) used as nano‐reinforcing agents were obtained through chemical reduction of graphene oxide by hydrazine hydrate. GNs were characterized and successfully dispersed into PP matrix to produce PP/GNs nanocomposites. The effects of GNs content on thermal, mechanical, and rheological properties were reported, and the obtained results were discussed in terms of morphology and state of dispersion and distribution of the GNs within the polymer matrix. Characterization by scanning electron microscopy and X‐ray diffraction of the nanocomposites has shown a relatively good dispersion of GNs in the polymer matrix, with the presence of only few aggregates. Increasing GNs content resulted in a significant increase in both mechanical and thermal properties with only few percent of GNs loading. Rheological behavior of the PP/GNs nanocomposites showed a Maxwellian‐like behavior for low GNs concentrations and a viscoelastic solid‐like behavior for GNs content exceeding the concentration of the percolation threshold. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers  相似文献   

12.
Nanocomposites of polycarbonate/acrylonitrile butadiene styrene (PC/ABS) with (70/30) composition containing different amounts of graphene nanoplates (GNPs) (1, 3, and 5 wt%) were prepared by melt‐blending in a twin‐screw extruder. The structural, morphological, mechanical, and thermal properties of the nanocomposites were investigated. The Young's modulus and flexural modulus of the nanocomposites were increased by 30 and 54%, respectively, when 3 wt% GNPs was added. The flexural strength and tensile strength of the PC/ABS/GNPs nanocomposites increased up to a loading of 3 wt% GNPs. The incorporation of GNPs enhanced the thermal stability and char yield of the nanocomposites. X‐ray diffraction and field emission scanning electron microscopy showed uniform dispersion and alignment of GNPs in PC/ABS matrix. The interaction between the GNPs and the PC/ABS matrix were confirmed by Fourier transform infrared spectra. Therefore, the PC/ABS/GNP nanocomposites with improved flexural and tensile properties, without loss of extensibility and good thermal properties may have promising applications in automotive, electric tools, household, communication, and safety appliances. POLYM. COMPOS., 37:1633–1640, 2016. © 2014 Society of Plastics Engineers  相似文献   

13.
Acrylic acid (AA) grafted high‐density polyethylene (HDPE)/bentonite (BT) composites and HDPE/BT composites were prepared via melt compounding. XRD and TEM results indicated that the modification of AA grafting promoted the dispersion and intercalation of BT in HDPE matrix; IR proved that there were interactions between AA and BT sheets. Consequently, with increasing BT content, the tensile strength and Young's modulus of HDPE‐g‐AA/BT nanocomposites increased, while that of HDPE/BT composites decreased. Moreover, the addition of BT to HDPE‐g‐AA decreased the ability of crystallization of the matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2429–2434, 2005  相似文献   

14.
Graphene nanosheets were prepared by complete oxidation of pristine graphite followed by thermal exfoliation and reduction. Polyethylene terephthalate (PET)/graphene nanocomposites were prepared by melt compounding. Transmission electron microscopy observation indicated that graphene nanosheets exhibited a uniform dispersion in PET matrix. The incorporation of graphene greatly improved the electrical conductivity of PET, resulting in a sharp transition from electrical insulator to semiconductor with a low percolation threshold of 0.47 vol.%. A high electrical conductivity of 2.11 S/m was achieved with only 3.0 vol.% of graphene. The low percolation threshold and superior electrical conductivity are attributed to the high aspect ratio, large specific surface area and uniform dispersion of the graphene nanosheets in PET matrix.  相似文献   

15.
Polylactic acid (PLA)/organo‐montmorillonite (OMMT) nanocomposites toughened with thermoplastic polyurethane (TPU) were prepared by melt‐compounding on a novel vane extruder (VE), which generates global dynamic elongational flow. In this work, the mechanical properties of the PLA/TPU/OMMT nanocomposites were evaluated by tensile, flexural, and tensile tests. The wide‐angle X‐ray diffraction and transmission electron microscopy results show that PLA/TPU/OMMT nanocomposites had clear intercalation and/or exfoliation structures. Moreover, the particles morphology of nanocomposites with the addition of TPU was investigated using high‐resolution scanning electronic microscopy. The results indicate that the spherical TPU particles dispersed in the PLA matrix, and the uniformity decreased with increasing TPU content (≤30%). Interestingly, there existed abundant filaments among amount of TPU droplets in composites with 30 and 40 wt% TPU. Furthermore, the thermal properties of the nanocomposites were examined with differential scanning calorimeter and dynamic mechanical analysis. The elongation at break and impact strength of the PLA/OMMT nanocomposites were increased significantly after addition of TPU. Specially, Elongation at break increased by 30 times, and notched impact strength improved 15 times when TPU loading was 40 wt%, compared with the neat PLA. Overall, the modified PLA nanocomposites can have greater application as a biodegradable material with enhanced mechanical properties. POLYM. ENG. SCI., 54:2292–2300, 2014. © 2013 Society of Plastics Engineers  相似文献   

16.
We present a novel approach to improving organoclay exfoliation in a nonpolar matrix, polyethylene. High‐density polyethylene (HDPE) particles were modified by exposure to a reactive gas atmosphere containing F2 and O2. This treatment was aimed at increasing the polarity of the polymer with the formation of carboxyl, hydroxy, and ketone functionalities on the particle surface. The surface‐treated high‐density polyethylene (ST‐HDPE) particles were then melt‐mixed with an appropriate organoclay to form nanocomposites. Transmission electron microscopy (TEM), wide‐angle X‐ray scattering, stress–strain analysis, and Izod impact measurements were used to evaluate the nanocomposite morphology and physical properties. These data were compared to those of equivalent nanocomposites prepared from unmodified HDPE and high‐density polyethylene grafted with maleic anhydride (HDPE‐g‐MA). The nanocomposites prepared from the ST‐HDPE particles exhibited much better properties and organoclay dispersion than those prepared from unmodified HDPE. The level of reinforcement observed in ST‐HDPE‐based nanocomposites was comparable to, if not better than, that seen in HDPE‐g‐MA‐based nanocomposites. However, a comparison of the TEM micrographs suggested better organoclay exfoliation in HDPE‐g‐MA than the current version of ST‐HDPE. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2980–2989, 2006  相似文献   

17.
Polyamide‐6/clay nanocomposites were prepared employing melt bending or compounding technique followed by injection molding using different organically modified clays. X‐ray diffraction and transmission electron microscopy were used to determine the molecular dispersion of the modified clays within the matrix polymer. Mechanical tests revealed an increase in tensile and flexural properties of the matrix polymer with the increase in clay loading from 0 to 5%. C30B/polyamide‐6 nanocomposites exhibited optimum mechanical performance at 5% clay loading. Storage modulus of polyamide‐6 also increased in the nanocomposites, indicating an increase in the stiffness of the matrix polymer with the addition of nanoclays. Furthermore, water absorption studies confirmed comparatively lesser tendency of water uptake in these nanocomposites. HDT of the virgin matrix increased substantially with the addition of organically modified clays. DSC measurements revealed both γ and α transitions in the matrix polymer as well as in the nanocomposites. The crystallization temperature (Tc) exhibited an increase in case of C30B/polyamide‐6 nanocomposites. Thermal stability of virgin polyamide‐6 and the nanocomposites has been investigated employing thermogravimetric analysis. POLYM. COMPOS., 28:153–162, 2007. © 2007 Society of Plastics Engineers  相似文献   

18.
Poly(l-lactic acid) (PLLA)/graphene nanoplatelets (GnP) nanocomposites were prepared through solvent casting and coagulation methods. The better dispersion of graphene was achieved by ultrasounds and its effect on crystallinity, thermomechanical and electrical properties of PLLA were studied and compared in both methods. Differential scanning calorimetry (DSC) was used to investigate the crystallinity of PLLA and its composites. Field emission gun scanning electron microscope (FEG-SEM) and wide-angle X-ray scattering (WAXS) were employed to characterize the microstructure of PLLA crystallites. Dynamic mechanical thermal analysis (DMTA) was performed to study the thermomechanical properties of the nanocomposites. FEG-SEM images illustrated finer dispersion of GnP in samples obtained by coagulation method with respect to solvent casting method. Graphene imparted higher electrical conductivity to nanocomposites obtained by solvent casting under ultrasound due to better formation of graphene network. DSC thermograms and their resulting data showed positive effects of GnP on crystallization kinetics of PLLA in both methods enhanced by the nucleating effect of graphene particles. Meanwhile, the effect of GnP, as nucleating agent, was more prominent in samples produced by coagulation method without utilization of ultrasounds. WAXS patterns represented the same characteristic peaks of PLLA in nanocomposite specimens suggesting similar crystalline structure of PLLA in presence of graphene, and the intensified peaks of nanocomposites compared to neat PLLA confirmed the DSC results regarding its improved crystallinity. Graphene increased storage modulus in rubbery region and glass transition temperature of nanocomposites in the coagulation method due to restricted mobility of PLLA chains.  相似文献   

19.
Preparation and morphology of Polyamide 6 (PA6)/high density polyethylene (HDPE)/Styrene/Ethylene–Butylene/Styrene grafted with maleic anhydride (SEBS‐g‐MA)/Modified clay nanocomposites were studied. Mixing was performed using melting process in an extruder co‐rotating twin screw. After etching the materials with boiling toluene and THF at room temperature, the morphology of sample checked by scanning electron microscopy (SEM) analyses. X‐ray diffraction (XRD) used for evaluation of the effects of organo‐clay addition in the structure of nanocomposites. XRD traces showed that the characteristic (001) peak of the nanocomposites shifted to the lower degree region. XRD and SEM results showed more uniformly distribution and dispersion of HDPE in the PA6 matrix. Better sample morphology obtained, regarding less distance, and more uniformity between nanoparticles. The mechanical properties like tensile strength, impact strength, hardness and thermal properties of these toughened nanocomposites are discussed in terms of the nanoclay, SEBS‐g‐MA contents and morphology. Adding nanoclay improved hardness of nanocomposites product but reduced toughness and thermal properties. Meanwhile the presence of SEBS‐g‐MA as a compatibilizer improved toughness, thermal properties, hardness property, and the balance properties are achieved. POLYM. ENG. SCI., 55:29–33, 2015. © 2014 Society of Plastics Engineers  相似文献   

20.
Poly(urethane‐co‐vinyl imidazole) (PUVI)/graphene nanocomposites were facilely prepared by a kind of noncovalent way. Herein, the 1‐vinylimidazole acted as dispersion agent as well as monomer, graphene was uniformly dispersed in the copolymer matrix without obviously agglomeration. A significant enhancement of mechanical and thermal properties of the PUVI/graphene nanocomposites were obtained at low graphene loading; specifically, a 147% improvement of tensile strength, a nearly 10 times increase of elastic modulus and a 12°C enhancement of thermal decomposition temperature were achieved at a graphene loading of 1.5 wt%. Moreover, the volume resistivity of the PUVI/graphene nanocomposites decreased by an order of magnitude after adding 0.5 wt% graphene, demonstrating an obvious change in the electrical property of the nanocomposites prepared. POLYM. COMPOS. 2012. © 2012 Society of Plastics Engineers  相似文献   

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