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1.
The well dispersion of functionalized multi‐walled carbon nanotube (f‐MWCNT) in nylon 6 matrix was prepared by solution mixing techniques. The isothermal and nonisothermal crystallization kinetics of nylon 6 and nylon 6/f‐MWCNT nanocomposites were studied by differential scanning calorimetry (DSC), X‐ray diffraction and polarized optical microscopy analysis. DSC isothermal results revealed that the activation energy of nylon 6 extensively decreased by adding 1 wt % f‐MWCNT into nylon 6, suggesting that the addition of small amount of f‐MWCNT probably induces the heterogeneous nucleation. Nevertheless, the addition of more f‐MWCNT into nylon 6 matrix reduced the transportation ability of polymer chains during crystallization process and thus increased the activation energy. The nonisothermal crystallization of nylon 6/f‐MWCNT nanocomposites was also discussed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 158–169, 2008 相似文献
2.
Polyamide‐6 (PA6)/vermiculite nanocomposites were fabricated through the direct melt compounding of maleic anhydride‐modified vermiculite (MAV) with PA6 in a twin‐screw extruder followed by injection molding. The structure and morphology of the nanocomposites were determined by X‐ray diffraction and scanning and transmission electron microscopy techniques. The results revealed the formation of intercalated and exfoliated vermiculite platelets in the PA6 matrix. Tensile measurement showed that the tensile modulus and strength of the nanocomposites tended to increase with increasing vermiculite content. The thermal properties of the nanocomposites were determined by dynamic mechanical analysis, differential scanning calorimetry, and thermogravimetry measurements. The storage modulus of the PA6–MAV nanocomposites increased to almost twice that of the neat PA6. The thermal stability of the nanocomposites increased dramatically, and this was associated with the addition of vermiculite. The effect of the addition of maleic anhydride on the formation of the PA6–vermiculite nanocomposites was examined. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2860–2870, 2002 相似文献
3.
Synthesis and studies of thermal,mechanical and electrical properties of MWCNT–cyclodextrin as a nanoparticle in polyamide matrix based on 2,2‐Bis[4‐(4‐aminophenoxy)phenyl] propane
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In the present research, polyamide (PA) ( 6 ) was synthesized by the polycondensation reaction of 2,2‐Bis[4‐(4‐aminophenoxy)phenyl] propane as a diamine ( 4 ) with adipic acid ( 5 ) in the optimized condition. The resulting PA was characterized using Fourier transform infrared spectroscopy, Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, inherent viscosity (ηinh), X‐ray diffraction, and solubility tests. Also, the thermal property of the new PA ( 6 ) was investigated by using Thermogravimetric analysis. To apply multiwall carbon nanotube (MWCNT) as an effective reinforcement in polymer composites, it is essential to have appropriate proper dispersion, interfacial adhesion between the MWCNT and polymer matrix, and increasing solubility. With this end particularly, functionalized MWCNTs were combined with a soluble molecule, and a series of modified MWCNT with cyclodextrin (Cy) known as PA/MWCNT‐Cy composite film (2, 5, and 8 wt%) were prepared by a solution intercalation technique. Field emission scanning electron microscopy images showed that MWCNT‐Cy was well dispersed in the PA matrix. Thermogravimetric analysis indicated an increase in thermal stability of nanocomposites as compared with the pristine PA. Anisotropic structure of the synthesized films and dispersed MWCNT‐Cy in the films approved by use of X‐ray diffraction and field emission scanning electron microscopy. The resultant PA/MWCNT‐Cy composite films were electrically conductive, which is favorable for many practical uses. Measurements of mechanical properties of these composite films showed high strength in 8% MWCNT‐Cy content. Also, results showed increases in Young's modulus and tensile strength. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
4.
G. Antoniadis K. M. Paraskevopoulos D. Bikiaris K. Chrissafis 《Journal of Polymer Science.Polymer Physics》2009,47(15):1452-1466
A series of poly(ethylene terephthalate)/multi‐walled carbon nanotubes (PET/MWCNTs) nanocomposites were prepared by in situ polymerization using different amounts of multi‐walled carbon nanotubes (MWCNTs). The polymerization of poly(ethylene terephthalate) (PET) was carried out by the two‐stage melt polycondensation method. The intrinsic viscosity (IV) of the composites is ranged between 0.31 and 0.63 dL/g depending on the concentration of the MWCNTs. A decrease of IV was found by increasing MWCNTs content. This is due to the reactions taking place between the two components leading to branched and crosslinked macromolecules. These reactions are, mainly, responsible for thermal behavior of nanocomposites. The melting point of the nanocomposites was shifted to slightly higher temperatures by the addition till 0.55 wt % of MWCNTs while for higher concentration was reduced. The degree of crystallinity in all nanocomposites was, also, reduced by increasing MWCNTs amount. However, from crystallization temperature, it was found that MWCNTs till 1 wt % can enhance the crystallization rate of PET, whereas at higher content (2 wt %), the trend is the opposite due to the formation of crosslinked macromolecules. From the extended crystallization analysis, it was proved that MWCNTs act as nucleating agents for PET crystallization. Additionally, the crystallization mechanism due to the existence of MWCNT becomes more complicated because two mechanisms with different activation energies are taking place in the different degrees of crystallization, depending on the percentage of MWCNT. The effect of molecular weight also plays an important role. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1452–1466, 2009 相似文献
5.
Fangming Xiang Yunyun Shi Xiaoxi Li Ting Huang Chen Chen Ya Peng Yong Wang 《European Polymer Journal》2012,48(2):350-361
The effect of functionalized multiwalled carbon nanotubes (FMWCNTs) on the phase morphology of immiscible high density polyethylene/polyamide 6 (HDPE/PA6, 50/50) blend has been investigated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to study both the morphology variation of the nanocomposites and the selective distribution of FMWCNTs in the nanocomposites. It is clear that adding small amount of FMWCNTs (<2.0 wt.%) does not exert profound influence on the sea-island morphology of the nanocomposites. However, at moderate content of FMWCNTs (2.0 and 5.0 wt.%), a typical cocontinuous morphology is detected. Further increasing FMWCNTs content (10.0 wt.%) induces phase inversion. The crystallization behaviors of both HDPE and PA6 components were investigated by using differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD). The results show the apparent nucleation effect of FMWCNTs for PA6 crystallization due to the selective distribution of FMWCNTs in PA6 phase. Rheological measurements exhibit the presence of FMWCNTs network structure in the nanocomposites. It is suggested that the formation of the cocontinuous morphology and the novel crystallization behaviors of PA6 at high content of FMWCNTs are ascribed to the formation of the FMWCNTs network structure. 相似文献
6.
A. T. Seyhan Alejandra de la Vega M. Tanoglu K. Schulte 《Journal of Polymer Science.Polymer Physics》2009,47(15):1511-1522
This study aims to investigate the curing behavior of a vinyl ester‐polyester resin suspensions containing 0.3 wt % of multiwalled carbon nanotubes with and without amine functional groups (MWCNTs and MWCNT‐NH2). For this purpose, various analytical techniques, including Differential Scanning Calorimetry (DSC), Fourier infrared spectroscopy (FTIR), Raman Spectroscopy, and Thermo Gravimetric Analyzer (TGA) were conducted. The resin suspensions with carbon nanotubes (CNTs) were prepared via 3‐roll milling technique. DSC measurements showed that resin suspensions containing CNTs exhibited higher heat of cure (Q), besides lower activation energy (Ea) when compared with neat resin. For the sake of simplicity of interpretation, FTIR investigations were performed on neat vinyl ester resin suspensions containing the same amount of CNTs as resin. As a result, the individual fractional conversion rates of styrene and vinyl ester were interestingly found to be altered dependent on MWCNTs and MWCNT‐NH2. The findings obtained from RS measurements of the cured samples are highly proportional to those obtained from FTIR measurements. TGA measurements revealed that CNT modified nanocomposites have higher activation energy of degradation (Ed) compared with the cured polymer. The findings obtained revealed that CNTs with and without amine functional groups alter overall thermal curing response of the surrounding matrix resin, which may probably impart distinctive characteristics to mechanical behavior of the corresponding nanocomposites achieved. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1511–1522, 2009 相似文献
7.
Preparation and nonisothermal crystallization behavior of polyamide 6/montmorillonite nanocomposites
Polyamide 6 (PA6)/montmorillonite (MMT) nanocomposites were prepared via melt intercalation. The structure, mechanical properties, and nonisothermal crystallization kinetics of PA6/MMT nanocomposites were investigated by X‐ray diffraction (XRD), tensile and impact tests, and differential scanning calorimetry (DSC). Before melt compounding, MMT was treated with an organic surfactant agent. XRD traces showed that PA6 crystallizes exclusively in γ‐crystalline structure within the nanocomposites. Tensile measurements showed that the MMT additions are beneficial in improving the strength and the stiffness of PA6, at the expense of tensile ductility. Impact tests revealed that the impact strength of PA6/MMT nanocomposites tended to decrease with increasing MMT content. The nonisothermal crystallization DSC data were analyzed by Avrami, Ozawa, modified Avrami‐Ozawa, and Nedkov methods. The validity of these empirical equations on the nonisothermal crystallization process of PA6/MMT nanocomposites is discussed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2878–2891, 2004 相似文献
8.
Zhi‐Cheng Qiu Jing‐Jing Zhang Yan Zhou Bo‐Ya Song Jing‐Jing Chang Ke‐Ke Yang Yu‐Zhong Wang 《先进技术聚合物》2011,22(6):993-1000
Poly(p‐dioxanone) (PPDO)/vermiculite (VMT) nanocomposites with exfoliated structure were prepared successfully by in situ intercalative polymerization of p‐dioxanone (PDO) in the presence of organo‐modified vermiculite (OVMT) with the aid of ultrasonic action. The nano‐structure of the nanocomposites was established using X‐ray diffraction (XRD) analysis and transmission electron microscopy (TEM) observations. The investigation of crystallization behavior by differential scanning calorimetry (DSC) and polarized optical microscopy (POM) proved that exfoliated OVMT platelets acted as a template for spherulite growth. The thermal stability of nanocomposites was enhanced than that of pure PPDO. Dynamic mechanical analysis (DMA) indicated nanoscale OVMT platelets restricted the motion of PPDO segments, which benefitted the increase of storage and loss modulus. The tensile properties showed that nanocomposites were reinforced and toughened significantly by the addition of nanoscale OVMT platelets. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
9.
Structural and morphological studies on the deformation behavior of polypropylene/multi‐walled carbon nanotubes nanocomposites prepared through ultrasound‐assisted melt extrusion process
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José M. Mata‐Padilla Carlos A. Ávila‐Orta Francisco J. Medellín‐Rodríguez Ernesto Hernández‐Hernández Rosa M. Jiménez‐Barrera Víctor J. Crúz‐Delgado Janett Valdéz‐Garza Silvia G. Solís‐Rosales Adriana Torres‐Martínez Myriam Lozano‐Estrada Enrique Díaz‐Barriga Castro 《Journal of Polymer Science.Polymer Physics》2015,53(7):475-491
Structural and morphological behavior under stress–strain of polypropylene/multi‐walled carbon nanotubes (PP/MWCNTs) nanocomposites prepared through ultrasound‐assisted melt extrusion process was studied by means of optical microscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, small angle X‐ray scattering (SAXS), and wide angle X‐ray scattering (WAXS). A high ductile behavior was observed in the PP/MWCNT nanocomposites with low concentration of MWCNTs. This was related to an energy‐dissipating mechanism, achieved by the formation of an ordered PP‐CNTs interphase zone and crystal oriented structure in the undeformed samples. Different strain‐induced‐phase transformations were observed by ex situ SAXS/WAXS, characterizing the different stages of structure development during the deformation of PP and PP/MWCNTs nanocomposites. The high concentration of CNTs reduced the strain behavior of PP due to the agglomeration of nanoparticles. A structural pathway relating the deformation‐induced phase transitions and the dissipation energy mechanism in the PP/MWCNTs nanocomposites at low concentration of nanoparticles was proposed. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 475–491 相似文献
10.
Dynamically vulcanized thermoplastic vulcanizate (TPV) nanocomposites based on polyamide-6 (PA6) and acrylonitrile butadiene rubber (NBR) reinforced by halloysite nanotubes (HNT) were prepared via a direct melt mixing process. The effects of HNT on the physical, mechanical, and rheological properties of nanocomposites were investigated. The prepared PA6/NBR/HNT nanocomposites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning colorimeter (DSC), dynamic mechanical thermal analysis (DMTA), and rheological measurements. The morphology study of prepared nanocomposites shows that the introduction of HNT into the PA6 phase causes a decrease in the size of NBR droplets. The mechanical measurements revealed that Young’s modulus of TPV nanocomposites increased with the HNT loading up to 54%. DMTA results show that the introduction of 10 wt% of HNT into the PA6/NBR TPV leads to a 30% increase in storage modulus. The rheological measurements revealed that the storage modulus of nanocomposites has an increase of more than 200% in the presence of 7 wt% of HNT loading. Analytical stiffness modeling of Young’s modulus of the TPV nanocomposites was investigated using Hui–Shia and Wu models. Both models have some deviations from experimental results and been modified to predict Young’s modulus of the nanocomposites containing HNT with more precisions. The viscosity behavior of TPV nanocomposites was studied using a Carruea–Yasuda model and showed that the yield stress of nanocomposites increases with higher HNT loadings, indicating the formation of a nanotube network along with NBR phase network. 相似文献
11.
Qijie Xu Ning Zhang Wei Li Shuang Zhang Weiwei He 《Journal of polymer science. Part A, Polymer chemistry》2019,57(2):165-170
Polyamide 6/ZnO nanocomposites (noted as PA6/ZnO) were prepared by an in situ co‐producing method, during which Zn2(OH)2CO3 decomposed into nano‐ZnO in the process of the opening‐ring polymerization of caprolactam at high temperature. Transmission electron microscopy, X‐ray diffraction, thermogravimetric analysis, and differential scanning calorimetry were used to analyze the size and dispersive properties of nano‐ZnO, the crystallization and melting properties, the thermal properties, and crystal structure of PA6/ZnO composite, respectively. The results showed that the nano‐ZnO derived from Zn2(OH)2CO3 via in situ polymerization of PA6‐ZnO was uniformly dispersed in PA6 matrix. However, the overall nano‐ZnO crystallization rate and crystal size in the PA6 matrix were hindered by the bulky PA6 molecular chains. The mechanical properties were evaluated using universal tensile and impact testing instruments. The results revealed that PA6/ZnO composite with 0.2% nano‐ZnO content possessed excellent tensile strength, enhanced by 75% in comparison with the pure PA6. The nano‐ZnO had little influence on the impact strength of PA6. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 165–170 相似文献
12.
In this study, polyamide 12 (PA12)/untreated halloysite nanotubes (HNTs) nanocomposites are prepared in a semi‐industrial scale extruder using a non‐traditional “one step” water‐assisted extrusion process. A morphological study is carried out using a combination of scanning electron microscopy and transmission electron microscopy analyses to evaluate the influence of water injection and filler content on the quality of clay dispersion. The use of water injection slightly improves the nanoscale dispersion at low HNTs content (<8 wt.%), while this effect is more pronounced at higher filler loading (16 wt.%). A mechanism explaining the physico‐chemical action of water during extrusion is proposed. The materials are characterized with respect to their mechanical, thermo‐mechanical, thermal and fire properties. A strong correlation is found between nanostructure and physical properties; the more uniform dispersion of the clay nanotubes, the higher mechanical reinforcement, thermal stability and fire retardancy of PA12 nanocomposites. Tensile tests results are interpreted in terms of three mechanical models: the Halpin–Tsai's model for stiffness and the interfacial strength model and the Pukanszky's equation for yield strength. Linear fits of the experimental data confirm that the superior reinforcement of nanocomposites prepared using water injection results from improved clay dispersion and better interfacial adhesion between PA12 and HNTs. In view of these promising results, the proposed direct melt compounding method could be easily scaled‐up towards the production of PA12–HNTs nanocomposites at an industrial scale. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
13.
Hai‐ming Chen Jie Chen Li‐na Shao Jing‐hui Yang Ting Huang Nan Zhang Yong Wang 《Journal of Polymer Science.Polymer Physics》2013,51(3):183-196
Organic montmorillonite (OMMT) and the one‐dimensional functionalized multiwalled carbon nanotubes (FMWCNTs) were introduced into poly(L ‐lactide) (PLLA) to prepare PLLA/OMMT and PLLA/FMWCNT nanocomposites, respectively. The effects of nanofillers on melt crystallization and cold crystallization of PLLA were comparatively investigated by using polarized optical microcopy, differential scanning calorimetry and wide angle X‐ray diffraction. The results show that FMWCNTs exhibit higher nucleation efficiency for the melt crystallization of PLLA, whereas OMMT is the better one for the cold crystallization of PLLA. Rheological properties show that both OMMT and FMWCNTs at relatively higher concentrations can form the percolated network structure in the PLLA matrix, however, the latter nanocomposites exhibit relatively denser or more compact percolated networks. The difference of the networks between OMMT and FMWCNTs is suggested to be the main reason for the different cold crystallization behaviors observed in the PLLA/OMMT and PLLA/FMWCNT nanocomposites. The dynamic mechanical analysis measurements show that OMMT is the better one to improve the stiffness of the nanocomposites in the present work. The thermogravimetric analysis measurements show that FMWCNTs have higher efficiency in improving the thermal stability of PLLA compared with OMMT. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013 相似文献
14.
Yunyun Shi Yanli Li Fangming Xiang Ting Huang Chen Chen Ya Peng Yong Wang 《先进技术聚合物》2012,23(4):783-790
Toughening of poly( L ‐lactide) (PLLA) by elastomer attracts much attention in recent years; however, it is usually associated with the deterioration of modulus and/or strength, resulting in limitation in many applications of the material. In this work, functionalized multiwalled carbon nanotubes (FMWCNTs) were introduced into ethylene‐co‐vinyl acetate toughened PLLA blends. The effects of FMWCNTs content on crystalline structure of PLLA matrix and the morphology of the blends, as well as the selective distribution of FMWCNTs in the ternary nanocomposites were investigated using differential scanning calorimetry (DSC), wide angle X‐ray diffraction, scanning electron microscope, and transmission electron microscope. The results show that FMWCNTs exhibit excellent nucleation role in improving the cold crystallization behaviors of PLLA during the annealing and/or DSC heating processes. The results of mechanical property measurements demonstrate that the modulus, strength, and ductility of the blends can be further improved simultaneously through introducing FMWCNTs. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
15.
Tzong‐Ming Wu Shiang‐Jie Yen Erh‐Chiang Chen Ray‐Kuang Chiang 《Journal of Polymer Science.Polymer Physics》2008,46(7):727-733
This study describes the preparation of a nanocomposites fabricated from monodispersed 4‐nm iron oxide (Fe3O4) coated on the surface of carboxylic acid containing multi‐walled carbon nanotube (c‐MWCNT) and polypyrrole (PPy) by in situ chemical oxidative polymerization. High‐resolution transmission electron microscopy images and X‐ray diffraction (XRD) data indicate that the resulting Fe3O4 nanoparticles synthesized using the thermal decomposition are close to spherical dots with a particle size about 4 ± 0.2 nm. The resulting nanoparticles were further mixed with c‐MWCNT in an aqueous solution containing with anionic surfactant sodium bis(2‐ethylhexyl) sulfosuccinate to form one‐dimensional Fe3O4 coated c‐MWCNT template for further preparation of nanocomposite. Structural and morphological analysis using field‐emission scanning electron microscopy, high‐resolution transmission electron microscopy, and XRD showed that the fabricated Fe3O4 coated c‐MWCNT/PPy nanocomposites are one‐dimensional core (Fe3O4 coated c‐MWCNT)‐shell (PPy) structures. The conductivities of these Fe3O4 coated c‐MWCNT/PPy nanocomposites are about four times higher than those of pure PPy matrix. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 727–733, 2008 相似文献
16.
Adriana C. Pinheiro Adriana C. A. Casagrande Osvaldo L. Casagrande Jr. 《Journal of polymer science. Part A, Polymer chemistry》2014,52(24):3506-3512
A series of linear low‐density polyethylene (LLDPE) nanocomposites containing different types of nanofiller (TiO2, MWCNT, expanded graphite, and boehmite) were prepared by in situ polymerization using a tandem catalyst system composed of {TpMs}NiCl ( 1 ) and Cp2ZrCl2 ( 2 ), and analyzed by differential scanning calorimetry, dynamic mechanical analysis (DMA), and transmission electron microscopy (TEM). Based on these analyses, the filler content varied from 1.30 to 1.80 wt %. The melting temperatures and degree of crystallinity of the LLDPE nanocomposites were comparable to those of neat LLDPE. The presence of MWCNT as well as boehmite nucleated the LLDPE crystallization, as indicated by the increased crystallization temperature. The DMA results showed that the presence of TiO2, EG, and CAM 9080 in the LLDPE matrix yielded nanocomposites with relatively inferior mechanical properties compared to neat LLDPE, suggesting heterogeneous distribution of these nanofillers into the polymer matrix and/or the formation of nanoparticle aggregates, which was confirmed by TEM. However, substantial improvement in the storage modulus was achieved by increasing the sonication time. The highest storage modulus was obtained using MWCNT (1.30 wt %). © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3506–3512 相似文献
17.
Debdatta Ratna T. N. Abraham S. Siengchin J. Karger‐Kocsis 《Journal of Polymer Science.Polymer Physics》2009,47(12):1156-1165
A simple and novel aqueous method was elaborated to disperse multiwall carbon nanotubes (MWCNT) in a poly(ethylene oxide) (PEO) matrix using the sodium salts of suberic acid (half and fully neutralized versions, HNSA and FNSA, respectively) as the modifiers. The incorporation of HNSA significantly improved the dispersion of MWCNT in PEO as reflected in a significant increase in melt viscosity and storage modulus in rheological measurements and dynamic mechanical thermal analysis, respectively. FNSA was proved to be the less efficient in this respect. This was explained in terms of cation‐Π (between FNSA, HNSA, and electron cloud of the CNT) and H‐bonding interactions (between HNSA and PEO) in accordance with Fourier transform infrared spectroscopic results. The dielectric and crystallization behaviors of the PEO/MWCNT/salt systems were studied and discussed, as well. The advantage of this method, applicable for water soluble polymers, is that it does not fully destroy the Π electron cloud of CNT opposed to chemical functionalization techniques. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1156–1165, 2009 相似文献
18.
Thermomechanical properties and crystallization behavior of poly(ethylene terephthalate) (PET) nanocomposites containing layered double hydroxide (LDH) were investigated. To enhance the compatibility between PET matrix and LDH, dimethyl 5‐sulfoisophthalate (DMSI) anion intercalated LDH (LDH‐DMSI) was synthesized by coprecipitation method, and its structure was confirmed by Fourier transform infrared (FTIR) spectrometer and X‐ray diffraction (XRD) measurements. Then, PET nanocomposites with LDH‐DMSI content of 0, 0.5, 1.0, and 2.0 wt% were prepared by in‐situ polymerization. The dispersion morphologies were observed by transmission electron microscopy (TEM) and XRD, showing that LDH‐DMSI was exfoliated in PET matrix. Thermal and mechanical properties, such as thermal stability, tensile modulus, and tensile yield strength of nanocomposites, were enhanced by exfoliated LDH‐DMSI nanolayers. However, elongation at break was drastically decreased with LDH loading owing to the increased stiffness and microvoids. The effect of exfoliated nanolayers, which acted as a nucleating agent confirmed by differential scanning calorimeter (DSC), on the microstructural parameters during isothermal crystallization, was analyzed by synchrotron small‐angle X‐ray scattering (SAXS). It is believed that nanocomposites could be crystallized more easily owing to the increased nucleation sites, which lead to the decrease of average amorphous region size and the long period with the increase of LDH‐DMSI content. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 28–40, 2007 相似文献
19.
Genjie Jiang Hong Wu Bowen Yan Shaoyun Guo Jian Huang 《Journal of Polymer Science.Polymer Physics》2009,47(11):1112-1124
The solid‐melt interfaces between polyethylene (PE) and polyamide 6 (PA6) reinforced by in situ reactive compatibilization in a sequential two‐staged injection molding process has been studied in this work. The effects of the maleic anhydride grafted PE content and processing parameters, such as injection pressure, injection speed, melt temperature, and mold temperature, on the interfacial adhesion were investigated experimentally. The results of the interfacial adhesion characterized by lap shear measurement showed that the interfacial temperature and heat transfer between PE and PA6 interfaces play a very significant role in the bonding process. The fracture surfaces of the specimens prepared at different calculated interfacial temperature were investigated by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), which suggested that the fracture failure changes from adhesive to cohesive failure with increasing interfacial temperature. The contribution of crystalline parts of the in situ formed copolymers to the enhancement in interfacial adhesion also was determined by DSC analysis. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1112–1124, 2009 相似文献
20.
Surface modification of MWCNTs with glucose and their utilization for the production of environmentally friendly nanocomposites using biodegradable poly(amide‐imide) based on N‐trimellitylimido‐S‐valine matrix
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In the present investigation, the preparation, characterization, and surface morphology of poly(amide‐imide) (PAI)/multi‐walled carbon nanotubes (MWCNTs) bionanocomposites (BNCs) were the main goals of the study. At first, an optically active PAI based on S‐valine as a biodegradable segment was synthesized. Then, carboxyl‐modified MWCNTs were functionalized with glucose (f‐MWCNT) as a biological active molecule in a green method to achieve a fine dispersion of f‐MWCNT bundles in the PAI matrix. The existence of S‐valine in the PAI matrix and functionalized MWCNT with glucose resulted in a series of potentially biodegradable nanocomposites. The obtained BNCs were characterized by various techniques. Field emission scanning and transmission electron microscopy micrographs of the composites showed a fine dispersion of f‐MWCNTs in the polymer matrix because of hydrogen bonding and π–π stacking interaction between f‐MWCNTs and polymer functional groups and aromatic moieties. Adding f‐MWCNTs into polymer matrix significantly improved the thermal stability of BNCs because of the increased interfacial interaction between the PAI matrix and f‐MWCNTs and also good dispersion of f‐MWCNT in the polymer matrix. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献