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1.
Poly(lactic acid)/halloysite nanotube (PLA/HNT) nanocomposites were prepared using melt compounding followed by compression molding. Epoxidized natural rubber (ENR) was used to toughen the PLA nanocomposites. The properties of PLA/HNT nanocomposites were characterized by impact tests, thermal analysis (DSC), morphological analysis (FESEM, TEM), and Fourier transform infrared spectroscopy (FTIR). Water absorption tests were performed at three immersion temperature (30, 40, 50°C). The maximum water absorption (Mm), diffusion coefficient (D), and the activation energy of water diffusion (Ea) were determined. The impact strength of PLA/HNT6 nanocomposites was increased significantly to ~296% by the addition of 15 wt % ENR. The incorporation of HNT and ENR increase its nucleation effect and assist in the crystallization process of PLA. The HNT has good affinity with PLA and ENR, which was revealed by TEM and FTIR. The Mm of PLA was increased in the presence of HNT and ENR. Nevertheless, the D value and the Ea of the PLA nanocomposites were found to be affected by the HNT and ENR contents. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42850.  相似文献   

2.
Jinbo Li 《Polymer Bulletin》2006,56(4-5):377-384
Summary Epoxy resin/polyurethane interpenetrating polymer network nanocomposites with various contents of organophilic montmorillonite (oM-EP/PU nanocomposites) were prepared by a sequential polymeric technique and an in situ intercalation method. X-ray diffraction(XRD), and transmission electronic microscopy(TEM) analysis showed that organophilic montmorillonite (oMMT) disperses uniformly in epoxy resin/polyurethane interpenetrating networks(IPNs), and the intercalated or exfoliated microstructures of oMMT are formed. Differential scanning calorimetry(DSC) test proved that oMMT promotes the compatibility of EP phase and PU phase, and glass transition temperature(Tg) of oM-EP/PU nanocomposites improves with increasing oMMT content. Mechanical properties tests and thermal gravity analysis (TGA) indicated that oMMT and the IPNs of EP and PU exhibit synergistic effect on improving mechanical and thermal properties of pure EP. The mechanism of toughing and reinforcing of oM-EP/PU nanocomposites was further discussed by scanning electronic microscope(SEM).  相似文献   

3.
This investigation reports preparation of polyurethane and polyurethane/clay nanocomposites based on polyethylene glycol, isophorone diisocyanate (IPDI), an aliphatic diisocyanate and 1,4‐ Butanediol as chain extender by solution polymerization. In this case PU/clay nanocomposites were prepared via ex‐situ method using 1, 3, and 5 wt % of Cloisite 30B. Thermogravimetric analysis showed that the maximum decomposition temperature (Tmax) of the PU/clay nanocomposite is much higher than the pristine PU. The tensile properties improved upon increasing the organoclay (Cloisite 30B) content upto 3 wt %, and then decreased to some extent upon further increasing the nanoparticle loading to 5 wt %. Optical properties of the nanocomposites were studied by UV‐vis spectrophotometer. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) were used to study the morphology of the nanocomposites. It was observed that with the incorporation of 3 wt % nanoclay the crystallinity in PU nanocomposite increases, then diminishes with further loading. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3328–3334, 2013  相似文献   

4.
Poly(N‐methylpyrrole) (PNMPy), poly(N‐methylpyrrole‐TiO2) (PNMPy‐TiO2), and poly (N‐methylpyrrole‐ZnO) (PNMPy‐ZnO) nanocomposites were synthesized by in situ electropolymerization for cathode active material of lithium secondary batteries. The charge–discharging behavior of a Li/LiClO4/PNMPy battery was studied and compared with Li/LiClO4/PNMPy‐nanocomposite batteries. The nanocomposites and PNMPy films were characterized by cyclic voltammetry, in situ resistivity measurements, in situ UV–visible, and Fourier transform infra‐red (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The differences between redox couples (ΔE) were obtained for polymer nanocomposites and PNMPy films. During redox scan, a negative shift of potential was observed for polymer nanocomposite films. Significant differences from in situ resistivity of nanocomposites and PNMPy films were obtained. The in situ UV–visible spectra for PNMPy and polymer nanocomposite films show the intermediate spectroscopic behavior between polymer nanocomposites and PNMPy films. The FTIR peaks of polymer nanocomposite films were found to shift to higher wavelengths in PNMPy films. The SEM and TEM micrographs of nanocomposite films show the presence of nanoparticle in PNMPy backbone clearly. The result suggests that the inorganic semiconductor particles were incorporated in organic conducting PNMPy, which consequently modifies the properties and morphology of the film significantly. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41526.  相似文献   

5.
organoclay‐modified polyurethane/epoxy interpenetrating network nanocomposites (oM‐PU/EP nanocomposites) were prepared by adding organophilic montmorillonite (oMMT) to interpenetrating polymer networks (IPNs) of polyurethane and epoxy resin (PU/EP) which had been prepared by a sequential polymerization technique. Wide‐angle X‐ray diffraction (WAXD) and transmission electronic microscopy (TEM) analysis showed that the interpenetrating process of PU and EP improved the exfoliation and dispersion degree of oMMT. The effects of the NCO/OH ratio (isocyanate index), the weight ratio of PU/EP and oMMT content on the phase structure and the mechanical properties of the oM‐PU/EP nanocomposites were studied by tensile testing and scanning electronic microscopy (SEM). Water absorption tests showed that the PU/EP interpenetrating networks and oMMT had synergistic effects on improvement in the water resistance of the oM‐PU/EP nanocomposites. Differential scanning calorimetry (DSC) analysis showed that PU was compatible with EP and that the glass transition temperature (Tg) of the oM‐PU/EP nanocomposites increased with the oMMT content up to 3 wt%, and then decreased with further increasing oMMT content. The thermal stability of these nanocomposites with various oMMT contents was studied by thermogravimetric analysis (TGA), and the mechanism of thermal stability improvement was discussed according to the experimental results. Copyright © 2005 Society of Chemical Industry  相似文献   

6.
In situ filling of nanomaterials into polymers facilitates the dispersion of the nanofillers and their interface combination with the matrices, and reduces the agglomeration encountered in the nanocomposites prepared by a mechanical mixing method. Polytetrafluoroethylene (PTFE) nanocomposites filled with SiO2 nanospheres (SNS) were fabricated by an in situ sol–gel method in this paper. The SNS in situ filled was highly dispersed in PTFE and showed an excellent combination with the matrix, and the fabricated SNS/PTFE nanocomposites were found a pronounced improvement in stiffness, hardness, glass transition temperature, and hydrophobicity in comparison with the pristine PTFE and the ones prepared by mechanical mixing with the same content. Furthermore, significantly reduced coefficients of friction and volume wear rates were observed on the SNS/PTFE nanocomposites prepared by in situ sol–gel. An operating temperature high up to 200°C and very low volume wear rate were accessible on the optimized SNS/PTFE nanocomposite by in situ filling. The methodology, in situ filling of nanofillers into matrices, might pave a way to prepare nanocomposites with excellent mechanical, thermal, and tribological properties.  相似文献   

7.
Polyurethane/modified chitosan-Fe3O4 (PU/mCS-Fe3O4) nanocomposites were prepared by incorporating chitosan-Fe3O4 (CS-Fe3O4) into PU through chemical grafting using isophorone diisocyante (IPDI). The isocyanate group of IPDI was introduced on the surface of CS-Fe3O4 nanocomposites. The chemical functionalities of the CS-Fe3O4 and mCS-Fe3O4 were verified by Fourier-transform infrared and X-ray diffraction. The structure and properties were confirmed by scanning electron microscope, vibrating sample magnetometer, thermogravimetric analysis, atomic force microscope, and tensile testing. The experimental results indicate that thermal stability, tensile strength, and storage modulus of nanocomposites were improved with the increasing content of mCS-Fe3O4. Meanwhile, PU/mCS-Fe3O4 nanocomposites have less cytotoxicity and good antibacterial activities againstEscherichia coli and Staphylococcus aureus.  相似文献   

8.
《Polymer Composites》2017,38(2):396-403
A cationic gemini surfactant (N‐isopropyl‐N , N‐dimethyldodecan 1‐aminium bromide) was synthesized by quaternization reaction. The synthesized surfactant was characterized by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. Modified Na–bentonite (organoclay) was obtained by the intercalation of a gemini surfactant between the layers of sodium bentonite and characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), FTIR, thermogravimetry–differential thermal analysis (TGA–DTA) and differential scanning calorimetry (DSC) techniques. The results of XRD, TEM, FTIR, TGA, and corresponding DSC analysis indicate that gemini surfactant has been successfully intercalated into the clay layers. Rubber‐based nanocomposites have been prepared by incorporating various concentration of organically modified bentonite on to natural rubber/styrene–butadiene rubber (NR/SBR) rubber blend (75/25) using two roll mill. Effect of organoclay content on XRD, curing, mechanical, and scanning electron microscopy (SEM) properties of the nanocomposites are investigated. The morphological study showed the intercalation of nanoclay in NR/SBR blend chain. It was found that the organoclay decrease the optimum and scorch time of the curing reaction, increase maximum torque and the curing rate, which was attributed to the further intercalation during vulcanization process. Mechanical properties such as tensile strength, modulus and elongation at break have improved. POLYM. COMPOS., 38:396–403, 2017. © 2015 Society of Plastics Engineers  相似文献   

9.
Poly(ethyl methacrylate) (PEMA) and poly(2‐hydroxyethyl methacrylate) (PHEMA) nanocomposites with sepiolite in pristine and silylated form were prepared using the solution intercalation method and characterized by the measurements of XRD, TEM, FTIR‐ATR, TG/DTG, and DSC. The TEM analysis indicated that the volume fraction of fibers in sepiolite decreased and the fiber bundles dispersed in PEMA and PHEMA at a nanometer scale. These results regarding TEM micrographs were in agreement with the data obtained by XRD. The increase in thermal stability of nanocomposites of PEMA is higher than that of PHEMA according to the data obtained from TG curves. The DTG analysis revealed that sepiolite/modified sepiolite caused some changes, as confirmed by FTIR in the thermal degradation mechanism of the polymers. Tg temperatures of PEMA and PHEMA usually increased upon the addition of sepiolite/modified sepiolite. In addition, modification of sepiolite with 3‐APTS had a slight influence on thermal properties of the nanocomposites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers  相似文献   

10.
Poly(tetrafluoroethylene) (PTFE) powder was irradiated with 60Co γ-rays to improve its dispersing ability in polyurethane (PU) as a binder. The bonded solid lubricant films of the irradiated PTFE were prepared on an AISI 1045 steel block by spraying and curing at ambient temperature, with PU as the binder. The tribological properties of bonded solid lubricant films with the PTFE pigment volume fraction were examined on a ring-on-block friction and wear tester. The interfacial adhesion between the PU binder and PTFE powder was investigated using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), immersion heat, and X-ray photoelectron spectroscopy (XPS). It was found that γ-ray irradiation increases the activity of the PTFE powder surface and improves the interfacial adhesion between the PTFE powder and the PU binder, which is helpful for improving the wear resistance of the corresponding bonded solid lubricant films.  相似文献   

11.
This study examined the dynamic mechanical properties of sisal fiber reinforced unsaturated polyester (UP) toughened epoxy nanocomposites. The chemical structures changes in Epoxy, UP and UP toughened epoxy (Epoxy/UP) systems were characterized by Proton Nuclear magnetic resonance (1HNMR) spectroscopy. The morphological alterations of the nanocomposites were analyzed by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The untreated, chemically treated fibers, nanoclays, and the fiber reinforced Epoxy/UP nanocomposites were confirmed by FTIR spectrometer. The obtained mechanical results showed that alkali‐silane treated fibers improve the tensile strength (96%) and flexural strength (60%) of the Epoxy/UP nanocomposite than that of Epoxy/UP blend due to the strong interfacial bonding between the sisal fiber and matrix. The fracture toughness (KIC) and fracture energy (GIC) of treated sisal fiber reinforced DGEBA/UP/C30B nanocomposites found to be higher than that of untreated sisal fiber nanocomposites. The dynamic mechanical analysis (DMA) reveals that the fiber reinforced Epoxy/UP nanocomposites contains 30 wt% treated fiber and 1 wt% nanoclays, exhibits the highest storage modulus and better glass transition temperature (Tg) among the other kind of systems. The surface morphology of the fibers, fractured surface of the resins and composites were confirmed by scanning electron microscope (SEM). POLYM. COMPOS., 37:2832–2846, 2016. © 2015 Society of Plastics Engineers  相似文献   

12.
A mixture of two different polyols, (polytetramethylene ether glycol and polydimethylsiloxane), were employed to synthesize a new structure of polyurethane (PU) with methylene diphenyl diisocyanate (MDI) and 1,4‐butanediol as chain extender. PU nanocomposites containing variable amount (0.3, 0.5, 1, and 3 wt %) of amino‐grafted multiwalled carbon nanotubes (NH2‐MWNT) were prepared via in situ polymerization. The dispersion of NH2‐MWNT into polymer matrix was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fourier transform infrared spectroscopy (FT‐IR) confirmed the urethane‐urea chemical bonding between the PU chains and the NH2‐MWNT. Thermal stabilities of the nanocomposites were examined with thermogravimetric analysis (TGA) and the results indicated a remarkable improvement with increasing NH2‐MWNT contents. The results of dynamic mechanical thermal analysis (DMTA) including storage modulus (E′) and glass transition temperature (Tg), as well as tensile properties demonstrated that the yield strength, strain‐at‐break, and young modulus were enhanced by increasing NH2‐MWNT content. Rheological behavior including complex viscosity and storage and loss moduli of the PU nanocomposites improved with increasing NH2‐MWNT loading, as well. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44411.  相似文献   

13.
New synthetic Ni‐talc was used as filler in the synthesis of polyurethane (PU) nanocomposites by in situ polymerization and to emphasize the contribution of the new material compared with natural talc. Good dispersion of Ni‐talc was supported by homogeneous green coloration observed in the polymer matrix. X‐ray diffraction (XRD) analyses indicate the intercalation of polymeric matrix into the filler layers by the increase in d001‐spacing value of the Ni‐talc for the nanocomposites when compared to the pristine filler. The nanocomposites obtained with synthetic talc showed an improvement in the crystallization temperature and in thermal stability when compared to pure PU and the composite obtained with natural talc. The young modulus of PU/talc materials containing both Ni‐talc and natural talc were slight higher than pure PU. As shown by scanning electron microscope (SEM), Ni‐talc fillers were well dispersed into the polymeric matrix probably due to the good compatibility of both phases filler/polymer mainly achieved by the filler OH interaction with the urethane group of the polymeric chain. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41854.  相似文献   

14.
The polyurethane/C16C18‐MMT (the montmorillonite modified with cetyloctadecyldimethyl ammonium bromide) nanocomposites were synthesized by intercalative polymerization and cured under room temperature. The d‐spacing and the dispersion of the C16C18‐MMT in the nanocomposites were measured by X‐ray Diffraction (XRD) and Transmission Electron Microscope (TEM). The mechanical and thermal properties of the nanocomposites were measured by Universal Testing System, Electric Anti‐fold Instrument, Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC). It was found out that introducing C16C18‐montmorillonite (MMT) in the polyurethane (PU) displayed good mechanical properties and thermal stability. Rheology behavior in liquid state showed that the addition of the C16C18‐MMT to PU resulted in low gel time and high viscosity. POLYM. COMPOS. 27:470–474, 2006. © 2006 Society of Plastics Engineers.  相似文献   

15.
A new kind of intermediate hybrid nanocomposites (NCs) composed of poly(amic acid) (PAA) and surface modified ceria nanoparticles (NP)s had been prepared by sonochemical assisted synthesis. The PAA containing pendent benzamide units had been synthesized by the reaction of 3,5‐diamino‐N‐(4‐hydroxyphenyl) benzamide and benzene‐1,2,4,5‐tetracarboxylic dianhydride through polycondensation reaction. The structure of the prepared PAA was studied by spectroscopic techniques. The surface modifications of ceria NPs were achieved by using hexadecyltrimethoxysilane. Results of FTIR analysis demonstrated that the aliphatic chains have been covalently bonded to the surface of the CeO2 NPs. PAA/CeO2 NCs with different contents including 4, 8, and 12 wt% of CeO2 NPs was prepared by using sonochemical method. Characterization with FTIR, powder X‐ray diffraction, field emission scanning electron microscopy (FE‐SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) confirmed the success in synthesis of NCs with well dispersion properties. XRD analysis results showed that the obtained NCs displayed the crystalline nature of ceria NPs and the amorphous character of PAA matrix. The particles size of ceria NPs in NCs are about 50–70 nm as characterized by FE‐SEM, TEM, and AFM analyses. This work demonstrates the application of intermediates as new matrices for preparation of hybrid nanostructures. POLYM. ENG. SCI., 55:2339–2348, 2015. © 2015 Society of Plastics Engineers  相似文献   

16.
In this study, polyurethane (PU) was synthesized using 4,4,-diphenylmethane diisocyanate (MDI) as a hard segment, polycaprolactone diol (PCL) as the soft segments and 1,4-butandiol (1,4-BD) as a chain extender. Nanosilver/graphene (Ag/G) was added to the PU matrix to prepare Ag/G/PU nanocomposites. EDS, SEM and XRD are used for assaying the silver content and characterization of Ag/G. TEM, FT-IR, XRD and EDS were used to characterize the structure and morphology of the Ag/G/PUs nanocomposites. The TEM results show that Ag/G belongs to sheet structures and is dispersed in a PU matrix. The SEM showed that the strong interfacial adhesion between the Ag/G and PU is indicated. FT-IR spectra analysis shows that the functional group of PU is free of obvious changes by adding a small amount of Ag/G in the PU matrix. XRD results showed that the main crystalline peak (26°) of Ag/G became more apparent with increasing content of Ag/G, and EDS showed that the content of Ag increased with increasing content of Ag/G in the Ag/G/PUs nanocomposites. The thermal stability and mechanical properties of Ag/G/PUs nanocomposites are improved with increasing content of Ag/G. Contact angle and AFM results showed that the hydrophobicity and surface roughness increased with increasing content of Ag/G. Moreover, the Ag/G/PUs nanocomposites exhibit antibacterial activities toward Staphylococcus aureus as well as Escherichia coli and their antibacterial rates increase with increasing Ag/G. In addition, the electrical conductivity measurements showed that both surface and volume resistance of the Ag/G/PUs nanocomposites decreased as the amount of Ag/G increased.  相似文献   

17.
In the present work, polypyrrole (PPy) nanocomposites were synthesized using ferric chloride (FeCl3) as an oxidant by in situ polymerization at room temperature. Cadmium sulfide (CdS) nanoparticles were synthesized by ultrasonication technique with size ranging between 60 and 110 nm. The PPy/CdS nanocomposites were prepared by taking 1–3 wt % loading of CdS to measure the electrical conductivity. The PPy nanocomposites were characterized by using FTIR, X‐ray diffraction, UV, and SEM. Furthermore, these PPy/CdS nanocomposites were investigated to study their effect of electrical properties on gas sensitivity of ammonia and LPG. The nanocomposites showed improvement in conductivity and sensing response toward 250 ppm NH3 was found to be maximum (4.2) compared with 100 and 500 ppm NH3 gas, whereas in the case of LPG, it showed sensitive response. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42379.  相似文献   

18.
Polylactide (PLA)/graphene nanocomposites were prepared by a facile and low‐cost method of solution‐blending of PLA with liquid‐phase exfoliated graphene using chloroform as a mutual solvent. Transmission electron microscopy (TEM) was used to observe the structure and morphology of the exfoliated graphene. The dispersion of graphene in PLA matrix was examined by scanning electron microscope, X‐ray diffraction, and TEM. FTIR spectrum and the relatively low ID/IG ratio in Raman spectroscopy indicate that the structure of graphene sheets (GSs) is intact and can act as good reinforcement fillers in PLA matrix. Thermogravimetric analysis and dynamic mechanical analysis reveal that the addition of GSs greatly improves the thermal stability of PLA/GSs nanocomposites. Moreover, tensile strength of PLA/GSs nanocomposites is much higher than that of PLA homopolymer, increasing from 36.64 (pure PLA) up to 51.14 MPa (PLA/GSs‐1.0). POLYM. COMPOS., 35:396–403, 2014. © 2013 Society of Plastics Engineers  相似文献   

19.
A new reactive polyurethane/polyacrylate (PU/PA) blend was developed by mixing a core–shell polyacrylate latex containing keto groups in shell layer and a polyurethane dispersion incorporating multiple hydrazide groups which was synthesized by introducing the poly‐hydrazide groups into the end of the vinyl‐terminated polyurethane chains. Fourier transform infrared (FTIR) spectroscopy and gel permeation chromatography (GPC) results indicated that poly‐hydrazide groups had been incorporated in the polyurethane chains. Transmission electron microscopy (TEM) micrograph revealed that polyacrylate particles had a clear core–shell structure. The results of FTIR, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) indicated that the crosslinking reaction between two polymer systems had happened and crosslinking structure could effectively improve the compatibility between PA and PU. Thermogravimetric analysis (TGA) and mechanical tests results suggested that crosslinking structure could enhance the thermal stability and mechanical properties of blends. The influence of the PA content and the n(? CO? )/n(? NHNH2) ratio on the hardness, water resistance, solvent resistance, and gel fraction of the blend films were comprehensively studied. The optimal PA content and n(? CO? )/n(? NHNH2) ratio was 30% and 1.5:1 in this experiment, respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44443.  相似文献   

20.
The purpose of this study was to investigate the effect of bare wollastonite (BW) and modified wollastonite (MW) nano‐rods into the styrene butadiene rubber (SBR). SBR nanocomposites were prepared by the incorporation of different wt % (0.3–4.5) of BW and MW nanorods. All nanocomposites were characterized by thermal gravimetric analyzer (TGA) and differential scanning calorimeter (DSC). The particle size and morphology of BW and MW nanorods were characterized by field‐emission scanning electron microscope (FE‐SEM), transmission electron microscope (TEM), and Fourier transform infrared (FTIR) spectrophotometer, while FE‐SEM and AFM analyses were performed for BW/SBR and MW/SBR nanocomposites. The obtained results revealed the existence of stronger interaction between the SBR and MW nanorods into MW/SBR as compared to BW/SBR nanocomposites. FE‐SEM and AFM images showed a perfect dispersion of the MW nanorods in SBR matrix at 3 wt % loading. Thermal stability of MW/SBR nanocomposites was also increased significantly by the addition of MW nanorods. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42811.  相似文献   

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