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1.
Rutile‐type titanium dioxide (TiO2) nanorods were prepared, superficially modified and tested for the protection of polypropylene (PP) from the UVB and UVC irradiations. The silica coating blocked the active sites on the nanorods and the following calcination further reduced the amount of surface hydroxyl groups and thus, made the TiO2 nanorods more efficient against the photodegradation. Compared with spherical TiO2 nanoparticles, the calcined silica‐coated TiO2 nanorods demonstrated good photostabilization efficiency due to the excellent shielding effect and the improved dispersion of the nanoparticles in PP matrix. When used in combination with the conventional hindered amine light stabilizer (HALS), CHIMASSORB® 944, the surface modified TiO2 nanorods revealed strong synergistic effect during the photo‐oxidation of the PP composites. The capacity of photostabilization was much higher than the combination with the commercial spherical TiO2 nanoparticles and even higher than the typical HALS photostabilization system containing hindered phenol TINUVIN® 328. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40601.  相似文献   

2.
In the present study, sol–gel synthesized alumina (Al2O3) nanoparticles were characterized by Fourier transform infrared spectra, X‐ray diffraction, field‐emission scanning electron microscopy. Then, Al2O3 nanoparticles were employed to improve cure, mechanical, and thermal properties of maleated natural rubber (MNR) nanocomposites. The MNR nanocomposite with 2 phr nano Al2O3 exhibited excellent value of cure rate index and exceptionally high value of mechanical properties like modulus and tensile strength in comparison to unfilled MNR compound. Thermogravimetric analysis indicated that nano Al2O3 was able to improve the thermal stability of MNR composites to some extent. Additionally, the present study revealed that the interfacial interaction between MNR and nano Al2O3 was far better than that between NR and nano Al2O3 as confirmed from crosslinking degree measurement and morphological analysis. The present article offers a fresh approach to prepare high performance nano Al2O3‐based MNR compounds for future industrial application. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46248.  相似文献   

3.
Ternary composite films of poly(vinyl alcohol) (PVA), boric acid (BA), and detonation nanodiamond (DND) were prepared by aqueous solution method. Because of its excellent mechanical/thermal properties and low friction coefficient, DND is expected to offer PVA film superior performance if the puzzles of particle agglomeration in polymer matrix and fragile interface reaction between DND and PVA can be settled. BA was used as a crosslinking agent to form a strong network structure between DND and PVA. Investigation on microstructure of PVA/BA/DND films and bonding mechanisms therein shows that BA, DND, and PVA may crosslink by oxo‐bridges owing to the interaction of hydroxyl groups. The Young's modulus (E) of composite films was enhanced by nearly 3.3 times with only 0.8 wt % DND loading, and the antiwear, thermal stability, and waterproof properties can be significantly improved after the crosslinking. Meanwhile, the transparency of composite films can be well preserved even with large DND content. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45449.  相似文献   

4.
In this article, the effects of different silane coupling agents: 3‐glycidyloxypropyltrimethoxysilane (GOTMS), 3‐aminopropyltriethoxysilane (APTES), and 3‐methacryloxypropyltrimethoxysilane (MPTS), on the interface between polyimide (PI) and silica (SiO2), were investigated using molecular dynamic simulation. The results indicate that binding energy between PI molecules and SiO2 surface mainly comes from van der Waals interaction. Proper silane coupling agents generate a thin membrane on the surface of SiO2, which improves the thickness of the transition layer between PI molecules and SiO2 surface. And density of the transition layer was enhanced by APTES significantly. In addition, amino group (? NH2) improves the electrostatic interaction between PI molecules and SiO2 surface rather than epoxy group (? CH? CH2? O) and methacrylic oxide group (? O? CO? C(CH3)?CH2). As a result, APTES enhances the binding energy effectively. However, excessive silane coupling agent increases the distance between PI matrices and SiO2, which deteriorates performance of the interface. In addition, GOTMS and MPTS generate a thick and dense membrane on SiO2 surface, which induces the loose transition layer and poor binding energy. Overlap parameter between PI molecules and SiO2 surface grafted with silane coupling agent can be employed to evaluate the transition layer successfully. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45725.  相似文献   

5.
We have prepared a novel kind of magnetic nanoparticle with high adsorption capacity and good selectivity for Pb2+ ions by modifying the magnetic nanoparticles with polyvinyl alcohol (PVA) and thiourea. The resultant magnetic nanoparticles were used to adsorb Pb2+ ions from aqueous solution. The influence of the solution pH, the adsorption time, the adsorption temperature, coexisting ions, and the initial concentration of Pb2+ ions on the adsorption of Pb2+ ions were investigated. The results indicated that Pb2+ ions adsorption was an endothermic reaction, and adsorption equilibrium was achieved within 30 min. The optimal pH for the adsorption of Pb2+ ions was pH 5.5, and the maximum adsorption capacity of Pb2+ ions was found to be 220 mg/g. Moreover, the coexisting cations such as Ca2+, Co2+, and Ni2+ had little effect on adsorption of Pb2+ ions. The regeneration studies showed that thiourea functionalized PVA‐coated magnetic nanoparticles could be reused for the adsorption of Pb2+ ions from aqueous solutions over five cycles without remarkable change in the adsorption capacity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40777.  相似文献   

6.
Illite particles were exfoliated by the intercalation and subsequent deintercalation of dimethyl sulfoxide (DMSO) in the interlayer of illite, and the exfoliated illite particles were used to prepare a novel poly(ethylene oxide) (PEO)–illite nanocomposite. The resulting exfoliated illite and PEO–illite nanocomposites were characterized by X‐ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry, ion conductivity testing, thermogravimetry analysis, and mechanical testing. The XRD results showed that the acid treatment of illite to exchange K+ in the interlayer of illite with H+ was a necessary condition for the DMSO intercalation. SEM micrographs confirmed the exfoliation of the illite particles in the process of DMSO deintercalation from the interlayer of the illite–DMSO intercalation complex. A good dispersion of exfoliated illite in the PEO matrix was also confirmed. A gradual decrease in the PEO crystallinity in the PEO–illite nanocomposites was observed with increasing exfoliated illite concentration. The ion conductivity of the nanocomposites gradually increased with the filler content and reached 3.21 × 10−5 S/cm at an illite concentration of 20 wt %. The formation of an amorphous region around the exfoliated illite was beneficial for Li+‐ion conduction. The ion conductivity significantly increased when the amorphous regions were connected to each other to form a conducting path for Li+ ions with a high filler concentration of greater than 10 wt %. Meanwhile, the thermooxidative stability and mechanical properties of the PEO–illite nanocomposites were also enhanced when exfoliated illite was introduced into the polymer matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44226.  相似文献   

7.
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   

8.
In this study, N‐doping porous carbons (NPCs) with a 3D aperiodic hierarchical and layered structure were prepared by the sodium hydride (NaOH) activation of graphite nanofibers (GNFs)/polypyrrole (PPY) composites. The effects of the N groups and structural features on the CO2 adsorption capacity of NPCs were investigated by N2 full isotherms, XRD, SEM, and TEM. The CO2 adsorption capacity was measured by the CO2 isothermal adsorption at 25°C and 1 atm. It was found that GNFs served as a substrate and layered graphitic carbons were formed by the thermal annealing of PPY. The content of N groups and textural properties of NPCs were enhanced with increasing activation temperature, resulting in improved CO2 adsorption capacity. The CO2 adsorption isotherms showed that GPK‐600 exhibited the best CO2 adsorption capacity of 88.8 mg/g when the activation temperature was 600°C. The result indicates that the pore size and its distribution of NPCs lead to feasible contact CO2, and the presence of high N groups on the NPCs could have resulted in further stabilization of the surface effect. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40517.  相似文献   

9.
With an aim to develop injectable hydrogel with improved solution stability and enhanced bone repair function, thermogelling poly(ε‐caprolactone‐cop‐dioxanone)‐poly(ethylene glycol)‐poly(ε‐caprolactone–cop‐dioxanone) (PECP)/bioactive inorganic particle nanocomposites were successfully prepared by blending the triblock copolymer (PECP) with nano‐hydroxyapatite (n‐HA) or nano‐calcium carbonate (n‐CaCO3). The hydrogel nanocomposites underwent clear sol–gel transitions with increasing temperature from 0 to 50°C. The obtained hydrogel nanocomposites were investigated by 1H NMR, FT‐IR, TEM, and DSC. It was found that the incorporation of inorganic nanoparticles into PECP matrix would lead to the critical gelation temperature (CGT) shifting to lower values compared with the pure PECP hydrogel. The CGT of the hydrogel nanocomposites could be effectively controlled by adjusting PECP concentration or the content of inorganic nanoparticles. The SEM results showed that the interconnected porous structures of hydrogel nanocomposites were potentially useful as injectable scaffolds. In addition, due to the relatively low crystallinity of PECP triblock copolymer, the aqueous solutions of the nanocomposites could be stored at low temperature (5°C) without crystallization for several days, which would facilitate the practical applications. The PECP/bioactive inorganic particle hydrogel nanocomposites are expected to be promising injectable tissue engineering materials for bone repair applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

10.
The known Tandon‐Weng model originated from Mori–Tanaka theory commonly underestimates the Young's modulus of polymer nanocomposites containing spherical nanofillers. This phenomenon is attributed to disregarding the nanoscale interfacial interaction between polymer and nanoparticles, which forms a different phase as interphase in polymer nanocomposites. In this paper, the simplified Tandon‐Weng model is developed assuming interphase and the predictions of the developed model are compared with the experimental data. The calculations of the developed model completely agree with the experimental results at reasonable levels of interphase properties. Additionally, the effects of main material and interphase properties on the predictions of modulus are evaluated. The developed model predicts that a high‐content, thick, and strong interphase creates a high modulus in polymer nanocomposites. These logical observations demonstrate the correctness of the developed model for Young's modulus of polymer nanocomposites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43816.  相似文献   

11.
Thin flexible double‐layer microwave absorbers have been fabricated based on polypyrrole (PP)/natural rubber (NR) nanocomposites and their reflection loss characteristics were studied in the range of 8–18 GHz. The PP‐NR matrix was prepared from PP and NR in the ratio of 15:85. The polymers used in this work not only serve as the matrix but also improve the microwave absorption properties. The first layer or impedance matching layer which is comprised of graphite, Fe3O4, and TiO2 nanoparticles in PP‐NR transmits the electromagnetic (EM) wave without reflection. The second layer which is made up of PP‐NR filled with Fe3O4 disperses the EM wave energy. The design of a double‐layer nanocomposite is a method to match the wave impedance, enhance wave absorption ability, and broaden the absorption frequencies. In order to achieve high absorption properties, the EM parameters such as permittivity, permeability, and thickness were controlled precisely according to quarter‐wave plate. The morphology, absorption properties, scattering parameters, thermal and wetting characteristics of double‐layer nanocomposites were investigated. The minimum reflection loss (RL) was ?32 dB at 12.1 GHz and the absorbing bandwidth in which the RL < ?10 dB was 9 GHz for optimum specimen with 2 mm thickness. For this specimen, the contact angle was equal to 118.7° with water as the liquid. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46565.  相似文献   

12.
In this research, we contributed to the search for potential hydrogel–silver dressings by generating hydrogel–silver nanoparticles (AgNPs) composites prepared by the dipping of the crosslinked hydrogel poly(N‐vinylpyrrolidone‐co‐2‐acrylamido‐2‐methylpropanesulfonate sodium) (1:1) and poly(acrylamide‐co‐2‐acrylamido‐2‐methylpropanesulfonate sodium) (1:1) into an aqueous suspension of citrate‐stabilized AgNPs. The composites obtained were evaluated by an antibacterial activity assay on Staphylococcus aureus and Escherichia coli and subjected to an in vitro cytotoxicity assay for human fibroblasts. The composite formed from the hydrogel poly(N‐vinylpyrrolidone‐co‐2‐acrylamido‐2‐methylpropanesulfonate sodium) with 3 mol % N,N‐methylene bisacrylamide showed the highest antibacterial activity and the least cytotoxicity among the composites tested; this makes it an excellent alternative as a potential dressing for the treatment of deep and exudative wounds. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39644.  相似文献   

13.
In this work, carbon nanotubes (CNT) properties and interphase depth define the interphase conductivity in polymer CNT nanocomposites (PCNT). In addition, the operative CNT length and volume portion are linked to the conductivity transportation between CNT and insulated polymer medium to propose a simple model for conductivity. The significances of various terms on the interphase conductivity and conductivity of PCNT are justified and the model's predictions are examined using the experimental outputs of certain examples. Thin CNT and dense interphase obtain the extraordinary conductivity transportation, while CNT length and conductivity are ineffective. Moreover, thin, small, and high-conductive CNT as well as dense interphase introduce the high interphase conductivity. The estimations of conductivity appropriately follow the experimental data authorizing the established model. This model is capable to substitute the conventional models owing to the assumption of innovative nanocomposite's terms.  相似文献   

14.
This study describes a simple and effective method of synthesis of a polyurethane/graphene nanocomposite. Cationic waterborne polyurethane (CWPU) was used as the polymer matrix, and graphene oxide (GO) as a starting nanofiller. The CWPU/GO nanocomposite was prepared by first mixing a CWPU emulsion with a GO colloidal dispersion. The positively charged CWPU latex particles were assembled on the surfaces of the negatively charged GO nanoplatelets through electrostatic interactions. Then, the CWPU/chemically reduced GO (RGO) was obtained by treating the CWPU/GO with hydrazine hydrate in DMF. The results of X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Raman analysis showed that the RGO nanoplatelets were well dispersed and exfoliated in the CWPU matrix. The electrical conductivity of the CWPU/RGO nanocomposite could reach 0.28 S m?1, and the thermal conductivity was as high as 1.71 W m?1 K?1. The oxygen transmission rate (OTR) of the CWPU/RGO‐coated PET film was significantly decreased to 0.6 cmm?2 day?1, indicating a high oxygen barrier property. This remarkable improvement in the electrical and thermal conductivity and barrier property of the CWPU/RGO nanocomposite is attributed to the electrostatic interactions and the molecular‐level dispersion of RGO nanoplatelets in the CWPU matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43117.  相似文献   

15.
In this study, we demonstrated a novel three‐dimensional network of thermally stable fumed silica (FS)–resorcinol formaldehyde (RF) nanocomposites via an ionic‐liquid (IL)‐assisted in situ polycondensation process. The study involved subjecting the tailored nanocomposites to thermogravimetric analysis and oxyacetylene flame environment as per ASTM test standards for thermal ablative performance. X‐ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, high‐resolution transmission electron microscopy, Raman spectroscopy, and wettability studies were undertaken to underline the improvement correlation in the microstructure and material properties. Significant reductions in the linear ablation rate (66%) and mass ablation rate (26.6%), along with lower back‐face temperature profiles, marked enhanced ablative properties. The increased char yield (33.3%) and higher temperatures for weight losses evinced the improved thermal stability of the modified RF resin. The uniformly dispersed fused nanosilica with a glassy coating morphology on the ablative surface acted as barrier to oxidation. The results signify that the IL‐assisted modification of the RF resin with FS significantly enhanced ablative performance. A viable replacement to the conventional phenolic nanocomposites for thermal ablative applications to buy critical time for the containment and suppression of thermal‐heat‐flux threats is of paramount importance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45328.  相似文献   

16.
Inspired by mussel adhesive proteins, catechol functional groups play an important role in the ability of the mussel to adhere to organic and inorganic surfaces. A novel functional polyurethane (PU) based on hydrolysable tannins that contain a number of catechol groups was successfully synthesized and characterized. These catechol groups were used as a reducer for Ag (I) to form Ag (0), and to prepare polyurethane/silver nanoparticles composites. These kinds of polyurethane containing Ag nanoparticles showed obvious inhibition of bacterial growth because of the conjunct actions of the well‐known antibacterial property of silver and the antifouling property of PEG. It is possible for these materials to be applied widely into antibacterial adhesive coatings for surface modification due to their low cost and the material‐independent adhesive property of catechol groups in tannins. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41349.  相似文献   

17.
Oil–water separation has attracted research interest due to the damages of oily wastewater caused to the environment and human beings. Electrospun fiber membrane has high oil–water separation performance. A nanofibers membrane with multi-stage roughness was prepared by electrospinning using poly(vinylidene fluoride)(PVDF)-silica blend solution as raw material. The result shows that the water contact angle (WCA) of the nanofibers membrane was promoted from 138.5 ± 1° to 150.0 ± 1.5° when the SiO2 content was increased from 0 to 3 wt%. The nanofibers membranes exhibited excellent separation efficiency (99 ± 0.1%) under gravity drive, with high separation flux of 1857 ± 101 L·m−2·h−1. More importantly, the obtained PVDF-SiO2 nanofibers membranes showed excellent multi-cycle performance and stable chemical resistance, which would make them great advantages for the practical application of oil–water separation.  相似文献   

18.
Investigations on the production and development of nanoparticle-reinforced polymer materials have been attracted attention by researchers. Various nanoparticles have been used to improve the mechanical, chemical, thermal, and physical properties of polymer matrix composites. Boron compounds come to the fore to improve the mechanical and thermal properties of polymers. In this study, mechanical, thermal, and structural properties of structural adhesive have been examined by adding nano hexagonal boron nitride (h-BN) to epoxy matrix at different percentages (0.5, 1, 2, 3, 4, and 5%). For this purpose, nano h-BN particles were functionalized with 3-aminopropyltriethoxysilane (APTES) to disperse the h-BN nanoparticles homogeneously in epoxy matrix and to form a strong bond at the matrix interface. Two-component structural epoxy adhesive was modified by using functionalized h-BN nanoparticles. The structural and thermal properties of the modified adhesives were investigated by scanning electron microscopy and energy dispersion X-ray spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis techniques. Tensile test and dynamic mechanical analysis were performed to determine the mechanical properties of the adhesives. When the results obtained from analysis were examined, it was seen that the nano h-BN particles functionalized with APTES were homogeneously dispersed in the epoxy matrix and formed a strong bond. In addition that, it was concluded from the experimental results that the thermal and mechanical properties of adhesives were improved by adding functionalized nano h-BN particles into epoxy at different ratios.  相似文献   

19.
Exacerbated environmental concerns about petroleum‐based plastics provide the impetus to foster sustainable poly(lactic acid) (PLA) based food packaging. Nonetheless, PLA has its foibilities such as its brittleness, higher gas permeability, and slow crystallization. With the intent to mitigate the above shortcomings, we report a maiden effort for the fabrication of PLA/crystalline silk nano‐discs (CSNs) based bionanocomposites by melt‐extrusion for high temperature engineering and food packaging applications. Acid hydrolyzed silk fibroin from muga silk (Antheraea assama) yields CSNs, a crystalline hydrophobic discotic nanofiller with diameter of ~50 nm and thickness ~3 nm. At optimum loadings of 1 wt % uniform dispersed CSNs with percolated network structures covering the entire matrix can be seen. Due to enhanced crystal nucleation density, water vapor, and oxygen permeability reduced by ~30% and ~70%, respectively. Enhancement in toughness, percentage elongation, and tensile strength up to ~65%, ~40%, and ~10%, respectively, is obtained. Onset of thermal decomposition for the PLA/CSN improved ~10 °C, confirming the role of CSN in enhancing melt stability. Accordingly, this investigation renders a novel non‐invasive approach for increasing the crystallinity with improvement in thermomechanical and barrier properties which make this bionanocomposite, a promising candidate for food packaging applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46671.  相似文献   

20.
As a kind of reinforcing agent, the application of nanocrystalline cellulose (NCC) is widely limited in hydrophobic polymers owing to its rich hydroxyl surface. In this study, NCC was modified with lauric acid/p‐toluensulfonyl chloride mixture, then the modified nanocrystalline cellulose (mNCC) was incorporated into biopolyester poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) (P(3,4)HB) by solution casting to prepare P(3,4)HB/mNCC nanocomposites. The prepared mNCC and P(3,4)HB/mNCC nanocomposites were characterized by Fourier transform‐infrared, X‐ray diffraction, contact angle test, transmission electron microscopy, scanning electron microscopy, differential scanning calorimetric, polarized optical microscope, dynamic mechanical analysis, and thermogravimetric analysis. The results show that the crystallinity and mechanical properties of P(3,4)HB are greatly improved due to the fact that NCC can be modified successfully and the mNCC can distribute uniformly in nanoscale in the matrix with good compatibility along the interface. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2015–2022, 2013  相似文献   

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