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1.
The purpose of this study was to improve the physical properties and to expand the application range of starch‐based blend films added nano‐sized TiO2/poly(methyl methacrylate‐co‐acrylamide) (PMMA‐co‐AM). Starch‐based blend films were prepared by using corn starch, polyvinyl alcohol (PVA), nano‐sized PMMA‐co‐AM, nano‐sized TiO2/PMMA‐co‐AM particles, and additives, i.e., glycerol (GL) and citric acid (CA). Nano‐sized PMMA‐co‐AM was synthesized by emulsion polymerization and TiO2 nanoparticles were also prepared by using sol–gel method. Nano‐sized TiO2/PMMA‐co‐AM particles were synthesized by wet milling for 48 h. The morphology and crystallinity of TiO2, nano‐sized PMMA‐co‐AM and TiO2/PMMA‐co‐AM particles were investigated by using the scanning electron microscope (SEM) and X‐ray diffractometer (XRD). In addition, the functional groups of the TiO2/PMMA‐co‐AM particles were characterized by IR spectrophotometry (FTIR). The physical properties such as tensile strength (TS), elongation at break (%E), degree of swelling (DS), and solubility (S) of starch‐based films were evaluated. It was found that the adding of nano‐sized particles can greatly improve the physical properties of the prepared films. The photocatalytic degradability of starch/PVA/nano‐sized TiO2/PMMA‐co‐AM composite films was evaluated using methylene blue (MB) and acetaldehyde (ATA) as photodegradation target under UV and visible light. The degree of decomposition (C/C0) of MB and ATA for the films containing TiO2 and CA was 0.506 and 0.088 under UV light irradiation and 0.586 (MB) and 0.631 (ATA) under visible light irradiation, respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

2.
Using coupling agent isocyanatopropyltriethoxysilane (ICTOS) to modified nano‐TiO2, the polyimide (PI) with different titanium dioxide (TiO2) contents (0, 1, 2, 3, 4, and 5 wt %) doped nano‐composites were prepared by sol–gel method (PI/TiO2 ICTOS composites). The effect of ICTOS modification on polarization and time‐to‐breakdown properties of composites were investigated by thermally stimulated depolarization current (TSDC) method, dielectric, and Corona aging measurements. The TSDC spectra show that ICTOS modification enhanced α‐peak intensity and make β‐peak disappear in composites. Relevant trap parameters were calculated by an approximate model, and the results indicate that introduction of ICTOS is effective for the charge carrier traps, activation energy distribution in composites. Corona aging measurement show corona resistance was also sufficient improved in PI/TiO2 ICTOS composites. The changes of activation energy and intensity of traps in composites may be responsible for the corona resistance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45101.  相似文献   

3.
This contribution reports a simple approach for preparing PMA/TiO2 composite. In this method, nano TiO2 powders are previously treated by a combined modification process, namely, the alkali‐treatment followed by oleic acid surface‐grafting. Before polymerization, the modified TiO2 nanoparticles are dispersed into the maleic anhydride (MA) solution to form stable homogeneous gel. When the reaction temperature is raised to 150°C, the modified nano TiO2 can initiate the in situ anionic polymerization of MA. Finally, the PMA/TiO2 composites are obtained, in which all the TiO2 are fully coated by MA polymer (PMA). Therefore, it is not needed to reclaim the nano initiators because they are blended into the prepared polymers as the nano fillers. TEM and SEM experiment results can strongly demonstrate that the TiO2 nanoparticles are homogeneously dispersed in PMA matrix. This approach is easy‐to‐operate and applicable to the preparation of other nano composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

4.
Poly(ethylene phthalate) (PET)/nano‐TiO2 composites prepared via in situ polymerization were spun into fiber by the melt‐spinning process. The dispersion of nanosized rutile TiO2 in the PET was studied using transmission electron microscopy (TEM) and scanning probe microscopy (SPM) techniques. The mechanical properties and the properties of ultraviolet (UV) protection were investigated. The results showed that rutile TiO2 can be dispersed uniformly by the in situ polycondensation process. The mechanical properties of PET/TiO2 fiber were slightly affected by adding nano‐TiO2. The UV‐ray transmittance of PET/nano‐TiO2 fabrics was below 10% in the UV‐A band and below 1% in the UV‐B band. And the ultraviolet protection factor (UPF) of PET/nano‐TiO2 fabrics was greater than 50. All these PET/TiO2 nanocomposite fabrics exhibited excellent UV‐blocking properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1588–1593, 2006  相似文献   

5.
A novel poly(imide siloxane)/titania (PIS/TiO2) hybrid film was fabricated by sol‐gel process via in situ formation of TiO2 within PIS matrix. Poly(amic acid siloxane) (PAAS) was prepared from 4,4′‐oxydiphthalic anhydride, 2,2‐bis [4‐(4‐aminophenoxy) phenyl] propane, and α,ω‐bis(3‐aminopropyl)polydimethylsiloxane (APPS). Chelating agent, acetylacetone, and catalyst‐free polymerization were used to reduce the rate of hydrolysis of titanium alkoxide in the PAAS. X‐ray photoelectron spectroscopy data showed that the presence of APPS promotes the Ti surface composition of PIS/TiO2 hybrid film. The effects of TiO2 and APPS contents on the characteristics of surface, thermostability, coefficient of thermal expansion (CTE), and the strength of adhesion were investigated. The presence of TiO2 on the surface of the hybrid films enhanced the adhesive strength at the interface of PIS/TiO2 hybrid film and copper foil. When more TiO2 was incorporated into the PIS matrix, the PIS/TiO2 hybrid film exhibited lower CTE while retaining favorable mechanical and thermal properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

6.
A series of polyimide/titania (PI/TiO2) hybrid films have been successfully synthesized based on titanium tetrabutoxide (Ti(OEt)4), 3,3′,4,4′‐bezonphenone tetracarboxylic dianhydride (BTDA), 4,4′‐oxydianiline (ODA), and 1,3‐bis(aminopropyl) tetramethyldisiloxane (APrTMOS) by a sol–gel process. The atomic oxygen (AO) exposure tests were carried out using a ground‐based AO effects simulation facility. The chemical structure of PI/TiO2 films was characterized by Fourier transform‐infrared (FT‐IR) spectroscope before and after AO exposure. The glass transition temperature (Tg) and mechanical properties were examined by dynamic mechanical analysis (DMA) and universal mechanical testing machine, respectively. The tensile strength and elongation of the hybrid film decreased with the increase of TiO2 content, whereas the Tg increased with the increase of TiO2 content. The effects of TiO2 content on the morphology and structure evolvement of PI/TiO2 hybrid films were also investigated using field emission scanning electron microscopy (FE‐SEM) and X‐ray photoelectron spectroscope (XPS), respectively. The results indicated that a TiO2‐rich layer resulting from the Ti(OEt)4 formed on the PI film after AO exposure, which decreased the mass loss rate and obviously improved the AO resistance of PI films. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

7.
The purpose of this article is to investigate the effects of nano‐tianium dioxide (nano‐TiO2) on the high‐amylose starch/polyvingl alcohol (PVA) blend films prepared by a solution casting method. The results show that at the concentration of 0.6% of nano‐TiO2, the film demonstrated the best tensile strength at 9.53 MPa, and the elongation at break was noted as 49.50%. The optical transmittance of the film was decreased and the water resistance was improved with further increase of the concentration of nano‐TiO2. Using the techniques of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and field‐emission scanning electron microscopy (SEM), the molecular and the crystal structures of the films were characterized. The results indicate that the miscibility and compatibility between high‐amylose starch and PVA were increased with the addition of nano‐TiO2 into the films due to the formation of hydrogen and C? O? Ti bonds. The antimicrobial activities of the blend films were also explored. The results show that there were inhibitory zones around the circular film disc, which is attributable to the addition of nano‐TiO2. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42339.  相似文献   

8.
A series of novel ternary polyimide/SiO2/polydiphenylsiloxane (PI/SiO2/PDPhS) composite films were prepared through co‐hydrolysis and condensation between tetramethoxysilane, diphenyldimethoxysilane (DDS) and aminopropyltriethoxysilane‐terminated polyamic acid, using an in situ sol–gel method. The composite films exhibited good optical transparency up to 30 wt% of total content of DDS and SiO2. SEM analysis showed that the PDPhS and SiO2 were well dispersed in the PI matrix without macroscopic separation of the composite films. TGA analysis indicated that the introduction of SiO2 could improve the thermal stability of the composite films. Dynamic mechanical thermal analysis showed that the composite films with low DDS content (5 wt%) had a higher glass transition temperature (Tg) than pure PI matrix. When the content of DDS was above 10 wt%, the Tg of the composite decreased slightly due to the plasticizing effect of flexible PDPhS linkages on the rigid PI chains. The composite films with high SiO2 content exhibited higher values of storage modulus. Tensile measurements also showed that the modulus and tensile strength of the composite films increased with increasing SiO2 content, and the composite films still retained a high elongation at break due the introduction of DDS. The density and water absorption of the composite films were also characterized. Copyright © 2006 Society of Chemical Industry  相似文献   

9.
Polyimide/Al2O3 (PI/Al2O3) nanocomposite films based on pyromellitic dianhydride and 4,4′‐oxydianiline were fabricated by adding different proportions of nano‐Al2O3 inorganic particles via in situ polymerization. Microstructural analysis by scanning electron microscope (SEM) showed that the inorganic particles were homogenously dispersed in the PI matrix when mixed with appropriate amount of nano‐Al2O3. Fourier transform infrared spectroscopy and X‐ray diffraction analysis were also used to investigate the effect of nano‐Al2O3 on the polymerization process. The obtained composite films and pure film were characterized by thermogravimetry analysis, and the experimental results indicated that when comparing with pure film, the nanocomposite films displayed a better thermal stability than the pure one. Moreover, results also showed that the thermal stability of composite films steadily improved with increased content of nano‐Al2O3 particle. The electrical property test demonstrated that the composite films performed improving electrical breakdown strength and corona resistance. The microstructure changes of pure film and PI/Al2O3 nanocomposite films during corona aging have been analyzed by SEM. POLYM. COMPOS., 37:763–770, 2016. © 2014 Society of Plastics Engineers  相似文献   

10.
The aim of this work was to obtain anatase nano‐TiO2 by the sol–gel method at room temperature and to achieve self‐cleaning Bombyx mori silk fabrics. Nano‐TiO2 sols based on an aqueous system and an ethanol system were prepared separately by the sol–gel method using tetrabutyl orthotitanate as a precursor at room temperature. Particle size analyses showed that nano‐TiO2 particles in an aqueous system were much bigger and more variant than those in ethanol. X‐ray diffraction patterns revealed a pure anatase phase of nano‐TiO2 in an aqueous system. Crystalline transformation of TiO2 from anatase to rutile by photoradiation at ambient temperature was also proved. Thermogravimetric and differential scanning calorimetric analyses confirmed the phase transformation of nano‐TiO2. A scanning electron microscope equipped with an energy‐dispersive spectrometer was used to investigate the surface morphology and elements of Bombyx mori silk fabrics. The contact angles with water, the kinetics of photocatalytic degradation of Methylene Blue, and decontamination of red‐wine‐stained fabrics under ultraviolet radiation demonstrated that the fabrics had good self‐cleaning properties and photoinduced hydrophilicity.  相似文献   

11.
By a sol–gel processing, the nano‐TiO2/silk fibroin (SF) composite films were prepared. One‐dimensional (1D) Raman, two‐dimensional (2D) correlation Raman spectroscopy, and 13C cross‐polarization magic‐angle‐spinning nuclear magnetic resonance (13C CP‐MAS NMR) were used to characterize the structural evolution of SF as the nano‐TiO2 content increased from 0 to 0.4 wt%. The experimental data demonstrated that the secondary structures in the pure SF film and nano‐TiO2/silk fibroin (SF) composite films were random coil, α‐helix and β‐sheet structures. The nano‐TiO2 particles formed in the SF films might induce partial structural transitions from random coil and Silk I (α‐helix) to Silk II (β‐sheet). The transition identified by 2D‐Raman correlation spectra was the following order: silk I‐like structure, silk I (α‐helical structure), Silk II‐like structure, and Silk II (β‐sheet structure). POLYM. COMPOS., 36:121–127, 2015. © 2014 Society of Plastics Engineers  相似文献   

12.
Nano titanium dioxide (TiO2) sols were prepared by sol‐gel method with tetrabutyl orthotitanate (TBOT) as precursors, citric acid (CA) as inhibitors. Ultraviolet resistant capacity of finished cotton fabrics are greatly improved with good wrinkle‐resistance, whiteness and tensile strength as well. The optimum molar ratio for preparing nano‐TiO2 sols in this study is n[C2H5OH] : n[H2O] : n[CA] : n[HCl] : n[TOBT] = 20 : 6 : 1.2 : 0.025 : 1, at ambient temperature. Particle size distribution analysis of the sol reveals that the curve is right tailed with an average diameter of 72.8 nm. Factors affecting the performance of finished cotton fabrics by TiO2 sols, such as concentration of sodium hypophosphite (SHP), triethanolamine (TEA) in finishing bath, curing temperatures and time lengths were investigated by orthogonal experiments. The optimum finishing results can be obtained with 3% SHP, 3% TEA, curing at 165°C for 3 min. Aggregated nano‐TiO2 particles on surfaces of finished cotton fibers both washed and unwashed were investigated by high resolution cold field emission scanning electron microscope and energy dispersive X‐ray spectrometer. Esterification crosslinking between CA and cotton fibers were also demonstrated through infrared spectra. After a five‐time's wash, ultraviolet protection factor of finished cotton fabrics with nano‐TiO2 sols is up to 117.42 and dry crease recovery angles increase by 30.2° with slightly improved whiteness, while the breaking strength decreases by 18.8%. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

13.
Hybrid coatings (inorganic‐organic) were prepared using a blown and epoxidized soybean oil as the organic matrix. Both TiO2 particles and titanium sol‐gel precursors (Titanium tetra‐i‐propoxide, TIP; titanium (di‐i‐propoxide) bis(acetylactonate), TIA) were incorporated into the coating. Three sizes of TiO2 particles ranging from 32 nm to 500 nm were used for comparison with the metal‐oxo‐clusters. General mechanical coating properties, tensile properties, and viscoelastic properties of the sol‐gel (ceramer) system were evaluated for the coatings, and the sol‐gel derived metal‐oxo‐clusters were found to have higher tensile modulus, storage modulus (E ′), and Tg compared with the TiO2 particles.  相似文献   

14.
Nano‐TiO2/lacquer hybrid coatings are prepared by the blend of nano‐TiO2 and lacquer sap. Nano‐TiO2 particles are involved in the laccase‐catalyzed polymerization process of urushiol, which improves the properties of lacquer film. With increasing nano‐TiO2 from 0 to 5 wt %, the drying time of lacquer film to reach hardened dryness decreases from >12 h to 8 h 30 min under 30 °C and 80% relative humidity. Gel permeation chromatography analysis shows that the addition of nano‐TiO2 accelerates the polymerization of urushiol. It is also related to the formation of Ti? O? C bonds due to the reaction between nano‐TiO2 and the radicals produced by laccase‐catalyzed oxidation. The pencil hardness, flexibility, and adhesion of hybrid lacquer film can be improved and reach 4H, 1 mm, and grade 2, respectively. Its inhibition rate against Escherichia coli and Staphylococcus aureus increases from 22.6% and ?21.4% to 49.2% and 67.8%, respectively. Furthermore, nano‐TiO2 hybrid lacquer films also possess higher thermo‐stability than the raw lacquer film. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45865.  相似文献   

15.
Dielectric and conduction properties of polyimide/silica nano‐hybrid films were investigated with the silica content and the testing frequency, using a small electrode system. The hybrid films were prepared through sol‐gel process and thermal imidization, by using pyromellitic dianhydride and 4,4′‐oxydianiline as polyimide precursors, and tetraethoxysilane and methyltriethoxysilane as silica precursors. The dielectric coefficient of PI/SiO2 films was monotonically increased with increasing silica content, and decreased with increasing testing frequency. The dielectric loss of PI/SiO2 films had no obvious changes with increasing silica content, but monotonically increased with increasing testing frequency. These can be contributed to the different quantity and migration chunnels of current carriers, which were mainly influenced by a few of complicated factors. There were remarkable differences between conduction property of PI/TEOS‐SiO2 films and PI/MTEOS‐SiO2 films because of the different size and dispersion status of silica particles in the polyimide matrix. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers  相似文献   

16.
Acrylic/nano‐silica composite latexes were prepared by blending via high shear stirring (SS) or ball milling (BM) and in situ polymerization (IS). For comparison, composites filled with micro‐silica were also prepared. The mechanical and optical properties of the polymers formed by the composite latex filled with nano‐ or micro‐silica were investigated using an Instron testing machine, by dynamic mechanical analysis, ultraviolet–visible spectrophotometry and transmission electron micrography. The results showed that SS and BM methods could obtain better nanocomposite latex and polymers than the IS method, characterized by better dispersion of nanoparticles, higher tensile strength and Tg for SS and BM than for IS. The increase in absorbance and reduction in transmittance of UV (290–400 nm wavelength) were observed as nano‐silica content increased, whereas the UV absorbance or transmittance basically were kept unchanged for the composites filled with micro‐silica. © 2002 Society of Chemical Industry  相似文献   

17.
Polyimide/silica–titania (PI/SiO2–TiO2) hybrid films were prepared via an in situ sol–gel process. The PI precursor, poly(amic acid) (PAA), which contains 2,2'‐bis[4‐(4‐aminophenoxy)‐phenyl]propane (p‐BAPPP), 3,3',4,4'‐ benzophenetetracarboxylic anhydride (BTDA) and 3‐aminopropyltrimethoxysilane (APrTMOS), was first synthesized; this was followed by the addition of phenyltrimethoxysilane (PTMS) and/or tetraethyl orthotitanate (Ti(OEt)4) to fabricate PI/SiO2–TiO2 films. The relative content of SiO2 to TiO2 has remarkable effects on the crosslink structure and resultant properties of the hybrids. XPS results confirm that the amount of Si on the surface of the hybrids is higher than that in the bulk. The distribution of Ti in the hybrid films is contrary to the above trend because of the formation of three‐dimensional Si? O? Si, Si? O? Ti, and Ti? O? Ti networks. The SiO2 content of the hybrids containing only silica significantly affects their refractive index, contact angle, and dielectric constant. The films with added PTMS show higher contact angles than pure PI because nonpolar segments, ? C2H6 or benzene groups, tend to distribute on the surface. Upon the addition of (Ti(OEt)4), some hydrophilic segments on the surface of the hybrids are induced because of the formation of a crosslinked structure. The denser crosslinked molecular structure, and consequently lower CTE and higher Tg are obtained from hybrids containing more TiO2. By comparing the above properties and flexibility, the best composition of metal oxides (SiO2/TiO2) in hybrids is 20/80. That is, an optimum ratio of metal oxides in PI hybrids induces superior properties for advanced practical applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

18.
Macroporous polymer composites with photocatalytic activity are prepared by the polymerization of surface modified TiO2 nanoparticle stabilized high internal phase emulsions. Poly(ethylene glycol‐b‐propylene glycol‐b‐ethylene glycol) triblock copolymer is used to synthesize surface modified TiO2 anatase via a sol–gel method. Macroporous composites are obtained by the ring opening metathesis polymerization of dicyclopentadiene within the particle‐stabilized high internal phase emulsion templates. Photocatalytic activity of the resulting macroporous polymer composites is described by the kinetic data of the heterogeneous photocatalytic degradation reaction of 4‐nitrophenol.  相似文献   

19.
High‐impact polystyrene (HIPS)/nano‐TiO2 nanocomposites were prepared by surface pretreatment of nano‐TiO2 with special structure dispersing agent (TAS) and master batch manufacturing technology. The results show that when the nano‐TiO2 content is 2%, the notched impact strength, tensile strength, and elastic modulus of HIPS/nano‐TiO2 nanocomposites increased to a maximum. This result indicates that nano‐TiO2 has both toughening and reinforcing effects on HIPS. The heat‐deflection temperature and flame‐retardance of HIPS/nano‐TiO2 nanocomposites are also obviously improved as the nano‐TiO2 content is increased. The nanocomposites manufactured by the two‐step method have better mechanical properties than that made by a one‐step method. HIPS/nano‐TiO2 nanocomposites are also non‐Newtonian and pseudoplastic fluids. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 381–385, 2003  相似文献   

20.
Nanozirconia (nano‐ZrO2) was prepared by the sol–gel method and incorporated into poly(methyl methacrylate) (PMMA) by the in situ bulk polymerization of methyl methacrylate. The structure of the nano‐ZrO2 was confirmed by X‐ray diffraction (XRD), transmission electron microscopy, and Fourier transform infrared (FTIR) spectroscopy. The structure of the nano‐ZrO2 nanocomposites were studied by differential scanning calorimetry, FTIR spectroscopy, XRD, and scanning electron microscopy, and the results show that there were interactions between the nanoparticles and the polymer. The influence of the nano‐ZrO2 on the thermal stability of PMMA was investigated by thermogravimetric analysis (TGA). The results indicate that nano‐ZrO2 enhanced the thermal stability of the PMMA/nano‐ZrO2 nanocomposites. The effects of the heating rate in dynamic measurements (5–30°C/min) on kinetic parameters such as apparent activation energy (Ea) in TGA both in nitrogen and air were investigated. The Kissinger method was used to determine Ea for the degradation of pure PMMA and the PMMA/nano‐ZrO2 nanocomposites. The kinetic results show that the values of Ea for the degradation of the nanocomposites were higher than that of pure PMMA in air. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

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