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1.
In this study, poly(methylphenylsiloxane) (PMPS) and phenylene‐silica based hybrid material with interpenetrating networks was prepared by a two‐step sol–gel process. Firstly, in the presence of H2SO4, the phenylene‐silica was formed as sol particles with high branching degree by cohydrolysis and condensation of phenylene‐bridged monomer, tetraethoxysilane (TEOS), and hexamethyldisiloxane (MM). Then, the intermediate transformed into gel framework in polymer matrix using alkali catalyst, in order to produce a homogenous hybrid material with interpenetrating networks. The structure of prepared hybrid material was characterized by FTIR and NMR, suggesting that phenylene‐silica framework was imported into polymer matrix and the hybrid products have a much higher network chain density than neat PMPS. The thermogravimetric analysis (TGA) shows that the prepared materials start to degrade at around 490°C. The results of tensile test indicate that the typical PMPS/phenylene‐silica hybrid material has a tensile strength up to 26 MPa and demonstrate a certain degree of flexibility. An increase of phenylene content in phenylene‐silica particles tends to produce hybrid materials with improved thermal stability and tensile strength. The hybrid coating films after calcinating at 350 and 400°C for 2 h exhibit a good mechanical performance on adhesion, impact strength and flexibility. Electrochemical impedance spectroscopy (EIS) measurements show that the investigated films have an extremely high electric resistance (1010 Ohm·cm2) and a satisfied impermeability to 3.5 wt % sodium chloride solution. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

2.
In this article, we report the preparation of crosslinked epoxy microspheres with diameters of 5–10 μm prepared via phase‐inverted phase separation induced by polymerization in the thermosetting blend of epoxy and poly(ε‐caprolactone). The surfaces of the epoxy microspheres were functionalized to bear 2‐bromopropionyl groups, which were further used as initiators to obtain poly(glycidyl methacrylate) (PGMA) grafted epoxy microspheres via the surface‐initiated atom transfer radical polymerization approach. The PGMA‐grafted epoxy microspheres were then employed to react with 3‐aminopropyltrimethoxylsilane (APTMS) to obtain the functionalized epoxy microspheres, the surface of which contained a great number of trimethoxysilane groups. A co‐sol–gel process between the APTMS‐functionalized epoxy microspheres and tetraethoxysilane was performed, and organic–inorganic glassy solids were obtained. The organic–inorganic glasses were used as precursors for accessing macroporous silica materials via pyrolysis at elevated temperatures. The hierarchical porosity of the resulting macroporous silica was investigated by means of field emission scanning electronic microscopy, transmission electronic microscopy, and surface‐area Brunauer–Emmett–Teller (BET) measurements. We found that the macroporous silica possessed BET surface areas in the range 183.9–235.2 m2/g, depending on the compositions of their precursors. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

3.
In this article, a series of hybrid materials consisted of epoxy resin matrix and well‐dispersed amino‐modified silica (denoted by AMS) nanoparticles were successfully prepared. First of all, the AMS nanoparticles were synthesized by performing the conventional acid‐catalyzed sol–gel reactions of tetraethyl orthosilicate (TEOS), which acts as acceded sol–gel precursor in the presence of 3‐aminopropyl trimethoxysilane (APTES), a silane coupling agent molecules. The as‐prepared AMS nanoparticles were then characterized by FTIR, 13C‐NMR, and 29Si‐NMR spectroscopy. Subsequently, a series of hybrid materials were prepared by performing in situ thermal ring‐opening polymerization reactions of epoxy resin in the presence of as‐prepared AMS nanoparticles and raw silica (RS) particles (i.e., pristine silica). AMS nanoparticles were found to show better dispersion capability in the polymer matrices than that of RS particles based on the morphological observation of transmission electron microscopy (TEM) study. The better dispersion capability of AMS nanoparticles in hybrid materials was found to lead enhanced thermal, mechanical properties, reduced moisture absorption, and gas permeability based on the measurements of thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and gas permeability analysis (GPA), respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

4.
Ordered mesoporous silica has been drawn great interest in many areas of modern science and technology. In this study, mesoporous silica KIT‐6 was modified with 3‐mercaptopropyl‐trimethoxysilane by sono‐chemical method and reflux. Low‐angle powder X‐ray diffraction (XRD) and transmission electron microscopy (TEM) images confirmed the presence well‐ordered arrangement of large pores and a relatively ordered mesostructure for the functionalized materials. The nanocomposites of polyamide‐6 and modified‐KIT (3 and 6 wt %) were prepared under reflux and followed by sonication for 2h. The prepared hybrid nanocomposites were characterized by Fourier transform‐infrared spectroscopy, XRD, field emission‐scanning electron microscopy and TEM techniques. Thermogravimetric analysis data showed that the onset of decomposition temperature of the nanocomposites was higher than that of pristine polyamide‐6, shifting toward higher temperatures as the amount of modified‐KIT was increased. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43098.  相似文献   

5.
The (3‐methacryloxypropyl)trimethoxysilane (MPMS) capped acrylic resin/alumina hybrid materials with highly homogeneous structure were successfully prepared by in situ sol–gel process. The effects of the contents of alumina, ethylacetoacetate (EAA), and water as well as the types of catalyst on the structures and properties of the hybrid materials were studied. It was found that the Tg, thermal stability, microhardness, and Young's modulus of the hybrid materials were obviously improved with increasing alumina and water contents, low EAA content, and catalyst employed. POLYM. COMPOS., 2008. © 2007 Society of Plastics Engineers  相似文献   

6.
The transparent poly(butyl acrylate‐co‐maleic anhydride)/silica [P(BA‐co‐MAn)/SiO2] has been successfully prepared from butyl acrylate‐maleic anhydride copolymer P(BA‐co‐MAn) and tetraethoxysilane (TEOS) in the presence of 3‐aminopropyltriethoxysilane (APTES) by an in situ sol–gel process. Triethoxysilyl group can be readily incorporated into P(BA‐co‐MAn) as pendant side chains by the aminolysis of maleic anhydride unit of copolymer with APTES, and then organic polymer/silica hybrid materials with covalent bonds between two phases can be formed via the hydrolytic polycondensation of triethoxysilyl group‐functionalized polymer with TEOS. It was found that the amount of APTES could dramatically affect the gel time of sol–gel system, the sol fraction of resultant hybrid materials, and the thermal properties of hybrid materials obtained. The decomposition temperature of hybrid materials and the final residual weight of thermogravimetry of hybrid both increase with the increasing of APTES. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that the morphology of hybrid materials prepared in the presence of APTES was a co‐continual phase structure. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 419–424, 1999  相似文献   

7.
The formation of covalent bonds between silanols in copolymer and those in silica prevents organic–inorganic phase separation. Two series of hybrid composite materials, poly(vinyl acetate‐co‐vinyl trimethoxysilane)/TEOS and poly[vinyl acetate‐co‐3‐(trimethoxysilyl)propyl methacrylate]/TEOS, were fabricated using a modified sol‐gel process. The hybrids were transparent. Two kinds of silane coupling agents, vinyl trimethoxysilane (VTS) and 3‐(trimethoxysilyl)propyl methacrylate (γ‐MPS), were used to prevent macrophase separation through formation of covalent bonds. Thermal analysis showed that γ‐MPS was more effective than VTS for the formation of covalent bonds. Enhancement of thermal stability of the hybrids was investigated by thermogravimetric analysis. Photomicrographs of scanning electron microscopy and images of atomic force microscopy indicated that inorganic silica particles were homogeneously dispersed in less than 50 nm in organic matrix. The morphological properties of hybrids were strongly dependent on the organic–inorganic composition. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2310–2318, 2001  相似文献   

8.
Novel natural clay–polymer hybrid materials are prepared from natural bentonite that was modified with silane‐coupling agent, γ‐methacryloxypropyltrimethoxysilane (A‐174), and acrylonitrile. By changing the molar ratio of acrylonitrile in the initial monomer feed, several clay–hybrid materials were prepared. The structure and thermal stability of hybrid materials were investigated by various methods. The A‐174‐modified bentonite was dispersed in a solution of acrylonitrile in toluene. In this system, radical polymerization in the presence of AIBN was carried out. Product formed at the particle surface was either physically bound by entanglement or chemically bound by covalent bonding to the silane. In this way, core–shell morphology was obtained with an inorganic core and a polymer shell. The results showed that bonding at the surface of bentonite took place by hydrolytic cleavage of methoxy groups of A‐174 with hydroxy groups of bentonite. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 164–171, 2002; DOI 10.1002/app.10289  相似文献   

9.
Summary: In the present study (3‐methacryloxypropyl)trimethoxysilane (MPMS) containing acrylic resin/alumina hybrid materials with various alumina contents were prepared. The effects of ethylacetoacetate (EAA) content, catalyst type, and water content during sol–gel process for alumina sols on the microstructure and properties of the hybrid materials were investigated by SAXS, AFM, DSC, TGA, and nano‐indentation tester, respectively. It was found that the hybrid materials exhibited a homogeneity and the alumina phase of the hybrids had mass fractal dimension and open structure. The thermal and mechanical properties of the hybrid materials were obviously improved when alumina was incorporated. The EAA contents, catalyst type, and water content during sol–gel process for alumina sols had obvious effects on the microstructure and properties of the hybrid materials.

Typical load–displacement curves of the pure acrylic resin and hybrid materials with increasing alumina content.  相似文献   


10.
In this study, hybrid materials based on epoxy resin were prepared as transparent self‐supported films by a sol–gel process. 4,4′‐Diaminodiphenylmethane or oligomeric epoxy resin were used as precursors, which were conveniently functionalized with trialkoxysilanes as end‐groups. The effect of the introduction of poly (dimethylsiloxane) was also investigated. The hybrid films showed good thermal stability, a nondefined glass transition temperature, and a dense morphology without phase segregation. The tendency to a flat surface could be observed by atomic force microscopy. The hybrid films also showed good performance as coatings for glass plates, with an improved hydrophobic character in comparison to neat epoxy resin. POLYM. ENG. SCI., 48:141–148, 2008. © 2007 Society of Plastics Engineers  相似文献   

11.
The ultrasonically assisted preparation and characterization of poly(amide‐imide) (PAI) composites containing functionalized multi‐walled carbon nanotubes (MWCNTs) are reported. To improve the dispersion in and compatibility with the polymer matrix, the MWCNTs were surface‐modified with p‐aminophenol (p‐AP) under microwave irradiation. The process is fast, one‐pot, easy and results in a high degree of functionalization as well as dispersibility in organic solvents. The p‐AP‐functionalized MWCNTs (MWCNTs‐AP) were analysed by means of field emission and transmission electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction and thermogravimetric analysis (TGA). The results consistently confirm the formation of p‐AP functionalities on MWCNTs which are able to undergo additional reactions, while the structure of the MWCNTs remains relatively intact. MWCNTs‐AP/PAI hybrid films were prepared with various MWCNTs‐AP contents (5–15 wt%) using a solution‐casting technique. Microscopic observations show that the dispersion of the MWCNTs‐AP is improved as a result of the organic groups on the MWCNT surface and functional groups in the PAI structure. The properties of the obtained composites were characterized extensively using the aforementioned techniques. TGA results show that the hybrid films exhibit a good thermal stability. Tensile mechanical testing was performed for the prepared composites, the results of which indicate an increase in the elastic modulus and tensile strength with increasing MWCNTs‐AP content. © 2013 Society of Chemical Industry  相似文献   

12.
《Polymer Composites》2017,38(7):1454-1461
Well‐defined poly(N‐isopropylacrylamide) and poly(2‐(diethylamino) ethyl methacrylate) were synthesized first by a reversible addition‐fragmentation chain transfer process. These polymers were then reduced to generate an end thiol group to react with isocyanate groups on the surface of silica nanoparticles, which were pretreated with toluene‐2,4‐diisocyanate, by a one‐pot “click” reaction to prepare temperature and pH responsive polymer functionalized hybrid silica nanoparticles. The polymer functionalized silica hybrid nanoparticles were characterized by a range of techniques such as Fourier transform infrared spectroscopy and dynamic light scattering. The doubly responsive polymer functionalized silica hybrid nanoparticles show both temperature and pH responsive behavior and their solution properties were dependent on the ratio of the two polymers on the surface of silica. Covalent functionalization of the silica nanoparticle with well‐defined temperature and pH responsive polymers was accomplished via a one‐pot thiol‐isocyanate click reaction. This reaction was found to be extremely efficient in producing doubly responsive polymer functionalized silica hybrid nanoparticle, even at relatively low reaction temperature and short reaction time. Thermogravimetric analysis indicated that the same ratio of poly(N‐isopropylacrylamide) and poly(2‐(diethylamino)ethyl methacrylate) functionalized silica hybrid nanoparticle consisted of 42.46 wt% polymer. POLYM. COMPOS., 38:1454–1461, 2017. © 2015 Society of Plastics Engineers  相似文献   

13.
In this study, novel metallo‐supramolecular materials based on terpyridine‐functionalized polyhedral silsesquioxane were synthesized from 4′‐chloro‐2,2′:6′,2″‐terpyridine and amino‐group‐functionalized polyhedral oligomeric silsesquioxane. The obtained terpyridine‐functionalized polyhedral silsesquioxanes were converted to metallo‐supramolecular hybrid materials by coordination polycondensation reaction with Co(II) or Cu(II) ions. The supramolecular polymers created were characterized by means of structure, morphology and stimuli‐responsive performance employing scanning electron microscopy, amperometric techniques and UV–visible and Fourier transform IR spectroscopy. UV?visible and cyclic voltammetry studies showed that both the optical and electrochemical properties of metallo‐supramolecular materials are affected by the substituent at the pyridine periphery. The supramolecular polymers obtained exhibited electrochromism during the oxidation processes of cyclic voltammogram studies. As a result, these terpyridine‐functionalized polyhedral silsesquioxanes are good candidates for electronic, opto‐electronic and photovoltaic applications as smart stimuli‐responsive materials. © 2013 Society of Chemical Industry  相似文献   

14.
Novel high density polyethylene (HDPE)/SiO2 hybrid materials were prepared by the sol–gel process using tetraethoxysilane (TEOS). HDPE and synthesized HDPE‐g‐vinyl trimethoxysilane (VTMS) through melt grafting method was used as the raw material. The structure and thermal, mechanical properties of hybrid materials were investigated by Fourier transform infrared (FTIR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), simultaneous thermogravimetric (TG), differential thermal analysis (DTA), and tensile tests, respectively. Silica phase in the HDPE‐g‐VTMS hybrids showed a network structure and nano‐scale size. The covalent bonds between organic and inorganic phases were introduced by the HDPE‐g‐VTMS bearing trimethoxysilyl groups, which underwent hydrolytic polycondensation with TEOS. The thermal stability and mechanical properties of HDPE‐g‐VTMS hybrids were obviously improved by embedded silica networks. It was found that the silica content in the HDPE‐g‐VTMS hybrid material was linearly increased with the TEOS dosage. The formation of the HDPE‐g‐VTMS hybrid was beneficial for enhanced mechanical strength and thermal stability, in comparison with the neat HDPE. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39891.  相似文献   

15.
Polymethylphenylsilsesquioxane (PMPSQ–OH) and trimethylsilyl end‐blocked PMPSQ (PMPSQ–EC) were prepared. The thermal decomposition behavior of these polymers was studied by thermogravimetric analysis (TGA) and FT‐Raman spectroscopy. Hydroxyl‐functionalized polystyrene (PS–OH) was also prepared by anionic living polymerization. Thin hybrid films of PMPSQ/PS–OH with various blend ratios were obtained by spin‐coating on freshly cleaned glass. The surface morphology of the hybrid films was investigated by atomic force microscopy (AFM). In 80/20 PMPSQ/PS–OH hybrid film, the PS–OH component produced a very uniformly dispersed phase. This hybrid film contained small domains of PS–OH whose size ranged from 60 to 80 nm. As the content of PS–OH was increased, the domain morphology coarsened and phase inversion took place around 50 wt %. In the phase‐inversed system, the PMPSQ‐rich phase was uniformly distributed in the PS–OH‐rich continuous phase. In addition, temperature‐dependent dielectric properties of PMPSQ/PS–OH hybrids were investigated. Relaxation of the hybrids was observed with an increasing content of the PS–OH component due to the amorphous glass transition behavior of PS–OH. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2801–2812, 2003  相似文献   

16.
UV‐curable, organic–inorganic hybrid materials were synthesized via sol–gel reactions for tetraethylorthosilicate, and methacryloxypropyl trimethoxysilane in the presence of the acrylated phenylphosphine oxide resin (APPO) and a bisphenol‐A‐based epoxy acrylate resin. The sol–gel precursor content in the hybrid coatings was varied from 0 to 30 wt %. The adhesion, flexibility, and hardness of the coatings were characterized. The influences of the amounts of inorganic component incorporated into the coatings were studied. Results from the mechanical measurements show that the properties of hybrid coatings improve with the increase in sol–gel precursor content. In addition, thermal properties of the hybrids were studied by thermogravimetric analysis in air atmosphere. The char yield of pure organic coating was 32% and that of 30 wt % silicate containing hybrid coating was 30% at 500°C in air atmosphere. This result demonstrates the pronounced effect of APPO on the flame retardance of coatings. Gas chromatography/mass spectrometry analyses showed that the initial weight loss obtained in thermogravimetric analysis is due to the degradation products of the photoinitator and the reactive diluent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1906–1914, 2006  相似文献   

17.
A mixture of two epoxy resins, tetraglycidyl 4,4′‐diaminodiphenyl methane and bisphenol‐A diglycidylether, cured with 4,4′‐diaminodiphenyl sulfone, was used as matrix material for high‐performance epoxy hybrid nanocomposites containing organophilicly modified synthetic fluorohectorite and compatibilized liquid six‐arm star poly(propylene oxide‐block‐ethylene oxide) (abbreviated as PPO). The hydroxy end groups of the poly(propylene oxide‐block‐ethylene oxide) were modified, yielding a six‐arm star PPO with an average of two pendant stearate chains, two phenol groups, and two hydroxy end groups. The alkyl chains of the stearate end groups played an important role in tailoring the polarity of the polymer. Its phenol end groups ensured covalent bonding between liquid polymer and epoxy resin. Two different organophilic fluorohectorites were used in combination with the functionalized PPO. The morphology of the materials was examined by transmission electron microscopy. The hybrid nanocomposites were composed of intercalated clay particles as well as separated PPO spheres in the epoxy matrix. As determined by dynamic mechanical analysis, the prepared composites possessed glass‐transition temperatures around 220°C. Although the tensile moduli remain unaltered, the tensile strengths of the hybrid materials were significantly improved. The relatively high fracture toughness of the neat resin, though, was not preserved for the hybrid resins. Scanning electron microscopy of the fracture surfaces revealed extensive matrix shear yielding for the neat resin, whereas the predominant fracture mode of the hybrid nanocomposites was crack bifurcation and branching. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3088–3096, 2004  相似文献   

18.
The preparation and measurements of some properties of organic–inorganic hybrid materials derived from Ru(II)‐3‐4,5‐dihyroimidazol‐1‐yl‐propyltriethoxysilane inside a polysiloxane network have been achieved. The hydrolysis and polycondensation of Ru(II)‐3‐4,5‐dihyroimidazol‐1‐yl‐propyltriethoxysilane were performed in different experimental conditions, producing a new organic–inorganic silica. The alkoxysilyl groups available were used for the construction of inorganic backbone by the sol‐gel process, and the imidazole group was found suitable for incorporating Ru(II) by coordination. The coordination of metal complex is retained because there is no leaching from the metal complex containing gels. To ensure sufficient catalytic properties, a series of hybrid materials from tetraethoxysilane was prepared. These materials were identified and catalytic activities were tested for cyclization of (Z)‐3‐methylpent‐2‐en‐4‐yn‐1‐ol to 2,3‐dimethylfuran. Heterogeneous Ru(II) catalyst can also be recycled and reused without significant loss of selectivity or activity. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1329–1334, 2001  相似文献   

19.
Organic–inorganic nanocomposites consisting of co‐poly(vinyl chloride‐vinyl acetate‐vinyl alcohol) and silica were prepared via sol–gel process. Two types of hybrids were prepared, one in which interactions between hydroxyl group present in the copolymer chain and silanol groups of silica network were developed. In the second set, extensive chemical bonding between the phases was achieved through the reaction of hydroxyl groups on the copolymer chains with 3‐isocyanatopropyltriethoxysilane (ICTS). Hydrolysis and condensation of tetraethoxysilane and pendant ethoxy groups on the chain yielded inorganic network structure. Mechanical and thermal behaviors of the hybrid films were studied. Increase in Young's modulus, tensile strength, and toughness was observed up to 2.5 wt % silica content relative to the neat copolymer. The system in which ICTS was employed as binding agent, the tensile strength and toughness of hybrid films increased significantly as compared to the pure copolymer. Thermogravimetric analysis showed that these nanocomposite materials were stable up to 250°C. The glass transition temperature increases up to 2.5 wt % addition of silica in both the systems. Field emission scanning electron microscope results revealed uniform distribution of silica in the copolymer matrix. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

20.
The polystyrene–silica hybrid materials have been successfully prepared from styrene and tetraethoxysilane in the presence of silane‐coupling agents by an in situ sol‐gel process. Triethoxysilyl group can be incorporated into polystyrene as side chains by the free‐radical copolymerization of polystyrene with silane‐coupling agents, and simultaneously polystyrene–silica hybrid materials with covalent bonds between two phases were formed via the sol‐gel reaction. The 3‐(trimethoxysilyl)‐propyl‐methacrylate (MPS) systems were found to be more homogeneous than the corresponding allytrimethoxysilane hybrid system of equal molar content. In the MPS‐introduced system, the thermal properties of the materials were greatly affected by the presence of MPS. FTIR results indicate successful formation of the silica networks and covalent bonding formation of coupling agents with styrene. The homogeneity of polystyrene–silica systems was examined by scanning electron microscope and atomic force microscope. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2074–2083, 2002  相似文献   

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