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1.
In the presence of 3‐aminopropyltriethoxysilane (APTES), the transparent and yellowish poly(methyl acrylate‐co‐itaconic anhydride)/TiO2 [P(MA‐co‐Itn)/TiO2] hybrid materials were prepared from the copolymer of methyl acrylate and itaconic anhydride [P(MA‐co‐Itn)] and tetrabutyl titanate (TBT) via a sol–gel process. At first, the triethoxysilane groups were incorporated into the copolymer P(MA‐co‐Itn) as pendant side chains by the aminolytic reaction between the itaconic anhydride units of the copolymer and the amino group of 3‐aminopropyltriethoxysilane (APTES), and then the covalent bonds between the organic and inorganic phases were introduced by the hydrolysis and polycondensation of the triethoxysilane groups on the copolymer with TBT. FTIR analysis proved the existence of the covalent bonds. The influences of APTES on glass transition and morphology of the hybrid materials was studied by differential scanning calorimetry, scanning electron microscope, and atomic force microscope. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1763–1768, 2000  相似文献   

2.
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   

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.
BACKGROUND: Polyacrylate/silica nanocomposite latexes have been fabricated using blending methods with silica nanopowder, in situ polymerization with surface‐functionalized silica nanoparticles or sol–gel processes with silica precursors. But these approaches have the disadvantages of limited silica load, poor emulsion stability or poor film‐forming ability. RESULTS: In this work, poly[styrene‐co‐(butyl acrylate)‐co‐(acrylic acid)] [P(St‐BA‐AA)]/silica nanocomposite latexes and their dried films were prepared by adding an acidic silica sol to the emulsion polymerization stage. Morphological and rheological characterization shows that the silica nanoparticles are not encapsulated within polymer latex particles, but interact partially with polymer latex particles via hydrogen bonds between the silanol groups and the ? COOH groups at the surface of the polymer particles. The dried nanocomposite films have a better UV‐blocking ability than the pure polymer film, and retain their transparency even with a silica content up to 9.1 wt%. More interestingly, the hardness of the nanocomposite films increases markedly with increasing silica content, and the toughness of the films is not reduced at silica contents up to 33.3 wt%. An unexpected improvement of the solvent resistance of the nanocomposite films is also observed. CONCLUSION: Highly stable P(St‐BA‐AA)/silica nanocomposite latexes can be prepared with a wide range of silica content using an acidic silica sol. The dried nanocomposite films of these latexes exhibit simultaneous improvement of hardness and toughness even at high silica load, and enhanced solvent resistance, presumably resulting from hydrogen bond interactions between polymer chains and silica particles as well as silica aggregate/particle networks. Copyright © 2009 Society of Chemical Industry  相似文献   

5.
Composite poly(ε‐caprolactone) (PCL)–silica materials for potential use in orthopaedic applications have been prepared by a sol–gel method using an experimental design approach to investigate the effect of synthesis variables, separately and together, on the physical form of the organic polymer. A combination of differential scanning calorimetry, X‐ray diffraction and Fourier‐transform infrared methods were used to obtain information on the arrangement of the organic polymer in the hybrid material. As our studies investigated the effect of synthesis variables simultaneously, it was possible to establish that the increase of tetraethyl orthosilicate (TEOS)/PCL and HCl/TEOS molar ratios decreased the poly(ε‐caprolactone) crystallinity and provided for a better mixing of the two phases. At a mechanistic level it was possible to show that increase in catalyst content affected the condensation of silicon containing species. In vitro calcium phosphate‐forming ability tests using the static biomimetic method have been carried out on selected PCL–silica sol–gels. In vitro bioactivity was only observed for PCL–silica sol–gel composites with high silica content (30% weight). Changes in catalyst levels had a smaller but still significant effect. Calcium phosphate formation on largely non‐porous surfaces is proposed to occur via the formation of a silica sol–gel layer, and is influenced by the topography and the chemistry of the materials surface. Copyright © 2003 Society of Chemical Industry  相似文献   

6.
In this paper, poly(lithium acrylate‐co‐butyl acrylate) [P(AALi‐co‐BA)] was synthesized, and a P(AALi‐co‐BA)‐coated polypropylene (PP) separator was prepared by a simple dip‐coating process. In contrast to the conventional thick, dense gel polymer coating layer, a thin P(AALi‐co‐BA) layer was formed on the PP separator, which had less influence on the pore structure of the original PP separator and was beneficial for the migration of lithium ions through the separator. Furthermore, the AALi units in the copolymer could improve the wettability of the separator, while the BA units provided the separator with strong adhesion to the electrodes. As expected, the modified separators showed good wettability, high ionic conductivity, and excellent interface stability. In addition, the cycle stability and rate performance were also improved significantly. This facile, affordable, and effective method has great application potential for the modification of polyolefin‐based separators. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46423.  相似文献   

7.
Poly(methyl methacrylate–maleic anhydride) [P(MMA–MAn)] with active groups, anhydrides, was synthesized by radical copolymerization. Using P(MMA–MAn) as a basic polymer, the P(MMA–MAn)/SiO2 hybrid materials were obtained by a sol–gel process in different ways. The structures of the materials were characterized by IR spectra, and their properties were studied by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and dynamic analysis (DA). The results show that the hybrids prepared in different ways have different properties, and the contents of SiO2 also have influence on the properties of the hybrids. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 379–383, 2000  相似文献   

8.
Hairy particles were prepared by immobilization of poly(ethylene glycol) (PEG) on the surface of poly(styrene‐co‐maleic anhydride) (poly(S‐co‐MA)) spheres. It was found that the carbonyl groups on the poly(S‐co‐MA) surface can be conveniently esterified with the hydroxyl groups of PEG. Chemical and morphological changes were analyzed by FT‐IR, TEM, and water contact angle. Results revealed that, with the immobilization of PEG, the morphology of poly(S‐co‐MA) turned from a smooth surface to a hairy‐like structure and the hydrophilicity of the polymer particles improved. In addition, berry‐like polymer/silica particles can be obtained by using the hairy particles as template. The PEG hairy chains show steric repulsion during the deposition of silica nanoparticles by in situ sol‐gel process. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

9.
In the past work, the shear resistance of pure poly(n‐butyl acrylate) was low, even incorporation of inorganic filler, silica in the composition. It is well‐known that the copolymerization of n‐butyl acrylate (BA) with methyl methacrylate (MMA) will increase the glass transition temperature, and enhance the shear resistance of acrylic polymers. In the current work, the preparation of a series of acrylic water‐borne pressure‐sensitive adhesives (PSAs) with the controlled composition and structure for the copolymerization of BA and acrylic acid (AA) with different MMA contents, poly(BA‐co‐MMA‐co‐AA) was reported and its effects on adhesive properties of the latices were investigated. The latices of poly(BA‐co‐MMA‐co‐AA) were prepared at a solid content of 50% by two‐stage sequential emulsion polymerization, and this process consisted of a batch seed stage giving a particle diameter of 111 nm, which was then grown by the semicontinuous addition of monomers to final diameter of 303 nm. Dynamic light scattering (DLS) was used to monitor the particle diameters and proved that no new nucleation occurred during the growth stage. Copolymerization of BA with MMA raised the glass transition temperature (Tg) of the soft acrylic polymers, and had the effect of improving shear resistance, while the loop tack and peel adhesion kept relatively high. The relationship between pressure‐sensitive properties and molecular parameters, such as gel content and molecular weight, was evaluated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

10.
The optically transparent poly(methyl methacrylate‐co‐maleic anhydride) P(MMA‐co‐MA)/SiO2? TiO2 hybrid materials were prepared using 3‐aminopropyl triethoxysilane as a coupling agent for organic and inorganic components. Real‐time FTIR was used to monitor the curing process of hybrid sol, indicating that imide group formation decreased with increasing titania content. scanning electron microscopy, atomic force microscopy, and differential scanning calorimetry results confirmed their homogeneous inorganic/organic network structures. TGA analysis showed that incorporated titania greatly prohibits the thermodegradation of hybrid films, especially at the content of 5.3 wt %, showing an increase of about 32.6°C at 5% loss temperature in air. The UV degradation behavior of P(MMA‐co‐MA) studied by quasi‐real‐time FTIR showed that TiO2 incorporated in the hybrid network provides a photocatalytic effect rather than a UV‐shielding effect. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1714–1724, 2005  相似文献   

11.
The radical‐initiated terpolymerization of 3,4‐dihydro‐2H‐pyran (DHP), maleic anhydride (MA), and vinyl acetate (VA), which were used as a donor–acceptor–donor system, was carried out in methyl ethyl ketone in the presence of 2,2′‐azobisisobutyronitrile as an initiator at 65°C in a nitrogen atmosphere. The synthesis and characterization of binary and ternary copolymers, some kinetic parameters of terpolymerization, the terpolymer‐composition/thermal‐behavior relationship, and the antitumor activity of the synthesized polymers were examined. The polymerization of the DHP–MA–VA monomer system predominantly proceeded by the alternating terpolymerization mechanism. The in vitro cytotoxicities of poly(3,4‐dihydro‐2H‐pyran‐alt‐maleic anhydride) [poly(DHP‐alt‐MA)] and poly(3,4‐dihydro‐2H‐pyran‐co‐maleic anhydride‐co‐vinyl acetate) [poly(DHP‐co‐MA‐co‐VA)] were evaluated with Raji cells (human Burkitt lymphoma cell line). The antitumor activity of the prepared anion‐active poly(DHP‐alt‐MA) and poly(DHP‐co‐MA‐co‐VA) polymers were studied with methyl–thiazol–tetrazolium testing, and the 50% cytotoxic dose was calculated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2352–2359, 2005  相似文献   

12.
In this article, polydopamine (PDA) is efficiently adhered on the surface of graphene oxide (GO) by mussel‐inspired chemistry. The obtained reduced GO/PDA (RGO@PDA) nanocomposites are used for catalyzing reversible coordination‐mediated polymerization under microwave radiation. Well‐defined and iodine‐terminated polyacrylonitrile‐co‐poly(n‐butyl acrylate) (PAN‐co‐PnBA) is successfully fabricated by using RGO@PDA nanocomposites as catalysts. Importantly, green and novel strategy of PAN‐co‐PnBA‐type self‐healing nanocomposite materials is further fabricated with RGO@PDA as additive after polymerization as catalyst in one‐pot. As a reinforcement agent, RGO@PDA can also improve the mechanical and self‐healing properties of hybrid materials, which opens up a novel and green methodology for the preparation of self‐healing hybrid materials.  相似文献   

13.
The imidization of poly(styrene‐co‐maleic anhydride) (SMA) was conducted, and the glass‐transition temperatures (Tg's) of the resulting products were measured with differential scanning calorimetry. The contributions from functional groups of maleic anhydride, N‐phenylmaleamic acid, and N‐phenylmaleimide to Tg were examined. Tg increased in the order of SMA < styrene–N‐phenyl maleimide copolymer < styrene–N‐phenyl maleamic acid copolymer and followed the Fox equation. Tg of the imidized products of SMA could be controlled by the conversions of both ring‐opening and ring‐closing reactions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2418–2422, 2007  相似文献   

14.
The effects of three series of self‐synthesized poly(methyl methacrylate) (PMMA)‐based low‐profile additives (LPAs), including PMMA, poly(methyl methacrylate‐co‐butyl acrylate), and poly(methyl methacrylate‐co‐butyl acrylate‐co‐maleic anhydride) with different chemical structures and MWs on the volume shrinkage characteristics and internal pigmentability for low‐shrink unsaturated polyester (UP) resins during curing were investigated by an integrated approach of static phase characteristics of the ternary styrene (ST)/UP/LPA system, reaction kinetics, cured‐sample morphology, microvoid formation, and property measurements. The relative volume fraction of microvoids generated during the cure was controlled by the stiffness of the UP resin used, the compatibility of the uncured ST/UP/LPA systems, and the glass‐transition temperature of the LPAs used. On the basis of the Takayanagi mechanical model, the LPA mechanism on volume shrinkage control, which accounted for phase separation and microvoid formation, and factors leading to both a good volume shrinkage control and acceptable internal pigmentability for the molded parts are discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3388–3397, 2004  相似文献   

15.
We report a facile strategy for fabricating fluorescent quantum dot (QD)‐loaded microbeads by means of microfluidic technology. First, a functional fluorine‐containing microemulsion was synthesized with poly[(2‐(N‐ethylperfluorobutanesulfonamido)ethyl acrylate)‐co‐(methyl methacrylate)‐co‐(butyl acrylate)] (poly(FBMA‐co‐MMA‐co‐BA)) as the core and glycidyl methacrylate (GMA) as the shell via differential microemulsion polymerization. Then, CdTe QDs capped with N‐acetyl‐l ‐cysteine (NAC) were assembled into the poly(FBMA‐co‐MMA‐co‐BA‐co‐GMA) microemulsion particles through the reaction of the epoxy group on the shell of the microemulsion and the carboxyl group of the NAC ligand capped on the QDs. Finally, fluorescent microbeads were fabricated using the CdTe QD‐loaded fluorine‐containing microemulsion as the discontinuous phase and methylsilicone oil as the continuous phase by means of a simple microfluidic device. By changing flow rate of methylsilicone oil and hybrid microemulsion system, fluorescent microbeads with adjustable sizes ranging from 290 to 420 µm were achieved. The morphology and fluorescent properties of the microbeads were thoroughly investigated using optical microscopy and fluorescence microscopy. Results showed that the fluorescent microbeads exhibited uniform size distribution and excellent fluorescence performance. © 2014 Society of Chemical Industry  相似文献   

16.
Two latices—the poly(dimethylsiloxane) (PDMS)/poly(methyl methacrylate‐co‐butyl acrylate‐co‐methacrylic acid) system (PA latex) and the PDMS/poly(vinyl acetate‐co‐butyl acrylate) system (PB latex)—were prepared by seeded emulsion polymerization, and PA/PB complex latices were obtained through the interparticle complexation of the PA latex with the PB latex. In addition, for the further study of the interparticle complexation of the PA latex with the PB latex, copolymer latices [PDMS/methyl methacrylate‐co‐butyl acrylate‐co‐vinyl acetate‐co‐methacrylic acid) (PC)] were prepared according to the monomer recipe of the complex latices and the polymerization process of the component latices. The properties of the obtained polymer latices and complex latices were investigated with surface‐tension, contact‐angle, and viscosity measurements. The mechanical properties of the coatings obtained from the latices were investigated with tensile‐strength measurements. The results showed that, in comparison with the two component latices (PA latex and PB latex) and the corresponding copolymer latices (PC latices), the PA/PB complex latices had lower surface tension, lower viscosities, and better wettability to different substrates. The tensile strengths of the coatings obtained from the complex latices were higher than the tensile strengths of the coatings from the two component latices and copolymer latices. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2522–2527, 2004  相似文献   

17.
The separation of a chlorinated hydrocarbon from a dilute aqueous solution through a crosslinked acrylate copolymer–porous substrate composite membrane by pervaporation was investigated. Poly(n‐butyl acrylate‐co‐acrylic acid) and poly(n‐butyl acrylate‐co‐2‐hydroxyethyl acrylate) were synthesized and composite membranes were prepared, which were made from the crosslinked polymer and a porous substrate. Pervaporation measurement was carried out for a dilute aqueous solution of 1,1,2‐trichloroethane at 25°C and under a vacuum on the permeate side (below 10 mmHg). The separation factor, overall flux, 1,1,2‐trichloroethane concentration in the membrane, and the degree of swelling decreased with increase in the acrylic acid or 2‐hydroxyethyl acrylate content of the acrylate copolymer. The influence of the crosslinking agent content on the pervaporation performance was small, and the separation factor and the overall flux showed a convex curve. The structure of the crosslinking agent had no effect on the separation. The influence of the pore size of the substrate and the thickness of the polymer layer on the separation of 1,1,2‐trichloroethane was observed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 983–994, 1999  相似文献   

18.
Monodispersed crosslinked cationic poly(4‐vinylpyridine‐co‐butyl acrylate) [P(4VP‐BA)] seed latexes were prepared by soapless emulsion polymerization, using 2,2′‐azobismethyl(propionamidine)dihydrochloride (V50) as an initiator and divinylbenzene (DVB) or ethylene glycol dimethacrylate (EGDMA) as a crosslinker. The optimum condition to obtain monodispersed stable latex was investigated. It was found that the colloidal stability of the P4VP latex can be improved by adding an adequate amount of BA (BA/4VP = 1/4, w/w), and adopting a semicontinuous monomer feed mode. Subsequently, poly(4‐vinylpyridine‐co‐butyl acrylate)/Poly(styrene‐co‐butyl acrylate) [P(4VP‐BA)/P(ST‐BA)] composite microspheres were synthesized by seeded polymerization, using the above latex as a seed and a mixture of ST and BA as the second‐stage monomers. The effects of the type of crosslinker, the degree of crosslinking, and the initiators (AIBN and V50) on the morphology of final composite particles are discussed in detail. It was found that P(4VP‐BA)/P(ST‐BA) composite microspheres were always surrounded by a PST‐rich shell when V50 was used as initiator, while sandwich‐like or popcorn‐like composite particles were produced when AIBN was employed. This is because the polarity of the polymer chains with AIBN fragments is lower than for the polymer with V50 fragments, hence leading to higher interfacial tension between the second‐stage PST‐rich polymer and the aqueous phase, and between PST‐rich polymer and P4VP‐rich seed polymer. As a result, the seed cannot be engulfed by the PST‐rich polymer. Furthermore, the decrease of Tg of the second‐stage polymer promoted phase separation between the seeds and the PST‐rich polymer: sandwich‐like particles formed more preferably than popcorn‐like particles. It is important knowledge that various morphologies different from PST‐rich core/P4VP‐rich shell morphology, can be obtained only by changing the initiator, considering P4VP is much more hydrophilic than PST. The zeta potential of composite particles initiated by AIBN in seeded polymerization shifted from a positive to a negative charge. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1190–1203, 2002  相似文献   

19.
A copolymer of styrene and maleic anhydride was synthesized by free radical polymerization at 80°C using N,N‐dimethylformamide (DMF) as solvent and benzoylperoxide as initiator. The monomer feed ratio of styrene to maleic anhydride was varied in the range of 1 : 1 : to 3 : 1. The polymer yield was found to decrease with increase in styrene in the feed. The molecular weight of copolymers which were formed by taking styrene to maleic anhydride ratio of 1 : 1, 2 : 1, and 3 : 1, as determined by Ostwald Viscometery were about 1862, 2015, and 2276 respectively. The acid values of abovementioned three copolymers were found to be 480, 357, and 295, respectively. The typical viscosity values of 20% solids in ammonical solution of copolymers formed by taking feed ratios of Sty : MAn as 1 : 1 and 2 : 1 were 26 and 136 cp, respectively. For the feed ratio 3 : 1, a gel was formed. The synthesized copolymers were hydrolyzed by alkalis, namely, NaOH, KOH, and NH4OH. The dispersing ability of hydrolyzed styrene‐maleic anhydride (SMA) copolymers for dispersion of titanium dioxide was studied. The modified SMA copolymers were found to be effective dispersants for TiO2. Among the three alkalis studied, the Sodium salts of SMA were found to give better dispersion. The copolymer having a 1 : 1 feed ratio showed the best dispersing ability for TiO2 particles among the three ratios studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3194–3205, 2007  相似文献   

20.
Poly(styrene‐co‐maleic anhydride) (SMA)/silica and poly(styrene‐co‐acrylonitrile) (SAN)/silica hybrids were prepared via a sol‐gel route by using silicic acid oligomer (SAO) from water glass in this article. This convenient route is different from the traditional one from tetraethoxysilane (TEOS). The polycondensation behavior of the SAO and the aggregation behavior of the silica particles in the hybrids were investigated. The prepared SMA(SAN)/silica hybrids were characterized by infrared spectroscopy, dynamic light scattering, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. The results showed that the particle size of silica in hybrids increased with increasing silica loading and decreased dramatically by adding the coupling agents. The decomposition temperature and the glass‐transition temperature of the hybrids were higher than the precursory polymers. The mechanical properties of blends of acrylonitrile‐butadiene‐styrene copolymers (ABS) resin with the hybrids were also tested and the results indicated that the well‐dispersed silica particles in the hybrids indeed reinforced the blends. Some nanocomposites based on ABS were prepared in this way. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2289–2296, 2004  相似文献   

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