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Silica Nanocomposites (silica + nanocomposite)

Distribution by Scientific Domains

Polymers and Materials Science	100%

Distribution within Polymers and Materials Science

Polymer Science & Technology General	54%
General & Introductory Materials Science	18%

Selected Abstracts

Preparation of a variety of fluoroalkyl end-capped N -(1,1-dimethyl-3-oxobutyl)acrylamide oligomer/silica nanocomposites possessing no weight loss characteristic at 800°C

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2008
Hideo Sawada
Abstract A variety of fluoroalkyl end-capped N -(1,1-dimethyl-3-oxobutyl)acrylamide oligomer [RF -(DOBAA)n - RF]/silica nanocomposites, in which the oligomer contents are 18,96%, were prepared by reactions of the corresponding fluorinated oligomer with tetraethoxysilane and silica nanoparticles under alkaline conditions. Each fluorinated oligomer/silica composite thus obtained is nanometer size-controlled very fine particles (22,68,nm) possessing a good dispersibility and stability in a variety of solvents including water. Interestingly, the weight loss of RF -(DOBAA)n -RF/silica nanocomposites, in which the oligomer contents are 18,72%, were not observed at all even at 800°C, as well as the original silica nanoparticles, although the corresponding sub-micrometer size-controlled RF - (DOBAA)n -RF/silica composites (particle size: 359,nm) decomposed completely at 800°C to afford the weight loss in proportion to the content of RF -(DOBAA)n -RF oligomer in composites. On the other hand, a slight weight loss of RF -(DOBAA)n -RF/silica nanocomposites, in which the oligomer contents are 75,94%, was observed at 800°C compared to that of the original silica nanoparticles. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Pyrolysis studies of polyethylene terephthalate/silica nanocomposites

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007
Jin Zheng
Abstract The decomposition of pure polyethylene terephthalate (PET) and PET/silica nanocomposites was investigated by thermal gravimetry (TG) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The influence of the nanosized silica on the pyrolysis properties of the composites was found from the results that the activation energies of decomposition and the residual carbon content increase with silica nanoparticles. It is deduced that the increase of the activation energies and the residual carbon content result from the adsorption of the decomposed products on the surface of silica. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source]

Preparation of a variety of fluoroalkyl end-capped N -(1,1-dimethyl-3-oxobutyl)acrylamide oligomer/silica nanocomposites possessing no weight loss characteristic at 800°C

Synthesis and crystallization behavior of acetal copolymer/silica nanocomposite by in situ cationic ring-opening copolymerization of trioxane and 1,3-dioxolane

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008
Lanhui Sun
Abstract The acetal copolymer/silica nanocomposite was prepared by in situ bulk cationic copolymerization of trioxane and 1,3-dioxolane in the presence of nanosilica. The crystallization behavior of acetal copolymer/silica nanocomposite was studied by AFM, DSC, XRD, and CPOM, and the macromolecular structure of acetal copolymer/silica nanocomposite was characterized by FTIR and 1H-NMR. The 1H-NMR results showed that the macromolecular chain of acetal copolymer had more than two consecutive 1,3-dioxolane units in an oxymethylene main chain, while that of acetal copolymer/silica nanocomposite had only one 1,3-dioxolane unit in an oxymethylene main chain. There existed interaction between the macromolecular chains and nanoparticles (such as hydrogen bonds and coordination). On one hand, nanoparticles acted as nucleation center, which accelerated the crystallization rate but reduced the crystallinity. The spherulite sizes also decreased with addition of nanoparticles attributed to the nucleation effect. On the other hand, the presence of nanoparticles interrupted the spherical symmetry of the crystallite. In conclusion, the high surface energy and small scale of nanoparticles have a prominent impact on the polymerization mechanism and crystallization behavior of nanocomposite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

Preparation of a variety of fluoroalkyl end-capped N -(1,1-dimethyl-3-oxobutyl)acrylamide oligomer/silica nanocomposites possessing no weight loss characteristic at 800°C

Designed Multifunctional Nanocomposites for Biomedical Applications

ADVANCED FUNCTIONAL MATERIALS, Issue 10 2010
Humphrey H. P. Yiu
Abstract The assembly of multifunctional nanocomposite materials is demonstrated by exploiting the molecular sieving property of SBA-16 nanoporous silica and using it as a template material. The cages of the pore networks are used to host iron oxide magnetic nanoparticles, leaving a pore volume of 0.29,cm3,g,1 accessible for drug storage. This iron oxide,silica nanocomposite is then functionalized with amine groups. Finally the outside of the particle is decorated with antibodies. Since the size of many protein molecules, including that of antibodies, is too large to enter the pore system of SBA-16, the amine groups inside the pores are preserved for drug binding. This is proven using a fluorescent protein, fluorescein-isothiocyanate-labeled bovine serum albumin (FITC-BSA), with the unreacted amine groups inside the pores dyed with rhodamine B isothiocyanate (RITC). The resulting nanocomposite material offers a dual-targeting drug delivery mechanism, i.e., magnetic and antibody-targeting, while the functionalization approach is extendable to other applications, e.g., fluorescence,magnetic dual-imaging diagnosis. [source]

An Aqueous Emulsion Route to Synthesize Mesoporous Carbon Vesicles and Their Nanocomposites

ADVANCED MATERIALS, Issue 7 2010
Dong Gu
Onionlike mesoporous carbon and carbon,silica nanocomposites with multilayer vesicle structures can be synthesized by an organic,inorganic co-assembly method under hydrothermal conditions in an aqueous emulsion solution (see figure). The nanocomposite vesicles have ordered lamellar mesostructures with about 3,9 layers and carbon pillars are located between the neighboring shells. [source]

Synthesis and characterization of stereoregular poly(methyl methacrylate),silica hybrid utilizing stereocomplex formation

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2004
Achimuthu Ashok Kumar
Abstract Stereoregular poly(methyl methacrylate) (PMMA),silica nanocomposites were prepared using stereocomplex formation between i -PMMA and s -PMMA by an in situ method. The methodology adopted here is the simultaneous formation of organic gel and inorganic gel, the so-called interpenetrating polymer network (IPN) formation. The gelation of i - and s -PMMA were performed by stereocomplex formation with the associated segments forming the crosslinking points in the presence of tetramethoxysilane (TMOS). The effects of the i/s -ratio, PMMA concentration, molecular weight, and solvent nature on the hybrid materials formation were addressed. The presence of the stereocomplex in the silica matrix was confirmed by DSC and solvent extraction methods. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 785,794, 2004 [source]

Tensile creep behaviour of polymethylpentene,silica nanocomposites

POLYMER INTERNATIONAL, Issue 6 2010
Andrea Dorigato
Abstract For the first time, poly(4-methyl-1-pentene) (PMP) nanocomposites were prepared by melt compounding 2 vol% of fumed silica nanoparticles, in order to study the role of the nanofiller surface area and functionalization on the tensile mechanical response of the material, with particular focus on its creep behaviour. The high optical transparency of the polymer matrix was substantially preserved in the nanocomposites, while the mechanical properties (in particular the creep stability) were improved. Dynamic mechanical thermal analysis showed an improvement of the storage modulus, more evident above the glass transition temperature of the polymer matrix. Uniaxial tensile tests evidenced that the elastic modulus of the material was positively affected by the presence of silica nanoparticles, even if a slight reduction of the strain at break was detected. The reduction of the tensile creep compliance was proportional to the surface area of the nanofiller, being more evident at high stresses and elevated temperatures. Findley's law furnished a satisfactory fitting of the creep behaviour of the composites, even at high temperatures. It clearly emerges that the incorporation of fumed silica nanoparticles in PMP can be an effective way to overcome the problem of the poor creep stability of polyolefins, especially at high temperatures and high stresses. Moreover the possibility of retaining the original transparency of the material is fundamental for the production of completely transparent PMP components. Copyright © 2010 Society of Chemical Industry [source]