in atom transfer radical polymerization (atrp) of methyl acrylate (ma) with polyvinyl acetate macroinitiator in bulk at 90°c the plots of ln [m]0/[m] increased linearly with reaction time. the apparent propagation rate constant (kp app) of the reaction was obtained from the linear curve and used to calculate the free macroradical concentration ([r°]) in polymerization medium. the [r°] and also ...

cellulose was modified by polystyrene (ps) and polyacrylonitrile (pan) via free radical and living radical polymerization, and then cellulose was used as the matrix in the preparation of polymer/clay nanocomposite, through a solution intercalation method. for this purpose, first, the graft polymerization of styrene (st) onto cellulose fibers was performed by using suspension polymerization and ...

bioactive food components (such as phenolic compounds, carotenoids, anthocyanins, tochopherols, ascorbic acid, flavonoids, minerals, enzymes and pectin) are active ingredients in food or dietary supplements, which proven to have an important role in health, and are safe for human consumption. these compounds exert their antioxidant effects by different mechanisms such as single electron transfe...

exfoliated poly (chloromethyl styrene-co-styrene)-g-polyacrylonitryle/organo- modified montmorillonite [p(cmst-co-st)-g-pan/o-mmt] nanocomposite was synthesized through solution intercalation method by using atom transfer and nitroxide mediated radical polymerization. at first, poly (chloromethyl styrene-costyrene) copolymer was synthesized by nitroxide - mediated “living” free radical polyme...

the microstructure and thermal properties of the synthesized block copolymers and terpolymers via atom transfer radical polymerization (atrp) were studied. the mole fraction of the blocks and chain length of the pvac-b-pma block copolymers were estimated with 1h nmr spectroscopy.differential scanning calorimety measurement shows two different transitions at 36°c and 8°c assigned to pvac and pma...

atom transfer radical polymerization of styrene (st) and methyl methacrylate (mma) was performed at 90oc in the absence and presence of nanoclay (cloisite 30b). trichloromethyl-terminated poly(vinyl acetate) telomerand cucl/ pmdeta were used as a macroinitiator and catalyst system, respectively. the experimental results showed that the atom transfer radical polymerization of st and mma in the a...

antioxidants are made for the struggle and reconstruction of the damaged cells, because of their ability in destroying the free radicals. on account of their importance, a theoretical procedure was applied for the study of the molecular structure and radical scavenging activity of six hydroxyphenols which have been introduced as antioxidant compounds. all geometry structures were optimized by m...

Exfoliated poly (Chloromethyl styrene-co-styrene)-g-polyacrylonitryle/organo- modified montmorillonite [P(CMSt-co-St)-g-PAN/O-MMT] nanocomposite was synthesized through solution intercalation method by using atom transfer and nitroxide mediated radical polymerization. At first, poly (chloromethyl styrene-costyrene) copolymer was synthesized by nitroxide - mediated “living” free radical polyme...

The storage capacity of hydrogen on Na-decorated born nitride nanotubes (BNNTs) is investigated by using density functional theory within Quantum Espresso and Gaussian 09. The results obtained predict that a single Na atom tends to occupy above the central region of the hexagonal rings in (5,0) and (3,3) BNNT structures with a binding energy of -2.67 and -4.28 eV/Na-atom respectively. When a si...

Speech to speech translation can benefit from translation of emphasis. We propose to use an intonation model to retrieve and transfer events associated with emphasis in the intonation. This model decomposes the F0 contour into basic intonation atoms using the matching pursuit algorithm. We investigate the role of these components in the perception of emphasis. Some of the most prominent local c...