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Mohammad Ali Semsarzadeh,Maral Ghahramani 한국고분자학회 2015 Macromolecular Research Vol.23 No.10
Poly(methyl acrylate)-poly(dimethyl siloxane)-poly(methyl acrylate) (PMA-PDMS-PMA) and poly(methyl methacrylate)-poly(dimethyl siloxane)-poly(methyl methacrylate) (PMMA-PDMS-PMMA) triblock copolymers were synthesized with atom transfer radical polymerization technique. Thermodynamic properties of block copolymer solutions were investigated. Solubility parameter differences and Flory-Huggins interaction parameters of block copolymer-solvent systems were evaluated for the membrane application. Morphology study indicated cylindrical micelles of PDMS block copolymers. X-Ray analysis confirmed phase separated morphology of PDMS block copolymers in bulk. The effect of polyvinyl acetate (PVAc) on the morphology and its effect on the gas permeation behavior of PMA-PDMS-PMA triblock copolymer was studied. PMA-PDMS-PMA/PVAc blend membranes were shown a new fibrillar morphology. The gas permeation properties and selectivity of the blend membranes were also reported.
Mohammad Ali Semsarzadeh,Parisa Alamdari 한국고분자학회 2015 Macromolecular Research Vol.23 No.2
Cobalt mediated radical copolymerization of vinyl acetate (VAc) and methyl acrylate (MA) was successfullyperformed in the presence of cobalt(II) acetylacetonate (Co(acac)2), dimethylformamide (DMF) and benzoylperoxide (BPO) as catalyst, cobalt coordinating agent and initiator, respectively, at 45 oC. The individual monomerconversion and comonomer composition of copolymers were determined by 1H NMR spectroscopy. Molecularweight (Mn) and its distribution (Mw/Mn) were analyzed by GPC technique. The time dependence of ln[M]0/[M], thevariation of molecular weight with respect to the conversion, and molecular weight distribution of copolymers werestudied to evaluate controlled characteristics of copolymerization. It was found that Co(acac)2 successfully mediatedthe radical copolymerization of VAc and MA. Moreover, copolymer molecular weight and copolymerization rateincreased with increasing initial MA ratio. The spectroscopy analysis revealed VAc content in the copolymerincreased with conversion regardless of VAc initial ratio, indicating a gradient sequence distribution of the copolymer.
Mohammad Ali Semsarzadeh,Eshagh Vakili,Behnam Ghalei,Milad Fardi,Mojtaba Esmaeeli 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.5
Mixed matrix membranes of synthesized polyurethane (PU) based on toluene diisocyanate (TDI), polydimethylsiloxane(PDMS) and polytetramethylene glycol (PTMG) with polyvinyl alcohol based polar silica particles wereprepared by solution casting technique. The homogeneity and thermal properties of the prepared PDMS-PU/silica membraneswere characterized using scanning electron microscope (SEM), differential scanning calorimetry (DSC) andthermal gravimetric analysis (TGA). The SEM micrographs confirmed the distribution of silica particles in the polymermatrix without agglomerations. Gas permeation properties of membranes with different silica contents were studiedfor pure CO2, CH4, O2, He and N2 gases. The obtained results indicated the permeability of the condensable and polarCO2 gas was enhanced whereas permeability of other gases decreased upon increasing the silica content of the mixedmatrix membranes. The permeability of CO2 and its selectivity over N2 was increased from 68.4 Barrer and 22 in purePDMS-PU to 96.7 Barrer and 64.4 in the mixed matrix membranes containing 10 wt% of the silica particles.