• Membrane Journal
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• v.25 no.2
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• pp.123-131
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• 2015

The PTMSP/PDMS graft copolymer were synthesized from the PTMSP[poly(1-trimethylsilyl-1-propyne)] and the PDMS[poly(dimethylsiloxane)] and then the PTMSP/PDMS-borosilicate composite membranes were prepared by adding the porous borosilicates to the PTMSP/PDMS graft copolymer. The number-average molecular weight (${\bar{M}}_n$) and the weight-average molecular weight (${\bar{M}}_w$) of PTMSP/PDMS graft copolymer were 460,000 and 570,000 respectively, and glass transition temperature ($T_g$) of PTMSP/PDMS graft copolymer appeared at $33.53^{\circ}C$ according to DSC analysis. According to the TGA measurements, the addition of borosilicate to the PTMSP/PDMS graft copolymer leaded the decreased weight loss and the completed weight loss temperature went down. SEM observation showed that borosilicate was dispersed in the PTMSP/PDMS-borosilicate composite membranes with the size of $1{\sim}5{\mu}m$. Gas permeation experiment indicated that the addition of borosilicate to PTMSP/PDMS graft copolymer resulted in the increase in free volume, cavity and porosity resulting in the gradual shift of the mechanism of the gas permeation from solution diffusion to molecular sieving surface diffusion, and Knudsen diffusion. Consequently, the permeability of $H_2$ and $N_2$ increased and selectivity ($H_2/N_2$) decreased as the contents of borosilicate increased.

• Korean Membrane Journal
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• v.9 no.1
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• pp.57-63
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• 2007

Amphiphilic graft copolymer from poly(vinylidene fluoride) (PVDF) was synthesized using atom transfer radical polymerization (ATRP) for composite nanofiltration membranes. Direct initiation of the secondary fluorinated site of PVDF facilitates grafting of tert-butyl methacrylate (tBMA). Amphiphilic PVDF-g-PMAA graft copolymer with a 51:49 wt ratio was obtained by hydrolyzing poly(tert-butyl methacrylate) (PtBMA) to poly(methacrylic acid) (PMAA). Wide angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC) confirmed the decrease of crystallinity of PVDF upon graft copolymerization. Composite nanofiltration membranes were prepared from PVDF-g-PMAA as a top layer coated onto PVDF ultrafiltration (UF) support membrane. The morphology and hydrophilicity of membranes were characterized using scanning electron microscopy (SEM) and contact angle measurement. The rejections of composite membranes were 80.2% for $Na_2SO_4$ and 28.4% for NaCl, and the solution flux were 9.5 and $14.5\;L/m^2\;h$ at 1.0 MPa pressure.

• Journal of Biomedical Engineering Research
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• v.11 no.1
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• pp.47-56
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• 1990

The grafting of butyl methacrylate onto gelatin was investigated by potassium persulfate(KPS) redox system in aqueous solution. The optimum conditions of grafting were observed, and the physical property and the biocolnpatibility of graft copolymer membrane were examined. The gas permeability and the biodegradation by bacteria were decreased with the grafting percentage increased, and tensile strength increased with the grafting percentage increased.

• Elastomers and Composites
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• v.24 no.4
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• pp.265-275
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• 1989

The graft copolymerizations of acrylonitrile (AN) and methyl methacrylate (MMA) onto chloroprene rubber (CR) were carried out with benzoyl peroxide(BPO) as an initiator. The effect of solvent, mole ratio of AN to MMA, reaction time and temperature, and initiator concentration on graft copolymerization were examined. It was observed that the grafting efficiency increased as increasing mole ratio of AN to MMA. the graft copolymer, acrylonitrile- CR-methyl methacrylate (ACM), was identified by infrared spectroscopy and morphology. Thermal stability of ACM was found to be improved when compared with those of CR.

• Polymer(Korea)
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• v.29 no.2
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• pp.127-134
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• 2005

The relationships among mechanical properties, rheological properties, and morphology by reactive extrusion based on commingled pckaging film wastes contains polypropylene (PP) pckaging film system [PP/polyethylene (PE)/aluminum (Al)/poly(ethylene terephthalate) (PET)] and Nylon packaging film system[Nylon/PE/linear-low density polyethylene (LLDPE)] were investigated to improve the compatibility and toughness of these wastes using various compatibilizers such as ethylene vinylacetate (EVA), styrene-ethylene/butylene-styrene triblock copolymer (SEBS), styrene-ethylene/butylene-styrene-graft-maleic anhydride copolymer (SEBS-g-MA), polyethylene-graft-maleic anhydride (PE-g-MA), polypropylene-graft-maleic anhydride (PP-g-MA) , polyethylene-graft-acrylic acid (PE-g-AA) and polypropylene-graft-acrylic acid (PP-g-AA). Compared with simple melt blend system, the blends showed improvement of about $50\%$ increase in physical properties when SEBS and EVA were added. However, SEBS-g-MA thermoplastic elastomer which is highly reactive with amine terminal group of nylon, resulted in about $200\%$ increase in impact strength. This compatibilization effect resulted from the increase of interfacial adhesion and the reduction of domain size of dispersed phase in PP/Nylon blend system.

• Membrane Journal
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• v.18 no.2
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• pp.146-156
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• 2008

In this study, PTMSP of high permeability and high molecular weight was synthesized, and PTMSP-PDMS graft copolymer was synthesized from poly [1-(trimethylsily)propyne] (PTMSP) and hydroxy-terminated poly(dimethylsiloxane) (PDMS). The PTMSP-PDMS-silica composites were prepared by the addition of 15, 30, or 50 wt% tetraethoxysilane (TEOS) to PTMSP-PDMS graft copolymer by sol-gel process. To investigate the physico-chemical characteristics of PTMSP-PDMS-silica/PEI composite membranes, the analytical methods such as $^1H$-NMR, FT-IR, TGA, XPS, GPC, and SEM have been utilized. The gas permeability and selectivity properties of $H_2,\;O_2,\;N_2,\;CO_2,\;CH_4,\;n-C_4H_{10}$, were evaluated. Permeability of the composite membranes increased as TEOS content and pressure increased. Selectivity of $H_2,\;O_2,\;N_2,\;CO_2,\;CH_4,\;and\;n-C_4H_{10}$, showed the maximum value at 30 wt% of TEOS content and decreased thereafter.

• Membrane Journal
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• v.20 no.2
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• pp.169-172
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• 2010

Silver ions of poly(vinyl chloride)-g-poly(styrene sulfonic acid) (PVC-g-PSSA) graft copolymer were reduced to form silver nanoparticles under thermal condition ($80^{\circ}C$). We were successful in synthesizing silver nanoparticles with various morphologies by changing reaction time. At short reaction times (~1 h), silver nanoparticles with 5 nm in size were formed without disrupting a microphase-separated structure of graft copolymer. At medium reaction times (~5 h), silver nanoparticles were aggregated to form large clusters ranging 30~50 nm in size. At much longer reaction times (~18 h), hurricane-like silver clusters were observed due to strong particle aggregation.

• Membrane Journal
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• v.29 no.3
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• pp.164-172
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• 2019

In this work, we demonstrate a facile process to prepare an electrolyte membrane for the supercapacitor based on a graft copolymer consisting of starch and poly(acrylonitrile) (PAN). The graft copolymer (starch-g-PAN) was synthesized via free radical polymerization initiated by ceric ions. The starch-g-PAN was dissolved in ionic liquid, i.e. 1-ethyl-3-methylimidazolium dicyanamide (EMIM DCA) without any organic solvents at room temperature. The gelation of polymer electrolyte membranes occurred by applying high temperature, i.e. $100^{\circ}C$ for 1 hour. The resultant electrolyte membrane was flexible and thus applied to flexible solid supercapacitors. The performance of the supercapacitor based on starch-g-PAN graft copolymer electrolyte reached 21 F/g at a current density of 0.5 A/g. The cell also showed high cyclic stability with 86% of retention rate within 10,000 cycles. The preparation of starch-g-PAN based polymer electrolyte membrane provides opportunities for facile fabrication of flexible solid supercapacitors with good performance.

• Archives of Pharmacal Research
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• v.29 no.8
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• pp.712-719
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• 2006

In this study, we prepared core-shell type nanoparticles of a poly(DL-lactide-co-glycolide) (PLGA) grafted-dextran (DexLG) copolymer with varying graft ratio of PLGA. The synthesis of the DexLG copolymer was confirmed by $^1H$ nuclear magnetic resonance (NMR) spectroscopy. The DexLG copolymer was able to form nanoparticles in water by self-aggregating process, and their particle size was around $50\;nm{\sim}300\;nm$ according to the graft ratio of PLGA. Morphological observations using a transmission electron microscope (TEM) showed that the nanoparticles of the DexLG copolymer have uniformly spherical shapes. From fluorescence probe study using pyrene as a hydrophobic probe, critical association concentration (CAC) values determined from the fluorescence excitation spectra were increased as increase of DS of PLGA. $^1H-NMR$ spectroscopy using $D_2O$ and DMSO approved that DexLG nanoparticles have core-shell structure, i.e. hydrophobic block PLGA consisted inner-core as a drug-incorporating domain and dextran consisted as a hydrated outershell. Drug release rate from DexLG nano-particles became faster in the presence of dextranase in spite of the release rate not being significantly changed at high graft ratio of PLGA. Core-shell type nanoparticles of DexLG copolymer can be used as a colonic drug carrier. In conclusion, size, morphology, and molecular structure of DexLG nanoparticles are available to consider as an oral drug targeting nanoparticles.

• Polymer(Korea)
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• v.34 no.6
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• pp.553-559
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• 2010

The paper describes the preparation and characterization of conductive polyaniline-modified polymers by growing of aniline onto functionalized poly(styrene-co-p-methylstyrene) [P(St-co-MSt)]. For this purpose, P(St-co-MSt) was synthesized via nitroxide mediated radical polymerization (NMRP) and then N-boromosuccinimide was used for introduction of bromine to the benzylic positions of copolymer. Afterwards, 1,4-phenylenediamine was linked to the brominated P(St-co-MSt) and functionalized copolymer $[P(St-co-MSt)-NH_2]$ was prepared. The graft copolymerization of aniline monomers onto functionalized P(St-co-MSt) was initiated by oxidized phenylamine groups after addition of ammonium peroxydisulfate (APS), and p-toluenesulfonic acid-doped PANI was chemically grafted onto P(St-co-MSt) via oxidation polymerization. The obtained terpolymer was studied by FTIR and UV-Vis spectroscopy and its thermal behaviour were examined by DSC and TGA analyses. The conductivity of terpolymer was measured by four-point probe method and electroactivity was measured by cyclic voltammetry (CV). The solubility of P(St-co-MSt)-g-PANI was examined in common organic solvents.