• Macromolecular Research
• /
• v.10 no.3
• /
• pp.135-139
• /
• 2002

Blends of the linear bisphenol-A polycarbonate (L-PC) and randomly branched bisphenol-A polycarbonate (Br-PC), prepared by co-rotating twin screw extrusion, were investigated using differential scanning calorimetry (DSC), sag resistance time tester, extensional rheometry, and advanced rheometric expansion system (ARES). From the DSC results, the glass transition temperature (T$_{g}$) of the L-PC/Br-PC blend was increased with the increase of Br-PC in the blend, and the blend showed a single T$_{g}$, which suggests a miscible blend. The sag resistance time of the L-PC/Br-PC blend was increased with the increase of Br-PC in the blends. From the results of rheological measurements of the L-PC/Br-PC blends, the extensional viscosity and the complex viscosity of the blends were found to increase with the increase of Br-PC in the blends. The increase of extensional viscosity and complex viscosity was related with the increase of sag resistance time with the Br-PC in the L-PC/Br-PC blends.nds.

• Macromolecular Research
• /
• v.16 no.5
• /
• pp.457-466
• /
• 2008

The relation between the phase separated morphologies and their transport properties in the polymer blend membrane for direct methanol fuel cell application was studied. In order to enhance the proton conductivity and reduce the methanol crossover, sulfonated poly(arylene ether sulfone) copolymer, with a sulfonation of 60 mol% (sPAES-60), was blended with nonsulfonated poly(ether sulfone) copolymer (RH-2000, Solvay). Various morphologies were obtained by varying the drying condition and the concentration of the casting solution (10, 15, 20 wt%). The transport properties of proton and methanol molecule through the polymer blend membranes were studied according to the absorbed water. AC impedance spectroscopy was used to measure the proton conductivity and a liquid permeability measuring instrument was designed to measure the methanol permeability. The state of water in the blend membranes was confirmed by differential scanning calorimetry and was used to correlate the morphology of the membrane with the membrane transport properties.

• Elastomers and Composites
• /
• v.51 no.1
• /
• pp.56-62
• /
• 2016

The isothermal crystallization behaviors of blends of poly(ethylene naphthalate) (PEN) and a thermotropic liquid crystalline polymer (TLCP) were investigated by differential scanning calorimetry (DSC) as functions of crystallization temperature and blend composition. Avrami analyses were applied to obtain information on the crystal growth geometry and the factors controlling the rate of crystallization. The crystallization kinetics of the PEN/TLCP blends followed the Avrami equation up to a high degree of crystallization, regardless of crystallization temperature. The calculated Avrami exponents for PEN/TLCP revealed three-dimensional growth of the crystalline region in each blend. The crystallization rate of each blend increased as the crystallization temperature decreased, and decreased as the TLCP content increased. The crystallization of PEN in the blend was affected by the addition of TLCP, which acts as a nucleating agent.

• Transactions on Electrical and Electronic Materials
• /
• v.7 no.6
• /
• pp.309-312
• /
• 2006

This study shows to blend ethylene vinyl acetate(EVA) and a flame retardant agent, $Mg(OH)_{2}$, and synergists, zinc borate for improving flame retardancy of low density polyethylene(LDPE). And it studied the property of flame retardancy of LDPE/EVA blend by the amount of addition through LOI and TGA, estimated the electrical characteristics such as volume resistivity and breakdown strength. The flame retardancy of LDPE/EVA blend was much improved in case of adding zinc borate with 6phr degree, and the electrical characteristics were more or less decreased depending on increasing the amount of addition. Zinc borate used for improving the flame retardancy of LDPE/EVA blend let the added amount of a flame retardant agent, $Mg(OH)_{2}$ limited, and the electrical characteristics decreased extremely by adding a good deal of $Mg(OH)_{2}$.

• Macromolecular Research
• /
• v.11 no.1
• /
• pp.62-68
• /
• 2003

Thermotropic liquid crystalline polymer (TLCP)/poly(ethylene 2,6-naphthalate) (PEN)/poly(ethylene terephthalate) (PET) ternary blends were prepared by melt blending, and were melt-spun to fibers at various spinning speeds in an effort to improve fiber performance and processability. Structure and property relationship of TLCP/PEN/PET ternary blend fibers and effects of annealing on those were investigated. The mechanical properties of ternary blend fibers could be significantly improved by annealing, which were attributed to the development of more ordered crystallites and the formation of more perfect crystalline structures. TLCP/PEN/PET ternary blend fibers that annealed at 18$0^{\circ}C$ for 2 h, exhibited the highest values of tensile strength and modulus. The double melting behaviors observed in the annealed ternary blend fibers depended on annealing temperature and time, which might be caused by different lamellae thickness distribution as a result of the melting-reorganization process during the DSC scans.

• Proceedings of the Korean Fiber Society Conference
• /
• 2003.10a
• /
• pp.9-10
• /
• 2003

Cellulose/chitosan and sericin/chitosan blend films with various mixing ratios were prepared and tensile properties, solubilities to the aqueous solution of acetic acid and the degree of swelling by the distilled water were measured. The interaction between the components of blend film and the blending effect were investigated.

• Proceedings of the Korean Fiber Society Conference
• /
• 1998.04a
• /
• pp.54-57
• /
• 1998

Recently, Manley's group published several papers on the blend of PVDF and poly(1, 4-butylene adipate) (PBA) chosen as a model system of somicrystallineisemicrystalline polymer blend.[1-4]. This blend system has several advantages over the other PVDF/semicrystalline polymer blends.(omitted)

• Journal of Environmental Health Sciences
• /
• v.24 no.3
• /
• pp.48-53
• /
• 1998

Chitin is known as biodegradable natural polymer. But, in spite of various application of chitin from waste marine sources, commercial use of chitin has been limited due to highly resistance to chemicals and the absense of proper solvents. We made various viscosity of chitosan from chitin by change of Mima's method through the deacetylation which is various condition of NaOH concentration, reaction time and temperature. Also, Polyvinyl alcohol/chitosan blend films were prepared by different solution blends containing the ratio of 5, 10, 15 and 20% chitosan and low, medium, high molecular weight of chitosan to find a more useful biodegradable polymer. Thermal and mechanical properties of PVA/chitosan blend films such as DSC, impact strength, tensile strength and morphological changes by SEM were determined. The 10-15% PVA/chitosan(low, medium) blend films were similar to PVA. Also, PVA/chitosan blend films at the laboratory soil test(Pot Test) were completely degraded in month with four kinds of soils by microorganisms.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2001.10a
• /
• pp.149-152
• /
• 2001

Poly-butylene-terephalate(PBT) can be impact modified by blending with ABS material. The effects of the type of compatibilizer and ABS content on the mechanical properties of PBT/ABS blend were examined in this study. EVA-g-GMA and three type of polycarbonates were used as the compatibilizer. As the GMA content in EVA-g-GMA was increased, the tensile strength of PBT/ABS blend increased and the impact strength of it decreased. With increasing the EVA-g-GMA content in PBT/ABS blend, the tensile strength and impact strength decreased. With PC compatibilizer, the tensile strength of PBT/ABS blend decreased as the ABS content increased. However, the maximum impact strength was observed in 20~30% ABS content range.

• Carbon letters
• /
• v.12 no.2
• /
• pp.85-89
• /
• 2011

Coloured wastewater is released as a direct result of the production of dyes as well as from various other chemical industries. Many dyes and their breakdown products may be toxic for living organisms. Activated carbon is one of the best materials for removal of dyes from aqueous solutions. The present study describes the adsorption behaviour of methylene blue dye on three microporous activated carbons, where two samples (AC-1 and AC-2) were prepared by a polymer blend technique and the other is a microporous activated carbon (ARY-3) sample from viscose rayon yarn prepared by chemical-physical activation. The effects of contact time and activated carbon dosage on decolourisation capacity have been studied. The results show that activated carbon having mixed microporosity and mesoporosity show tremendous decolourisation capacity for methylene blue. In addition, the activated carbon in the powder form prepared by the polymer blend technique shows better decolourisation capacity for methylene blue than the activated rayon yarn sample.