• Fibers and Polymers
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• v.7 no.1
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• pp.36-41
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• 2006

PVC and SAN are often mixed to compensate for the disadvantages of each polymer. Miscibility and thermal stability of PVC/SAN blend were investigated in this study by blending SAN polymer having 20, 24, 28, 32 % of acrylonitrile contents. Two polymers were mixed using a melt blending method with a single screw extruder. DSC thermogram was used to evaluate miscibility of the two polymers. SAN having 24 % of acrylonitrile showed the best miscibility with PVC. In order to evaluate degradation behavior, blended polymer was heat treated in DSC furnace and glass transition temperature was measured consecutively. Glass transition temperature increased continuously with annealing time due to degradation and cross-linking of polymer chains. Melt index of blended polymer was always higher than that of PVC.

• Journal of Microbiology and Biotechnology
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• v.7 no.4
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• pp.282-286
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• 1997

The floc strength of Escherichia coli was enhanced by adding water soluble polymer flocculants (BPA-5020 and BPA-5000) to the particulate flocculant (BPA-1000) as indicated by the increase in the shear index. The shear index of the E. coli flocs increased from 0.39 with the particulate flocculant alone to 0.94 with the particulate flocculant in conjunction with the water soluble polymer flocculant. In addition, the sedimentation rate of flocs was higher and the sedimented volume of flocs was smaller when the particulate flocculant was used with the water soluble polymer flocculant. When E. coli was flocculated first with the water soluble flocculant and the particulate flocculant was added later into the E. coli flocs formed, the sedimentation rate of the flocs was greater than that of any other combination. The shear index of the flocs was, however, independent of the sequence of the flocculant addition.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.136-141
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• 1998

While a little research has been peformed on flexural behavior of reinforced polymer concrete (RPC)beams with the compressive strength lower than 900kg/$\textrm{cm}^2$ vary little exists in conjunction with the behavior of RPC 1,000kg/$\textrm{cm}^2$ or higher in compressive strength. In this paper the flexural performance of high strength polymer concrete beams with 1,450kg/$\textrm{cm}^2$ in compressive strength was evaluated. The unsaturated polyester resin was used to make polymer concrete as binder. The beams with stirrup singly/doubly were tested to examine the effect of tensile reinforcement ratio. As test results, reinforcement ratio increased with the increase moment strength, decreased with ultimate deflection, ductility index.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.65-72
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• 1996

The general property of plastic ophthalmic lens has been reviewed by the optical property and polymer structure. A PMMA which is synthesized by the polymerization of monomers of two or more kinds is termed a copolymer, and the main chain composes a skeleton of molecular structure in the polymer. Refraction index of polymer was governed mainly by the polarization of molecular and was followed to increase it conspicuously as Cl, Br, and Iodine was substitude to hydrogen. Thermal dependence of refraction index of polymer show that the higher distinctive characteristic than glass material.

• Structural Engineering and Mechanics
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• v.54 no.4
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• pp.711-723
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• 2015

This study investigates the identification of added mass and its location in the glass fiber reinforced polymer (GFRP) beam structures. The main emphasis of this paper is to ascertain the importance of inclusion of rotational degrees of freedom (dofs) in the introduction of added mass or damage identification. Two identification indices that include the rotational dofs have been introduced in this paper: the modal force index (MFI) and the modal rotational curvature index (MRCI). The MFI amplifies damage signature using undamaged numerical stiffness matrix which is related to changes in the altered mode shapes from the original mode shapes. The MRCI is obtained by using a higher derivative of rotational mode shapes. Experimental and numerical results are compared with the existing methods leading to a conclusion that the contributions of the rotational modes play a key role in the identification of added mass. The authors believe that the similar results are likely in the case of damage identification also.

• Explosives and Blasting
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• v.36 no.2
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• pp.1-9
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• 2018

In this paper, AUTODYN blasting simulation of single blast hole were conducted to evaluate the blasting effects of Polymer Gel. The coupling mediums used as the filling material around an explosive charge were air and gelatin. each simulation case was D I(decoupling index) 1.0, 1.25, 1.56 with air or polymer gel coupling materials. In order to evaluate blast effects full charge model was used as a reference for evaluation of blasting effects. The results of numerical analysis showed that fragmentation of a limestone model of were much more fractured by polymer gel medium than by air medium. As expected, the transmitted peak pressure was higher polymer gel coupled model than in air medium.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.5
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• pp.1-10
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• 2011

In this study, 13 water soluble polymers(6 natural polymer, 7 synthetic polymer) were treated on Hanji. Mechanical properties, morphology and oxidation index with thermal aging were measured on the aged Hanji, dewaxed Hanji and polymer treated Hanji. 3 natural polymer(such as CMC, EC, MC) and 3 synthetic polymers(such as PVA 1500, 2000, PEG 1500) treated Hanji had higher strength than other polymer treated Hanji. The oxidation index of 3% methyl cellulose solution treated Hanji did a little increase with thermal aging. Finally, methyl cellulose was found to be the most efficient method for strengthening the dewaxed Hanji. The best aging safety and thermal stability were obtained at the methyl cellulose 3% water solution.

• Polymer(Korea)
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• v.39 no.3
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• pp.499-505
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• 2015

Polyorganosiloxane having controlled cross-linking density and phenyl group content were prepared by dimethyldimethoxysilane (DMDMS), methyltrimethoxysilane (MTMS) and phenyltrimethoxysilane (PTMS). The effect of cross-linking density and phenyl group content on the physical properties of siloxane resin and its coated film have been invetigated. Si-NMR results confirmed that synthesized siloxane resins have equivalent D $T^{Me}$ $T^{Ph}$ structures according to applied mole ratios of DMDMS, MTMS and PTMS. Polyorganosiloxane having higher cross-linking density with high phenyl content showed the high molecular weight and increasing phenyl content resulted in higher refractive index as well as better thermal stability. Cross-linking density is more important factor than phenyl content to obtain higher pencil hardness of coated film on the glass. Our results concluded that even polyorganosiloxanes having similar siloxane structures show different physical properties as function of cross-linking density and phenyl content in polyorganosiloxane.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.1039-1042
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• 2001

A method for designing antireflection (AR) and antistatic (AS) films by the use of conducting polymer as an electrically conductive transparent layer is proposed. The conducting AR film is composed of four-layer with alternating high and low refractive index layer: silicon dioxide (n=1.44) and titanium dioxide (n=2.02) prepared at low temperature by sol-gel method are used as the low and high refractive index layer, respectively. The 3,4-polyethylenedioxythiophene (PEDOT) which has the sheet resistance of 10$^4$$\Omega$/$\square$ is used as a conductive layer. Optical constant of ARAS film was measured by the spectroscopic ellipsometer and from the measured optical constants the spectral properties such as reflectance and transmittance were simulated in the visible region. The reflectance of ARAS films on glass substrate was below 0.8 %R and the transmittance was higher than 95 % in the visible wavelength (400-700 nm). The measured AR spectral properties was very similar to its simulated results.

• Elastomers and Composites
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• v.52 no.1
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• pp.27-34
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• 2017

In this experiment, blends of ethylene vinyl acetate rubber (EVM) with a vinyl acetate (VA) content greater than 40 wt% and ethylene propylene rubber (EPM) were prepared by mechanical mixing; a number of parameters of the blends, including oil resistance, morphological and dynamic mechanical properties and flame retardancy, were subsequently measured. In the $100^{\circ}C$ oil resistance test, both the ammonium polyphosphate/dipentaerythritol/expandable graphite (APP/DPER/EG) and aluminum hydroxide (ATH) flame retardant systems showed an increase in volume change with increasing EPM content. For the ATH system, the dispersion shape was coarse and aggregation was observed. The results of a dynamic mechanical test showed slightly higher E' and E'' for the APP/DPER/EG flame retardant system when compared to the single ATH system. For both the APP/DPER/EG and ATH systems, the limited oxygen index (LOI) tests performed at increasing content of EPM showed a LOI value higher than 30, indicating excellent flame resistance.