• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.4
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• pp.385-391
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• 1992

In this paper, the electrical conduction phenomena of oriented polypropylene film were studied. Especially, as for the range of negative characteristics, it is observed that as increasing ambient temperature, the characteristics are shifted gradually towards the low intensity side of applied field with the decreasing width of the range as well as the fact that the current oscillation takes place at the both transition points of the characteristics. Finally, it is also suggestive that the oscillation characteristics observed on the negative resistance range of the biaxially oriented specimen show the possibility to utilize it as active element materials.

• Transactions on Electrical and Electronic Materials
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• v.1 no.1
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• pp.45-52
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• 2000

The conduction characteristics in Oriented polypropylene (OPP) film were studied over electric field intensities between 10 M/V m and 300 M/V m . The range of the conduction characteristics was divided in to five regions with increasing field intensity. Particularly, in the region from 70 Mb/m to 82 MV/m voltage-controlled negative resistance was displayed. In the negative resistance region current oscillations were also observed the negative resistance characteristics could by explaine by Gibbons theory.

• Journal of Ocean Engineering and Technology
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• v.9 no.1
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• pp.57-62
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• 1995

The hygrothermal effect on three different types of Glass/Polypropylene was investigated under the environment of 4$0^{\circ}C$ distilled water. The residual strength of Glass/Polypropylene with randomly oriented and fiber content of 4-wt%(R40) was found stable under the moisture content of 0.2%. In this case, the maximum moisture content was 0.53%. On the other hand, Glass/Polypropylene with unidirection and 42wt%(U42) and 50st%(U50) fiber content, respectively, showed the residual strength less stable than R40. However, the maximam moisture contents were 0.52% and 0.45% respectively.

• Journal of Adhesion and Interface
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• v.14 no.4
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• pp.192-196
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• 2013

In this study, a series of bi-axially oriented films based on homo polypropylene (PP) and hydrocarbon resin (HCR) modified PP were prepared to investigate their mechanical properties, optical properties, permeability to gases and water vapors and shrinkage ratio. Hydrogenated dicyclopentadiene (DCPD) resin and hydrogenated C9 resin were used as HCR in this study. Bi-axially oriented polypropylene (BOPP) films made with PP/HCR blends showed better mechanical properties (higher Young's modulus), better optical properties (lower haze), lower permeability to gases and water vapors and increased shrinkage ratio than BOPP films made with homo-PP. Hydrogenated DCPD resin and hydrogenated C9 resin showed similar contribution to the improvement in mechanical properties and optical properties of BOPP films, but there are a differences in permeability to gases and water vapors and shrinkage ratio.

• Elastomers and Composites
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• v.15 no.1
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• pp.3-9
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• 1980

The oxygen permeability and it's proofness of te various commercial polymer films have been investigated at the constant pressure and temperature. Oxygen proofness, the reciprocals of the oxygen permeability for the various samples, were determined by means of a coulometric oxygen permeability tester. The testing of sample films was performed at constant temperature $(23{\pm}1^{\circ}C)$ under 1 atm. for 24 hours. The order of the relative proofness observed are as follows; oriented Nylon (O. Nylon)> oriented Polyester (O. PET)>nonoriented Nylon (N. Nylon)>nonoriented Polyester (N.PET)> rigid Polyvinyl chloride (Rigid PVC)>semirigid Polyvinyl chloride (Semirigid PVC)> oriented Polypropylene (O. PP)>plasticized Polyvinyl chloride (P. PVC)> casted Polypropylene (C. PP)> low density Polyethylene (LDPE)>high density Polyethylene (HDPE, Inflation)> high density-polyethylene (HDPE, T-die) The oxygen proofness of the films was increased with the polarity cf polymer, the film thickness and mechanical orientation and decreased with the addition of plasticizer in PVC. For the use of wrapping materials, one film with the polar property in the main chain of the polymer molecule and the others with nonpolar property in it are laminated for the protection from oxygen and moisture.

• Polymer(Korea)
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• v.26 no.6
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• pp.745-751
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• 2002

The anisotropic Raman scattering properties of oriented syndiotactic poly propylene have been investigated using FT-Raman spectrometer in which the fluore scent problem of polymer samples can be removed. To assign the observed Raman bands to their respective symmetry species, the anisotropic scattering results for four different combinations of incident and scattered polarization were compared with those predicted by normal coordinate analysis and infrared dichroism measurement data.

• Journal of Adhesion and Interface
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• v.15 no.1
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• pp.9-13
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• 2014

The purpose of this work is to investigate the specific gravity, thermal, and mechanical property changes of polypropylene (PP)/mica composites before and after solid-state extrusion. On increasing the filler content, the specific gravity of the composites increased. The specific gravity of the oriented specimen containing filler in PP matrix is found to be much smaller than that of pre-specimen due to the formation of more microvoids. The presence of microvoids in the case of oriented composite specimen significantly affected the tensile and flexural properties of the composites. Both flexural strength and modulus of the composites showed maxima when the mica contents was 10 wt%, regardless of the orientation via solid state extrusion.

• Journal of the Korean Society of Safety
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• v.9 no.1
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• pp.48-55
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• 1994

In this paper, It is studied that the variation of the dielectric absorption of the specimen according to the change with $^{60}$ Co-${\gamma}$ ray irradiation dose of the influence of temperature and applied voltage. In order to investigate the effect of irradiated oriented polypropylene film, we have observed dielectric properties within the temporature range of 30~130 ($^{\circ}C$) and voltage range of 100~250 (V). As for the dependency of temperature by tan $\delta$, the $\alpha$ peak which appears at high temperature increases accordingly to the increment of irradiation dose which is contributed by the crystal region and moves towards the high temperature. The $\beta$ peak which appears the orientation by dipoles and molecular motions in the amorphous region at low temperature. For the dependency of voltage by tan $\delta$ at low temperature, the peak of the tan $\delta$ shifts accordingly to the increment of irradiation dose towards the high temperature region.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.2
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• pp.175-182
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• 1990

In order to investigate the conduction characteistics of the biaxially oriented polypropylene film, several measurements have been carried out in the range of temperature between 5['c] and 25['c] as well as the field intensity between 10[MV/m] and 300[MV/m]. The whole range of the characteristics observed at 15['c] appears to be divided into five regions` the Ohmic conduction region due to ionic carrier below 40[MV/m], the region from 40[MV/m] to 70[MV/m] in which the conduction mechanism is attributed to Poole-Frenkel effect, the region from 70[MV/m] to 82[MV/m] in which the negative resistance characteristics are observed, then the region from 82[MV/m] which is dominated by Schottky effect and finally, the region from 240[MV/m] up to the point where dielectric breakdown occurs in which the mechanism is based on Flowler-Nordheim theory.

• Journal of Adhesion and Interface
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• v.17 no.4
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• pp.131-135
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• 2016

We investigated the specific gravity and mechanical property changes of solid-state extruded polypropylene (PP)/talc composites before and after orientation. The specific gravity of the composites increases with increasing the filler contents. The specific gravity of the oriented specimen containing filler in PP matrix is found to be much smaller than that of pre-specimen due to the formation of more micro-voids. It was found that the tensile properties of the composites are increased up to the talc content of 10 wt%, but after the contents exceeding 10 wt%, the tensile properties are decreased. For oriented specimens, the tensile strength of the composites showed monotonously decrease with increasing talc contents. When the contents of talc is 10 wt%, the theoretical values according to Halpin-Tsai equation are close to the experimental values but over 20 wt% of talc contents, the deviation of the experimental values from the theoretical prediction becomes higher. The maximum flexural strength and modulus were observed for PP/talc composites when the talc contents was 10 wt% for both pre-specimen and oriented specimen.