• Proceedings of the KIEE Conference
• /
• 1999.07d
• /
• pp.1992-1994
• /
• 1999

Dicumyl peroxide (DCP) is used for crosslinking agent in general. And the correlation between polyethylene and DCP is significant in particular radiation environment. On this paper, The effects on $Co^{60}{\gamma}$-ray irradiation of polyethylene doped dicumyl peroxide(DCP) were investigated. We experimented on electrical properties as following; electrical tree inception and growing type for applying AC step voltage, AC breakdown strength, volume resistivity, capacitance and dissipation factor at high frequency as increasing dosage. Also, chemical analysis was performed TGA, gel content.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1995.05a
• /
• pp.129-131
• /
• 1995

In order to investigated the effects of crystal stucture in electrical breakdown of plyethylene film, Low molecular materials in polyethylene are removed by the method as follow Polyethylene was dissolved in xylene and filtered through a glass fiber filter, And then, a polyethyene thin films of thickness 0.4~1.4$\mu\textrm{m}$ are prepared with heat treatment from solution casting. To evaluate the performance of PE film. Electrical breakdown of PE film as measured on M(Al)-I(PE)-M(Al) systemes.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2002.10a
• /
• pp.288-291
• /
• 2002

The carbon fiber or glass fiber reinforced prepregs were manufactured using electrostatic flocking technology. The powder of high density polyethylene was used as a matrix. The base film of polyethylene was prepared using a fluidized bed of polyethylene powder under the high electric field. We obtained HDPE film with uniform thickness of minimum $80\mu\textrm{m}$. And the fibers were aligned on the molten HDPE film by the electroflocking process. The short fibers with 1mm were easily electrically charged and aligned under the high electric field. The carbon fibers with high conductivity were elasily electrically charged than the glass fibers with low conductivity. So lower electric field was needed for the carbon fibers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1996.11a
• /
• pp.283-286
• /
• 1996

A signal generated by partial discharge in low density Polyethylene (LDPE) and cross- linked polyethylene (XLPE) has been detected by ultrasonic sensors. The observed signal is analysed with the quantity of partial discharge, number of peaks, and energy ($\Sigma$y$^2$). It was found that signals between LDPE and XLPE are quite different and that the signal of XLPE has very long duration time and rising time, and that the quantity of partial discharge of XLPE is saturated. It was also found that tree retardant XLPE (TR-XLPE) has lower quantity of partial discharge, number of peaks, and energy than naturalal XLPE.

• Textile Coloration and Finishing
• /
• v.6 no.2
• /
• pp.17-23
• /
• 1994

Carboxylic acid group gradient surface where the density of carboxylic acid groups changes gradually along the sample length was prepared. Carboxylic acid group gradient surface was produced by the treatment of low density polyethylene sheet using a corona with gradually increasing power, followed by the grad polymerization of acrylic acid. The prepared gradient surface was characterized by the measurement of water contact angle, Fourier-transform infrared spectroscopy in the attenuated total reflectance mode, and electron spectroscopy for chemical analysis.

• Proceedings of the KIEE Conference
• /
• 1999.07d
• /
• pp.1667-1670
• /
• 1999

In this paper, We are studied the electrical properties of thin film mixed with LLDPE and EVA, and the specimen is selected as Low Linear Density Polyethylene and Ethylene Vinyl Acetate produced by mixture ratio of 50:50, 60:40, 70:30 and 80:20. (thickness $100[{\mu}m],\;70[{\mu}m],\;50[{\mu}m],\;30[{\mu}m]$). As the electrical properties. one is electrical conduction characteristics of the due to mixture ratio of linear low density polyethylene (LLDPE) and ethylene vinyl acetate(EVA), the other is AC breakdown of specimens due to variation of the thickness. From the result of XRD, it is confirmed that specimen of 80 : 20 and virgin LLDPE have high peaks at $2\theta=21.4[^{\circ}]$ and the peak by the contribution of amorphous at $2{\theta}=19.5[^{\circ}]$ is constant with no relation to mixture ratio, but virgin EVA is somewhat lower.

• International Journal of Highway Engineering
• /
• v.10 no.2
• /
• pp.205-219
• /
• 2008

The polymers, low-density polyethylene (LDPE) and styrene-butadiene-styrene(SBS) -modified asphalt mixtures are advanced asphalt pavement materials in which $3{\sim}6%$ of them, and/or some other additive, by weight of total binder are added. The purpose of modifying asphalt material is to improve typical weakness such as rutting and cracking resistance of normal asphalt mixtures. These materials have been proved to show many advantages and practical applicability in the plant and field. Wet processed PMA binder and/or dry processed asphalt mixtures are developed as field products for many years. The objective of this paper is to show the characteristics of the LDPE and SBS-modified asphalt mixtures by comprehensive evaluation and comparison with those of normal asphalt mixtures.

• 전기의세계
• /
• v.29 no.8
• /
• pp.524-531
• /
• 1980

In order to investigate the effect of inorganic dielectric fine particle mixed in Low Density Polyethylene on the deterioration by treeing, a comparative study for initiation and development of the tree has been carried out between the pure thin film specimen and the same geometrical specimen mixed with a constant weight percent by a defiend particle size of $Al_{2}$O$_{3}$ and SiO$_{2}$, having larger dielectric constants than that of the base material. According to the results, it has been observed that as increasing dielectric constant, the initiation of tree is expedited, however, the development of the tree reached at the surface of filler particles shows the suppressive trends. From these facts, a reasonable interpretation may be possible by considering the effect of intensified electrical field around the tip in the presence of filler particles, that the initiation and the development of tree are a mechanical break down process caused by Maxwell stress due to the concentration of electrical field at the tip. This suppressive effect is specifically suggestive for the reason that a discharge route must be constructed around the particle surface because of the intensified field strength near filler, which, in turn, reduces the geometrical curvature of the tip so that the local intensity of electrical field can be relaxed. Further more an experimental evidence for this assumption was able to observe in this investigation.

• 전기의세계
• /
• v.30 no.7
• /
• pp.441-447
• /
• 1981

As a preceeding work for the study on dielectric characterstics of a kind of low density polyethylene introduced morphological change by mechanical method, glass transition temperature which is regarded as a macroscopic aspect for relaxation of molecular chain segments has been observed by means of temperature dependent dilatometric measurement. The origina specimen clearly shows two knees which correspond to two peaks (.gamma. and .betha. peak) in the intenal friction measurement, suggesting the existence of separated glass transition temperatures at 150.deg.k and 260.deg.k respectively. On the specimen irradiated to 100 Mrad both glass transition temperatures tend to shift towards high temperature sides because of crosslinking by irradiation. furthemore an evidence can be seen that radiation effect, even in amorphous phase, is also slelctive depending on slight morphological differences. The specimen extended to four times in length shows a peculiar nature such as negative linear thermal expansion coefficient increasing with temperature between 220.deg.k and ambient temperature and that this fact is interpreted by considering that c axis of the lattice aligns along the extended direction by drawing, further c axis inherently possesses the characteristics of negative linear thermal expansion coefficient. For the observations that the relatively small positive linear expansion on the specimen extended to ca. two times as well as the part below 220.deg.k of the specimen extended to four times, it is considered for the reason of the facts that the incompletely oriented region indicated as the middle part of Peterlin's model tends to restore partially to orginal arrangement-a kind of phase transition-as increasing with temperature.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.6 no.5
• /
• pp.27-37
• /
• 1992

We studied the dielectric and dynamic mechanical losses according to the quenching condition in low density polyethylene being used to power cables. According to severe quenching condition, characteristics of the temperature in internal friction los peak have decreased the magnitude of loss peak as amorphous region lengthen. From now on, the frequency dependent characteristics of dielectric loss have investigated at room temperature, and the dielectric loss peak due to interface polarization, between crystal and amorphous region, occurs about 30[Hz], and that, the peak due to orientation polarization in correspondence to the loss peak in internal friction has observed at about 3 [MHz]. As quenching velocity increased, the effect on quenching condition about the dielectric loss has decreased the magnitude of the loss peak. Thus, estimation has been carried out on the activation energies nd the degree of crystallinity by means of X-ray diffraction are obtained as follows: room quenching : 26.4 [kal/mole] and 54.73 [%], ice quenching : 25.6 [kcal/mole] and 48.47 [%], liquid nitrogen quenching specimens : 22.56 [kcal/mole] and 40.95 [%].