• Polymer(Korea)
• /
• v.39 no.3
• /
• pp.433-440
• /
• 2015

Aluminum trihydroxide (ATH) has been commonly employed as a flame retardant for ethylene vinyl acetate (EVA) copolymers. In the present work, ATH was obtained from a recycling process of multi-layer packaging film wastes. EVA/ATH composite samples were prepared using a two roll-mill and flame retardancy of EVA/ATH composites were examined using limiting oxygen index (LOI) and flame retardancy test (UL94). We observed excellent flame retardancy in case of adding 150 phr or more of recycled ATH to EVA. Particle size and specific surface area play crucial roles in LOI value and UL-94 classification of the EVA/ATH composites. Smaller particle size and higher specific surface area of ATH was found out to improve the flame retardancy. Regarding tensile properties, crosslinked EVA/ATH compounds which is practically used for electric cables had similar to or even better tensile property values than the ones without ATH.

• Proceedings of the KIEE Conference
• /
• 1999.07d
• /
• pp.1648-1650
• /
• 1999

In the present study. we investigated the role of fillers, alumina trihydrate (ATH) and calcined clay, on the mechanical and electrical properties of EPDM compounds. Mechanical properties and tracking resistance improved with increasing ATH fillers. whereas volume resistivity, tan$\delta$ and dielectric constant decreased when ATH was replaced by clay filler. Futhermore, it was more prominent in $90^{\circ}C$ hot water test. This was explained with polarity of ATH, and the smaller particle size of ATH filler than clay filler.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.11a
• /
• pp.206-209
• /
• 2002

The purpose of this research was to find influence of compounding materials on electrical properties of silicone rubber such as tracking characteristic. The tracking characteristic was tested through controlling the ATH, a widely use anti-tracking agent. Regarding the particle size and coupling agent of ATH, compound silicone rubber with ATH of coupling agent and larger diameter showed better anti-tracking properties. It can be included that ATH of coupling agent use vinyl silane, dispose of tracking characteristic was achieve excellant results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.11a
• /
• pp.216-219
• /
• 2002

Much quantity of anti-tracking agent, ATH is added to the silicone rubber for the protection of silicone rubber against surface discharge. Hydrophobicity recovery properties of silicone rubber could be different by the content, surface treatment state and particle size of ATH. Because hydrophobicity of silicone rubber is depend much on the surface state of ATH. In this paper, the properties of silicone rubber is investigated according to the addition of different particle size of ATH to the silicone rubber. Hydrophobicity recovery properties and arc resistance of silicone rubber were investigated according to the addition of different particle size of ATH. Hydrophobicity recovery properties of silicone rubber were evaluated by the measurement of contact angle.

• Journal of the Korean Society of Safety
• /
• v.20 no.3 s.71
• /
• pp.58-63
• /
• 2005

In this research, silicone rubber with additions of inorganic filler, alumina trihydrate$(Al(OH)_3\;:\;ATH)$, was aged acceleratedly and cyclically by the salt-fog and heating. The optimum amount of ATH addition to silicone rubber have been investigated by measurements of leakage current in the change of electrical properties and tensile strength, %elongation in mechanical properties and FT-IR, TG, SEM in the change of the chemical properties. With regard to un-aged silicone rubber, as the ATH addition amount increases, conductive path formation time was shortened in the electrical properties and tensile strength was increased, %elongation was decreased. In case of identical ATH addition amount, as cyclic aging increases, surface resistivity, tensile strength and %elongation were decreased. Considering the cyclic aging, the most effective amount of ATH addition was about 90phr.

• Journal of Cardiovascular Imaging
• /
• v.26 no.4
• /
• pp.201-213
• /
• 2018

BACKGROUND: Children with significant adenotonsillar hypertrophy (ATH) may show right ventricular (RV) dysfunction. We aimed to evaluate RV dysfunction in such children before adenotonsillectomy by evaluating peak longitudinal right atrial (RA) strain (PLRAS) in systole. PLRAS, electrocardiogram (ECG) and conventional echocardiographic parameters were compared to distinguish children with significant ATH with sleep-related breathing disorder (ATH-SRBD) from controls. METHODS: Fifty-six children (23 controls and 33 children with ATH-SRBD without symptoms of heart failure) were retrospectively studied. Preoperative echocardiograms and ECGs of children with ATH-SRBD who underwent adenotonsillectomy were compared to those of controls. Available postoperative ECGs and echocardiograms were also analyzed. RESULTS: Preoperatively, prolonged maximum P-wave duration (Pmax) and P-wave dispersion (PWD), decreased PLRAS, and increased tricuspid annulus E/E' were found in children with ATH-SRBD compared to those of controls. From the receiver operating characteristic curves, PLRAS was not inferior compared to tricuspid annulus E/E', Pmax, and PWD in differentiating children with ATH-SRBD from controls; however, the discriminative abilities of all four parameters were poor. In children who underwent adenotonsillectomy, echocardiograms $1.2{\pm}0.4$ years after adenotonsillectomy showed no difference in postoperative PLRAS and tricuspid annulus E/E' when compared with those of the preoperative period. CONCLUSIONS: Impaired RA deformation was reflected as decreased PLRAS in children with ATH-SRBD before adenotonsillectomy. Decreased PLRAS in these children may indicate subtle RV dysfunction and increased proarrhythmic risk. However, usefulness of PLRAS as an individual parameter in differentiating preoperative children with ATH-SRBD from controls was limited, similar to those of tricuspid annulus E/E', Pmax, and PWD.

• Clinical and Experimental Pediatrics
• /
• v.57 no.11
• /
• pp.484-488
• /
• 2014

Purpose: Chronic upper airway obstruction causes hypoxemic pulmonary vasoconstriction, which may lead to right ventricle (RV) dysfunction. Adenotonsillar hypertrophy (ATH) is the most common cause of upper airway obstruction in children. Therefore, we aimed to evaluate RV function in children with ATH. Methods: Twenty-one children (male/female, 15/6; mean age, $92.3{\pm}39.0$ months; age range, 4-15 years) with ATH and 21 healthy age- and gender-matched controls were included in this study. Tricuspid annular plane systolic excursion and RV myocardial performance index were measured by transthoracic echocardiography. Further, the plasma level of N-terminal of probrain natriuretic peptide (NT-proBNP), an indicator of RV function, was determined. Results: The snoring-tiredness during daytime-observed apnea-high blood pressure (STOP) questionnaire was completed by the patients' parents, and loud snoring was noted in the ATH group. The plasma NT-proBNP level was significantly higher in the ATH group than that in the controls ($66.44{\pm}37.63pg/mL$ vs. $27.85{\pm}8.89pg/mL$, P=0.001). The echocardiographic parameters were not significantly different between the groups. Conclusion: We were unable to confirm the significance of echocardiographic evidence of RV dysfunction in the management of children with ATH. However, the plasma NT-proBNP level was significantly higher in the ATH group than that in the control, suggesting that chronic airway obstruction in children may carry a risk for cardiac dysfunction. Therefore, more patients should be examined using transthoracic echocardiography. In addition, pediatricians and otolaryngologists should consider cardiologic aspects during the management of children with severe ATH.

• Proceedings of the KIEE Conference
• /
• 2003.07c
• /
• pp.1442-1444
• /
• 2003

폴리머 애자용 shed 재료의 전기방전에 대한 열화내성과 표면이 오염된 조건하에서도 우수한 발수성 유지는 제품의 장기성능에 있어서 가장 중요한 인자들이다. 내트래킹성 확보를 위한 보강재로는 ATH가 주로 사용되고 있으며 ATH의 첨가량이 많을 수록 내트래킹성은 대체로 향상되는 것으로 되어 있다. 그러나 애자 제조시 무결점 성형성의 만족이 대단히 중요하기 때문에 ATH를 고충진하는 경우 사용하는 process oil들의 종류 및 첨가량을 고려한 ATH 첨가량의 최적화는 필요하다. 본 논문에서는 ATH를 170 part로 다량으로 첨가하면서 화학적 구조와 점도가 다른 몇 가지 실리콘 fliud들을 사용하여 무결점 성형에 적합한 가소도를 갖는 컴파운드를 제조하여 기본물성과 초고압 옥외절연물의 shed 재료로서 장기성능에 영향을 주는 방전열화내성과 표면발수성의 회복특성을 평가하였다. 컴파운드의 성형작업성과 관련이 큰 가소도는 fluid 점도에 따라 상당한 차이를 보이므로 실리콘 fluid 종류의 선택과 첨가량의 최적화에는 성형작업성, 발수성 회복특성, 열화내성 등의 고려가 필요하다. 무결점 애자성형을 위한 진공 사출에서 고무 컴파운드의 가소도가 중요한데 동일한 ATH첨가조건에서 일정한 가소도를 갖게 하는데 필요한 양은 fluid들의 종류에 따라서 상당한 차이가 있었다. 코로나 처리후 발수성 회복특성은 fluid들의 분자크기와 반응기의 종류에 따라 상당히 영향을 받았으며 분자가 클수록 초기회복속도는 다소 느렸지만 평상시에 늘 유지되는 상시발수성은 다소 높게 유지되었다. 아크와 트래킹 방전에 의한 무게 감소는 ATH가 과량으로 첨가되어 상당히 적었으며 fluid의 분자가 크면서 페닐기를 가진 fluid들이 첨가된 고무가 우수한 특성을 보였다.

• Proceedings of the KIEE Conference
• /
• 2002.07c
• /
• pp.1437-1439
• /
• 2002

실리콘 고무는 내열성, 내후성, 발수성, 내오염성, 내트래킹성 등이 우수하여 옥외절연물용의 외피 재료로 널리 사용되고 있다. 폴리머 애자에서 전기방전 (코로나, 트래킹 등)에 의한 외피표면의 발수성 저하가 절연물의 장기성능에 있어서 가장 중요한 인자들 중에 하나이다. 실리콘 고무에는 ATH가 다량 첨가되는데 ATH의 첨가량, 표면처리상태, 입도 등에 의해 실리콘 고무의 발수성과 발수성회복 특성은 다르게 나타난다. 본 논문에서는 입도가 다른 2종의 ATH를 선택하여 실리콘 폴리머 대비 ATH의 첨가량을 달리하여 실리콘 고무의 발수성에 관련한 특성을 조사하였다. ATH의 입도 및 코로나 처리시간에 따라서 접촉각의 변화를 관찰하였으며, 코로나 처리 후 경과시간에 따른 발수성의 회복특성을 접촉각의 측정을 통하여 조사하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.227-230
• /
• 2003

Silicone rubber has very excellent chemical stability and hydrophobicity. A hydrophobic surface can prevent the formation of continuous water films on the surface in wet and heavily contaminated conditions. This phenomenon contributes to the suppression of leakage current and partial discharges on insulator surfaces. Silicone rubber has been used much for housing materials of polymer insulators. ATH is added to the silicone rubber for improvement of its resistance against surface discharge. In this paper, ATH with different particle size and content was added to the silicone rubber during compounding. Silicone rubber was deteriorated by a corona treatment. Hydrophobicity recovery rate after corona treatment and arc resistance of silicone rubber were investigated. Hydrophobicity recovery rate of silicone rubber was evaluated by the measurement of contact angle. Arc resistance was evaluated by measuring weight loss of silicone rubber after arc resistance test. It was observed that the hydrophobicity recovery rate and arc resistance of silicone rubber were different when different particle size and content of ATH were added.