• 폴리머
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• 제26권1호
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• pp.37-44
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• 2002

폐폴리염화비닐수지(waste Polyvinyl chloride, RPVC)와 폐폴리에틸렌수지(waste polyethylene, RPE)의 블렌드를 용융 혼합으로 제조하였으며 상용화제로서 주쇄는 에틸렌 구조를, 측쇄는 에스터 그룹으로 이루어진 공중합체들을 첨가하여 모폴로지 및 인장특성에 미치는 영향을 조사하였다. RPVC가 연속상인 조성비 85/15 wt%, 중간조성 50/50 wt%, RPE가 연속상인 조성비 15/85 wt%로 RPVC/RPE의 조성비를 변화시켜 이들 조성비에서의 상용화제의 영향을 조사하였다. 모폴로지 관찰로 볼 때 RPVC/RPE 블렌드는 $10\mu\textrm{m}$ 이상의 도메인 크기를 보여 상용성이 나쁘며 특히 중간조성에서 가장 나쁜 상용성을 나타내었다. 에틸렌비닐아세테이트 공중합체(EVA)와 에틸렌에틸아크릴레이트 메틸메타크릴레이트 그라프트 공중합체 (ethylene ethylacrylate-graft-methyl methacrylate copolymer, EEA-MMA)가 상용화제로서 우수한 결과를 나타내었다.

• Environmental Engineering Research
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• 제10권2호
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• pp.54-61
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• 2005

Liquid-phase catalytic degradation of waste high-density polyethylene (HDPE) over ZSM-5 (powder type (PW)) and ZSM-5+binder (granule type (GR)) has been investigated with a stirred semi-batch operation at 400°C. Two ZSM-5 catalysts with a different crystal size were synthesized and also each ZSM-5 (25%) Catalyst was mixed with a same binder (kaolin: silica sol: alumina = 55%:10%:10%). The performance of prepared catalysts that has different physicochemical properties was discussed with the cumulative amount distribution, molecular weight distribution and also paraffin, olefin, naphthene and aromatic (PONA) distribution in liquid product. These liquid product quality and distributions were changed depending on the physicochemical properties of the catalyst. Moreover, the characteristic of ZSM-5 in the catalyst was strongly influenced on the activity and PONA distribution in liquid product.

• 한국건설순환자원학회지
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• 제16권1호
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• pp.23-25
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• 2021

• Asian-Australasian Journal of Animal Sciences
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• 제19권12호
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• pp.1728-1736
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• 2006

The effects of green tea (Camellia sinensis) waste silage and supplemental polyethylene glycol (PEG) on rumen fermentation and blood components were studied in cattle. Six Holstein steers were fed three diets in a 3${\times}$3 Latin square design, replicated twice. One diet was a control with no added silage, and the other two diets were supplemented (20% of the dry matter) with green tea waste silage either with (PEG) or without PEG (tea). Most of the fermentation parameters including major volatile fatty acids (VFA) were not affected by the diet treatments. The concentrations of high density lipoprotein cholesterol in the PEG group and urea nitrogen in the tea and PEG groups were greater than those in the control before morning feeding. The plasma 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid equivalent concentration was not different before morning feeding, but 3 h after morning feeding, its concentrations in both the tea and PEG groups were higher than in the control. Although the concentration of plasma vitamin A in the animals was not affected by feeding green tea waste silage, the concentrations of plasma vitamin E were significantly higher in the tea and PEG groups than in the control, both before and 3 h after morning feeding. The results from the present study suggest that feeding diets containing 20% of the dietary dry matter as green tea waste silage to Holstein steers has no negative impact on their ruminal fermentation, and increases their plasma antioxidative activity and concentration of vitamin E.

• 폴리머
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• 제28권6호
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• pp.468-477
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• 2004

폐폴리(염화 비닐) 수지 [waste poly(vinyl chloride), RPVC]와 폐폴리에틸렌 수지 (waste polyethylene, RPE)의 용융 블렌드에 대한 연구로 상용성 향상을 위해 비닐 아세테이트 함량이 다른 4종류의 에틸렌 비닐 아세테이트 공중합체 (EVA)와 에틸렌 메타크릴산 나트륨염 공중합체 (이오노머)를 상용화제로 사용하였으며, 혼합 순서 및 횟수를 변화시키며 물성의 변화를 조사하였다. 비닐 아세테이트의 함량이 높은 EVA가 상용화제로 첨가되었을 경우, 소량 첨가시 큰 인장 강도의 변화를 확인할수 있었으며 이오노머의 경우에는 첨가되는 양에 따라 인장 강도가 서서히 증가되는 경향을 관찰할 수 있었으며, 이러한 결과는 형태학적 특성 변화를 관찰하여 확인할 수 있었다. 블렌드에서의 상용화제의 종류에 따른 상용성은 적외선 분광기를 사용하여 관찰하였으며, 기계적 물성 분석을 통해 EVA 첨가시 이에 따른 인장 강도의 증가를 확인 할 수 있었다. 또한, 혼합 순서 및 횟수 변화에 따른 물성의 변화를 확인하였다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.259-265
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• 2000

This study is a fundamental research for recycling waste vinyl in asphalt concrete mixture for roadway pavement. The mixing method and proper content of waste polyethylene(PE) film were determined through preliminary mix design. This study was performed mix designs using 2 type graduations of aggregate and used two types waste PE film. The asphalt concrete mixture was satisfied with the specification of the Ministry of Construction and Transportation. Its showed that dense grade asphalt concrete mixture containing waste vinyl were higher performance in comparision to other mixtures(common dense grade mixture and gap grade mixtures). From results of this study, it was confirmed that addition of waste vinyl improved on quality of asphalt concrete mixture.

• Elastomers and Composites
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• 제38권4호
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• pp.316-325
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• 2003

본 연구에서는 폐폴리에틸렌 (W-PE)/폐에틸렌비닐아세테이트공중합체 (W-EVA) 블렌드계에 무기계 및 인계 난연제 등을 첨가하여 난연폴리올레핀 발포체를 제조하고, 수지대비 난연제, 특히 무기계 난연제의 종류 및 함량 변화에 따른 발포 및 난연특성의 변화를 조사하였다. 그 결과 W-PE/W-EVA 블렌드계의 조성비가 50/50 (w/w)이고, 수지 대비 난연제의 함량이 220phr의 범위 내에서 가교반응을 쉽게 이룰 수 있을 것으로 생각되는 폐고분자재료를 사용함으로써 가교 및 발포가 효과적으로 이루어져 V-PE 난연 발포체와 비교해 비교적 균일한 독립기포를 갖고, 발포율이 오히려 증가 (100 % 이상)함을 알 수 있었으며, 난연특성 (limiting oxygen index; LOI, heat release rate; HRR, total heat release; THR, effective heat of combustion; EHC등) 또한 높음을 확인할 수 있었다. 그리고 난연제의 종류 및 함량이 발포 및 난연특성에 미치는 영향이 큼을, 그리고 무기계 난연제의 난연 및 연기발생억제 효과를 확인하였다. 무기계 난연제 중 수산화알루미늄은 LOI 상승에, 수산화마그네슘은 발포율 상승 및 HRR, COY를 낮추는 데 효과적임을 알 수 있었고, 수산화알루미늄과 수산화마그네슘을 동시에 사용했을 때 상호작용에 따른 시너지 효과로 난연성을 보다 향상시킴을 확인하였다.

• Elastomers and Composites
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• 제41권2호
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• pp.97-107
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• 2006

폐타이어와 폐수지 처리 문제를 해결하기 위한 방법으로 재생 폴리에틸렌 수지와 신재HDPE를 폐타이어 분말(GWTP)과 치합형 동방향 회전 이축 압출기(Fuly Intermeshing Co-rotating Twin Screw Extruder)를 이용하여 각 조성별로 용융 훈련하여 재생 PE/폐타이어 복합체를 제조하였다. 본 연구에서는 플라스틱 수지 (재생 PE, HDPE)와 폐타이어 분말의 혼합비를 $0\sim50$wt.%로 하였으며, ASTM에 의거하여 인장강도, 파단신율, 충격강도 등의 물성 변화를 확인하였다. 폐타이어 분말 함량이 증가할수록 인장강도가 감소하고 파단신율이 증가하였다. 한편 충격강도는 폐타이어 분말 함량이 30 wt.%일 때 최대이고, 함량이 증가할수록 충격 강도가 감소하는 경향을 나타내었다. 형태학적 고찰에서는 폐타이어 분말의 함량의 증가함에 따라 파단면이 거칠어지는 형상을 관찰하였다. 모세관점도계(Capillary Rheometer)를 이용하여 재생 PE/폐타이어 분말 복합체의 전단속도의 변화에 따른 용융전단점도의 변화와 연화점 (Ts) 등의 유변학적 성질을 분석한 결과, 폐타이어 분말 함량 증가에 따라 외부 응력에 대한 흐름 저항성을 증가시켜 용융점도가 상승하는 결과를 보였으며 측정된 전단율에서 전단 점도는 Power-law 거동을 보였다.

• Journal of Radiation Protection and Research
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• 제42권3호
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• pp.141-145
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• 2017

Background: The concrete walls inside the vaults of cyclotron facilities are activated by neutrons emitted by the targets during radioisotope production. Reducing the amount of radioactive waste created in such facilities is very important in case they are decommissioned. Thus, we proposed a strategy of reducing the neutron activation of the concrete walls in cyclotrons during operation. Materials and Methods: A polyethylene plate and B-doped Al sheet (30 wt% of B and 2.5 mm in thickness) were placed in front of the wall in the cyclotron room of a radioisotope production facility for pharmaceutical use. The target was Xe gas, and a Cu block was utilized for proton dumping. The irradiation time, proton energy, and beam current were 8 hours, 30 MeV, and $125{\mu}A$, respectively. To determine a suitable thickness for the polyethylene plate set in front of the B-doped Al sheet, the neutron-reducing effects achieved by inserting such sheets at several depths within polyethylene plate stacks were evaluated. The neutron fluence was monitored using an activation detector and 20-g on de Au foil samples with and without 0.5-mm-thick Cd foil. Each Au foil sample was pasted onto the center of a polyethylene plate and B-doped Al sheet, and the absolute activity of one Au foil sample was measured as a standard using a Ge detector. The resulting relative activities were obtained by calculating the ratio of the photostimulated luminescence of each foil sample to that of the standard Au foil. Results and Discussion: When the combination of a 4-cm-thick polyethylene plate and B-doped Al sheet was employed, the thermal neutron rate was reduced by 78%. Conclusion: The combination of a 4-cm-thick polyethylene plate and B-doped Al sheet effectively reduced the neutron activation of the investigated concrete wall.

• Geomechanics and Engineering
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• 제30권6호
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• pp.517-524
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• 2022

Every year, millions of waste tires are discarded across the world. Storage of waste tires presents many problems such as fire threats, epidemics, and non-economic factors. Furthermore, the disintegration process of waste tires is not economical or practical due to its time-consuming, and disposal requirements. In this study, half-section waste tires (HSWTs) were integrated with high-density polyethylene (HDPE) pipes under different relative density conditions. The main aim of the study was to reduce the deformation values of embedded HDPE pipes in sandy soil and to evaluate the soil-pipe interaction. In comprehensive laboratory tests, half-section waste tires were integrated in two different ways: in the middle of the pipeline and along the pipeline. Accordingly, it was concluded that the effectiveness of waste tires reduces the deformation and bending moment values in the critical regions of pipes. As a result of reinforcement in the mid-point of the pipe defined as the most critical region, 52% and 36% less deformation was observed in the crown and springlines of the pipe, respectively. In addition, the bending moment values for the same critical section were determined to be 40% less in the crown and 28% less in the springline regions of the pipe.