• Tribology and Lubricants
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• 제8권1호
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• pp.48-55
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• 1992

The friction characteristic of plastics (PTFE, Nylon, Acetal and phenolic) was studied on the lubricated condition with a pin on disk machine. Mineral oil without additive (base oil) and water were used as liquid lubricants at the controlled temperature. From the experimental work, it was found out that the coefficient of friction of plastics was controlled by the mechanical properities of plastic more than that of liquid for various load and temperature. Viscosity of liquid has affected on the friction only at low temperature under lighb load. Among the tested plastics, the coefficient of friction of PTFE was the lowest under light load and at low temperature while Nylon at medium load and temperature, and Acetal at heavy load and high temperature. The coefficient of friction of soft plastics like PTFE and Nylon were increased as the load and temperature were increased, while that of hard plastic (Acetal) was decreased and that of thermo setting plastic (phenolic) was mixed. Also for soft plastics, the coefficient of friction under heavy load was always higher than that under light load, while hard plastic was vice versa.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.341-345
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• 2001

New technoloty called microcellular foaming process was developed at MIT in 1980's. Although it has many good things, it could not be used it all sides of manufacturing plastics. Because it takes a long time for making foamed goods. So microcellular foaming injection molding process appeared to solve this problem. The first purpose of this research is to measure the impact strength as foaming magnitude of microcellular foamed plastics. There are two methods such as batch process and microcellular foaming injection molding process in making foamed plastics. According to the experimental data, the impact strength of each specimen was measured to find out the influence of foaming magnitude of microcellular foamed plastics.

• 한국정밀공학회지
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• 제18권1호
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• pp.195-200
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• 2001

There is a great demand for reducing the amount of material used in mass-produced plastics parts, for material cost constitutes up to 75% of the total production cost. Plastics do not easily decay which causes environmental problem. Furthermore, material reduction therefore decreases the amount of oil needed for the manufacture of plastics and thus help conserve this natural resource. Therefore, microcellular foamed plastics(MCPs) was developed at MIT to solve these problem alternation 1980's. Until now, however, microcellular foaming process not designed systematically because the key factors governing the process were not clear. The goal of this research is to obtain the optimal design of the microcellular plastics by using axiomatic approach.

• Membrane and Water Treatment
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• 제14권4호
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• pp.147-153
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• 2023

Urbanization has been causing such new pollutants as micro-plastic, thus the environmental impact of new pollutants on ecosystem is rapidly increasing. When it comes to micro-plastic, a representative artificial trace pollutant, its risk has been increased at a much faster rate, however the depth study associated with stormwater sediment and wetland was relatively rare. In this research, soil samples from storm water sediment were analyzed for distribution characteristics of micro-plastics in the J wetland (registered as Ramsar wetland, May 2021 and a representative environmental site in South Korea). Analyzed soil samples found approximately 201 ± 93 particle/kg (based on unit weight, Total micro plastic particles / Total Sample weight) micro-plastics in the samples. When considering the total quantitative numbers in stormwater sediment in the entire area of the J wetland, over 15,000 micro-plastics were estimated to be contaminating such area. In addition, in terms of qualitative numbers, micro-plastics were contaminating the J wetland with 94.7 % ratio of styrofoam type (43.9%) and polyethylene type (50.8%). These research results can be used as base data sets for controlling micro-plastics in the J wetland.

• 한국식품과학회지
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• 제40권4호
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• pp.365-374
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• 2008

환경문제가 대두되면서 이미 선진국의 포장재 공급업체들은 소비자의 관심과 재활용 규제가 친환경 포장재 수요를 불러일으킬 것으로 전망하였다. 이러한 수요에 대응하기 위해 옥수수와 같은 식물을 활용해 만든 여러 형태의 바이오 플라스틱을 출시해 왔으며, 국내 업체들에서도 점차 이에 대한 관심을 높여가고 있다. 점차 강화되고 있는 폐기물 부담금과 불안정한 국제 유가를 고려할 때, 바이오 플라스틱은 소비자들의 친환경 제품에 대한 관심과 연결되어 국내 플라스틱 산업의 새로운 활로가 될 것으로 기대된다. 이를 위해서는 비교적 초기단계에 있는 국내 친환경 플라스틱 기술에 대해 기업과 대학에서 활발한 연구가 이루어져야 할 것으로 보인다. 빠르면 2-3년 내에 생분해성 플라스틱을 주원료로 한 도시락 용기, 컵라면 용기 및 각종 상품용 포장용기가 실용화되고, 장기적으로는 폐수내의 중금속 이온 제거제를 비롯하여 생체 의료용제 등과 같은 첨단의 고부가 생명 공학기술을 응용한 다양한 종류의 환경 친화 제품의 출시가 예상되며, 향후 생분해성 플라스틱 산업은 시장 잠재력과 성장성이 무한한 환경 관련 사업으로 평가된다.

• 산업식품공학
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• 제15권3호
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• pp.257-261
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• 2011

본 연구에서는 자연분해재 펠릿과 polyethylene들을 이용해 LDPE와 신장율과 인장강도가 유사한 생붕괴성 플라스틱 필름들을 제조하였다. 식품 포장재로서의 안전성, 광분해성, 열분해성 및 곰팡이 생분해성을 평가한 결과 제작된 생붕괴성 플라스틱 필름들은 식품 포장재로 사용하기에 안전하고 LDPE 필름에 비해 상대적으로 우수한 분해 특성을 나타내어 환경친화적인 식품 포장 소재로 사용될 가능성을 보여주었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.751-754
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• 2001

A possibility of using waste plastics as a source of secondary fuel in blast furnace has been of recent interest. The success of this process, however, will be critically dependent upon the optimization of operating systems. for instance, the supply of waste plastics must be reliable as well as economically attractive compared with conventional secondary fuels such as heavy oil, natural gas and pulverized coal. In this work, we put special importance on the improvement of the combustibility of waste plastics as a way to enhance energy efficiency in blast furnace. As experimental variables to approach this target, the effects of plastic particle size, blast temperature, and the level of oxygen enrichment were investigated using a custom-made blast model designed to simulate a real furnace. Lastly, the combustion efficiency of the mixture of waste plastics and pulverized coal was tested. The observations made from these experiments led us to the conclusion that with the increase of both blast temperature and the level of oxygen enrichment, and with the decrease of particle size, the combustibility of waste PE could be improved at a given distance from tuyere. Also it was found that the efficiency of coal combustion decreased with the addition of plastics; however, the combustion efficiency of mixture could be comparable at longer distance from tuyere.

• 자원리싸이클링
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• 제12권4호
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• pp.44-50
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• 2003

혼합되어 배출되는 플라스틱을 분리 및 선별하기 위한 기존의 방법들은 플라스틱 비중의 유사성, 입도의 제한 등의 요인으로 인해 단일재질의 플라스틱으로 분리하는데 많은 어려움이 따른다. 본 연구에서는 플라스틱의 재질별 연화온도와 점착 특성이 다른 점에 착안하여 열 점착 방식을 이용하여 혼합 플라스틱을 분리하는 방식을 개발하고자 하였다. 일상생활에서 사용되는 범용수지를 시료로 이용, batch 방식의 실험장치를 제작하여 온도를 변화시키면서 각 플라스틱의 점착 온도 범위, 점착율을 실험적으로 조사하였다. 또한 접촉시간과 플라스틱의 착색제의 유무, 입자 크기 등 다양한 조건들을 변화시키면서 그에 따른 영향을 조사하였으며 이를 실제 혼합 폐 플라스틱에 적용하여 분리효율을 조사하였다. 실험 결과 혼합 플라스틱에서 비중이 유사한 LDPE와 HDPE, PET와 PVC, 그리고 PP와 PVC 등을 온도의 변화에 의해 선택적으로 분리할 수 있음을 확인하였다.

• 공업화학
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• 제3권2호
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• pp.201-206
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• 1992

Annual amount of plastics waste including rubber and leather waste, generated in 1990 was about 2,600,000 tons. Amount of generation of plastics waste has rapidly increased, but fractions of recycling and incineration have gradually decreased. Recently, two-stage incinerator, consisting of gasifier and gas combustor, draws much attention in Korea. Plastics are gasified in the starved air condition in the gasifier and produced gas is fired in the combustor. Combustion of produced gas is much easier than that of solid plastics, and produces a little pollutants. Standardzation of technology and process automation are still needed, but this incineration technology is in the commercial stage. Next topic concerned with this two-stage incineration will be how to treat complex plastics waste including toxic substances generated from automobiles and household appliances. Pyrolysis, realized by indirect heating in inert atmosphere, can provide high-quality products with minimum emissions. Many plastics are easily decomposed into oil in pyrolysis conditions, which can be utilized as chemical feedstocks, or gasoline or kerosene depending on feed materials and operating conditions. This has been demonstrated in several pilot-scale tests performed in Japan, Germany, etc. Easy removal of HCl from PVC is one of the most decisive merits of pyrolysis process. But in general, further efforts should be made for the process to obtain marketability. The future of pyrolysis process depends on public concern about environmental problems and oil prices.

• 콘크리트학회논문집
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• 제18권1호
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• pp.117-124
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• 2006

본 연구에서는 복합 재질 폐플라스틱(PA)을 이용한 폴리머콘크리트의 작업성, 경화시간 및 경화수축에 미치는 결합재 첨가량 및 PA 혼입량의 영향에 대하여 검토하였다. 그 결과 복합 재질 폐플라스틱을 재활용한 폴리머콘크리트의 작업성은 결합재 첨가량, PA 혼입량 및 필러 혼입량의 증가에 따라 증가하는 경향을 나타냈다. 복합 재질 폐플라스틱을 이용한 폴리머콘크리트의 경화시간은 촉매제 첨가량 및 양생온도의 증가에 따라 짧아지는 경향을 나타냈다. 복합 재질 폐플라스틱을 이용한 폴리머콘크리트의 길이변화는 결합재 첨가량 및 PA 혼입량의 증가에 따라 증가하는 경향을 보였다. 본 연구 결과가 복합 재질 폐플라스틱 종말품의 재활용에 조금이나마 기여할 수 있을 것을 기대하며 향후 지속적인 연구개발을 통하여 더욱 광범위한 복합재질 폐플라스틱 종말품의 재활용이 이루어질 수 있을 것으로 판단된다.