• Journal of Energy Engineering
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• v.8 no.1
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• pp.189-201
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• 1999

범용 열가소성 플라스틱(polyethylene(PE), polypropylene(PP), polystyrene(PS), polyethylene-terephthalate(PET), acrylonitrile-butandiene-styrene(ABS))과 폐윤활유의 동시처리 열분해반응 실험을 수행하였다. 반응실험은 40$m\ell$ 용량의 회분식 미분반응기(microreactor)를 이용한 실험과 1리터 용량의 autoclave를 이용한 실험의 두 가지로 구분하여 행하였다. 전자의 경우는 통계적 실험적계획법(statistical experimental design)의 하나인 회전계획실험(rotatable design experiments)으로서 오각형 실험계획(pentagonal experimental design)에 의거한 반응변수 실험을 수행한 후 반응표면(response surface)을 회기분석법에 의하여 분석함으로써 최대의 오일 수율을 얻을 수 있는 최적 반응조건을 추적, 결정하였다. Autoclave 반응실험의 기본적인 목적은 실제 연속공정에 있어서 열분해 반응기 거동을 모사하기 위한 전초단계로서 충분한 시료의 확보를 통하여 이 때 생성된 연로유의 체계적인 분석(비등점분포특성, 진공증류, 기체분석, 원소분석, 발열량, 비중 등)을 행함으로써 연료유 수율 및 품질을 모사하고자 하였다. 미분반응기 실험에 있어서 주 범용열가소성수지인 PE, PP 그리고 PS는 각각의 최적반응조건하에서 거의 100%에 가깝게 오일로 전환되었지만 응축수지인 PET와 그래프트공중합수지인 ABS의 오일수율은 각기 78% 및 90%로서 상대적으로 낮게 나타났다. Autoclave를 이용한 실험의 경우 혼합플라스틱을 폐유에 대하여 40wt% 혼합하여 열분해하였을 때, 80wt% 오일, 15wt% 코우크, 그리고 나머지 5wt%는 탄화수소기체(C1-C6)로 전환되었다. 진공증류(252$^{\circ}C$,2 torr) 결과, 기/액-분리도는 3으로서 이는 생성오일의 75wt%가 경질연료유(가솔린, 등유, 경유)로 회수 가능하였다.

• Resources Recycling
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• v.15 no.1 s.69
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• pp.20-27
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• 2006

PVC is the thermoplastic offering excellent material properties. PVC has been used in wide variety of applications, however, it causes environmental problems when it is discarded because of its high chlorine content. Since dechlorination reaction of PVC is taking place at relatively low temperature compared to the pyrolysis temperature of plastics, study on the dechlorination reaction has been carried out as a pre-treatment process. Twin screw reactor which shows excellent mixing capabilities is employed. Experimental variables are the first and second reactor temperature, PVC content in mixed plastics, viscosity of mixed plastics, feeding rate, rotational speed or the second reactor. Over $90\%$ of dechlorination ratio can be obtained under proper operation conditions. Chlorine gas evolved from reactor is absorbed in water and can be recovered as a hydrochloric acid. Analysis had been done on chlorine flows by taking material balance over realtor.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.83-96
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• 2005

PVC is the thermoplastic offering excellent material properties. PVC is used in wide variety of applications, however, it causes environmental problems when it is discarded because of its high chlorine content. Since dechlorination reaction of PVC is taking place relatively low temperature compared to the pyrolysis temperature of plastics, study on the dechlorination reaction has been carried out as a pre-treatment process. Twin screw reactor which shows excellent mixing capabilities is employed. Experimental variables are first and second reactor temperature, PVC content in mixed plastics, viscosity of mixed plastics, feeding rate, rotational speed of the second reactor. Over 90% of dechlorination rate can be obtained under proper operation conditions. Chlorine gas evolved from reactor is absorbed in water and can be recovered as a hydrochloric acid. Analysis had been done on chlorine flows by taking material balance over reactor.

• Elastomers and Composites
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• v.45 no.3
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• pp.156-164
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• 2010

Thermoplastic elastomers (TPEs) exhibit both elastomeric behaviors at used temperature range and melt processibility. Polyamide based thermoplastic elastomers (TPAEs) are segmented block copolymers with hard blocks consisting of polyamide segments, while the soft blocks usually consist of flexible segments having a low glass transition temperature. The TPAE is one of the engineering TPEs possessing high thermal stability, excellent mechanical performances, chemical resistance and excellent processibility. And they showed wide range of physical and functional properties depending upon the structure of each segment and their relative contents and the hybridization with various inorganic particles. In this review, synthesis, properties, and possible applications of TPAEs are summarized.

• Journal of Aerospace System Engineering
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• v.16 no.1
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• pp.12-16
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• 2022

Currently, Induction welding is attracting attention as a non-contact, clean and fast welding process. However, since thermoplastic resins are not affected by electromagnetic fields, induction welding requires a heating element called a susceptor. Researches are being conducted with the aim of achieving high-quality bonding, however, the factor of a heating element is an issue, hence the need to set a standard. Specimen fabrication and testing are conducted according to ASTM D5868. In this study, we propose that the evaluation criteria be judged on the basis of three factors; the condition of the welded joint surface, void content, and lap shear strength. Since the adhesive surface to be welded melts and solidifies as it cools, rapid temperature changes can generate pores. In addition, if the heating is not uniform, it is difficult to expect the desire performance. Using PA6 (CF 30%) thermoplastic, susceptor fabrication, induction welding and performance verification were conducted.

• Elastomers and Composites
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• v.41 no.4
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• pp.245-251
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• 2006

Thermoplastic elastomer was prepared from dynamical vulcanization of isotactic polypropylene(iPP)/nitrile rubber blend (NBR/iPP=70/30 wt/wt) in an internal mixer using dicumyl peroxide (DCP) as a curing agent and zinc dimethacrylate (ZDMA) as a coagent. There was a great improvement in tensile and tear strength, elongation-at-break and lower tension set when ZDMA was incorporated into the blend, which is supposed to be due to the increase in crosslink density or the rubber phase and the reduction in size of the rubber particles. It was revealed that the dynamically vulcanized blend exhibited good reprocessibility, indicating its thermoplastic nature.

• Design & Manufacturing
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• v.15 no.2
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• pp.1-10
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• 2021

In this study, the current state of the plastics industry has been examined. The direction of development and innovation is reviewed and commented. The technical statuses of various sectors such as thermoplastic resin, composite material, mold engineering, and simulation have been scrutinized. In addition, the industrial status of each sector has been reviewed. Then, the challenges that the plastics manufacturing industry has to deal with have been discussed. Especially, the situation in Republic of Korea has been elaborated in detail. Based on the discussion, an open innovation strategy has been suggested. It has been argued in this work that the open innovation strategy will enables efficient funding and development by avoiding resource consuming rent seeking.

• Resources Recycling
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• v.23 no.4
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• pp.30-36
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• 2014

300,000 tons of waste tires are annually being produced with development of the automotive industry in Korea. Landfill and incineration treatment system are causing the economic problem through secondary environmental pollution and waste. Therefore, as one of the ways to take advantage of this, Thermo-Plastic Vulcanized (TPV) composite was prepared by the ground waste tire and plastic powders. The waste tire powder was gained by mechanical fracturing through crushers. The waste tire powder was ground by a shear crushing method and a 2-stage disk mill method instead of cutting crushing one. The waste tire powder of 50 mesh was mixed with Polypropylene(PP) in various proportions. TPVs were prepared by an extrusion, and tensile and impact tests were performed. In addition, the same experiments were repeated in 40, 80, 140 mesh conditions in order to observe size effect of waste tire powders.

• Applied Chemistry for Engineering
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• v.25 no.2
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• pp.121-133
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• 2014

Block copolymers including ABA triblock architectures are useful as thermoplastic elastomers and toughened plastics depending on the relative glassy and rubbery content. These materials can be blended with other polymers and utilized as additives, toughening agents, and compatibilizers. Most of commercially available block copolymers are derived from petroleum. Renewable alternatives are attractive considering the finite supply of fossil resources on earth and the overall economic and environmental expenses involved in the recovery and use of oil. Furthermore, tomorrow's sustainable materials are demanding the design and implementation with programmed end-of-life. The present review focuses on the preparation and evaluation of new classes of renewable ABA triblock copolymers and also emphasizes on the use of carbohydrate-derived poly(lactide) or plant-based poly(olefins) having a high glass transition temperature and/or high melting temperature for the hard phase in addition to the use of bio-based amorphous hydrocarbon polymers with a low glass transition temperature for the soft components. The combination of multiple controlled polymerizations has proven to be a powerful approach. Precision-controlled synthesis of these hybrid macromolecules has led to the development of new elastomers and tough plastics offering renewability, biodegradability, and high performance.

• Journal of the Korean Institute of Gas
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• v.17 no.5
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• pp.64-68
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• 2013

Non destructive testing(NDT) methods of electrofusion(EF) joints of thermoplastics pipes are required for fusion joint safety and for the long term reliability of a pipe system. Electrofusion joints, which are joined at the proper fusion process and procedures, may encounter defects due to the difference of ovality between pipes and coupling, improper fusion process or porosity result from electrofusion joining. These defects can cause the failure of pipeline and by extension, they can be caused the limit to expand the use of plastics pipes. This paper studies inspection results using ultrasonic imaging method for damaged polyethylene electrofusion joints. Gas was leaking from 250mm diameter polyethylene electrofusion joints at February 2004 which was electrofused at December 1994 and operation pressure was 2.45kPa. First, surface inspection was conducted and then in order to find the types of defects examination using ultrasonic imaging method was performed. Lack of fusion and inappropriate inserting for polyethylene pipes into electrofusion coupling were found and causes of the gas leak were judged that misalignment and insert defect. Cutting inspection was performed and each inspection results were compared to. Results of ultrasonic imaging method and cutting inspection were the same.