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Catalytic Degradation of Mixture of Polyethylene and Polystyrene
Lee, Seung-Yup,Yoon, Jik-Hyun,Park, Dae-Won 한국공업화학회 2002 Journal of Industrial and Engineering Chemistry Vol.8 No.2
The catalytic degradation of a mixture of polyethylene (PE) and polystyrene (PS) was investigated in a semi-batch reactor. The influence of the nature of the cracking catalyst and the reaction temperature was also studied. The main degradation product was liquid oils with gasoline range carbon number distributions. Natural clinoptilolite zeolite (HNZ) exhibited an equivalent catalytic performance to silica-alumina (SA). The HZSM-5 catalyst produced the highest amount of gaseous products. An increase in the degradation temperature resulted in a decrease in ethylbenzene and propylbenzene, but an increase in styrene. A Thermogravimetric analysis revealed an interaction between PE and PS in the catalytic degradation.
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Development of simvastatin electrospun fibers: a novel approach for sustained drug delivery
Sudheer Betha,B. Pamula Reddy,M. Mohan Varma,D. Basava Raju,Venkata Ramana Murthy Kolapalli 한국약제학회 2015 Journal of Pharmaceutical Investigation Vol.45 No.1
In the present investigation simvastatin electrospunfibers were developed using electrospinningapparatus with drug–polymer w/w ratios of 1:1, 1:2, 1:3and 1:4. Also solid mixtures were prepared with sameratios by employing kneading technique as conventionalapproach for comparison in drug release rate. Polyethyleneoxide WSR coagulant 301, a hydrophilic matrix formingpolymer, was used as carrier for sustained release of simvastatin. The ability of polyethylene oxide to control thedrug release rate in both the formulations was also investigated. Studies were performed to characterize the optimizeddosage form. Drug was crystalline in pure form. SEM surface morphology studies as well as powder X-raydiffractometry studies to developed fibers reveals that thecrystalline drug was converted into amorphous form afterfiber development. No physical incompatibility was foundin FTIR and DSC studies of pure drug and physical mixtureof drug, polymer. In vitro studies were performed insodium phosphate buffer (pH 7.0) containing 0.5 % SLS. Simvastatin release was sustained over a period of 12 h inelectrospinning fibers developed with drug to polymer w/wratio 1:4 and 98.86 ± 0.42 % drug release was observed,interestingly with the same ratio there was a burst releaseof drug was obtained in case of solid mixtures ‘‘within spanof 1 h’’. Polyethylene oxide showed vast difference in drugrelease rate due to the techniques chosen to prepare formulations. The stability studies were also performed to theoptimized product and no significant variance wasobserved in all the evaluation parameters. From the variousmathematical models the drug release kinetics was estimatedand found that the drug release followed zero orderrelease rate kinetics with non fickian process as drugrelease mechanism.
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열매유형 용융전기방사장치를 이용한 폴리에틸렌 혼합물의 용융점도와 섬유직경의 상관관계 연구
양희성(Hee Sung Yang),김효션(Hyo Sun Kim),나종성(Jong Sung Na),서영수(Young Soo Seo) 한국고분자학회 2014 폴리머 Vol.38 No.4
용융전기방사법은 유기용매를 사용하지 않아 용액전기방사업에 비하여 친환경 기술로 관심을 받고 있다. 그러나 용융전기방사법으로 제작된 섬유의 직경은 수 마이크론에서 수십 마이크론에 이르고 있어 그 응용성에 제한을 받고 있다. 본 연구에서는 자체 제작한 용융전기방사 장비를 사용하여 용융점도에 따른 방사섬유의 직경의 변화를 체계적으로 연구하였다. 장비가 허용하는 온도 범위에서 방사 가능한 용융점도를 갖도록 저밀도 폴리에틸렌에 폴리에틸렌모노알콜과 폴리에틸렌 왁스를 혼합하여 실험에 사용하였다. 이 고분자 혼합물들을 사용하여 용융점도의 변화에 따라 수 마이크론에서 수십 마이크론까지의 크기를 가진 고른 표면의 섬유를 제조할 수 있었다. 또한 산화된 폴리에털렌 왁스를 혼합물에 사용하여 고분자의 극성에 따른 직경의 변화를 관찰하였다. 부가적으로 인가 전압과 방사 거리 등이 방사섬유의 직경에 미치는 영향을 조사하였다. Electrospinning has gained interests as a polymer processing technique for nanofiber fabrications. It is well known that both polymer solutions and polymer melts can be electrospun. Among them, melt electrospinning is envi-ronmentally friendly technique duo to the absence of solvent. However, the diameter of melt-electrospun fibers is typ-ically thicker than solution-electrospun fibers. By using a home-made melt-electrospinning device, micron-sized fibers with smooth and even surfaces were electrospun successfully. We demonstrate that low-density polyethylene fibers can be reduced in diameter with a viscosity-reducing additive such as low molecular weight polyethylene monoalcohol and polyethylene wax. The diameter was further further reduced by blending it with oxidized polyethylene wax duo to polarity increment. Additionally. parameters affecting the diameter were analyzed such as an applied voltage and a spinning dis-tance.
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혼화재료 및 양생조건에 따른 폴리에틸렌 섬유보강 시멘트 복합재료의 에너지흡수성능 강화
김민재(Kim, Min-Jae),최홍준(Choi, Hong-Joon),전부기(Chun, Booki),신원식(Shin, Wonsik),류두열(Yoo, Doo-Yeol) 한국방재학회 2020 한국방재학회논문집 Vol.20 No.1
본 연구에서는 시멘트 복합재료의 혼화재료 및 양생조건을 조정하여 체적비 2%의 폴리에틸렌 섬유를 혼입한 시멘트 복합재료의에너지흡수성능을 향상시켰다. 사용된 혼화재료는 고로슬래그, 시멘트 킬른 더스트, 석회석 분말, 실리카퓸이고 시멘트 복합재료의 양생조건은 90 ℃, 72시간과 40 ℃, 120시간으로 두 가지이다. 혼화재료의 시멘트 대체율을 기준으로 총 6가지 배합에대하여 압축강도와 직접인장실험을 수행한 후 초고성능 콘크리트 및 ECC의 실험결과와 비교되었다. 실험결과에 따르면90 ℃ 양생기준 최고 압축강도는 117 MPa이고 혼화재료의 시멘트 대체율이 증가함에 따라서 시편의 압축강도가 감소하는것으로 확인되었다. 직접인장 실험의 경우 40 ℃ 양생 시편의 인장강도가 90 ℃ 양생 시편들에 비해서 다소 낮았으나, 인장변형성능이 최대 305%의 증가율을 보이며 7.7%를 기록하였다. 이에 따라서 에너지흡수성능이 80% - 292% 사이의 증가율을 보였다. 또한 미세균열의 수가 크게 증가하고 미세균열의 폭이 감소하는 등 시편들의 균열 및 파괴양상에서도 명확한 차이가 관측되었다. This study aims to enhance the energy absorption capacity of cementitious composites with 2 vol.% of polyethylene fibers, by adjusting mixing ingredients and curing conditions. Ground blast furnace slag, cement kiln dust, limestone powder, and silica fume were incorporated, and two different curing conditions were applied: 72 h of curing at 90 ℃ and 120 h of curing at 40 ℃. Compressive strength test and direct tensile test were performed on 6 mixtures and the test results were compared with those of ultra-high-performance concrete and engineered cementitious composite specimens. The maximum compressive strength of the 6 mixtures was measured to be approximately 117 MPa. The higher cement replacement ratio of the other components resulted in a decrease in the compressive strength of the specimens cured at 90 ℃. In the direct tensile test, the specimens cured at 40 ℃ exhibited lower tensile strength than those cured at 90 ℃, but the strain capacity was increased by approximately 305% and reached 7.7%. This also resulted in an enhancement of the energy absorption capacity from 80%-292% because of the differences in micro-cracking and fracturing behaviors, such as an increase inthe number of micro-cracks and decrease in crack width.
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Polyoxyalkylene Glycol Acrylate기 Gel Polymer Electrolyte를 적용한 리튬이온폴리머전지의 전기화학적 특성
김현수,김성일,나성환,문성인,Kim, Hyun-Soo,Kim, Sung-Il,Na, Seong-Hwan,Moon, Seong-In 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.2
In this work, a gel polymer electrolyte (GPE) was prepared using polyoxyalkylene glycol acrylate (POAGA) as a macromonomer LiCoO$_2$/GPE/graphite cells were prepared and their electrochemical properties were evaluated at various current densities and temperatures. The ionic conductivity of the GPE was more than 6.2${\times}$10$^{-3}$ S$.$$cm^{-1}$ / at room temperature. The GPE had good electrochemical stability up to 4.5 V vs. Li/Li$^{+}$. POAGA-based cells were showed good electrochemical performances such as rate capability, low-temperature performance, and cycleability. The cells, also, passed a safety test such as the overcharge and nail-penetration test.t.
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