• 제목/요약/키워드: polyethylene terephthalate(PET)

검색결과 336건 처리시간 0.026초

Diffusion of CO2 Molecules in Polyethylene Terephthalate/Polylactide Blends Estimated by Molecular Dynamics Simulations

  • Liao, Li-Qiong;Fu, Yi-Zheng;Liang, Xiao-Yan;Mei, Lin-Yu;Liu, Ya-Qing
    • Bulletin of the Korean Chemical Society
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    • 제34권3호
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    • pp.753-758
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    • 2013
  • Molecular dynamics (MD) simulations have been used to study the diffusion behavior of small gas molecules ($CO_2$) in polyethylene terephthalate (PET)/polylactide (PLA) blends. The Flory-Huggins interaction parameters (${\chi}$) determined from the cohesive energy densities are smaller than the critical value of Flory-Huggins interaction parameters (${\chi}_{critical}$), and that indicates the good compatibility of PET/PLA blends. The diffusion coefficients of $CO_2$ are determined via MD simulations at 298 K. That the order of diffusion coefficients is correlated with the availably fractional free volume (FFV) of $CO_2$ in the PET/PLA blends means that the FFV plays a vital role in the diffusion behavior of $CO_2$ molecules in PET/PLA blends. The slopes of the log (MSD) as a function of log (t) are close to unity over the entire composition range of PET/PLA blends, which confirmes the feasibility of MD approach reaches the normal diffusion regime of $CO_2$ in PET/PLA blends.

Monte Carlo simulation and study of REE/PET composites with wide γ-ray protection

  • Tongyan Cui;Ruixin Chen;Shumin Bi;Rui Wang;Zhongjian Ma;Qingxiu Jia
    • Nuclear Engineering and Technology
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    • 제55권8호
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    • pp.2919-2926
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    • 2023
  • In this paper, rare earth element (REE)/polyester composites were designed with lanthanum oxide, gadolinium oxide, and lutetium oxide as ray shielding agents, and polyethylene terephthalate (PET) as the base. Monte Carlo simulation was carried out using FLUKA software. We found that the radiation protection performance of the composite is affected by the type and amount of REE; a higher amount of REE equated to a better radiation protection performance of the composite. When the thickness of the composite and total thickness of the REE is constant, the number of superimposed layers inside the composite does not affect its shielding performance. Compared with a single-type REE/PET composite, a mixed-type REE/PET composite has a wider range of γ-ray absorption and better radiation protection performance. When the mass ratio of PET to REE is 2:8 and different types of REE are mixed with equal mass, several 0.2 cm-thick mixed-type REE/PET composites can shield >70% of 60 and 80 KeV γ-rays.

Polyethylene terephthalate 중의 가동이온의 계면특성과 이동도에 관한 연구 (A study on the characteristics of interlace and Mobility of Movable Ion in polyethylene Terephthalate)

  • 이호섭;오금곤;국상훈
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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    • pp.233-235
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    • 1988
  • This study investigate that the behavior of movable ion in PET effect on the characteristics of the insulting materials. This examine that movable ion signal to. participation of $Ca^2\;Sb^3$ resulting catalyst refuse and characteristics of activation energy that is need to reionization of movable ion type and neutralized case as measuring characteristics of polarity reversal current or thermally stimulated current.

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전주금형 제작을 위한 폴리머의 엑시머 레이저 어블레이션 (Excimer Laser Ablation of Polymer for Electroformed Mold)

  • 이제훈;신동식;서정;김도훈
    • 한국정밀공학회지
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    • 제21권12호
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    • pp.13-20
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    • 2004
  • Manufacturing process for the microfluidic device can include such sequential steps as master fabrication, electroforming, and injection molding. The laser ablation using masks has been applied to the fabrication of channels in microfluidic devices. In this study, manufacturing of polymer master and mold insert for micro injection molding was investigated. Ablation of PET (polyethylene terephthalate) by the excimer laser radiation could be used successfully to make three dimensional master fur nickel mold insert. The mechanism fur ablative decomposition of PET with KrF excimer laser $({\lambda}: 248 nm, pulse duration: 5 ns)$ was explained by photochemical process, while ablation mechanism of PMMA (polymethyl methacrylate) is dominated by photothermal process, the .eaction between PC (polycarbonate) and KrF excimer laser beam generate too much su.face debris. Thus, PET was adopted in polymer master for nickel mold insert. Nickel electroforming using laser ablated PET master was preferable for replication method. Finally, it was shown that excimer laser ablation can substitute for X-ray lithography of LIGA process in microstructuring.

Comparison of postharvest quality of Aralia elata shoot according to packaging methods

  • Yonghyun Kim;Narae Han;Hyowon Park;Uk Lee;Hyun Ji Eo
    • 한국식품저장유통학회지
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    • 제30권4호
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    • pp.562-572
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    • 2023
  • In this study, we aimed to evaluate the quality of Aralia elata shoots according to different packaging methods during storage at 2℃. The highest level of dehydration and wilting incidences were observed in polypropylene containers with polyvinyl chloride wrap (PP+PVC), and these levels continually increased during the entire storage period, compared to other packaging methods. The overall marketability of A. elata shoot packaged in polyethylene terephthalate container (PET) and PP with the mineral-coted functional warp (PP+F) constantly declined during storage with a similar level of 38.6 and 36.0% at 15 days in storage, respectively. PP with PET cover packaging (PP+PET) showed the lowest decay and wilting rates during the entire storage, and the wilting score at 10th day was 51.9, 58.0, 51.8% suppressed, as compared to PET, PP+PVC, and PP+F, respectively. Consequently PP+PET packaging effectively decreased the deterioration of A. elata and maintained marketability for 10 days of storage at 2℃.

전기설비용 polyethylene terephthalate의 electret 특성연구 (Electret Characteristics of polyethylene terephthalate for electret installation)

  • 국상훈;서장수
    • 한국조명전기설비학회지:조명전기설비
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    • 제10권3호
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    • pp.78-85
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    • 1996
  • 표면전위측정 수단을 이용하여 polyethylene terephthalate의 electret 구조를 해명하는 실험을 하였다. 시료에 전극을 증착하므로서 내부의 전하생성과 감쇠를 관측하였다. electret 의 기구에는 hetero charge 와 home charge가 공존하고 있으며 model로 2전하이론을 기반으로 연구하였는데 hetero charge는 쌍극자와 내부의 이온 변위로 되고 hetero charge를 형성하는 것은 외부에서 주입된 전하라고 생각된다.

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