• Advances in materials Research
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• 제7권2호
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• pp.149-162
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• 2018

Following our previous work, we have conducted further systematic studies to investigate the effects of reactive blending on the thermal and mechanical properties of blends of poly(lactic acid) (PLA) and a liquid rubber, polybutadiene (LPB). The toughened PLAs were prepared by melt-blending the PLA with various contents (0-9 wt.%) of the LPB in the absence or presence of dicumyl peroxide (DCP), a radical initiator. It was found that the rubber domains were homogeneously dispersed at the nanoscale in the PLA matrix up to 9 wt.% of LPB thanks to the reactive blending in the presence of DCP. Owing to the compatibilization of PLA with LPB through reactive blending, the elongation and toughness of PLA was enhanced, while the hydrolytic degradation of PLA was reduced.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.39-41
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• 2012

The influence of coal blending methods such as out-furnace (external or pre-mixed) blending and in-furnace (initially non-mixed) blending with different excess oxygen (highest, medium, and lowest stoichiometric conditions) on unburned carbon and NOx emissions of blend combustion in an entrained flow reactor (EFR) has been analyzed, using experimental and numerical approaches for binary coals used by Korean power plants. The results confirm that under the medium condition, contrasting processes such as reactive and un-reactive effects occur with SBRs in the out-furnace blending method. The in-furnace blending method results in an improvement in the efficiency of unburned carbon fractions and a further reduction in the NOx emission. Under the highest condition, the unburned carbon fraction in both the out-furnace and the in-furnace blending methods corresponds with the tendency under the medium condition with contrasting processes of lower magnitude, whereas the NOx emission in the highest condition increases slightly. Under the lowest conditions, the unburned carbon fraction in the out-furnace blending method gradually decreases as SBR decreases, without a competition effect. The reduction of NOx emission under the lowest conditions is more effective than those under other conditions for the two blending methods because of a homogeneous and heterogeneous NOx reduction mechanism.

• 폴리머
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• 제30권2호
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• pp.118-123
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• 2006

폴리(부틸렌 테레프탈레이트)(PBT)와 폴리(에틸렌 테레프탈레이트)(PET)의 용융 가공시 발생하는 상호에스테르 교환반응이 PBT/PET 블렌드의 유변 물성에 미치는 영향에 대하여 살펴보았다. PBT에 PET를 용융 블렌딩하면 PET의 상대적인 낮은 점도에 의하여 PET의 함량이 증가할수록 PET의 점도가 감소됨을 알 수 있었으며 이와 함께 용융가공시 발생하는 분자량 감소와 PBT와 PET 상호간에 발생하는 상호에스테르 교환반응에 의하여 추가적인 용융점도 감소가 있음을 확인하였다. 또한 PBT와는 달리 윤활제로 사용한 calcium stearate(CaST)는 PBT/PET 블렌드에서 윤활 작용은 미약한 반면 이들 블렌드의 열분해에 따른 분자량 감소와 상호에스테르 교환반응을 촉진하여 추가적인 용융점도 감소를 초래함을 알 수 있었다.

• Nuclear Engineering and Technology
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• 제56권9호
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• pp.3942-3949
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• 2024

This study focuses on investigating the chemical degradation characteristics of cementitious barriers used in low-and intermediate-level radioactive waste repository by reactive transport modeling. The impact of the blending with supplementary cementitious materials (SCMs) in the barriers on the chemical degradation was evaluated to find the optimum barrier design. A number of different barrier designs were examined by replacing ordinary Portland cement (OPC) by SCMs (i.e., fly ash, silica fume, and blast-furnace slag). The simulation results showed that silica fume blended barrier has better durability against chemical degradation by rainwater compared to fly ash or blast-furnace slag blended barriers. In addition, the chemical durability of silica fume-based barrier increased with increasing replacement level up to about 20 %. It seems that the amount of formed calcium silicate hydrate (CSH) in the initial cement-based barrier highly affects the overall chemical durability. The newly developed reactive transport model demonstrated its capability for understanding the barrier performance and investigating the optimal design of the barrier system.

• Elastomers and Composites
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• 제48권4호
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• pp.249-255
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• 2013

Hydrogen terminated PDMS와 allyl alcohol를 Karstedt's 촉매 존재하에서 hydrosilylation 반응을 이용하여 hydroxypropyl terminated PDMS를 합성한 후, 3관능 HDI isocyanurate trimer와 hydroxyethyl methacrylate를 one-pot 반응으로 초분지 형태의 다관능 실리콘 변성 우레탄 아크릴레이트 올리고머(PUA 올리고머)를 합성하였다. 합성된 PUA 올리고머의 특성은 FT-IR과 GPC를 사용하여 분석하였으며, 그들의 중량평균 분자량은 약 9000 g/mol 이었다. 합성된 PUA 올리고머와 반응성 모노머인 phenylthioethyl acrylate를 여러 가지 조성비로 혼합하고 UV-광경화반응을 이용하여 연성 경화물을 제조하였다. 연성 경화물의 굴절률은 phenylthioethyl acrylate 첨가함에 따라 증가하였으나 반응성 모노머 함량과 관계가 없었다. 또한, 연성 경화필름의 광투과도 변화도 없었다.

• Elastomers and Composites
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• 제50권3호
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• pp.189-195
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• 2015

In this study, we prepared epoxidized poly ethylene-ter-1-decene-ter-divinylbenzene (Epo-PEHV) as a reactive compatibilizer to prevent phase separation phenomenon which occurs upon blending polypropylene (PP) and ethylene-vinyl alcohol copolymer (EVOH). Firstly, PEHV was prepared under high catalyst activity according to content of catalyst and cocatalyst. After then, we modified vinyl group of the terpolymer with epoxy group. We observed that the terpolymer was successfully epoxidized by 1H-NMR and FT-IR analysis. The Epo-PEHV was added by 2, 5, 10% in PP/EVOH blends. The morphologies and mechanical properties of PP/Epo-PEHV/EVOH blends were analyzed by SEM and UTM, respectively. Epo-PEHV enhanced the interfacial adhesion of PP and EVOH blends.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.260-260
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• 2006

Sericin was modified by solution blending (10-30 wt%) with 70-90 wt% polyacrylamide (PAM) in water. The reactive sites of sericin such as serine and tyrosine were attached to PAM. Proton Nuclear Magnetic Resonance ($^{1}H-NMR$) and thermogravimetric analysis were used to characterize the modified sericin. The electrospinning conditions i.e. the blend composition and the power supply voltage, at a tip to target distance of 15 cm were studied. The morphology of nanoparticles and nanofibers was observed by scanning electron microscopy. The average particles size of the nanoparticle obtained was 191 nm and nanofibers was 150-300 nm.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1082-1082
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• 2001

Extrusion is one of the most important processes in polymer industry. The characterization of the polymer melt during processing will improve this process noticeably, One possibility of characterizing the actual processed polymer melt is the inline near infrared (NIR) spectroscopy, With this method several polymer properties can be observed during processing, e.g. composition, moisture ormechanical properties of the melt. For this purpose probes for transmission and reflection measurements have been developed, withstanding the high temperatures and pressures appearing during extrusion process (tested up to 300$^{\circ}C$ and 10 ㎫). For the transmission system an optical bypass was developed to eliminate disturbing spectral influences and hence increase the long term stability, which is the prerequisite for an industrial application. Measurements in transmission and reflection produced comparable results (or blending processes, where the prediction error was less than 1%. An optimum RMSEP of only 0.24% was found for preprocessed polymer blends measured in transmission on a laboratory extruder. A transflection measurement allowed for the first time the recording of relevant NIR-spectra in the screw area of an extruder. The application to a (PE+PP) blending process delivered promising results. This new measurement mode allows the observation of the ongoing processes within the screw area, which is of maximum Interest for reactive extrusion processes. Due to economic reasons the calibration transfer between different extrusion systems is also of high importance. Investigations on simulated and real-world spectra showed that a calibration transfer is possible. A new method alternatively to the well-known direct standardization procedures was developed, which is based on an automatic data pretreatment. This procedure delivers comparable results for the calibration transfer. Overall this paper presents concepts, components and algorithms for the inline near infrared (NIR) spectroscopy for polymer extrusion, which allows the use of it in a real industrial extrusion process.

• 청정기술
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• 제15권3호
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• pp.180-185
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• 2009

자동차용 웨더스트립 제조공정 중 발생하는 에틸렌-프로필렌 고무 스크랩을 고온전단분쇄기를 이용하여 표면활성화 된 분말을 얻은 후 이를 폴리프로필렌과 블렌드하여 열가소성탄성체를 제조하기 위한 기초연구를 수행하였다. 에틸렌-프로필렌 고무 스크랩 분쇄 시 표면활성제를 1.5 phr 첨가하면 최적의 표면활성화 된 분말을 얻을 수 있었다. 폴리프로필렌의 경우는 maleic anhydride를 반응블렌드에 의해 그라프트시켜 기능화 하였다. 기능화된 에틸렌-프로펄렌 분말과 폴리프로필렌을 블렌드하여 열가소성탄성체를 제조할 때 계면젖음 특성이 중요하기 때문에 계면젖음성을 향상시키기 위하여 상용화제로 poly(ethylene-co-acrylic arid)를 폴리프로필렌에 첨가하였다. Poly(ethylene-co-acrylic acid)는 폴리프로필렌의 표면장력을 감소시켰으며 이로 인해 에틸렌-프로필렌 분말과의 계면젖음성이 크게 증진될 것으로 기대된다.

• 한국농공학회논문집
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• 제52권4호
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• pp.93-101
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• 2010

The purpose of this study is to provide basic data for utilization in environment-friendly and economically outstanding CSG construction method by physical and mechanical properties of CSG materials including characteristics of uniaxial compressive strength, microscopic structure and freezing and thawing resistance in accordance with the cement content and curing time of the cement, and size of specimen. In this study, specimens with cement content of 4, 6, 8 and 10% of the total weight were, and, in order to examine the characteristics of the sizes of specimen, specimens with ${\Phi}50{\times}100mm$, ${\Phi}100{\times}200mm$ and ${\Phi}150{\times}300mm$ were manufactured to assess the features including compressive strength, microscopic structure, freezing and thawing, and degree of wet-dry. As results, it was found that with greater size specimen or contents of cement in the specimen, compressive strength, freezing and thawing resistance, and wet-dry resistance increase. Moreover, reactive products for each size of specimen were examined and it was possible to verify that some typical needle structured ettringite was generated due to blending of cement through microscopic structure analysis such as SEM and EDS analysis.