• 제목/요약/키워드: Shirasu porous glass (SPG) membrane technology

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SPG 막유화법을 이용한 고분자 입자 제조기술의 동향 (Technology Trend for the Preparation of Polymeric Particles by SPG Technique)

  • 이상국;김성욱;최경호;임은희
    • Elastomers and Composites
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    • 제44권3호
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    • pp.222-231
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    • 2009
  • 단분산이면서 마이크로 크기의 입자로 쉽게 조절이 가능한 SPG (Shirasu porous glass) 막유화법이 최근 각광을 받고 있다. SPG 막유화법은 다중에멀젼, 단분산, 다양한 형태 등을 쉽게 제조할 수 있는 장점을 가지고 있어서 기능성 입자를 만드는데 적합한 방법으로 최근 적용분야로는 토너입자, 식품첨가제, 약물전달 등으로 적용분야가 넓다. SPG 막유화법에서 입자크기 및 형태 조절 요소로는 개시제, 첨가제, 단량체, 가교제, 중합금지제 등이 있으며, SPG의 장점인 단분산을 싼 단가로 대량생산에 접목시킬 수 있기 때문에 여러 분야에서 다양한 접근이 가능하다.

Evaluation of Time-Temperature Integrators (TTIs) with Microorganism- Entrapped Microbeads Produced Using Homogenization and SPG Membrane Emulsification Techniques

  • Mijanur Rahman, A.T.M.;Lee, Seung Ju;Jung, Seung Won
    • Journal of Microbiology and Biotechnology
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    • 제25권12호
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    • pp.2058-2071
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    • 2015
  • A comparative study was conducted to evaluate precision and accuracy in controlling the temperature dependence of encapsulated microbial time-temperature integrators (TTIs) developed using two different emulsification techniques. Weissela cibaria CIFP 009 cells, immobilized within 2% Na-alginate gel microbeads using homogenization (5,000, 7,000, and 10,000 rpm) and Shirasu porous glass (SPG) membrane technologies (10 μm), were applied to microbial TTIs. The prepared micobeads were characterized with respect to their size, size distribution, shape and morphology, entrapment efficiency, and bead production yield. Additionally, fermentation process parameters including growth rate were investigated. The TTI responses (changes in pH and titratable acidity (TA)) were evaluated as a function of temperature (20℃, 25℃, and 30℃). In comparison with conventional methods, SPG membrane technology was able not only to produce highly uniform, small-sized beads with the narrowest size distribution, but also the bead production yield was found to be nearly 3.0 to 4.5 times higher. However, among the TTIs produced using the homogenization technique, poor linearity (R2) in terms of TA was observed for the 5,000 and 7,000 rpm treatments. Consequently, microbeads produced by the SPG membrane and by homogenization at 10,000 rpm were selected for adjusting the temperature dependence. The Ea values of TTIs containing 0.5, 1.0, and 1.5 g microbeads, prepared by SPG membrane and conventional methods, were estimated to be 86.0, 83.5, and 76.6 kJ/mol, and 85.5, 73.5, and 62.2 kJ/mol, respectively. Therefore, microbial TTIs developed using SPG membrane technology are much more efficient in controlling temperature dependence.

Core-shell Poly(D,L-lactide-co-glycolide )/Poly(ethyl 2-cyanoacrylate) Microparticles with Doxorubicin to Reduce Initial Burst Release

  • Lee, Sang-Hyuk;Baek, Hyon-Ho;Kim, Jung-Hyun;Choi, Sung--Wook
    • Macromolecular Research
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    • 제17권12호
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    • pp.1010-1014
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    • 2009
  • Monodispersed microparticles with a poly(D,L-lactide-co-glycolide) (PLGA) core and a poly(ethyl 2-cyanoacrylate) (PE2CA) shell were prepared by Shirasu porous glass (SPG) membrane emulsification to reduce the initial burst release of doxorubicin (DOX). Solution mixtures with different weight ratios of PLGA polymer and E2CA monomer were permeated under pressure through an SPG membrane with $1.9\;{\mu}m$ pore size into a continuous water phase with sodium lauryl sulfate as a surfactant. Core-shell structured microparticles were formed by the mechanism of anionic interfacial polymerization of E2CA and precipitation of both polymers. The average diameter of the resulting microparticles with various PLGA:E2CA ratios ranged from 1.42 to $2.73\;{\mu}m$. The morphology and core-shell structure of the microparticles were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The DOX release profiles revealed that the microparticles with an equivalent PLGA:E2CA weight ratio of 1:1 exhibited the optimal condition to reduce the initial burst of DOX. The initial release rate of DOX was dependent on the PLGA:E2CA ratio, and was minimized at a 1:1 ratio.

막유화법을 이용한 단분산성 실리카-루비덤® 마이크로 입자의 제조 및 잠열 특성 (Preparation of Monodispersed Silica-Rubitherm®Microparticles Using Membrane Emulsification and Their Latent Heat Properties)

  • 김수연;정연석;이선호;유진오;염경호
    • 한국응용과학기술학회지
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    • 제32권2호
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    • pp.215-225
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    • 2015
  • 최근들어 에너지 고갈로 인해 에너지 저장 및 대체 에너지에 대한 관심이 점차 높아 지고 있다. 이로 인해 상변화 물질을 이용한 에너지 저장 및 이동에 대한 연구가 활발히 진행 되고 있다. 본 연구에서는 SPG막(Shirasu porous glass membrane)을 통한 막유화법을 이용하여 상변화 물질인 파라핀계 루비덤$^{(R)}$ (RT-21과 RT-24)을 분산상으로 하여 단분산성 마이크로 입자를 제조하고, 외부를 실리카로 코팅하여 열정 안정성을 향상시키고 열적 특성을 조사하였다. 단분산성 루비덤$^{(R)}$ 입자의 제조를 위해 분산상 압력, 유화제 농도, 루비덤$^{(R)}$과 실리카의 비율을 변수로 하여 평균 입자 크기 $7-8{\mu}m$를 얻었다. Differential scanning calorimetry (DSC)와 Thermogravimetry analysis (TGA)를 이용하여 열적 안정성과 잠열 등의 열적 특성을 조사하였고, Particle size analyzer (PSA), Scanning electron microscopy(SEM), optical microscopy를 이용하여 입자 분포와 캡슐화 유무를 확인하였다. 또한, Fourier transform infrared spectroscopy (FT-IR)를 통하여 정성분석을 시행하였다. 결과적으로, 막유화법을 이용하여 얻은 실리카 코팅된 단분산성 루비덤$^{(R)}$ 입자는 향상된 열적 안정성을 보였으며, 순수한 루비덤$^{(R)}$의 80% 이상의 잠열을 유지하는 것을 보여 기존의 상변화 물질의 상안정성을 보완하여 열저장성 기능성 벽지와 건축물, 인테리어 제품에 사용 가능함을 알 수 있었다.