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삼중블록공중합체와 저분자량 단일중합체 혼합물의 미세상분리 동력학
Ordering Kinetics of Triblock Copolymer/Low Molecular Weight Homopolymer Mixtures

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Authors
이승헌; 차국헌
Issue Date
1998-06
Publisher
한국유변학회 = The Korean Society of Rheology
Citation
Korean J. Rheology, 10, 65 (1998)
Keywords
block copolymer/homopolymer mixtureorder-disorder transition (ODT)ordering kineticstime-resolved rheological measurementtime-resolved small-angle X-ray scattering(SAXS)
Abstract
본 연구에서는 polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene (SEBS) 삼중블록공중합체와 저분자량 단일중합체인 Hercotac 1149 (Hl149)의 70/30 (w/w)혼합물의 미세상분리와 그 동력학을 유변물성 측정법과 SAXS 실험을 통하여 연구해 보았다 먼저 혼합물의 미세상분리 온도를 유변물성 측정법과 SAXS 실험을 통해 각각 구한 다음,샘플을 미세상분리 온도보다 높은 온도에서 그 이하의 온도로 급냉시킨 후 유변물성과 산란강도의 시간에 따른 변화로부터 미세상분리 동력학에 대한 정보를 구하였다. 이렇게 얻어진 데이터를 Avrami형태의 핵생성 성장 (NG)메커니즘으로 해석해 보았는데, 최대산란강도 Imax뿐 만 아니라 저장 점탄성계수 G'과 손실 점탄성계수 G''의 시간에 따른 변화를 잘 예측할 수 있었다. 한편, 서로 다른 두 time-resolved 실험으로부터 Avrami 플롯을 그려서 구해진 Avrami 변수들은 같은 급냉 깊이에서는 서로 잘 일치함을 확인하였다. 반감기는 급냉 깊이가 증가함에 따라 점차 감소하는 경향을 보였는데, 이는 급냉 깊이가 클수록 미세상분리가 더 빨리 진행되고 있음을 보여주는 것이다. 또한, Avrami지수는 급냉 깊이가 증가함에 따라 3에서 4로 급격히 변했는데, 이로부터 급냉 깊이가 작을 때에는 70/30(w/w) SEBS/Hl149 혼합물의 미세상분리가 불균일 핵생성 성장 메커니즘에 따라 진행되고, 급냉 깊이가 더 커지면 미세상분리가 스피노달 상분리 메커니즘으로 변하고 있음을 예측할 수 있었다. ; The order-disorder transition (ODT) and the ordering kinetics of a 70/30 (w/w) mixture of polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene (SEBS), Kraton G1652 , and a commercial tackifier, Hercotac 1149 (Hl149) was investigated using both time- resolved rheological and synchrotron small-angle X-ray scattering (SAXS)measurements. TODT. of the mixture was first determined independently by each static measurement. Time-resolved measurements were then carried out by quenching the sample from disordered to ordered state. The time-resolved data were analyzed based on the nucleation and growth (NG) mechanism of the Avrami class. It was found that the NG mechanism reasonably describes the time evolution of G' and G" as well as I max for the 70/30 (w/w) mixture after a given quench except the initial induction on period. The Avrami parameters obtained from both time-resolved measurements bas ed on the NG mechanism (Avrami plots) were found to be in good agreement with each other for the same quench depth. The half-time was found to decrease gradually as the quench depth was increased, indicating that the ordering proceeds faster for a deeper quench. The Avrami exponent was found to change suddenly from about 3 to 4 in going from a shallow to a deeper quench. This implies that for a shallow quench the ordering of 70/30 (w/w) mixture proceeds via the heterogeneous NG mechanism, while there exists a transition in the ordering kinetics into the spinodal decomposition (SD) mechanism when the sample is further quenched.
ISSN
1226-119X
Language
English
URI
http://www.cheric.org/research/tech/periodicals/view.php?seq=9516

http://www.rheology.or.kr

https://hdl.handle.net/10371/5914
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College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Chemical and Biological Engineering (화학생물공학부)Journal Papers (저널논문_화학생물공학부)
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