화학공학소재연구정보센터
Polymer(Korea), Vol.18, No.2, 224-230, March, 1994
블록공중합물이 첨가된 폴리스티렌/폴리이소프렌 블렌드의 상분리 현상
Phase Separation Behaviors for the Polystyrene/polyisoprene Blend with Added Block Copolymer
초록
상용성이 없는 이성분계 고분자 블렌드를 이루는 쌍의 모델화합물로 폴리스티렌(PS)과 폴리이소프렌(PI)을 택하고. 이에 PS와 PI의 이블록공중합체(diblock copolymer)인 Poly(styrene-bisoprene)(SI)를 상용화제의 모델 화합물로 택하여, 블록공중합물이 비상용성 고분자 블렌드의 상분리 현상에 미치는 영향을 알아보았다. 이를 위하여 자체 제작한 광산란 장치를 사용하여 상분리 과정을 관찰하였다. 상용화 효과가 있는 SI의 경우 첨가된 SI의 양이 증가할수록 분산상의 성장도가 느려졌으며, 이는 계면장력의 감소에 기인하는 것으로 밝혀졌다. 한편, 첨가되는 SI의 분자량이 낮아 미세상 전이온도(Microphase Separation Temperature : MST)가 상분리 진행온도보다 낮은 경우에는 SI가 블렌드에 분자상태로 혼합되어 있어 계면장력의 감소를 가져오지 못해 상용화 효과를 보여주지 않았다.
To investigate the effect of block copolymer addition, as a compatibilizer, on the phase separation behaviors of the immiscible polymer blend, Polystyrene(PS) and Polyisoprene(PI) were chosen as model compounds for a binary blend pair, and Poly(styrene-b-isoprene) (SI) as a compatibilizer. Using a time-resolved light scattering apparatus, the phase separation kinetics were investigated for the blends with or without block copolymers. The block copolymer, which shows the compatibilization effect, reduced the interfacial tension between the continuous medium and separated domains, thus making the size of domains be decreased and the separation rate be retarded. To examine the dependancy of the molecular structure of block copolymer on the compatibilization, various types of SI's differing in total molecular weight were employed. For a series of low molecular weight SI's whose microphase separation temperatures are lower than the experimental temperature, there was no compatibilization effect. It was also found that there were good agreements, even though in a semiqualitative sense, between the experimental results and theoretical prediction proposed by Lifshitz and Slyozov.
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