剪切流場下對嵌段共聚物微觀相配向的影響

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Title:	剪切流場下對嵌段共聚物微觀相配向的影響
Other Titles:	The orientation effect of shear flow on microphase structure of a block copolymer
Authors:	林柄良 Lin, Bin-Liang
Contributors:	楊怡寬 Yang, I-Kuan 東海大學化學工程與材料工程學系
Keywords:	嵌段共聚物;剪切流場;小角散射;微觀相結構 block copolymers;shear flow;SAXS;microphase separation
Date:	2009
Issue Date:	2011-02-22T07:44:42Z (UTC)
Abstract:	本研究探討聚苯乙烯-聚(乙烯/丁烯)-聚苯乙烯三嵌段共聚物 Asahi H1052在熔融態下的微觀相結構受到剪切流場的影響。本研究所探討之薄膜材料是使用熱壓成型方式作成。此薄膜被放入真空烘箱在設定的溫度下靜置24小時，最後驟冷至冰水溫度，保持在設定溫度下的微觀結構，以便隨後之各種分析與試驗。本研究利用流變的測量以及小角散射所產生的散射峰位置比來鑑定材料的微觀相；接著透過流變儀產生大振幅震盪的剪切流場，再驟冷的方式來觀察微觀相受剪切的影響。討論的變因主要為溫度、剪切時間、應變。本研究結果顯示在170℃時，H1052之相型態及結構不受大震幅剪切的影響。在150℃下受大震幅剪切時，此共聚物的原始配向會先受到破壞，接著在速度方向產生配向，但相型態基本上不會改變。在150℃下受振幅為100％之大震幅剪切會產生柱狀結構中六角排列方式的改變，六角形之邊朝剪切面與點朝剪切面的兩種排列形式共存且隨時間消長；應變為200％之剪切只觀察到點朝剪切面的形式。 This work investigates the effect of shear flow on the microphase structure of a tri-block copolymer (SEBS, Asahi H1052). The tested samples were prepared by hot press and annealed in vacuum oven for 24 hours before quenched by ice water to freeze the structure at the designated temperature. SAXS were performed to characterize and monitor the evolution of the microphase structure of the copolymer. Oscillatory shear was applied to the melt of the copolymer at different temperatures, frequencies, amplitudes for different periods of time. It was found that at 170℃ oscillatory shear has essentially no effect on the phase structure. While exposed to oscillatory shear at 150℃, the melt remains in cylindrical phase and the initial orientation of melt is first destroyed then the axes of the cylinder of the hexagonal microphase are aligned in velocity direction. Oscillatory shear with strain of 100% orients the cylindrical structure with coexistence of two orientations including point-up and plane-up orientation. For oscillatory shear with 200% strain, only point-up orientation was found.
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