聚對苯二甲酸丙二酯(PTT)/聚己內酯(PCL)熔融摻混對結晶性質和相容性之研究

crystallization and Miscibility of poly(Trimethylene Terephthalate) and poly(ε-caprolactone) by melt blending

洪琮棋(Cong-Gi Hong)

指導教授 ： 程耀毅

國立臺北科技大學/工程學院/有機高分子研究所/碩士(2005年)

摘要

本研究利用微分掃描熱卡計（DSC）、偏光顯微鏡（POM）、掃描式電子顯微鏡（SEM）及廣角X光繞射儀（WAXD），來深入探討兩成分摻合系統poly(trimethylene terephthalate) 聚對苯二甲酸丙二酯(PTT)/ poly(ε-caprolactone)聚己內酯(PCL)（PTT）在不定形區之玻璃轉化行為及微觀相型態。在此摻合系統中，經由熱分析結果皆得到二個玻璃轉移溫度Tg，在低溫-65℃為PCL，而45℃為PTT。進一步藉由POM與SEM觀察微觀相型態，也皆為不均勻的二相型態，因此證實此摻合系統為不相容的系統。純PTT可發現明顯的環狀消光環（ring-banded spherulite）及馬爾他十字（Malteses-cross）的球晶。
另一方面，非等溫在不同的冷卻速率，PTT的結晶溫度會隨PCL成分增加，有先升後降的趨勢。PCL的結晶度會隨著PTT成分增加而增加，而PTT結晶度則變化不大。並以DSC作PTT/PCL等溫結晶之試驗，並藉由Avrami equation來求得各組成之n、k值。接著利用Hoffman-Weeks方法，預測出各摻混系統的平衡熔點，再由摻合物熔點下降分析所獲得的Flory-Huggins interaction parameter 為 －0.25576。接著利用Hoffman-Lauritzen 晶體成長速率方程式及Thompson-Gibbs 關係式估計出端表面自由能(flod surface interfacial free energy) 與板晶厚度(crystal lamellar thickness)。在XRD分析中也可分析出PCL結晶面的coherence length及PCL的結晶率(CI)，得知經過熱處理的PTT/PCL摻混之結晶發現隨著熱處理的時間增加，結晶率會有明顯的減少。

關鍵字

聚對苯二甲酸丙二酯 ； 聚己內酯 ； 玻璃轉移溫度

並列摘要

Miscibility and morphology of poly(trimethylene terephthalate) (PTT)/ poly(ε-caprolactone) (PCL) blend were investigated by differential scanning calorimeter (DSC) , polarized-light microscopy (POM) , scanning electron microscopy (SEM) and wide-angle X-ray diffraction(WAXD) . Two distinct glass transition temperatures (Tg) could be observed by of DSC . The upper Tg around 45℃ , was close to that of neat PTT , and the lower Tg around -65℃ , was close to that of neat PCL . The POM and SEM results indicated two separate morphology . According to these results , PTT/PCL should be immiscible . There was ring-banded spherulites with Malteses-cross patterns observed in neat PTT .
Ferthermore , the crystallization tempterature of PTT was first increased then decreased the increase of PCL content .The degree of crystallization of PCL was increased with the increase of PTT , which was obsearved in PTT . The DSC isothermal crystallization at various crystallization temperatures has been applied for PTT/PCL systems . Crystallization kinetics was determined by the Avrami equation. The Flory-Huggins interaction parameter, χ12, for PTT/PCL blend was determined to be －0.25576 through the melting point depression analysis, indicateing partial miscibility in blends of PTT and PCL. The flod surface interfacial free energy and crystal lamellar thickness have been estimated by Hoffman-Lauritzen equation and Thompson-Gibbs equation. By XRD, we found crystal size and degree of crystallinity of PCL decrease with the increase of heating time.

並列關鍵字

poly(trimethylene terephthalate) ； poly(ε-caprolactone) ； glass-transition temperature

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