加馬輻射對聚丁二酸二乙酯等溫結晶行為影響之研究

The Effect of Gamma-ray Irradiation on Isothermal Crystallization of Poly(Ethylene Succinate)

周昱呈(Yu-Cheng Chou)

指導教授 ： 李三保

國立清華大學/工學院/材料科學工程學系/碩士(2012年)

摘要

本論文探討受不同劑量的加馬輻射對於聚丁二酸二乙酯等溫結晶行為的影響，利用示差掃描熱卡計(DSC)和偏光顯微鏡(POM)觀察在不同劑量的加馬輻射影響下的熱性質、整體等溫結晶速率、球晶成長速率以及形貌。
聚丁二酸二乙酯的玻璃轉換溫度為-19.9℃；隨著輻射劑量的增加玻璃轉換溫度也隨之上升但是熔點降低。從DSC數據可得知整體結晶速率常數k隨著結晶溫度的下降(從70℃到35℃)而上升但是到30℃又下降。在相同結晶溫度下，隨著輻射劑量的增加達到完整結晶的時間也越久。聚丁二酸二乙酯在等溫結晶之後，經由升溫過程可觀察到多重熔融峰，一般認為是由於升溫過程中的熔融再結晶所造成，並求得平衡熔點會隨著輻射劑量的增加而下降。聚丁二酸二乙酯的球晶成長速率在50℃左右為最大值；並隨著輻射劑量的增加成長速率有顯著的下降，推測其中原因可能是因為加馬輻射對於高分子產生交聯使得分子鏈段移動性下降。將球晶成長速率利用Lauritzen-Hoffman成核理論加以分析，可得到聚丁二酸二乙酯由Regime II轉移到Regime III的溫度為72.5℃且活化能為2.507 kJ/ mole；隨著輻射劑量的增加Regime轉移溫度隨之下降但活化能反之上升。利用相同方式分析由DSC所得到的t1/2-1可得知活化能一樣會隨著輻射劑量的上升而增加。

關鍵字

等溫結晶 ； 加馬射線 ； 聚酯

並列摘要

The isothermal crystallization of semicrystalline polymers and its blends have been studied for a long time, but there is less attention mention about the effect of gamma-ray irradiation on isothermal crystallization of semicrystalline polymers. In this research, the thermal properties, overall isothermal crystallization, spherulitic morphology and growth rate of non-irradiated and irradiated PESU were investigated by DSC and POM measurement and analyzed by Avrami equation and Lauritzen-Hoffman nucleation theory.
The glass transition temperature of non-irradiated PESU is -19.9℃. The values of Tg increases with increasing of gamma-ray dose. The multiple melting behavior of PESU was observed after isothermal crystallization during DSC heating scan and the equilibrium melting temperature Tm0 was determined. The values of Tm0 decrease with increasing of gamma-ray dose. The overall isothermal crystallization rates of PESU increase with decreasing crystallization temperature from 70 to 35℃ but decrease at 30℃ as the same trend as the half time of crystallization t1/2-1 regardless of gamma-ray irradiation. The crystallization rate k of irradiated PESU is lower than that of non-irradiated PESU at the same crystallization temperature. Both non-irradiated and irradiated PESU show a maximum value of the growth rate and non-irradiated PESU being higher than that of irradiated at the same crystallization temperature. On the basis of LH theory, there is one transition between regime III and regime II was found at around 72.5℃ and the activation energy is 2.507 kJ/ mole. With the increasing of gamma-ray dose, the regime transition temperature decreases but activation energy increases. The values of t1/2-1 from DSC were used the same method to determined activation energy. The activation energy also increases with increasing of gamma-ray dose.

並列關鍵字

isothermal crystallization ； γ-ray ； succinate

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