Glass Transition Temperature Determination of Poly(ethylene terephthalate) Thin Films Using Reflection−Absorption FTIR
Glass Transition Temperature Determination of Poly(ethylene terephthalate) Thin Films Using Reflection−Absorption FTIR
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DOI：
10.1021/ma035709f
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发表时间：
2004-03
期刊：
影响因子：
5.5
通讯作者：
Ying Zhang;Jianming Zhang;Yonglai Lu;Yongxin Duan;Shouke Yan;D. Shen
中科院分区：
文献类型：
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作者：
Ying Zhang;Jianming Zhang;Yonglai Lu;Yongxin Duan;Shouke Yan;D. Shen
采用原位反射吸收红外技术，通过检测加热过程中1340 cm-1（反式构象）和1370 cm-1（正态构象）两个可比谱带吸光度比的突变来确定聚对苯二甲酸乙二醇酯薄膜的玻璃化转变温度。研究发现，PET 薄膜的 Tg 相对于散装样品的 Tg 有所降低，并且对薄膜厚度有很大的依赖性。还计算了每个膜的反式和左态之间的构象能差（ΔE）。结果表明，计算的 ΔE 的厚度依赖性与测量的 Tg 的厚度依赖性几乎一致。此外，还研究了旋涂制备的薄膜中PET链的松弛行为以及退火对Tg测量的影响。
By using the in-situ reflection−absorption infrared technique, the glass transition temperatures of poly(ethylene terephthalate) thin films were determined by detecting the abrupt change in the absorbance ratio of two comparable bands at 1340 cm-1 (trans conformation) and 1370 cm-1 (gauche conformation) during heating. It was found that the Tg of thin PET films reduces with respect to that of bulk sample and has a great dependence on the film thickness. The conformational energy difference (ΔE) between trans and gauche states of each film was also calculated. The results indicate that the thickness dependence of calculated ΔE is nearly consistent with that of Tg measured. Furthermore, the relaxation behavior of the PET chains in thin films prepared by spin-coating and the influence of annealing on the Tg measured were also investigated.