Mechanism of Polymer Glass Transition

聚合物玻璃化转变机理

• 批准号: 13650953
• 负责人: KANAYA Toshiji
• 金额: $ 2.5万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650953/
• 关键词: Glass transition; Boson peak; Fast process; Confinement; Thin film; Neutron scattering; 中性子散乱; 速い過程; 非エルゴード性; 長距離密度揺らぎ; ガス透過性; 光散乱

We have studied annealing effects of polymer thin films on glass transition using neutron and X-ray reflectivity. It was found that the previously reported negative expansivity of polymer thin films below about 20 nm is caused by unrelaxed structure due to lack of annealing. This structural relaxation occurs within one or two hours above the glass transition temperature. In addition to the relaxation process, we also found a very slow relaxation process above the glass transition temperature. The relaxation time was estimated at 423K to be 30 - 50h. One of the candidates of this slow motion is "sliding motion" proposed by de Gennes. The dynamics of polymer thin fims were directly studied using inelastic neutron scattering and for the first time we observed boson peak of the films 100 and 40 nm thick.We also studied motional slowing down of glass-forming polybutadiene near the glass transition temperature in a very wide Q range. In this experiment for the first time we found that the Q-dependence of relaxation time does now show a maximum at the second peak position of structure factor S(Q).

利用中子反射率和X射线反射率研究了聚合物薄膜的退火效应对玻璃化转变的影响。发现先前报道的低于约20 nm的聚合物薄膜的负膨胀率是由由于缺乏退火而导致的未松弛结构引起的。这种结构松弛在玻璃化转变温度以上的一个或两个小时内发生。除了弛豫过程，我们还发现了一个非常缓慢的玻璃化转变温度以上的弛豫过程。在423 K时的弛豫时间为30 - 50小时。这种慢动作的候选者之一是de Gennes提出的“滑动运动”。用非弹性中子散射直接研究了聚合物薄膜的动力学，首次观察到100和40 nm厚的薄膜的玻色子峰，并在很宽的Q值范围内研究了玻璃化聚丁二烯在玻璃化转变温度附近的运动减慢。在这个实验中，我们第一次发现弛豫时间的Q依赖性在结构因子S（Q）的第二个峰位置处显示出最大值。

项目成果

A.Patkowski, H.Glaeser, T.Kanaya, E.W.Fischer: "Apparent Non-Ergodic Behavior of Supercooled Liquids above the Glass Transition Temperature"Phys. Rev.. E64. 315031-315037 (2001)

A.Patkowski、H.Glaeser、T.Kanaya、E.W.Fischer：“玻璃化转变温度以上过冷液体的表观非历经行为”

T.Miyazaki, A.Shimazu, K.Ikeda, T.Kanaya: "Surface adsorption of propane, propylene and propane/propylene mixed gas on polyimide observed with X-ray and neutron reflectivity"Polymer. 44. 1553-1559 (2003)

T.Miyazaki、A.Shimazu、K.Ikeda、T.Kanaya：“用 X 射线和中子反射率观察丙烷、丙烯和丙烷/丙烯混合气体在聚酰亚胺上的表面吸附”聚合物。

T.Kanaya, K.Kaji: "Dynamics in the Glassy State and Near the Glass Transition of Amorphous Polymers as Studied by Neutron Scattering"Adv. Polym. Sci.. 154. 88-141 (2001)

T.Kanaya、K.Kaji：“通过中子散射研究非晶态聚合物的玻璃态和接近玻璃化转变的动力学”Adv。