...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Physics, D. Applied Physics: A Europhysics Journal >Dielectric study of the glass transition of PET/PEN blends
【24h】

Dielectric study of the glass transition of PET/PEN blends

机译：PET / PEN共混物玻璃化转变的介电研究

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

An analysis of the glass transition of four materials with similar chemical structures is performed: PET, PEN and two PET/PEN blends (90/10 and 70/30 w/w). During the melt processing of the blends transesterification reactions yield block and random PET/PEN copolymers that act as compatibilizers. The blends obtained in this way have been characterized by ~1H-NMR and differential scan calorimetry (DSC). A degree of randomness of 0.38 and 0.26 has been found for the 90/10 and 70/30 copolymers. It is shown by DSC that this copolimerization is enough to compatibilize the blends. The relaxation, the dielectric manifestation of the glass transition, has been studied by thermally stimulated depolarization currents. The relaxation has been analysed into its elementary modes by means of a relaxation map analysis. The activation energies of the modes of the glass transition do not change significantly between the four materials: in all cases the modes with a larger contribution have around 3 eV and modes with less than 1 eV are not detected. The change in the pre-exponential factor accounts entirely for the relaxation time change from material to material, that is larger as the PEN content increases. The compensation law is fulfilled and compensation plots converge for high-frequency modes. The polarizability decreases as the PEN content increases due to the increased stiffness of the polymer backbone. An analysis of the cooperativity shows that the central modes of the distribution are the most cooperative while high-frequency modes tend to behave more as Arrhenius. The low-frequency modes are difficult to study due to the asymmetry of the distribution of relaxation times. PEN turns out to be the less cooperative material. It is demonstrated how the parameters obtained from the dielectric study are able to reproduce calorimetric data from DSC scans and are, therefore, a valid description of the glass transition.
机译：进行了四种化学结构相似的材料的玻璃化转变的分析：PET，PEN和两种PET / PEN共混物（90/10和70/30 w / w）。在共混物的熔融加工过程中，酯交换反应产生嵌段共聚物和充当相容剂的无规PET / PEN共聚物。通过〜1 H-NMR和差示扫描量热法（DSC）表征了以此方式获得的共混物。对于90/10和70/30共聚物，发现随机度为0.38和0.26。 DSC表明，这种共聚合足以使共混物相容。弛豫是玻璃化转变的介电表现，已通过热激发的去极化电流进行了研究。已经通过弛豫图分析将弛豫分析为其基本模式。玻璃化转变模式的活化能在四种材料之间没有显着变化：在所有情况下，贡献较大的模式具有约3 eV，并且未检测到小于1 eV的模式。前指数因子的变化完全解释了材料之间的弛豫时间变化，即随着PEN含量的增加而变大。满足补偿律，并且针对高频模式，补偿图收敛。由于聚合物主链的刚度增加，极化率随着PEN含量的增加而降低。对合作性的分析表明，分布的中心模式最协作，而高频模式倾向于表现得更像阿伦尼乌斯。由于弛豫时间分布的不对称性，很难研究低频模式。 PEN是合作性较低的材料。证明了从介电研究中获得的参数如何能够从DSC扫描中复制量热数据，因此是玻璃化转变的有效描述。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号