尼龙1010的分子链段运动、局域态分布与结构的关系

【作者】 陆红波；

【导师】 张兴元；

【作者基本信息】 中国科学技术大学 ， 高分子化学与物理， 2006， 博士

【摘要】 半结晶聚合物中的局域态源自结构欠序、晶界、杂质以及羰基、过氧化自由基等缺陷，其本身复杂的链结构、聚集态结构可导致多种局域态分布。这方面的研究是聚合物电学性能研究领域的一个重要方面，对于了解聚合物内电荷载流子的存储和输运特性及聚合物在电学、光学、声学等领域的应用具有重要意义。由于电荷载流子的微观特性，聚合物的局域态特性很难用一般的探测手段来分析。 尼龙1010是一类常见的工程塑料，具有优异的物理，化学性能而被广泛应用于精密机械零件，航空和家用电器中。同时尼龙1010又是一种典型的半结晶聚合物，通过简单处理可获得不同聚集态结构的试样，当温度高于其玻璃化温度时，由于载流子的作用，尼龙1010的介电、热释电等电学性能与低温时发生明显的变化。因此对尼龙1010的分子链段运动、局域态分布与结构关系的研究具有重要的理论和实际意义。本文工作主要包括以下几部分。 1．通过对结构稳定的尼龙1010的介电松弛行为的研究来了解尼龙1010分子链段运动和载流子迁移的相关信息。尼龙1010在高温低频时呈现很大的介电系数，是由于载流子的运动所致。尼龙1010在室温以上主要存在3个松弛过程，随着温度的升高依次为：α松弛、MWS松弛、电极极化。α松弛对应尼龙1010的分子链段运动，MWS松弛对应于聚集在中间相的载流子的松弛行为，而电极极化则对应于聚集在试样表面与电极界面的载流子的松弛行为。通过分析α松弛、MWS松弛、电极极化松弛时间及直流电导率与温度的关系，发现载流子在尼龙1010试样内的迁移是由分子链段运动所致，在尼龙1010的中间相玻璃化转变温度的前后，载流子的迁移规律发生了改变。 2．在不同温度下对尼龙1010退火处理，不仅导致尼龙1010结晶度的改变，还会发发生热降解反应，通过研究退火处理对尼龙1010介电松弛行为的影响，探索结晶度的增加和热降解对分子链段运动和载流子迁移的影响。结晶的增加抑制尼龙1010的分子链段运动和载流子的迁移，热降解导致分子链段运动和载流子的迁移变的容易。退火处理对尼龙1010分子链段运动和载流子迁移的影响要更多还原

【Abstract】 The localized state in semi-crystalline polymer is origin from defects, such as structure imperfection, inter-phase, impurities, carbonyl, peroxy free radical, etc. The polymer’s complication chain structure and condensed state structure may both lead to various localized state distributions. The corresponding work is an important topic in the field of polymer electronic properties. It helps leading charge storage and transportation properties further in polymer and then has a great meaning on polymer’s application in electrics, optics, acoustics, etc. Because of their abstract microcosmic properties, the localized state properties are hardly to be analyzed by common detecting technique.Nylon 1010 is an engineering plastic in common use. Moreover nylon 1010 is a typical semi-crystalline polymer with different microstructure under various thermal histories and thermo-mechanical treatment. The high values of dielectric permittivity at high temperatures are due to charge carrier movement. The investigation of the relationship between localized state and aggregating structure is important both from the fundamental and technological point of view. The work was composed in parts as follows.To deeply understand the molecule movement and localized state properties of nylons prepared under various thermal histories and γ-irradiation, this article chooses nylon 1010 as a model and nylon 6 as a comparison to investigate the relationship between localized state and aggregating structure using TSDC technique combining dielectric relaxation spectroscopy (DRS) technique.1. Polymer chain movement and charge carrier transport in Nylon 1010 were studied by dielectric relaxation spectroscopy. The high values of dielectric permittivity at low frequencies and high temperatures are due to charge carrier movement. There are three relaxation processes above room temperature for nylon更多还原