增韧环氧树脂相结构

Phase structure of a toughened epoxy system

用SEM分别对不同配比的热塑/热固(TP/TS)原位共混增韧体系和“离位”增韧体系的浇注体固化后的相形貌进行了观察。结果显示:对于共混增韧体系,当热塑性树脂含量为16.7%-20.0%时体系发生相反转。通过对发生相反转体系的热固性颗粒尺寸的统计分析可知,随着TP含量的增加,热固性颗粒的粒子直径越来越小,且粒子直径的分散性也越来越小;在统计分析结果的基础上由数学分析给出了粒子直径与TP含量的经验关系式,由该经验式可知,热固性粒子直径的上下限分别是1.838μm和0.925μm,对应的质量分数分别约为16.0%和39.0%。对“离位”增韧的相形貌进行了分析,“离位”增韧体系形成了增韧层过渡层本体层的复合结构。TP含量在增韧层保持较高水平,在过渡层中迅速降低,在本体层中几乎不存在;同时为达到较好的增韧效果,过渡层厚度不应超过增韧层厚度。

The SEM was employed to determine the phase structure of the toughened epoxy system, both in-situ and ex-situ system, respectively. The results of the in-situ blending system indicate that the phase reversion occurs when the thermoplastic （TP） content is 16.7%-20. 0%. Spherical particle dimension of the phase-separated system was statistically analyzed, showing that the higher the TP component, the smaller the dimension and the narro- wer the dispersion of the spherical particle sizes. An experimental expression was obtained to establish the relationship between the TP content （φ） and the particle dimension （d）. Based on this expression it is estimated that the upper and lower limits of the particle dimension are 1. 838 μm and 0. 925 μm, respectively. For the ex- situ toughened resin, a multi-layer structure, i.e. toughened layer-interface layer-bulk layer, is formed. The content of TP keeps a high level in the toughened layer, followed by a dramatically drop in the adjacent plies; hardly any TP resin exists in the bulk layer. Also, the interface is expected of a relatively narrow thickness to achieve preferable toughness.