基于嵌段共聚物的双酚A型环氧树脂的增韧研究

环氧树脂是一类应用非常广的高分子材料。双酚A型环氧树脂是其中备受重视的一种，它因为自身强度高、易加工、性质稳定的特点而被广泛应用于土木工程、航天器材、电子封装等领域。但是由于其具有易脆性，双酚A型环氧树脂更为广阔的潜在应用受到了限制。因此研究如何增强环氧树脂的韧性不仅具有学术价值，更具有现实意义。嵌段共聚物在极性环境下自发形成的微观纳米胶束，按照不同结构分为球状、蠕虫状和囊泡状胶束。本论文利用嵌段共聚物的不同结构胶束对环氧树脂基底进行了增韧研究。

本论文制备了两亲性嵌段共聚物。以亲水性聚乙二醇大分子作为主链，以疏水性的苯乙烯作为疏水嵌段单体，进行共聚合反应获得具有两亲性的嵌段共聚结构。将嵌段共聚物与双酚A型环氧树脂共混固化，通过拉伸实验表征改性后的力学性能。

通过系统性实验研究了嵌段共聚物的浓度与嵌段比对形成胶束形貌的影响以及对力学性能的影响。研究发现：对于双嵌段共聚物来说，疏水性嵌段（苯乙烯）越长，其形成的胶束就越容易聚集，形成无定形相分离所需要的最低浓度越低。合成的三类嵌段共聚物中两亲性双嵌段共聚物对韧性的改进有限，一旦使用量超过临界团聚值，环氧树脂基底的韧性会急剧下降。相比较纯环氧树脂而言，具有10 wt%三嵌段共聚物增韧的环氧树脂的韧性提高了60 %。结果表明在所选的材料中两亲性三嵌段共聚物的增韧效果最佳，这对于提高环氧树脂韧性、实现环氧树脂更广泛的应用具有重要意义。

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