Nano-cylindrical phase formation in network polymer composites using self-assembly ability of block copolymers

研究了几种PMMA-b-PnBA-b-PMMA三嵌段共聚物（BCP）改性环氧树脂固化物的相结构。采用活性阴离子聚合法合成了双酚A二缩水甘油醚（DGEBA）嵌段共聚物（BCP），并将其用作环氧树脂的改性剂。芳香胺、酸酐和阴离子聚合催化剂作为固化剂导致DGEBA/BCP共混物在固化过程中发生宏观相分离。然而，酚醛清漆（PN）作为固化剂创建纳米相结构的DGEBA/BCP共混物通过激活的自组装能力的BCP在环氧共混物。嵌段共聚物中PMMA嵌段对PN固化环氧树脂的相容性是保持纳米级相结构的关键因素。在共混物中发现了球形胶束、圆柱形胶束和弯曲层状胶束等纳米相结构。纳米相的尺寸在直径或厚度方面为20-40 nm。共混物的纳米相结构的类型可以通过共混物的树脂组成、嵌段组成和嵌段共聚物的分子量来控制。

Phase structures of cured epoxy resins modified with several PMMA-b-PnBA-b-PMMA triblock copolymers(BCP) were studied. The BCPs synthesized by living anionic polymerization were applied as the modifiers for the epoxy resin : diglycidyl ether of bisphenol A(DGEBA). An aromatic amine, an acid anhydride and an anionic polymerization catalyst as curing agents resulted in macro-phase separation of the DGEBA/BCP blends during the cure process. However, a phenol novolac(PN) as the curing agent created nano-phase structures in the DGEBA/BCP blends by activating the self-assembling ability of the BCPs in the epoxy blends. The miscibility of the PMMA block in the BCPs to the PN cured epoxy resin was a key factor to keep the phase structures in nano size. Several nano-phase structures, such as spherical micelles, cylindrical micelles, and curved lamella-like micelles were found in the blends. The size of the nano-phases was 20-40 nm in terms of the diameter or the thickness. The types of the nano-phase structures could be controlled by the resin composition of the blends, the block composition and the molecular weight of the BCPs.