Design of tough nanostructured polymer networks using Polymerization Induced Self-Assembly in reactive media

We propose a new route to toughen epoxy thermosets from reactive block copolymer (BCP) dispersion masterbatches. Our approach relies on i) the controlled in situ formation and self-assembly of AB block copolymers (with an A core-forming rubbery block for mechanical energy dissipation and a B block ensuring stabilization of the self-assemblies) into a range of spherical, vesicular and most-desired worm-like morphologies by RAFT polymerization induced self-assembly (PISA) in epoxy monomers and ii) the subsequent polymerization of the epoxy monomers. In this context, we aim at i) establishing phase diagrams of the reactive dispersions as a function of solid content (10 to 40 wt %), molar mass of both blocks and their relative compositions to secure access to the most-desired higher-order morphologies in the epoxy monomer and ii) investigating the fate of these morphologies while curing the thermoset (dilution with the epoxy monomer and/or the hardener, heating cycles triggering curing).

本研究提出了一种基于反应性嵌段共聚物（reactive block copolymer, BCP）分散母粒增韧环氧热固性树脂的全新路径。本研究方案依托两大核心环节：其一，在环氧单体中通过RAFT聚合诱导自组装（RAFT polymerization induced self-assembly, PISA）技术，实现AB型嵌段共聚物的原位可控形成与自组装——其中A段为成核弹性嵌段，用于实现机械能耗散，B段则负责稳定自组装结构——最终得到球形、囊泡状以及最受关注的蠕虫状等多种形貌；其二，后续完成环氧单体的聚合反应。
在此研究背景下，本研究的目标分为两点：一是建立反应性分散体系的相图，该相图以固含量（10~40质量分数%）、两段嵌段的摩尔质量及其相对组成为调控变量，从而确保在环氧单体体系中获得目标高级形貌；二是探究热固性树脂固化过程中（即通过环氧单体和/或固化剂稀释、引发固化的升温循环过程）这些形貌的演变规律。