PI-CTBN-PI block copolymer and PI-CTBN block copolymer were obtained thru the reaction of amine terminated polyetherimide (PI) and carboxyl terminated butadiene-acrylonitrile copolymer (CTBN). These block copolymers were used as a toughening agent for diglycidyl ether of bisphenol-A epoxy resin that was cured with nadic methyl anhydride (NMA). Thermal properties, fracture toughness (KIC) and solvent resistance of toughened epoxy resin were measured. The KICof epoxy resin toughened with 20 phr of PI-CTBN-PI block copolymer was 3.12 MPaㆍm0.5while that of neat epoxy resin was 1.36 MPaㆍm0.5. Due to the phase separation and the good interfacial adhesion of terminal amine group, the fracture toughness was considered to have increased.

사슬 말단에 아민기를 갖는 아민말단 폴리이미드(PI)와 carboxyl terminated butadiene-acrylonitrile copolymer (CTBN)을 반응시켜 PI-CTBN-PI 블록공중합체 및 PI-CTBN 블록공중합체를 합성하였다. 이들 공중합체를 강인화제로 사용하여 강인화된 에폭시 수지를 제조하고 강인화된 에폭시 수지의 열적 특성, 강인성 및 내용매성을 측정하였다. 에폭시 수지의 KIC가 1.36 MPaㆍm0.5인데 비해 PI-CTBN-PI 블록공중합체가 20 phr 첨가된 에폭시 수지는 KIC가 3.12 MPaㆍm0.5로서 향상된 강인성을 보였다. 이는 상분리와 말단 아민기의 우수한 계면 접착력에 의해 강인성이 향상된 것으로 사료된다