Exploring the Impact of Blend and Graft of Quinoline Derivative in Low‐Temperature Curable Polyimides

Abstract

The utilization of accelerators has been a common approach to prepare low‐temperature curable polyimide (PI). However, the accelerators have gradually fallen out of favor because of their excessive dosages and negative effect on the properties of PI. In this work, a new strategy of introducing accelerators by grafting to eliminate these disadvantages is presented. A novel quinoline derivative named NQL was designed for this purpose, and an ultra‐low dosage of only 2.5 mol% was sufficient to prepare low‐temperature curable PI. The favorable low‐temperature curing effect of NQL was attributed to its strong alkalinity (pKa = 18.47) and electron‐donating ability (HOMO = ‐6.22 eV). At a curing temperature of 200 °C, the PI with 2.5 mol% NQL showed outstanding properties (Young's modulus of 5.73 GPa, elongation of 37.3%, tensile strength of 237 MPa and coefficient of thermal expansion of 16 ppm/K). In particular, NQL could even lower the curing temperature to 180 °C and the ultra‐low temperature curable PI film still retained excellent properties. These results demonstrate that introducing low‐temperature curable accelerators by partial grafting instead of blending is a promising way to furnish low‐temperature curable PI, and provide insights into the preparation of polyimide with high performance in advanced packaging.This article is protected by copyright. All rights reserved