Effect of H+ and N+ Irradiation on Structure and Permeability of the Polyimide Matrimid®
Abstract:This paper presents a comparison of the impact of H+ and N+ ion irradiation on the chemical structure, microstructure, and gas permeation properites of the polyimide, Matrimid®. While irradiation with both ions resulted in evolution of chemical structure with loss of functional groups and crosslink formation, there was greater modification of polyimide structure following N+ irradiation at similar total deposited energy. Irradiation with N+ resulted in simultaneous large increases in permeance and permselectivity at comparatively low ion fluences or irradiation time. For example, irradiation at 4 × 1014 N+/cm2 resulted in a 2.5 fold increase in He permeance with a selectivity of He/CH4 of 340. Much higher H+ fluences were required to achieve similar total deposited energy and combined increases in permeance and permselectivity. The larger modification in chemical structure and gas permeation properties following N+ irradiation was attributed to the relatively large energy loss and damage from the nuclear energy relative to electronic energy loss.
Document Type: Research Article
Affiliations: Department of Chemical & Environmental Engineering, University of Toledo, OH, USA
Publication date: December 1, 2008