Preparation and Characterization of Polymer Blend based on Sulfonated Poly (Ether Ether Ketone) and Polyetherimide (SPEEK/PEI) as Proton Exchange Membranes for Fuel Cells

摘要

Blends of sulfonated poly (ether ether ketone) (SPEEK) and polyetherimide (PEI) were prepared in live different weight ratios using N-rnethyl-2-pyrrolidone (NMP) as solvent by the solution cast technique. The degree of sulfonation (DS) of the sulfonated PEEK was determined from deuterated dimethyl sulfoxide (DMSO-d_6) solution of the purified polymer using 'H NMR method. The properties studied in the present investigation includes conductivity, water uptake, thermal stability and structure analysis of pure SPEEK as well as SPEEK-PEI polymer blend membranes. The experimental results show that the conductivity of the membranes increased with increase in temperature from 30 to 80°C, except for that of pure SPEEK membrane which increased with temperature from 30 to 60°C while its conductivity decreased with increasing temperature from 60 to 80°C. The conductivity of 70wt.%SPEEK-30wt.%PEI blend membrane at 80% relative humidity (RH) is found to be 1.361 x 10~(-3) Scrn~(-1) at 30°C and 3.383 x 10~(-3) Scm~(-1) at 80°C respectively. It was also found that water uptake and thermal stability of the membranes slightly improved upon blending with PEI. Structure analysis was carried out using Fourier Transform Infrared (FTFR) spectroscopy which revealed considerable interactions between sulfonic acid group of SPEEK and imide groups of PEI. Modification of SPEEK by blending with PEI shows good potential for improving the electrical and physical properties of proton exchange membranes.