Nor Aida Zubir and Ahmad Fauzi Ismail

pp. 823 - 831

Abstract

This paper reports the development of PTFE membranes as the base substrates for producing
proton exchange membrane by using radiation-grafting technique. An aqueous dispersion of PTFE, which
includes sodium benzoate, is cast in order to form suitable membranes. The casting was done by using
a pneumatically controlled flat sheet membrane-casting machine. The membrane is then sintered to fuse
the polymer particles and cooled. After cooling process, the salt crystals are leached from the membrane by
dissolution in hot bath to leave a microporous structure, which is suitable for such uses as a filtration
membrane or as a base substrate for radiation grafted membrane in PEMFC. The effects of sintering
temperature on the membrane morphology and tensile strength were investigated at 350^o
C and 385^o
C
by using scanning electron microscopy (SEM) and EX 20, respectively. The pore size and total void space
are significantly smaller at higher sintering temperature employed with an average pore diameter of
11.78 nm. The tensile strength and tensile strain of sintered PTFE membrane at 385^o
C are approximately
19.02 + 1.46 MPa and 351.04 + 23.13 %, respectively. These results were indicated at 385^o
C, which represents significant improvements in tensile strength and tensile strain, which are nearly twice those at 350^o
C.

Keywords

• proton exchange membrane
• sintering temperature
• radiation-grafted membrane