SEM-analysis of surface properties of experimental sulfocation-exchange membranes Ralex

Abstract

A comparative analysis of the effect of the manufacturing technology of heterogeneous sulfocationexchange
membranes Ralex CM Pes produced by MEGA a.s. (Czech Republic) on the structural properties
of their surface by SEM was carried out. The CM Pes membrane is a composite of a sulfocation-exchanger
with polyethylene and reinforcing polyester fiber. In the manufacture of experimental membranes, the particle
sizes of the ion-exchanger differed at a constant volume ratio of cation-exchange resin and polyethylene.
The resin particle sizes were varied by using different milling time. The study of the surface of swollen
membrane samples was performed by scanning electron microscopy in the low-vacuum mode. Quantitative
assessment of the fraction of ion-exchange material and porosity on the membrane surface was carried out
using the authors’ software package.
With an increase in the milling time of the ion-exchanger from 5 to 80 min, the structure of the
membrane surface becomes more homogeneous due to a decrease in the resin particle sizes and the distance
between them, as well as a decrease in the fraction and size of structure defects. A more than 1.5-fold decrease
in the size of ion-exchanger particles and in the distance between them was revealed. The fraction of
the ion-exchanger with a radius of less than 1 μm increases significantly. At the same time, there is a 1.5-fold
decrease in the fraction, as well as in the size of pores and structure defects. The ratio of the fractions of the
conducting and nonconducting phases on the membrane surface remains almost constant (15-17%).