Article’s title
The article's title reflects the content and purpose of the article?
Yes
Was the aim of the work clearly defined and successfully accomplished?
Yes
Does the article embrace contemporary issues in the area?
Yes
Does the article contain new and not published results?
Yes
Was the article clearly written and easily understood?
Easily understood
Conclusions illustrate the research results, recommendations and giving suggestions for future research
Yes
The references are full and grounded?
Yes
How adequate was the writing and used terminology?
Adequate
Remarks and suggestions to the authors of the article
The paper is interesting and useful in selected research area and can be accepted without remarks. At the same time, it is unclear, based on what data the conclusion about better thermal stability of silica-containin PEM was made. It will be nice to add the TG-picture of sample S2 to confirm this. Besides, the effect of silica on PEM properties is not clear, so expanded of silica content is needed for optimization of silica content (for example PEM with SGS content 0.5 % may be very interesting).
I confirm that there is no conflict of interests regarding reviewed article.
I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.