Advisor not letting me publish
I don't know what sort of hold the advisor has over you. Perhaps you are in a field that "requires" that he be a co-author on your work. 

After you graduate, assuming that your postdoc is elsewhere he would seem to have little control over your actions. 

But, if it is really just motivation that you want to maintain, you can always write the papers and see what you have. Even if custom prevents you from publishing now, it won't always and it might also serve to bring your thoughts together. 

After you graduate and move on, your relationship to the advisor will also change and you should have more authority over your own actions. 

I realize that this advice is somewhat optimistic and my field may be different enough from yours that it is inadvisable. But, my view, is that you should be treated with more respect.