Yes. The text from a thesis chapter is rarely the same as the subsequent journal article, even in draft form. Journal articles are usually based on a chapter or sub-section of a thesis, but are first edited to suit the audience of the intended journal, and then are edited a second time through the peer review process.
We recommend that you check the policy of your intended journal publishers, and discuss your publication options with your Research Supervisor.
Please note: you have the option to restrict your thesis to local access if you find your publisher insists on exclusive publication.