Is uncredited use of grad students' unpublished research by professors accepted/common practice in academia? I'm a master's student, and over the course of my studies I've conducted a few independent studies in which I investigate specific research questions that I formulate on my own. Those independent studies have culminated in final papers, and I then use the material in those papers as part of articles I publish and presentations I give at conferences--am trying to build up a public profile on these topics.

Recently, a professor of mine asked to see research I had done for one of those studies, ostensibly to use as background for something the professor was working on. I'm not this professor's employee or otherwise under contract for a project of the professor's. I'm conducting independent research during classes that I pay for as part of my degree. The professor is in other words just my adviser and teacher.

I provided the professor my research and presentation materials, and then heard the professor use my work--word for word--in a subsequent presentation. The professor had not sought out my consent before doing this, and I was not cited.

The same professor again asked for a full, unpublished paper I had written to use as background for a different project the professor was undertaking. I declined to provide the paper because I did not know how it would be used (though I didn't say that).

Am curious about whether this is accepted and/or common practice in academia. And if it is, should I just send my paper to the professor?
No, this not accepted and/or common practice in academia. (Your use of the plagiarism tag was correct.) It is of course unethical and not right to copy other's work and not mention them.