Is this your topic sentence? It is actually two sentences. I suggest shortening it a bit. Your topic sentence should focus on making your argument in the clearest, strongest way possible. Instead of simply saying you are against technology in schools, be specific. After all, even an overhead projector or a television is technology. What you are referring to is the internet, I think. You do not want students to have unrestricted access to the internet in class. So be specific in your topic sentence.
Students should not have unrestricted access to the internet during class because it is disruptive to the learning environment.
Then you will go on to explain your reasons. Students might watch YouTube videos of piano-playing cats instead of the Japanese Internment Camp video they are supposed to be watching. Students might check their email when the teacher is lecturing. This is where you list your reasons.