Some Reactions of Microgel in Polyacrylamide Solutions

Although there is disagreement concerning the role of microgel in mobility control, there is little doubt that appreciable amounts of crosslinked microgel exist in commercial preparations of partially hydrolyzed polyacrylamide, and in Dow Pusher chemical the cross-links are to some extent anhydride bridges. Other hydrolyzable crosslinks, such as imides, may also be present, but since for these purposes their behavior is similar to that of anhydrides, equations for only the latter will be written. The purpose of this study is to report some reactions this crosslinked material undergoes with various additives, particularly with compounds containing 2 or more hydroxyl groups. These reactions may be useful in mobility control technology since, as with the reactions between Pusher and formaldehyde, they are a means of controlling the effective molecular weight of the polymer in solution.