If you start rotating an icon which is 16x16 then you will be getting artifacts which you describe as "blur". I suggest to minimize the number of rotations. A human eye sees the animation as fluent at about 16 frames per second. So instead of animating 360 frames during 2 seconds which is larger than your monitor can show anyway, animate 30 frames during those 2 seconds. For each frame the icon will be rotated 12 degrees further.