However, even when exposed in de-ionized water, the tested material also
lost weight after a certain period of time. Typically, fillers including
silicon dioxide and calcium carbonate are often impregnated into
silicone rubbers to improve their mechanical properties. While
exposed to aqueous solution, the polysiloxane backbone of silicon
rubbers swells up and causes the fillers to leach out, leading to the
weight loss of the tested materials. In addition, the existence of F
in both simulated and strong acid solutions could also result in the
chemical decomposition of silicone rubbers under acidic environment.
Thus, the weight loss in strong acid aqueous solution is more
pronounced.