Study of hydrolysis behaviour of polyborosiloxane

The hydrolysis behaviour of polyborosiloxane (PBS) was investigated, and the hydrolysis resistance was evaluated. The change in chemical structure during the hydrolysis of PBS was characterized by FTIR, 11B-NMR, etc. It was observed that the ternary borate ester in PBS was gradually hydrolyzed into binary and mono borate ester, and finally boric acid (BA) was produced. Rheological tests were used to investigate the effect of hydrolysis on the mechanical properties of PBS. It was observed that the plateau modulus and relaxation time of PBS decreased after immersion due to both the hydrolysis of PBS and the plasticizing effect of free water in the samples. It was also shown that as the free water evaporated during the drying process, the plateau modulus of the immersed PBS recovered somewhat. With regard to the hydrolysis resistance of PBS, the original PBS with a higher content of ternary borate ester has better hydrolysis resistance.