Figure 4.
Residual weight (%) of the polyurethane films after degradation in phosphate buffer solution: (a) PU 1, (b) PU 2, (c) PU 3, and PU 4.
Residual weight (%) of the polyurethane films after degradation in phosphate buffer solution: (a) PU 1, (b) PU 2, (c) PU 3, and PU 4.