Fig. 5

Optical images at 30 N load a) Pure PU, b) 0.2 PU/ND, and c) 0.5 PU/ND at 0 h UV treatment, d) Pure PU, e) 0.2 PU/ND, f) 0.5 PU/ND with 400 h UV treatment.

Optical images at 30 N load a) Pure PU, b) 0.2 PU/ND, and c) 0.5 PU/ND at 0 h UV treatment, d) Pure PU, e) 0.2 PU/ND, f) 0.5 PU/ND with 400 h UV treatment.