Figure 2.

A, 1/Mn versus time for PLA in tetrahydrofuran (THF) solutions and solid samples. Dilute solutions include those with 0.05 and 0.1 wt% of polymer where individual polymer chains dispersed in solvents. Concentrated solutions include those with 0.3 to 2 wt% polymer where polymer chains entangled with each other. The solid sample contains 99 wt% polymer. All the samples contained 1 wt% of water (made by adding 1 wt% of water to the PLA solutions in THF). B, hydrolysis rate constant k₂ and viscosity of solutions versus polymer concentration. The viscosity is reciprocal to the molecular mobility.