Urethans degradation with loss

Urethans from carboxylic acid amides Degradation with loss of 1 -atom... 

The urethane-doped POC bioelastomers were prepared as follows in the first step, citric acid and 1,8-octanediol were bulk polymerized at 140 °C at the molar ratio of 1 1.1 for achieving POC prepolymers in the second step, the POC prepolymers were dissolved in 1,4-dioxane to form a 3% (wt/wt) solution, and reacted with HDI with stannous octoate as catalyst (0.1%wt) at 55 °C for preparing urethane-doped POC prepolymers at different feeding ratios of 1 0.6, 1 0.9 and 1 1.2 (POC prepolymer/HDI) in the third step, the urethane-doped POC prepolymers were cast into a Teflon mould and allowed to dry with a laminar airflow until all the solvents were evaporated, and then were further maintained in an oven at 80 °C to obtain the cured urethane-doped POC bioelastomers. Tg of the bioelastomers ranged from 0.64 to 5.20 °C. The urethane-doped POC bioelastomers with higher isocyanate content exhibited faster degradation rates, and their mass losses were lower than 16% after 2 months in phosphate buffer solutions. 

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