Kinetic Analysis of Nanocomposites Prepared in situ Consisting of an Aliphatic Biodegradable Polyester and Fumed Silica Nanoparticles

PPSu/fumed silica nanocomposites are prepared by in situ polymerization using 0.25, 0.5, 1, and 2.5 wt.-% SiO2. The SiO2 content affects both esterification and polycondensation reactions directly. By increasing the SiO2 content in esterification, the rate of water production decreases. The reaction between PPSu and silanol groups of SiO2 is confirmed by XPS analysis. A quantitative model is developed to describe the influence of the SiO2 particles on the water production rate during esterification. The main reason for this is the adsorption of the produced water on the particles. The rate of adsorption/desorption processes is assumed to be comparable to the water evaporation rate in order to reproduce the experimental water production curves.