A novel method to improve the thermal stability of poly(propylene carbonate)

In the present work, a surfactant, the phosphoric ester of poly(ethylene oxide) (10) nonylphenyl (abbreviated as NP-10P throughout the paper), was incorporated into poly(propylene carbonate) (PPC) by melt-blending. Characterization data by TGA and Py-GC/MS have suggested that the obtained PPC/NP-10P complex displays excellent thermal stability compared to pure PPC. The thermal decomposition temperature, with a 5% loss in weight, increases by about 103 degrees C from 180 degrees C for PPC to 283 degrees C for PPC with 15 wt% NP-10P. Furthermore, with only 1 wt% of NP-10P incorporated into the PPC, an increase of about 74 degrees C in the decomposition temperature is found. The pyrolysis mechanism of PPC before and after modification with NP-10P varies from chain unzipping degradation to chain random scission followed by unzipping degradation. The results of P-31 NMR, FTIR and intrinsic viscosity measurements have illustrated that the PPC is end-capped with NP-10P, which leads to the improvement of thermal stability and the change in pyrolysis mechanism of PPC. Moreover, this new finding will facilitate development and widespread applications of this biodegradable material.