Modification of Thermal and Mechanical Properties of PEG-PPG-PEG Copolymer (F127) with MA-POSS.

Pluronic F127 exhibits thermogelling behaviour at 20⁻30 °C via a micelle packing mechanism. Disruption of the micelle packing increases the sol-gel temperature, but results in the decrease of modulus. Herein, we reported a method to modify F127 with polyhedral oligosilsesquioxane (POSS) to impart a higher gelling temperature without yielding the property and strength of the thermogel. The thermal degradation temperature was enhanced to 15 °C after POSS incorporation and the gelling temperature shifted 10 °C higher, without sacrificing the modulus of the gel. Rheological studies supported the claim that the gel property was reinforced after POSS incorporation. F127-POSS copolymer matrix stored more energy from POSS reinforcement, which saw larger Lissajous curve areas before the collapse of the microstructure for the same amount of stress applied. These results indicated that modification with POSS would raise the sol-gel transition temperature without sacrificing the modulus of the gel.