Effect of Fluorocarbon Side Chain on the Microphase Morphology and Rheological Behavior of Thermoplastic Polyurethanes

Fluorinated diols (FDO) with dangling chain were introduced into polyether urethanes (PEUs) as chain extender in order to achieve internal plasticization. Based on temperature dependent Fourier transform infrared (FTIR) spectroscopy results, the fluorinated polyether urethanes (FPEUs) exhibited weaker hydrogen bonding between C=O and N-H groups with addition of FDO. The crystallinity of hard domain was destroyed determined by thermal analysis. Combined with the results of dynamic mechanical analysis (DMA) and dissipative particle dynamics (DPD) simulation, it was proved that more loosely aggregated hard domains with weakened interaction separated from soft segment were formed. Rheological analysis indicated that FDO reduced the complex viscosity and viscous flow activation energy which endowed the polymer with more flexibility. Despite the loss of hydrogen bonds, there was no significant decline in mechanical property resulting from the decrease of hard segment dissolved in soft segment phase. The presence of fluorinated carbon side chain could function as internal plasticizer and contribute to the processability of polyurethane.