Effect of molecular weight on the properties of polyethylene glycol polyurethane-co-polydimethylsiloxane polyurethane

A series of thermoplastic polyurethanes (TPUs) composed of polyethylene glycol polyurethane (PEG-PU) and polydimethylsiloxane polyurethane (PDMS-PU) were prepared to examine the effects of the PEG molecular weight (MW) on the surface and physical properties. The adaptive PEG-PU-co-PDMS-PU structures resembled the architectures of a diblock copolymer, which used the MW-fractionated PEG. The sufficient MW dependence was observed within the range 200 < MW < 400, indicating that the increased urethane groups of PEG-PU block limit the surface and physical properties of these samples. The difference in properties according to the degree of the urethane groups was evaluated using a universal test machine (UTM) as well as by measuring the contact angle and water vapor transmission rate (WVTR).