Effects of mixing procedure on the structure and physical properties of ester-ether-type soft segment waterborne polyurethane

Abstract

The effects of the mixing procedure for the preparation of ester-ether-type waterborne polyurethane (WBPU) on the structure and properties of the cast film are studied here. The following three types of WBPU processing are examined: film formed from WBPU mixing ether-type WBPU with ester-type WBPU (CEM series), film formed from WBPU synthesized with PEG2000 and PCL2000 polydiol as the soft segments (CEB series), film formed from WBPU synthesized with triblock ester-ether copolydiol (PCL-polyethylene glycol-PCL) as the soft segment (CET series). The water vapor permeability (WVP) for the application to nylon fabrics is also studied. The results show that the mixing procedure greatly affects the properties of the ester-ether-type WBPU. The CEB series has better phase mixing than the CET series, and the CEM series has a phase boundary between the ester-and ether-type WBPU. The CEM series has a better Young's modulus and breaking stress and poorer breaking strain than the CEB and CET series. In addition, samples with lower ethylene oxide (EO) content have better phase mixing and mechanical properties. On the other hand, the ester-ether-type WBPU has a higher WVP than the ester-type WBPU and the WVP increases with the EO content. The order of the mixing procedures for WVP is CET > CEB > CEM. © 1996 John Wiley & Sons, Inc.