EFFECTS OF MIXING PROCEDURE ON THE STRUCTURE AND PHYSICAL-PROPERTIES OF ESTER-ETHER-TYPE SOFT SEGMENT WATERBORNE POLYURETHANE

The effects of the mixing procedure for the preparation of ester-ether -type waterborne polyurethane (WBPU) on the structure and properties o f the cast film are studied here. The following three types of WBPU pr ocessing are examined: film formed from WBPU mixing ether-type WBPU wi th ester-type WBPU (CEM series), film formed from WBPU synthesized wit h PEG2000 and PCL2000 polydiol as the soft segments (CEB series), film formed from WBPU synthesized with triblock ester-ether copolydiol (PC L-polyethylene glycol-PCL) as the soft segment (GET series). The water vapor permeability (WVP) for the application to nylon fabrics is also studied. The results show that the mixing procedure greatly affects t he 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 bound ary between the ester- and ether-type WBPU. The CEM series has a bette r 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 t he other hand, the ester-ether-type WBPU has a higher WVP than the est er-type WBPU and the WVP increases with the EO content. The order of t he mixing procedures for WVP is CET > CEB > GEM. (C) 1996 John Wiley & Sons, Inc.