PCL-PEG-PCL TRIBLOCK ESTER-ETHER COPOLYDIOL-BASED WATERBORNE POLYURETHANE - II - EFFECT OF NCO OH MOLE RATIO AND DMPA CONTENT ON THE PHYSICAL-PROPERTIES/

This article was focused on the effects of the NCO/OH molar ratio and 2,2-bis(hydroxyl methyl) propionic acid (DMPA) content during prepolym erization on the physical properties of synthesized waterborne polyure thane (WBPU) by using the polycaprolactone-poly(ethyl glycol)-polycapr olactone triblock copolydiol (PCL-PEG-PCL) as the soft segment. The re sults showed that the particle size of the WBPUs' dispersion decreased with a decreasing NCO/OH molar ratio or increasing DMPA content. Rega rding thermal and mechanical properties, the WBPUs had a higher T-g's and lower T-m's and a higher breaking stress and a lower briefing stra in of film with the NCO/OH molar ratio or DMPA content increase. The i ncreasing NCO/OH molar ratio was advantageous to the water vapor perme ability (WVP)-breaking stress balance, but the effect of the DMPA cont ent on the WVP was not significant. The WBPU with PCL-PEG-PCL as the s oft segment had a smaller particle size dispersion and a better WVP-br eaking stress balance than those of WBPU with the blending PCL and PEG as the soft segment. (C) 1998 John Wiley & Sons, Inc.