PCL–PEG–PCL triblock ester–ether copolydiol-based waterborne polyurethane. II. Effect of NCO/OH mole ratio and DMPA content on the physical properties

✍ Scribed by Meng-shung Yen; Shu-chin Kuo

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 222 KB
• Volume: 67
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19980214)67:7<1301::aid-app21>3.0.co;2-2

✦ Synopsis

This article was focused on the effects of the NCO/OH molar ratio and 2,2bis(hydroxyl methyl) propionic acid (DMPA) content during prepolymerization on the physical properties of synthesized waterborne polyurethane (WBPU) by using the polycaprolactone-poly(ethyl glycol) -polycaprolactone triblock copolydiol (PCL-PEG-PCL) as the soft segment. The results showed that the particle size of the WBPUs' dispersion decreased with a decreasing NCO/OH molar ratio or increasing DMPA content. Regarding 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 breaking strain of film with the NCO/OH molar ratio or DMPA content increase. The increasing NCO/OH molar ratio was advantageous to the water vapor permeability (WVP)-breaking stress balance, but the effect of the DMPA content on the WVP was not significant. The WBPU with PCL-PEG-PCL as the soft segment had a smaller particle size in dispersion and a better WVPbreaking stress balance than those of WBPU with the blending PCL and PEG as the soft segment.