Preparation and Physical Properties of MDEA-based Polyurethane Cationomers and their Application to Textile Coatings

Abstract

Cationic aqueous polyurethane (CAPU) coatings were prepared by the acetone process using 4,4-methylene bis (isocyantocyclohexane) (H12MDI), N-methyldiethyolamine (N-MDEA) and a series of various polydiols (polyethylene glycol (PEG), polypropylene glycol (PPG) and polytetramethylene glycol (PTMG) for ether-type polyols and polycaprolactone (PCL) for ester-type polyol) with different molecular weights (Mn =1000, 2000 and 3000 g/mole). The surface tension of CAPU dispersion, contact angle, thermal properties of CAPU casting film and its tensile strength were examined. The waterproof (WP) and water vapor permeability (WVP) of coated fabric and its washing durability were also studied. Our results showed the ether-based CAPU showed a higher surface tension value, contact angle and WVP with a sequence of PEG-PU > PTMG-PU > PPG-PU > PCL-PU, and it increased with increasing Mn of the soft segment. As for the thermal properties, the PEG-PU had the highest glass transition temperatures of the soft segment (Tgs) and melting point (Tms) than those of PCL -PU, PTMG-PU and PPG-PU. For the thermal stability of CAPUs casting film, the PEG-PU had ideal thermal stability, followed by PTMG-PU and PCL -PU, and the CAPU with a larger Mn of the soft segment had better thermal stability. The PTMG-PU had excellent tensile strength, followed by PCL -PU and PPG-PU. For coated fabric, the trend of WVP followed the order: PEG-PU > PTMG-PU > PPG-PU > PCL -PU, while the WP followed the order: PTMG-PU > PCLPU > PPG-PU > PEG-PU. Finally, the CAPUcoated fabric had an excellent performance after washing and its wash-durability was still 80 %. © 2007, Sage Publications. All rights reserved.