Water remaining properties of nonwoven fabrics treated with the polyurethane polymers containing carboxylic acid group and the thermal and structural characterization of the polymers

Three low-molecular-weight polyurethanes (LMWPU) containing various amounts of carboxylic acid were synthesized and applied on the nonwoven fabric for the improvement of water remaining property. The chemical structure of the LMWPUs was confirmed with H-1-NMR and C-13-NMR. The molecular weights of those three LMWPUs ranged from 3100 to 4200 g/mol. The results showed that the add-on values were increased with the increasing of the content of 2,2-bis(hydroxymethyl)propicnic acid in LMWPU at a same resin concentration in padding bath. However, the water remaining values were decreased with the increasing of the content of 2,2-bis(hydroxymethyl)propionic acid in LMWPU for a given add-on value. The thermal properties, such as thermo-degradation and the values of T-g and T-m of the polymers, could not affect the water remaining property of the treated fabrics. The analyses of X-ray diffraction patterns and polarizing microscope observations showed that LMWPU with higher content of polytetramethyleneglycol had higher amorphous region. This phenomenon clearly supported that the values of water remaining were strongly affected by the amorphous region of the LMWPU polymers. (c) 2007 Wiley Periodicals, Inc.