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The reaction of toluene diisocyanate (TDI) with dimethylol propionic acid (DMPA) or diaminopentane sulphonic acid sodium salt and other additives to form the structure of anionic polyurethane (PU) ionomer molecule has been proven by FT-IR spectroscopy.In aqueous solution, the surface tension of anionic PU ionomer molecule is seen to slightly increase with increasing concentration of ES-200. This is because the adsorption of hydrophobic groups of ionomer molecules at the surface of aqueous solution becomes even more ordered. Under the same experimental conditions, the surface tension of anionic PU ionomer molecule appears to slightly decrease with increasing concentration of DMPA, as a result of increased hydrophobic groups of ionomer molecule adsorbed at the surface of aqueous solution. The number average particle size of anionic PU ionomer molecule in aqueous solution appears to steadily increase with an increase in the concentration of DMPA or ES-200. This is because the intermolecular interaction between ionomer±ionomer molecules themselves and between ionomer±water molecules may increase the free volume of anionic PU ionomer molecule, thus causing their number average particle size to increase.Experimental results indicate that both the tensile strength and the modulus of self-cured film of anionic PU ionomer molecule appear to decrease with increasing concentration of DMPA or ES-200, as a result of intramolecular interaction. However, the elongation of self-cured film of anionic PU ionomer molecule is seen to increase with increasing concentration of DMPA or ES-200. This may be the result of weakening crosslinking due to strong intramolecular interaction of ionomer molecule. For the peel strength of self-cured film of anionic PU ionomer coated on the fabric (30% polyester/ 70% cotton), it has been found that the peel strength increases with increasing concentration of DMPA or ES-200, as a result of increased hydrophilic interaction between ionomer molecules themselves.

ABSTRACT:The reaction of dye with toluene diisocyanate and dimethyldichlorosilane in the presence of other additives to form a colored siloxane-based polyurethane (PU) ionomer has been proven to occur by infrared spectra. In aqueous solution, the numberaverage particle size for the colored siloxane-based PU ionomer was found to increase with an increase in the NCO-to-OH ratio, dye concentration, and dimethyldichlorosilane concentration, as a result of increased free volume of the ionomer molecules. It is worthy to note that the amount of air diffusing into the film cast from colored siloxanebased PU ionomer was found to increase with an increase in the concentration of dimethyldichlorosilane instead of raising the ratio of NCO to OH or the concentration of dye, as a result of the formation of more porosities. In addition, the tensile strength of this film will be strengthened by raising the NCO/OH ratio or the concentration of dimethyldichlorosilane, whereas the elongation, on the other hand, can be substantially increased with increasing the concentration of dye instead of increasing the concentration of dimethyldichlorosilane for use in the PU ionomer system.

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ABSTRACT:The reaction of methylene diphenylene diisocyanate with ethylene glycol, dimethyl dimethoxysilane, dimethyl diethyloxysilene, and other additives in the presence of N,N-dimethylformamide and toluene to form the structure of water-vapor-permeable polyurethane (PU) resin was proven with Fourier transform infrared spectra. Experimental results clearly showed that the amount of oxygen that permeated the film made with the PU resin increased with an increase in the concentration of ethylene glycol, diethylene glycol, or triethylene glycol. This was due to an increased number of hydrophilic groups attached to the backbone of the PU resin molecules. These hydrophilic groups, because of the intermolecular interactions between PU resin molecules, made PU resin molecules form an expanded conformation with large porosities. Interestingly, the water vapor permeability of the PU resin appeared to increase with an increasing concentration of ethylene glycol, dimethyl dimethoxysilane, or dimethyl diethoxysilane but not to increase with an increasing concentration of diethylene glycol, triethylene glycol, or poly(ethylene glycol) with dimethyl dimethoxysilane. The former was due to intermolecular interactions resulting in an expanded conformation with large porosities, but the latter was due to intramolecular interactions resulting in a compact conformation or a micellelike structure with small porosities. Therefore, the water vapor permeability of the former increased, but the latter remained unchanged or decreased. Our experimental results suggest that the use of poly(ethylene glycol) 400, ethylene glycol, dimethyl dimethoxysilane, and other strong hydrophilic compound in the preparation of modified PU resins substantially raises the amount of water vapor diffusing into films made with these resins.