| 초록 |
Anionic aqueous-based polyurethane (PU) dispersions were prepared by pre-polymer mixing method. The PU dispersions were prepared by polyaddition reaction with poly ethylene glycol (PEG), dimethylol propionic acid (DMPA) and diisocyanates which are 4,4'-diphenlymethane diisocyanate (MDI) and isophorone diisocyanate (IPDI). The MDI-terminated PU prepolymer can not be well dispersed in the water because of its high reactivity. IPDI was used to terminate the OH-terminated prepolymer which was synthesized with MDI and excess PEG firstly. Various formulations were designed to investigate the effect of process variables such as mole ratio of NCO to OH, DMPA content, and degree of MDI containing proportion in diisocyanates. In this work, MDI-IPDI hybrid PU dispersion was prepared and was characterized by Fourier transform infrared spectrum analysis and gel permeation chromatography. PU particle size was ranged from 80nm to 150nm. The MDI-IPDI hybrid PU casting films were observed in terms of mechanical and thermal properties with universal testing machine, differential scanning calorimetry, and thermogravimetry. |
