SYNTHESIS AND CHARACTERIZATION OF POLYURETHANE DISPERSIONS BY TRADITIONAL AND AUTOMATED METHODS

Materials. Dimethylolproponic acid (DMPA) was supplied by Perstorp. N-Methyl-2-pyrrolidone (NMP, Sigma-Aldrich, 99.5 %), dibutyltin dilaurate (DBTDL, Aldrich, 95 %), triethylamine (TEA, Aldrich, 99.5 %), ethylenediamine (EDA, Aldrich, 99 %) were used without further purification. Linear polyester polyol and dicyclohexylmethane diisocyanate were obtained from BayerMaterial science. Instrumentation. Viscosity measurements were done using Brookfield DV-I+ Viscometer and the viscosity was measured at room temperature around 23 °C with spindle S63 at 100 rpm. The particle size was measured using Submicron Particle Sizer, NICOMP™ 380 and the measurements were done after filtering the solution with 5 µm filter. Both Gaussian and Nicomp methods were used to see the comparison of the particle size. An automated surface energy measurement unit manufactured by Symyx Discovery Tools, Inc and First Ten Angstroms was used to measure coating surface energy. Droplets of water and methylene iodide (MI) were deposited on the coating separately and a CCD camera imaged the droplets and then automated image analysis was used to determine the contact angles. Three droplets of water and MI were used for each measurement. Surface energy was calculated from the contact angles data using the Owens-Wendt equation. The synthesis for the automated method was done in Chemspeed Autoplant A100™ and details of the Autoplant are given below and Figure 1 show the reactor system. 12 This Autoplant system can handle more complex process conditions than the batch system. The system consists of 12 Process Development (PD) units. Each PD unit contains two 100 ml stainless steel reactors having mechanical stirring up to 600 rpm and reflux cooling. The temperature in each reactor can be controlled independently over a range of 10 to 250 °C. Solid and liquid reagents can be automatically charged to each