Reticulation of aqueous polyurethane systems

Abstract

The DSC method has been employed to monitor the kinetics of reticulation of aqueous polyurethane systems without catalysts, and with the commercial catalyst of zirconium (CAT®XC-6212) and the highly selective manganese catalyst, the complex Mn (III)-diacetylacetonemaleinate (MAM). Among the polyol components, the acrylic emulsions were used for reticulation in this research, and as suitable reticulation agents the water emulsible aliphatic polyisocyanates based on hexamethylendoisocyanate with the different contents of NCO-groups were employed. On the basis of DSC analysis, applying the methods of Kissinger, Freeman-Carroll and Crane-Ellerstein the pseudo kinetic parameters of the reticulation reaction of aqueous systems were determined. The temperature range of the examination was from 500C to 4500C with the heat rate of 0.50C/min. The reduction of the activation energy and the increase of the standard deviation indicate the catalytic action of the selective catalysts of zirconium and manganese. The impact of the catalysts on the reduction of the activation energy is the strongest when using the catalysts of manganese and applying all the three afore-said methods. The least aberrations among the stated methods in defining the kinetic parameters were obtained by using the manganese catalyst.

DSC metodom praćena je kinetika umrežavanja vodenih poliuretankih sistema, bez katalizatora, sa komercijalnim katalizatorom cirkonijuma (KAT®XC-6212) i visokoselektivnim manganovim katalizatorom, kompleksom Mn(III) - diacetilacetonatomaleinatom (MAM). U ovom radu za umrežavanje od poliolnih komponenti korišćene su akrilne emulzije a kao pogodni umreživači koričćeni su vodoemulgujući alifatični poliizocijanati na bazi heksametilendiizocijanata sa različitim sadržajem NCO-grupa. Na osnovu DSC-analize, metodama Kissinger-a, Freeman-Carrollaa i Crane-Ellerstein-a, određeni su prividni kinetički parametri reakcije umrežavanja vodenih sistema. Temperaturni opseg ispitivanja koričćen je od 50 do 450oC sa brzinom grejanja od 0.5oC/min. Smanjenje energije aktivacije i povećanje standardne devijacije ukazuju na katalitičko dejstvo selektivnih katalizatora cirkonijuma i mangana. Učešće katalizatora u smanjenju energije aktivacije je najveće kod katalizatora mangana, korišćenjem sve tri bbbmetode izračunavanja kod ispitivanih uzoraka u odnosu na cirkonijumov katalizator. Najmanja odsupanja između pomenutih metoda u određvanju kinetičkih parametara dobijena su korišćenjem manganovog katalizatora.