CARACTERIZACION DEL CURADO DE RESINAS UREA FORMALDEHIDO POR CALORIMETRíA DIFERENCIAL DE BARRIDO (DSC)

urea formaldehyde resins were prepared in a two step condensations process with molar ratios of formaldehyde / urea that fluctuated between 1.10 - 1.40. the thermal behavior of the curing process was studied by differential scanning calorimetry (dsc) under different environmental conditions. the dsc thermograms of uf resins, with nh4cl as catalyst, showed that main crosslinking reactions, for resins with low molar formaldehyde levels, took place at 100oc. crosslinking reactions, for resins without catalyst or with high formaldehyde molar ratios, took place at temperature between 120 - 180oc