TY - JOUR
T1 - Comparison of thermal curing behavior of liquid and solid urea-formaldehyde resins with different formaldehyde/urea mole ratios
AU - Nuryawan, Arif
AU - Park, Byung Dae
AU - Singh, Adya P.
N1 - Publisher Copyright:
© 2014 Akadémiai Kiadó, Budapest, Hungary.
PY - 2014/10/1
Y1 - 2014/10/1
N2 - This study was undertaken to compare thermal cure kinetics of urea-formaldehyde (UF) resins, in both liquid and solid forms as a function of formaldehyde/urea (F/U) mole ratio, using multi-heating rate methods of differential scanning calorimetry. The requirement of peak temperature (T p ), heat of reaction (ΔH) and activation energy (E) for the cure of four F/U mole ratio UF resins (1.6, 1.4, 1.2 and 1.0) was investigated. Both types of UF resins showed a single T p , which ranged from 75 to 118°C for liquid resins, and from 240 to 275°C for solid resins. As the F/U mole ratio decreased, T p values increased for both liquid and solid resins. ΔH values of solid resins were much greater than those of liquid resins, indicating a greater energy requirement for the cure of solid resins. The ΔH value of liquid UF resins increased with decreasing in F/U mole ratio whereas it was opposite for solid resins, with much variation. The activation energy (E a ) values calculated by Kissinger method were greater for solid UF resins than for liquid resins. The activation energy (E α ) values calculated by isoconversional method which showed that UF resins in liquid or solid state at F/U mole ratio of 1.6 followed a multi-step reaction in their cure kinetics. These results demonstrated that thermal curing behavior of solid UF resin differed greatly from that of liquid resins, because of a greater branched network structure in the former.
AB - This study was undertaken to compare thermal cure kinetics of urea-formaldehyde (UF) resins, in both liquid and solid forms as a function of formaldehyde/urea (F/U) mole ratio, using multi-heating rate methods of differential scanning calorimetry. The requirement of peak temperature (T p ), heat of reaction (ΔH) and activation energy (E) for the cure of four F/U mole ratio UF resins (1.6, 1.4, 1.2 and 1.0) was investigated. Both types of UF resins showed a single T p , which ranged from 75 to 118°C for liquid resins, and from 240 to 275°C for solid resins. As the F/U mole ratio decreased, T p values increased for both liquid and solid resins. ΔH values of solid resins were much greater than those of liquid resins, indicating a greater energy requirement for the cure of solid resins. The ΔH value of liquid UF resins increased with decreasing in F/U mole ratio whereas it was opposite for solid resins, with much variation. The activation energy (E a ) values calculated by Kissinger method were greater for solid UF resins than for liquid resins. The activation energy (E α ) values calculated by isoconversional method which showed that UF resins in liquid or solid state at F/U mole ratio of 1.6 followed a multi-step reaction in their cure kinetics. These results demonstrated that thermal curing behavior of solid UF resin differed greatly from that of liquid resins, because of a greater branched network structure in the former.
KW - Activation energy
KW - Cure kinetics
KW - Formaldehyde/urea mole ratio
KW - Heat of reaction
KW - Peak temperature
KW - Urea-formaldehyde resin
UR - http://www.scopus.com/inward/record.url?scp=84907380186&partnerID=8YFLogxK
U2 - 10.1007/s10973-014-3946-5
DO - 10.1007/s10973-014-3946-5
M3 - Article
AN - SCOPUS:84907380186
SN - 1388-6150
VL - 118
SP - 397
EP - 404
JO - Journal of Thermal Analysis and Calorimetry
JF - Journal of Thermal Analysis and Calorimetry
IS - 1
ER -