초록 |
The objective of this research was to investigate the activation energy and viscoelastic properties of urea-formaldehyde (UF) resin, melamine-formaldehyde (MF) resin and UF-MF resin mixtures by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). The purpose of adding MF resin to the UF resin was to reduce the formaldehyde emissions. The storage modulus (E'), loss modulus (E") and loss factor (tan δ) of each resin were measured by DMTA. The Ea value of the UF resin decreased as the MF resin content ratio increased, and because of this lower activation energy, the UF-MF resins cured faster than the UF resin. Formaldehyde is incorporated more easily and completely into melamine than into urea. These results showed that MF resin reacts with formaldehyde faster than UF resin because of its high -NH ratio. |