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  • 1 National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
  • | 2 Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva cesta 5, 1000, Ljubljana, Slovenia romana.cerc-korosec@fkkt.uni-lj.si, peter.bukovec@fkkt.uni-lj.si
  • | 3 Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia ida.poljansek@bf.uni-lj.si
  • | 4 Melamin, kemična tovarna d.d. Kočevje, Tomšičeva cesta 9, 1330, Kocevje, Slovenia primoz.ogorelec@melamin.si
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Abstract

The influence of the preconditioning at different temperatures on the cure kinetics of melamine–urea–formaldehyde resins coated on stone wool was investigated under acidic conditions using differential scanning calorimetry and thermogravimetry. The higher pre-treatment temperature was applied, to which resin-coated stone wool was exposed, the lower was the mass loss during the experiment. Kinetic model parameters were determined in two different manners, with the parameters being independent of preconditioning temperature and dependent on the latter. The apparent orders of reaction were approximately two (all of them being within the range 0.96–2.33), which would imply that cross-linking predominantly proceeds via the bimolecular reaction of either melamine or urea and formaldehyde. Nonetheless, the apparent orders of reaction decreased as a function of preconditioning temperature. The apparent activation energies varied less with preconditioning temperature, assuming values between 64.2 and 78.5 kJ mol−1. The applicability of nth-order reaction kinetic models was consequently validated for two other dynamic thermal regimes.

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