Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
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Effects of Hardener and Extender Contents on Curing Behavior of Urea-Melamine-Formaldehyde Resin

  • Eom, Young-Geun (Department of Forest Products, College of Forest Science, Kookmin University) ;
  • XU, Guang-Zhu (Department of Forest Products, College of Forest Science, Kookmin University) ;
  • Lee, Young-Kyu (Material Property Analysis Lab., National Instrumentation Center for Environmental Management, Seoul National University) ;
  • Kim, Hyun-Joong (Lab. of Adhesion & Bio-Composites, Program in Environmental Materials Science, Research Institute for Agriculture and Life Sciences, Seoul National University)
  • Received : 2008.08.12
  • Accepted : 2008.09.05
  • Published : 2008.09.25
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Abstract

This study was conducted to discuss the effects of hardener and extender contents on peak temperature, reaction enthalpy (${\Delta}H$), gelation time, viscosity change, and pH value in three types of UMF (urea-melamine- formaldehyde) resin with the help of perpHecT LogR meter, differential scanning calorimetry (DSC), and advanced rheometric expansion system (ARES), The results indicated that the pH value of Control A steeply decreased to 5,2 in the early stage but relatively remained constant thereafter as in Synthesis 1 and Synthesis 2, The peak temperature and time decreased as well, whereas ${\Delta}H$ and viscosity increased with the increase of hardener content. On the other hand, ${\Delta}H$ was not changed up to the extender content of 5% and then decreased with its further addition, And the pH value and peak temperature showed no change with the increase of extender content at the hardener content of 5% in three types of UMF resin, The effect of hardener content in this experiment, however, appeared more conspicuous in Control A than in the other two types of Synthesis 1 and Synthesis 2, These results might be caused by higher molecular weight with longer chains of methylene ($-CH_2-$) and methylene ($-CH_2-O-CH_2-$) ether bridges or much more branched chains in Control A.

Keywords

References

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