Thermal stability of isocyanate as particleboard’s adhesive investigated by TGA (Thermogravimetric Analysis)

Abstract

The objective of this study was to evaluate the thermal stability of isocyanate as particleboard adhesives by means of TGA (thermogravimetric analysis). In this study, thermal properties particularly thermal stability of isocyanate-water/wood system was studied up to a temperature of 500 ºC using thermal analyzer (Mettler Toledo). When isocyanate was used as the binder in particleboard system; the reactive –NCO group reacted with water (because wood is a hygroscopic material and contains free and bound water) and also with the –OH group from wood. The isocyanate was H3M purchased from PT. Polichemie Asia Pacific and the wood particle was Eucalyptus sp. taken from PT. Toba Pulp Lestari. About 10 mg of the mixture either isocyanate with water or wood in various weight ratios were scanned at two different heating rates (slow and fast; 2.5 and 20 °C/min, respectively) with a temperature range from 25 to 500 °C. Results of this study indicate there were more resistant segments to heat in the mixture of isocyanate and water shown from the residual weights about 61-71% compared to in the mixture of isocyanate and wood particle (only 54-62%). Furthermore, there were fewer steps to degrade in the mixture of isocyanate and water shown from the number of peak temperatures about 1-2 peaks than that in the mixture of isocyanate and wood particle (2-4 peaks). New evidence also emerges that isocyanate reacted with water first shown from the weight loss from the low temperature in the mixture of isocyanate and wood particle.