Abstract
The following fillers were added to rigid polyurethane–polyisocyanurate foams in the amount of 2,5-10wt%: silica, kaolin and epoxy resin. The effect of these fillers on the thermal resistance of the foams was studied. The biggest influence on the temperature of the first loss in foam mass (beginning of change in mass) is addition of silica. The temperature increased from 44℃ (foam without filler W) to 88℃ (foam containing 10% wt/wt of silica S10). The temperature at the extrapolated beginning of the first mass loss in the foam (beginning of decomposition) increases from 102℃ (Wfoam) to 110℃ (K10 foam), to 222℃ (S10 foam), to 144℃ (E10 foam). The temperature of the highest speed of loss in mass (beginning of rapid decomposition) increases from 220℃ (W) to 425℃ (S10) and to 243℃ (E10) for foams with kaolin and Epidian 5, respectively. As the content of silica and epoxy resin (Epidian 5) were increased in foam composition, softening point of foams increased from 230℃ (foam W) to 239℃ (foam K10) and to 244℃ (foam E10). Addition of kaolin resulted in softening point decrease to 198℃ (foam S10).
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