Estimating Thermal Behavior and Analyzing Evolved Species of Adhesives Through Thermogravimetric Analysis combined with Spectrometric Techniques

Four tyoes of commercial adhensives, ureaformaldehyde resin adhensives (UF9, malamine-urea formaldehyde copolymer resin adhensives (MUF), phenol firmaldehyde resin adhensives (PF) and diphenylmethane diisocyanate adhensives (MDI) were studied, by first using thermogravimetric analysis (TGA) alone, and then by using thermogravimetric analysis with infrared spectrometry (TGA-IR). Results obtained from the TGA tests found that MDI exhibited the highest initial decomposotion at a temperature of 297℃ and better overall thermo-stability than one other types of adhensives. PF and MDI provided a better yield of char at about 24.88 and 20.61 wt%, respectively, at 850℃. This showed that their thermal behavior was better than that of UF (5.40 wt%) or MUF (6.99wt%). The IR response of all adhensives in the TGA-IR tests showed that the absorbance of UF, MUF and MDI was higher than that of PF; this indicated that the concentration of evolved species of PF was less than that of MDI, and less than that of urea copolymer series adhensives, UF and MUF. It has been suggested that PF is the most environmentally friendly adhensive, because it has the least environmental impact when used in many industrial and domestic applications, such as for structural mebers in furniture or architecture. These results, when compared to the molecular structures of the adhensives, enabled us to point out the kinds of evolved species (funcianal bases or the change in molecular structures) for referencing the thermo-degradation processes of the adhensives. Using TGA-IR, to analyze the thermal behavior of 4 types of adhensives, in combination with TGA analysis, has led to useful results, involving the identification of pyrolysis products