Melamine ‐ formaldehyde resins II.—Thermal degradation of model compounds and resins

Abstract

The thermal degradation of a series of cured melamine‐formaldehyde resins and of two relevant model compounds has been investigated using thermogravimetry accompanied by the analysis of volatile products. Low temperature degradation reactions which occur up to ∼350°C involve the loss of water and formaldehyde, the latter arising from reversible demethylolation reactions. It is proposed that ether linkages, which model compound studies indicate would yield formaldehyde in the low temperature region, are not present to any significant degree in cured resins. Deep‐seated rupture of the polycondensate system takes place at temperatures above ∼375°C when a number of independent reactions involving both side‐chain and ring degradation give rise to products among which ammonia, hydrogen cyanide, carbon monoxide and melamine have been examined.

Melamine-derived carbon sponges for oil-water separation

“…By combining the TGA and FTIR results, many authors suggested a mechanism for the thermal degradation of melamine [50,51,47,48]. Up to 350 • C, several reactions can take place such as water evaporation, the elimination of formaldehyde from ether links to form methylene bridges, the degradation of free melamine, the degradation of residual methylol groups.…”

“…Above 600 • C, the complete decomposition of the triazine rings and other organic products led to the vanishing of all peaks which become a very broad band in the infrared spectra. The breaking of the triazine rings has been reported to occur between 600 and 675 • C [50,47,48].…”

“…The main mass loss (30.5 wt%) occurred between 350 • C and 400 • C and could be associated to the breakdown of the methylene bridge (HN-CH 2 -NH) of the melamine structure. Over 400 • C, the mass loss (52.7 wt%) was attributed to the thermal decomposition of the triazine ring [49,50,51,48,39].…”

Properties of liquefied wood modified melamine-formaldehyde (MF) resin adhesive and its application for bonding particleboards

“…In addition to the main area of thermal decomposition, there was also observed weight loss at the temperature 80-95°C which is associated with the evaporation of water in the sample. [36] In the temperature range 220-240°C, another weight loss occurred which increased with increasing level of MF substitution with LW. Although some authors [36,37] associate the weight loss in this temperature range with further evaporation of water and evaporation of formaldehyde for our adhesive mixtures this might not be the case.…”

Effect of nitrogen additives on thermal decomposition of cotton

“…The treated fabrics were heated from room temperature to 450 8C in a quartz tube under nitrogen atmosphere. The residual char was then analyzed for nitrogen content by combustion method [19]. The results of this experiment are shown in Table 4, indicating that the amount of nitrogen remaining in the char depends on the thermal stability of additives as well as characteristics of intermediates formed during the thermal decomposition of the additives.…”