Thermal degradation of blends of ethylene-ethyl acrylate copolymer with some inorganic fillers

Abstract

The thermal stability of blends of ethylene-ethyl acrylate (EEA) copolymer with Al(OH) 3, Mg(OH) 2, MgO and TiO 2 has been investigated in an inert atmosphere using thermogravimetry-differential thermogravimetry TG-DTG, and under vacuum using thermal volatilisation analysis (TVA). The condensable volatile degradation products from the TVA experiments were separated by subambient TVA and investigated by IR spectroscopy, GC, MS and GC-MS techniques. The cold ring fraction was characterised by IR spectroscopy and GC. The degradation products from EEA copolymer with each of these types of filler were mainly similar to the degradation products from the copolymer degraded alone, except that acids such as acetic acid and propanoic acid either were present in trace amounts or were not present. In the case of the blend with TiO 2, however, the amount of acids was greater and that of carbon dioxide was reduced. The filler Mg(OH) 2 was found to prevent the formation of ethylene. The mechanisms of formation of degradation products from blends are altered in the presence of the fillers and are discussed in detail.