Study of poly(ethylene oxide)/Carbopol blends through thermal analysis andinfrared spectroscopy

Properties such as miscibillity, interaction and the thermal degradation be havior of blends of poly(ethylene oxide) (PEO) with Carbopol were studied b y thermal analysis (DSC, TGA) and infrared spectroscopy (FTIR). The miscibi lity of PEO/Carbopol blends in all composition ranges was confirmed, and th e interaction is favored by hydrogen bonding between the carboxylic acid gr oup of Carbopol and the PEO ether oxygen. TGA analysis showed that, with te mperature increase, anhydride formation occurred first, confirmed by the FT IR bands in 1806, 1756 and 1047 cm(-1). Thermal degradation products such a s carbon dioxide appear as a result of fragmentation of the anhydride ring structures and decarboxylation of the Carbopol acid groups. Bands related w ith unsaturated structures (1605 cm(-1)) were observed at 310 degrees C and 470 degrees C, presumably as a result of scissions of the main carbon-carb on chain. The activation energy of PEO/Carbopol blends increased with the C arbopol content in the blend, indicating that the thermal degradation is de layed with the presence of Carbopol. (C) 2000 Elsevier Science Ltd. All rig hts reserved.