At. Ponomarenko et al., Thermogravimetry as a method for investigating the thermal stability of polymer composites, J THERM ANA, 55(2), 1999, pp. 537-549
Thermogravimetry was used to investigate the effects of different inorganic
functional fillers on the heat resistance of polymer matrices. The kinetic
parameters of thermal oxidative degradation were shown to depend on the po
lymer, the chemical composition of the filler surface, the filler concentra
tion, and the processing method, which determines the distribution of fille
r particles in the polymer matrix. Magnetic fillers (carbonyl iron, and hex
aferrites of different structural types) were shown to be chemically active
fillers, increasing the heat resistance of siliconorganic polymers. Their
stabilizing effect is due to blocking of the end silanol groups and macrora
dicals by the surface of the filler and non-chain inhibition of thermal oxi
dative degradation. In the case of fiber-forming polymers (UHMWPE, PVOH and
PAN), most magnetic fillers are chemically inert, but at concentrations of
30-50 vol% they increase the heat resistance of the composite. Addition of
carbon black increased the heat resistance of the thermoplastic matrix. Th
e dependence of the thermal degradation onset temperature on the kaolin con
centration in the polyolefin matrix exhibited a maximum. Analysis of the ex
perimental results demonstrated the operating temperature ranges for differ
ent composites, and their maximum operating temperature.