Thermal Stability and Degradation Kinetics of Polystyrene/Organically-Modified Montmorillonite Nanocomposites

Abstract

Organically-modified montmorillonite (MMT) clays have been prepared using ammonium salts containing quinoline, pyridine, benzene, and styrenic groups. The nanocomposites were prepared by melt blending and the formation of nanocomposites was characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Thermal stability and flammability were evaluated by thermogravimetric analysis (TGA) and cone calorimetry measurements, respectively. The presence ofmodified MMT at 5% loading resulted in significant improvement in thermal stability compared to the virgin polymer. Effective activation energies for mass loss were determined via a model-free isoconversional approach from TGA data obtained under N2 and under air. The additives served to raise the activation energy, with a more significant impact observed under pyrolysis conditions. The onset temperature of degradation and temperature of maximum decomposition rate are increased, while the peak heat release rate and mass loss rates are significantly reduced in the presence of three of the modified clays. No reduction in the total heat released is observed.

Characterization of Feedstock Filament Extruded from Secondary Sources of PS, ABS and PVC

“…The peak of mass loss was at 420 °C. This is consistent with a previously published result [37]. The evolved gas analysis of rABS showed that possible gases were acrylonitrile (m/z 53), benzene (m/z 77, 78), styrene (m/z 51, 78, 104), toluene (m/z 91, 92) and methylstyrene (m/z 118).…”

High‐performance hexagonal boron nitride/bismaleimide composites with high thermal conductivity, low coefficient of thermal expansion, and low dielectric loss

“…The big heat capacity and thermal conductivity of hBN may be responsible for this result, which means that hBN preferably absorbs the heat, and thus the composites start to degrade at higher temperatures. [30] The experimental char yields are greatly larger than the theoretical values calculated by the "mixture rule" ( Table 1), indicating that there is a synergistic effect on delaying the thermal decomposition, which may be attributed to the good dispersion of hBN in the resin matrix and the good interfacial adhesion because the presence of homogeneously dispersed hBN layers in the resin matrix with chemical reaction provides a good barrier for heat and mass transfer [31] and thus better thermal stability. With careful observation, the deviation between theoretical and experimental char yields achieves the largest value for the composites with 10 -15 wt% hBN because there is an optimum content of hBN for the good dispersion, and a very large amount of hBN is not beneficial in getting a good dispersion of hBN.…”

Polycardanol and Poly(cardanol‐co‐styrene): Synthesis, Characterization, and Performance as Asphaltene Flocculant

“…In contrast, the PS thermogram exhibits one-step decomposition. [19,[21][22][23] The onset of degradation occurred at around 220 C, and from this temperature the polymer chains are degraded until higher temperatures, at around 460 C, at which temperature the entire mass of the PS was degraded. PCNS 50:50 and PCNS 60:40 presented better thermal stability than PCN, that is, the decomposition of PCNS 50:50 and PCNS 60:40 began at a higher temperature than that of the PCN.…”