Evolution of thermal properties of natural rubber nanocomposites functionalized by nickel–zinc ferrite and potassium strontium niobate nanopowders

Abstract

Several composites and nanocomposites based on a polymeric matrix and ceramic fillers are being pursued for use as multifunctional and innovative materials. Nevertheless, there is a series of challenges to be solved in this area such as the understanding of the role of interfaces and the synergy between matrix and fillers. In this work, vulcanized natural rubber nanocomposites were prepared with different concentrations of two kinds of ceramic nanoparticles, potassium strontium niobate (KSr 2 Nb 5 O 15 or KSN) and nickel-zinc ferrite (Ni 0.5 Zn 0.5 Fe 2 O 4 or NZF), synthesized by a chemical method known as the modified polyol method. Morphological and thermal characterizations were carried out by AFM, TG/DTG, TG/FTIR and DSC. The thermal properties of nanocomposites were compared and discussed as functions of concentration, type and surface of nanoparticles. The results obtained suggest that the base concentration for both types of nanoparticles inside the polymer matrix volume greatly adds to the increase in thermal stability up to 11 % and the glass transition temperature up to 10°C. A similar evolution for the glass transition temperature (T g), thermal stability temperature (T S) and dielectric permittivity (e 0) was identified, suggesting that these phenomena are mainly dominated by the same mechanisms. These results point to the possibility for the thermal parameter modulation in magnetic and ferroelectric nanocomposites by means of a suitable control of concentration and properties of the KSN and NZF nanoparticles. Keywords Nickel-zinc ferrite Á Potassium strontium niobate Á Functionalized nanocomposites Á Thermal properties Á Thermal stability Á Glass transition temperature & Aldo Eloizo Job

Flexible fluorescent films based on quantum dots (QDs) and natural rubber

“…The three‐dimensional (3D) infrared spectra have three axes which correspond to wavenumber (axis x ), temperature (axis y ), and absorbance values (axis z ). In this sense, we observed that 3D infrared spectra of the samples with and without QDs are similar and the vibrational frequencies of those spectra are associated with the thermal degradation of rubber according to previous publications, therefore the IR bands from the samples could correspond to gases from the degradation of the polyisoprene. Here, if we select IR spectra at 354 °C from 3D FTIR and the gases released from the RFs and RF/QDs, it is possible to observe clearly the IR bands associated with the rubber degradation and no IR bands related to QDs.…”

“…In this sense, we observed that 3D infrared spectra of the samples with and without QDs are similar and the vibrational frequencies of those spectra are associated with the thermal degradation of rubber according to previous publications, therefore the IR bands from the samples could correspond to gases from the degradation of the polyisoprene. Here, if we select IR spectra at 354 °C from 3D FTIR and the gases released from the RFs and RF/QDs, it is possible to observe clearly the IR bands associated with the rubber degradation and no IR bands related to QDs. Vibrational frequencies shown in Figure correspond to asymmetric stretching of CH 2 at 2927 cm −1 , symmetric stretching of CH 2 at 2869 cm −1 , stretching of CC at 1635 cm −1 , angular deformation CH 2 at 1455 cm −1 , angular deformation CH 3 at 1369 cm −1 , and CH wagging in the CH 3 883 cm −1 .…”

“…Figure shows the thermal characterization of RF with and without QDs. The TGA and DTG thermograms exhibit a similar mass loss peak at 356 °C for all samples, as seen in the analysis performed with the solution of rubber cream (see Figure ) wherein the DTG peak at 353 °C refers to the polyisoprene degradation . Total mass loss around 600 °C is associated with typically NR residues .…”

Cure characteristics, mechanical, thermal, and coloring properties of natural rubber/dye‐loaded shell powder composites

“…The maximum degradation rates of all vulcanizates were located at around 373 °C, which indicated that the elastomeric properties of the vulcanized NR were maintained in the composites. A small shoulder with low intensity, marked by a red arrow, at around 420 °C was confirmed for all materials, which was assigned to the different degradation temperatures for the constituents of NR . In this study, the thermal stability temperature ( T s ) of the materials was measured by the temperature when 1% of mass loss occurred.…”

“…The composites with various filler content exhibit similar thermal gravimetric curves. The fast mass loss between 300 and 490 °C was attributed to the thermal degradation of polyisoprene, dipentene, and p ‐menthene . The maximum degradation rates of all vulcanizates were located at around 373 °C, which indicated that the elastomeric properties of the vulcanized NR were maintained in the composites.…”