Thermal Stability and Flammability of Epoxy Composites Filled with Multi-Walled Carbon Nanotubes, Boric Acid, and Sodium Bicarbonate

Epoxy composites filled with 0.5 wt% of multi-walled carbon nanotubes (MWCNTs), 10 and 15 wt% of boric acid and sodium bicarbonate separately, as well as composites filled with a combination of MWCNTs-boric acid and MWCNTs-sodium bicarbonate were prepared. The thermal behavior of the prepared samples was investigated under heating in oxidative environment using thermogravimetric analysis. The hardness was measured using the Shore D hardness test. To evaluate the flammability of the samples, the ignition temperature and time-to-ignition were determined. It was concluded that sodium bicarbonate in the studied concentrations (10 and 15 wt%) is not appropriate for use as a filler capable of improving the thermooxidative stability and reducing the flammability of epoxy polymers. The improvement in the thermal properties can be achieved by using the combination of boric acid and multi-walled carbon nanotubes as fillers. The thermooxidative destruction of the samples filled with boric acid passes more slowly and more evenly via the formation of B2O3 as a result of its decomposition.

THE COMPARATIVE ANALYSIS OF PREPARED MIXTURES OF CRAMBE ABYSSINICA SEED OIL WITH MINERAL AND SYNTHETIC OIL

The base oils must meet the high technical and ecological requirements for the raw materials used in the production of lubricants. The relevant useful properties can be obtained by mixing the vegetable oil with mineral or synthetic oil. The paper presents the results of tests of mixtures of oil obtained from Crambe Abyssinica seeds with mineral and synthetic oil. A variation of tested mixtures with regard to thermooxidative stability and antiwear properties were found. The mixtures with the most favourable properties were recommended as a base oils during the production of ecological lubricants.

Metal-containing nanocomposites based on isotactic polypropylene

The effect of additives of metal-containing nanofillers, including zinc oxide nanoparticles, on the properties of nanocomposites based upon isotactic polypropylene (PP), using X-ray phase analysis (XPA) and thermogravitometric (TGA) analysis was studied.The improvement of the strength and rheological indexes, as well as the thermooxidative stability of the nanocomposites obtained was revealed.

Synthesis and properties of new 2,3,5,6-tetraaminopyridine based polyheteroarylenes

Two new polyheteroarylenes (polydiimidazopyridines) based on 2,3,5,6-tetraaminopyridine and aromatic dicarboxylic acids were synthesized and characterized. The polymers show high viscosity properties and exceptional thermooxidative stability. Polydiimidazopyridine containing a phosphoric acid group possesses excellent filmforming properties and can be processed to proton conducting membranes that have record high proton conductivity in the temperature range of 20-200 °C after doping with orthophosphoric acid.

The Modification of a Rubber–Epoxy Matrix with Carbon-Containing Fillers for Heat-Shielding Materials

Materials based on a rubber–epoxy matrix filled with coal-tar pitch and petroleum coking additive were investigated. The effect of the fillers on the degradation rate of the cured material and the coke residue yield was studied using data of thermogravimetric and differential thermal analyses and differential scanning calorimetry, It was established that the introduction of coal-tar pitches lowers the thermooxidative stability of the polymer matrix, while the introduction of petroleum coking additive raises it. In tests under isothermal and dynamic conditions, the greatest amount of coke residue is formed after annealing of the composite with petroleum coking additive. Burnout of the coke residue of the given material occurs in the widest temperature range. The influence of the nature of the filler and the test temperature on the mechanical properties of the materials was investigated. It was established that at elevated temperature the best deformation and strength properties are possessed by material with the petroleum coking additive. The prospects of using the obtained materials as heat-shielding coatings were assessed.