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The research described in the present work investigated the effect of thermal and photoaging and rubber waste content on the properties of acrylonitrile–butadiene rubber modified with montmorillonite (MMT). The MMT was mixed with plasticizer before the compounding in two roll mills. The modulus at 300% strain of samples without scrap maximally increased by 50% and 30% after thermal and photoaging, respectively, most probably due to an increase in the crosslink density. The maximum increases of the modulus, measured at 300% strain, of the unaged and aged rubber nanocomposite were exhibited by samples which each contained 10 wt.% of rubber waste. The MMT nanoparticles, well dispersed in the matrix, combined with good interfacial interaction between the different components, led to relative retention of the thermal and photo-oxidation aging coefficients and the large shape retention coefficient of the tested samples. Fourier transform infrared spectra showed that the crosslinking of the rubber nanocomposites containing waste occurred through the nitrile groups and C = C double bonds under the influence of aging. Scanning electron microscopy micrographs indicated that the MMT nanoparticles were uniformly embedded and well dispersed in the matrix. The rough and homogeneous fracture surfaces of the nanocomposite samples were not affected by incorporated waste. As a result of UV irradiation and thermal heating, aggregates were less visible and the fracture surfaces more homogeneous and compact. [ABSTRACT FROM AUTHOR]

The present work investigates the ablative and thermal properties of phenol formaldehyde glass-fabrics laminates filled with mixtures of corundum Al2O3 and carbon C powders. The laminates specimens of dimensions 10x25x35 mm were treated with hot combustion gases having a temperature of more than 2800°C. The carbonization of the thermosetting matrix was observed. Statistical methods for planning experiments were used, and the effect of components on the average rate of ablation, the maximum back side temperature of specimen and the average mass waste under intensive heat flow after 30 s of treatment with hot combustion gases was established. The best thermal protective properties were exhibited by the laminate containing 30% matrix, 25% fibre glass-fabric reinforcement, 9% corundum, and 36% carbon powder. [ABSTRACT FROM AUTHOR]

The aim of our research was to investigate the effect of a small nanocellulose (NC) addition on an improvement of the mechanical properties of epoxy composites. A procedure of chemical extraction from pressed lignin was used to obtain nanocellulose fibers. The presence of nanoparticles in the cellulose pulp was confirmed by FTIR/ATR spectra as well as measurement of nanocellulose particle size using a Zetasizer analyzer. Epoxy composites with NC contents from 0.5% to 1.5% w / w were prepared. The obtained composites were subjected to strength tests, such as impact strength (IS) and resistance to three-point bending with a determination of critical stress intensity factor (Kc). The impact strength of nanocellulose composites doubled in comparison to the unmodified epoxy resin (EP 0). Moreover, Kc was increased by approximately 50% and 70% for the 1.5 and 0.5% w / w NC, respectively. The maximum value of stress at break was achieved at 1% NC concentration in EP and it was 15% higher than that for unmodified epoxy resin. The highest value of destruction energy was characterized by the composition with 0.5% NC and corresponds to the increase of 102% in comparison with EP 0. Based on the analysis of the results it was noted that satisfactory improvement of the mechanical properties of the composite was achieved with a very small addition of nanofiller while other research indicates the need to add much more nanocellulose. It is also expected that this kind of use of raw materials will allow increasing the economic efficiency of the nanocomposite preparation process. Moreover, nanocomposites obtained in this way can be applied as elements of machines or as a modified epoxy matrix for sandwich composites, enabling production of the structure material with reduced weight but improved mechanical properties.