Two diphenylantimony(III) derivatives of dithiophosphorus ligands, i.e. Ph2SbS2PPh2 and Ph2SbS2P(OPr-i)2, which were previously found to exhibit antitumor properties, have been now investigated for potential mutagenic effects in healthy and Ehrlich ascites tumor-bearing mice. Two short-term tests, i.e. the micronucleus test and the cytogenetic analysis, were used as end-points for mutagenicity. The results are consistent with a mutagenic potential for both organoantimony(III) compounds tested, the effect being higher for the phosphorodithioato derivative.

The composite materials for self-regulating heaters are conductive composites based on a polymer matrix and a dispersed conductive filler consisting in either carbon black or another carbon material, such as graphite or nanotubes. Similar materials are suitable for sensors and current limitations. As these materials used in heating applications work usually at elevated temperatures in presence of air, the ageing processes would be an important limiting factor of their lifetime. Therefore, thermal oxidation processes and crystallinity changes during the service of these products are of major interest in durability studies. The potential interference of carbon-based materials with the oxidation and ageing of polymer matrix shall be known in order to correctly estimate the durability of such materials. The effect of radiation exposure is studied taking into account the potential use of such materials in radiation environments. In this work, the activation energies of some initial, unaged and aged products at elevated temperatures are compared in order to characterize the effect of thermo-oxidative ageing and hence to evaluate their durability. The effect of some antioxidants is also discussed. The crystallinity, calculated from DSC was used for evaluation of the physical changes induced within the aged materials, following the procedures described in previous work. FTIR-ATR technique was used for characterization of chemical changes induced by ageing.

The present paper is focused on evaluating the most suitable dispersion method in the epoxy matrix of two self-healing systems containing dicyclopentadiene (DCPD) and 5-ethylidene-2-norbornene (ENB) monomers encapsulated in a urea-formaldehyde (UF) shell, prior to integration, fabrication and impact testing of specimens. Both microstructural analysis and three-point bending tests were performed to evaluate and assess the optimum dispersion method. It was found that ultrasonication damages the microcapsules of both healing systems, thus magnetic stirring was used for the dispersion of both healing systems in the epoxy matrix. Using magnetic dispersion, 5%, 7%, 10%, 12% and 15% volumes of microcapsules were embedded in glass fibre composites. Some of the samples were subjected to thermal cycling between −20 °C and +100 °C for 8 h, to evaluate the behaviour of both healing systems after temperature variation. Impact test results showed that the mechanical behaviour decreases with increasing microcapsule volume, while for specimens subjected to thermal cycling, the impact strength increases with microcapsule volume up to 10%, after which a severe drop in impact strength follows. Retesting after 48 h shows a major drop in mechanical properties in specimens containing 15% MUF-ENB microcapsules, up to total penetration of the specimen.

This paper presents the characterization of carbonic functional phase based on carbon mesophase/carbon nanotubes nanocomposites used as functional filler in a polymeric matrix by optical microscopy, X-ray diffraction and functional by electrical resistivity measurements. The nanocomposites were prepared by adding of single walled carbon nanotubes (SWNT) or multi walled carbon nanotubes (MWNT) in a petroleum pitch. It was reported that SWNT behaves as either a metal or a semiconductor depending on the wrapping angle of the graphene sheet and its diameter, while MWNTs are always conductive. Carbonic functional phase was obtained by heat treatment of pitch/nanotubes mixtures at 450oC and 900oC temperatures. Polymeric composites were obtained by adding carbonic functional phase in an epoxy resin matrix. The polymeric composites were functional characterized from electrical point of view, establishing their behaviour. The electrical behaviour of the (SWNT/MWNT)/PP systems heat treated at 450�C is not largely influenced by the CNTs, because they are not creating any conducting connections. The composite systems, heat treated at 450�C, show a high resistivity of 105 ohm�cm, while the systems heat treated at 900�C show a lower electrical resistivity of 10-1 ohm�cm.

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