The electrical resistivity and thermal properties of multi-walled carbon nanotube/polypropylene (MWCNT/PP) composites have been investigated in the presence of coupling agents applied for improving the compatibility between the nanotubes and the polymer. A novel olefin-maleic-anhydride copolymer and an olefin-maleic-anhydride copolymer based derivative have been used as compatibilizers to achieve better dispersion of MWCNTs in the polymer matrix. The composites have been produced by extrusion followed by injection moulding. They contained different amounts of MWCNTs (0.5, 2, 3 and 5 wt%) and coupling agent to enhance the interactions between the carbon nanotubes and the polymer. The electrical resistivity of the composites has been investigated by impedance spectroscopy, whereas their thermal properties have been determined using a thermal analyzer operating on the basis of the periodic thermal perturbation method. Rheological properties, BET-area and adsorption-desorption isotherms have been determined. Dispersion of MWCNTs in the polymer has been studied by scanning electron microscopy (SEM)

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Nowadays successful recycling of rubber waste has been one of the greatest challenges in waste management. Difficulties in mechanical recycling are especially caused by the variability of raw materials, therefore, a processing simply combining them usually results in end-products with poor mechanical stability. Drawbacks of mechanical recycling of mixed plastics and blends of plastics and rubbers can be overcome by application of compatibilizing additives. Taking the commercial types into account only a few general kinds are available and their effectiveness is hindered by the structure as it cannot be fitted to the chemical structures of plastics processed together. Our study has been addressed to give a comprehensive outlook into a rubber recycling process and successful application of compatibilizing strategies for improving mechanical performance of waste elastomer containing polypropylene. Investigations have been carried out on effective elastomer concentrations, meanwhile on elastomer ratios of various types to each other and on proper structures of compatibilizers. Various mechanical properties could be improved even by 44% due to experimental additives compared to uncompatibilized blends. Mechanical test results have been confirmed by SEM, rheology and FT-IR, to name some of them.

PBT [poly(butylene terephthalate)] is an important engineering thermoplastic having several advantageous properties; however, its brittle behaviour is a disadvantage. Blending with a polymer or applying various types of commercial additives are the two methods widely used for taking advantage of PBT while improving its poor impact properties. In our experimental work, different types of commercially available additives have been applied for improving the mechanical properties of glass fibre-reinforced PBT. Blending a cyclic oligomer with GF/PBT samples made them much more elastic, which was shown by better resistance against tensile, flexure, dynamic and cyclic tensile stresses.

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The scope of our work has been the development of a new type of coupling agent by which processing of long carbon fibre-reinforced thermoplastic composites by conventional injection moulding can be possible. The experimental additive was expected to hinder fibre breakage and to simultaneously improve the mechanical properties of the composites. Resistance of LLDPE reinforced with 1-10 wt% long carbon fibres against tensile, flexure and impact stresses has been investigated. Tensile strength of carbon fibre/LLDPE composites has increased by 10-30%; flexure strength has gained 15-90% related to the neat polymer depending on the fibre concentration. The effect of a blowing agent on the mechanical properties has also been investigated. At least 20% higher yield strength has been measured for the foamed sample with 5% carbon fibre related to the nonfoamed one with the same fibre content. The higher the fibre content was, the higher the improvements in the mechanical properties became. Fibre-matrix interaction has been studied on scanning electron microscopy graphs where a well-connected polymer layer has been observed to the fibre surface.

Polymer blending has been a simple and efficient way for designing and controlling the performance of polymeric materials using easily available types. Both polycarbonate and polyamide have excellent mechanical properties and thermal stability but their disadvantages such as limited chemical or water resistance can be eliminate by tailoring them. Main difficulties in processing of PC/PA blends are the poor compatibility and high moisture adsorption capacity of the two raw materials complicating processing and also deteriorating mechanical properties of the products. Compatibilizing additives such as olefin-maleic-anhydride copolymer based compounds used in the experimental work can help to overcome the abovementioned difficulties. To determine the processing conditions of the raw materials several drying temperatures have been tested and thermal degradation has been examined by FT-IR spectroscopy. Experimental compatibilizing additives based on an olefin-maleic-anhydride copolymer have been investigated to enhance mechanical properties of the blends prepared by extrusion moulding. Mechanical, rheological, SEM and FT-IR measurements have been performed and at least one additive has been found to be efficient in improving selected properties.