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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.

The aim of this research was to increase the compatibility between PLA and starch with vegetable oil-based additives. Based on tensile results, it can be stated, that Charpy impact strength could be improved for 70/30 and 60/40 blends in both unconditioned and conditioned cases, regardless of vegetable oil, while no advantageous change in impact strength was obtained with PLA-g-MA. Considering sample with the highest starch concentration (50%), the flexural modulus was improved by using sunflower oil-based additive, Charpy impact strength and elongation at break was increased using rapeseed oil-based additive in both conditioned and unconditioned cases. SEM images confirmed the improvement of compatibility between components.

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Over the past 50 years demand for plastics drastically increased worldwide resulting in plastic wastes causing serious environmental problems. The main market sector of European plastics industry is the packaging industry most of which are polyolefins and poly(ethylene-terephtalate). In the EU, 29.1 million tonnes of plastic waste were collected in 2018, of which 32.5% was recycled, 42.6% was recovered for energy, and 24.9% was landfilled (Plastics-the Facts, 2019). Although landfilling of collected waste in the EU is steadily declining, there is still too much unused waste. Polymer blends based on waste resources can solve the issues of recycling. The main purpose of the research was to produce polymer blends from waste based PET that have appropriate mechanical properties and rheological behaviour as well in order to find application areas where product requirements are not strict. Blends containing waste based PET were extrusion moulded and calenderd producing extrusion strings and films. Rheological and tensile properties of three types of PET/engineering thermoplastic blends (PET/PC, PET/PA and PET/ABS) were studied. Miscibility of components of the blends is limited leading to weak mechanical properties such as low tensile strength and/or elongation at break. Due to that phenomenon compatibilizing additives are also required. As compatibilizing additives olefin-maleic-anhydride copolymer based additives have been used in our experiments. Structure of additives differed from each other both in ratio and length of carbon chains of compounds linked to maleic-anhydride groups. Blends have been studied with PET content ranging from 10 to 90%. As an outstanding result improving of mechanical properties was achieved, for example almost 40% growth was observed in elongation at break of extruded 80/20 PET/PA blends in the presence of 0.2% compatibilizing additive compared to the sample without additive, meanwhile its strength has also improved. Graphic Abstract

Over the past 50 years demand for plastics drastically increased worldwide resulting in plastic wastes causing serious environmental problems. The main market sector of european plastics industry is the packaging industry most of which is polyolefins and poly(ethythylene-terephtalate). Polymer blends based on waste resources can solve the issues of recycling. We have studied rheological and tensile properties of three types of PET/engineering thermoplastic blends (PET/PC, PET/PA and PET/ABS) produced with different processing techniques. Miscibility of components of blends is limited leading to weak mechanical properties such as low tensile strength and/or elongation at break. Due to that phenomenon compatibilizing additives are also required. As compatibilizing additives olefin-maleic-anhydride copolymer based additives have been used in our experiments. Structure of additives differed from each other both in ratio and length of carbon chains of compounds linked to maleic-anhydride groups . Blends have been studied with PET content ranging from 10 % to 90 %. As an outstanding result we have managed to achieve improving mechanical properties, for example almost 400 % growth was observed in elongation at break of extruded 80/20 PET/PA blends in the presence of 0.2 % compatibilizing additive compared to the sample without additive, meanwhile its strength has also improved.

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Quantification of alkanolamines is imperative for health and chemical safety risk reasons. A fast method that requires less equipment has been developed for the determination of free diethanolamine in different types of additives. Repeatability tests were carried out. The free diethanolamine content of commercially available additives has been determined. We have recommended industrial applicability.