In the present paper the impacts of particle size of different waste elastomer fillers and homogenization time with the polymer matrix have been studied. Oscillatory rheometric tests have been conducted on EPDM-containing polyethylene, iGC measurements and SEM images have been investigated to understand the phenomena behind the mechanical properties. One of the practically useful outcomes have been the extension of LVE range of blends with the whole fraction of EPDM particles (0.00-1.25 mm) compared to larger particle domains, such as 0.40-0.63 mm; 0.63-1.00 mm and 1.00-1.25 mm; since the smaller particles increase the interfacial area favourable for stress transfer. The most influenced mechanical property was the elongation at break followed by the impact strength in w-EPDM blends but no other statistical correlation between the particle size distribution and the sample preparation method and the measured mechanical properties has been found for the other type filler containing blends. A relationship between the crossover frequency, i.e., 'apparent molecular weight' and homogeneity of the dispersion of waste EPDM particles containing polymers has been found and confirmed by the mechanical properties either. The relative apparent molecular weight, expressed in rad/s, determined from the intersection of G ' and G '' obtained through frequency sweep tests can be used to quantify the homogeneity related to the dispersion of polymer/waste elastomer blends with the same composition but different particle sizes.

Ester derivatives of experimental olefin-maleic anhydride copolymers synthesized at the University of Pannonia have been investigated by both classical and instrumental analytical methods that contribute to a deeper understanding of how that type of additives functions as compatibilizers for plastics and rubbers.Titration-based acid and saponification numbers have provided limited information about the chemical structure of the experimental copolymer compounds. A prompt, precise and low-cost method or combination of methods has been required to access to the ratio of the various derivatives not only straight after esterification but also for quality control during long-term storage considering the even stricter sustainability aspects either. Reproduction and scaling-up synthesises can be also followed by the combined measuring techniques of Fourier-transform infrared spectroscopy (FT-IR) and oscillatory rheometry. Structural changes occurred in the additives could be followed through monitoring their Ester Indices (EI) during the measurement, which can be connected also to the long-term properties. Experimental additives (AD) like AD-1 and AD-2 types with lower EI values of 21.5 % and 32.1 %, respectively, resulted in higher upper limits of the linear viscoelastic (LVE) range (15 % and 10 %). Conversely, the higher EI values of AD-3 and AD-4 led to significantly lower or even immeasurable upper limits of the LVE range. Additives with solid behaviour showed slight dependence on frequency above the crossover point that indicated strong connections disappearing.

Manufacturers use a large number of components in the production of modern rubber products. The selection of the constituents of the rubber recipe is primarily determined by the purpose of use. The different fields of applications of rubbers require the presence of appropriate mechanical properties. In this respect, it can be useful to know which substances forming the rubber recipe have significant influence on the different mechanical properties. In this study, the statistical analysis of the influence of rubber components on the hardness of natural rubber (NR) is proposed based on literature review. Based on the literature data, various statistical analyses, like linear regression, constrained linear regression, Ridge regression, Ridge sparse regression and binary classification decision trees were performed to determine which rubber components have the most significant effect on the hardness. In the statistical analyses, the effect of a total of 42 constituents of rubber compound on hardness was investigated. Most of the applied statistical methods confirmed that the traditional frequently used rubber components, such as carbon black and sulfur, have a primary effect on the hardness. However, the substances forming the rubber compound that are not widely used in practice or newly developed components appear differently in the lists of significant additives obtained by the different statistical methods.

The conventional qualification methodologies, such as internal viscosity measurement and Melt Flow Index (MFI) tests, which are routinely applied to pristine materials and homogenous waste, are not directly transferrable to the qualification process of plastic mixtures. The current investigation is oriented towards the development of a pragmatic suite of measurements techniques aimed at facilitating the qualification of diverse real polyethylene terephthalate (PET) waste streams. This is primarily achieved through the integration of oscillatory rheology, calorimetry and computed tomography (CT). Samples derived from both selective income (SI) and sorting residue (SR) of a manual selective waste sorting plant are included, along with an examination of PET material originating from refuse-derived fuel (RDF). To establish references for comparison, manually collected bottles with (BCL) and without (B) caps and labels are employed, leveraging their known composition and purity. Calorimetry reveals that the glass transition temperature (T-g) is the most sensitive parameter for tracking the structural and compositional changes in waste PET-based streams. The utilization of temperature sweep test in rheology for determining the melting temperature (T-m) proves advantageous, offering a significantly shorter measurement time (similar to 1:24) compared to calorimetry. Importantly, this approach yields the T-m of the genuine composition rather than individual components. Detection of metal content contaminations in PET waste streams is made possible through CT, while frequency tests in rheological measurements demonstrate effectiveness in discerning their effects.

Titration is a measurement for maleic-anhydride containing polymers with significant chemicals consumption, time and human resource requirement meanwhile all the carbonyl groups have to be supposed to be in the cyclic form but it is not always the situation. Core of the FT-IR method has been determination of carbonyl groups in various chemical environments. The FT-IR method is developed to obtain more precise and prompt results about anhydride rings in the copolymer chain than with titration in the whole coupling number range with minimal chemicals consumption. Quantitatively apprising FT-IR results peaks of carbonyl groups have been considered since those yield well-isolated and high intensity peaks in the spectrum. Two distinct methods have been adopted for integration of areas under the selected stretching vibrations. Not all the anhydrides have been supposed to be in ring form in the copolymers but partially in acidic form that can be only taken into account by double counting during titration instead of the correctly single counting. FT-IR spectrum has been feasible for tracing that progress but titration isn't.Moreover, if difference between acid number from titration and FT-IR methods based on the chemical structure is high compatibilizing additive synthesis requires excess of reagents. • A method enabling the identification of carbonyl groups in maleic-anhydride containing polymers in various chemical environment without chemical consumption. • The method is based on the calculation of functional group ratios applying the integrated area of selected absorption peaks.

Under the era of circular economy, the deposit-refund system (DRS) for e.g.polyethylene terephthalate (PET) is thought to be a good choice to achieve a more structured plastic recycling.The present research has the aim to make a comprehensive description and a practical guideline in order to evaluate how collection and separation system influence the quality and efficiency of mechanical recycling of PET.The DRS has been symbolized by manually collected bottles with (BCL) and without (B) caps and labels.Samples have been given from the selective income (SI) and the sorting residue (SR) of a manual selective waste sorting plant and PET fraction of refuse derived fuel (RDF).Based on preliminary qualification results such as melt flow indices (MFI), PET bottles are worth selecting into the main colours like water clear, blue, and all the others together, referred to as PET-A, PET-B, and PET-D fractions of the sorting plant.The SR seemed to be a beneficial raw material for PET recycling as both mechanical and rheological properties were proper enough.PET separated from the Mechanical Biological Treatment (MBT) plant as RDF showed the worst processing and mechanical properties, but both can be improved with deeper precleaning.X-ray tomography (CT) scans have shown a correlation between the source of waste and the gas void structure which influence the macroscopic mechanical properties.

Nowadays polyethylene is one of the polymers produced in the greatest volume, therefore, parallelly the amount of generated waste polyethylene (w-HDPE) significant as well. Valorisation and recycling of w-HDPE can be realized by blending with different types of polymers and/or elastomers in order to result in thermoplastic elastomer end-product for example. One potential candidate can be ethylene-vinyl acetate (EVA) nevertheless interfacial interaction between between w-HDPE and EVA is inadequate reflected in deterioration of mechanical properties of the blend in spite of the fact that they possess favourable mechanical properties themselves and they may complement each other. For the purpose of boosting of interfacial interactions between these two polymers experimental olefin-maleic-anhydride based additives have been incorporated in the blends after optimization of the processing temperature. Impact and tensile tests have been carried out in our research work besides microscopy measurements and investigation of the effects of additive structure by FT-IR and rheology.

Waste high-density polyethylene (w-HDPE)/ acrylonitrile–butadiene–styrene (ABS)/ground tire rubber (GTR) have been melt blended by two-roll milling. Ternary blends of w-HDPE/ABS/GTR have been observed to be incompatible in the composition range studied which revealed in the deteriorated mechanical properties. Two main types of compatibilizers such as an experimental olefin-maleic anhydride copolymer based one synthesized by the authors and a commercial maleic anhydride grafted polypropylene (MA-g-PP) have been chosen for enhancing compatibility between the components ergo the mechanical properties. For characterizing tensile and impact properties of the blends mechanical tests have been carried out besides the scanning electron microscopy (SEM), X-ray diffraction and Fourier transform infrared spectroscopy. The most advantageous result in industrial practice can be that the experimental additive allows to apply higher GTR concentration ergo gives the opportunity to recycle higher level of GTR.

Nowadays polyethylene is one of the polymers produced in the greatest volume and the amount of generated waste high‐density polyethylene (w‐HDPE) is significant as well. Valorization and recycling of w‐HDPE can be realized by blending with different types of polymers and/or elastomers for example, ethylene‐vinyl acetate (EVA). For the purpose of boosting of interfacial interactions between these two polymers experimental olefin‐maleic‐anhydride based additives have been incorporated into the blends after optimization of the processing temperature. Impact and tensile tests have been carried out in our research work besides microscopy measurements and investigation of the effects of additive structure by FT‐IR and rheology. At higher processing temperature (220°C) both tensile properties and Charpy impact strength were increased, latter one improved by 245% measured at 5°C while elongation at break enhanced by 182% with incorporation of some experimental additives compared to the neat 70/30 w‐HDPE/EVA. Changes in the hydrocarbon molecular chains of experimentally compatibilized blends were observed based on FT‐IR results and rheological measurements. It can be concluded that one of the most basic notions of sustainability, the 4R's (reduce, recycle, reuse, recover) has been satisfied in a successful way.

Sustainability and enhancement of recycling differing polymer waste has become a leading driver for industries associated with this type of waste. However, polymer waste streams that have not seen as 'typical' have existed in smaller but not insignificant amounts. This study has focused on the recycling of such a waste resource that is not classified as a typical one in developed countries but appears in other locations globally where opportunities for careful waste pretreatment are hindered, therefore creating a challenge for waste handling and the application of modern techniques. Compatibilizing is a strategy employed to recycle ground tire rubber (GTR) by blending with waste high density polyethylene (wHDPE). Such processing methods and measurement techniques have been chosen to allow easy access without extra costs. For enhanced incorporation of the filler into the matrix olefin-maleic-anhydride copolymer based additives have been synthesized and have succeeded in creating a more homogenous blend with samples having a good surface appearance and mechanical properties. Outstanding Charpy impact strength at room temperature (10.1 kJ/m(2)) has been achieved in compatibilized 70/30 w-HDPE/ GTR (containing 20% PE-contaminant), while elongation at break and tensile strength have been 10.3% and 14.9 MPa. Morphological structure of rubber resources and blends have been assessed by SEM while analytical properties and other features of experimental compatibilizing additives have been studied by e.g. FT-IR. (C) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license.

Nowadays, global warming and the ensuing climate change are one of the biggest problems for humanity, but environmental pollution and the low ratio of waste management and recycling are not negligible issues, either. By producing alkali-activated cements (AACs), it is possible to find an alternative way to handle the above-mentioned environmental problems. First, with a view to optimizing experimental parameters, metakaolin-based AACs were prepared, and in it, waste tire rubber was used as sand replacement (5–45 wt %). Insufficient wetting between the rubber particles and the matrix was corrected through different surface treatments of the rubber. For improving the mechanical/strength properties of the specimens, fibrous waste kaolin wool (0.5–1.5 wt %) was added to the AAC matrix. Considering the results of model experiments with metakaolin, blast-furnace-slag-based AAC composites were developed. The effects of storage conditions, specimen size and cyclic loading on the compressive strength were investigated, and the resulting figures were compared with the relevant values of classic binders. The strength (44.0 MPa) of the waste-based AAC composite significantly exceeds the required value (32.5 MPa) of clinker saving slag cement. Furthermore, following cyclic compressive loading, the residual strength of the waste-based AAC composite shows a slight increase rather than a decrease.

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.

Abstract 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.

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

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.

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.

INTRODUCTION The quality and function of movements undergo deterioration due to weight gain. Aerobic training normalizes body weight, improves the health status, and in addition, it is expected to improve the dynamics of movements. The aims of this study were to prove the beneficial effects of recreational physical activities on the movements. METHODS Participants were divided into five different age categories: second childhood, adolescence, mature age I, mature age II, and aging. Squatting and vertical jumping of the participants were measured at the beginning and at the end of a 5-month training program. These movements simulated ordinary daily movements. Changes in the body were determined by InBody230. APAS 3D system was used for movement analysis. RESULTS The results showed significant improvements in body weight, fat mass, muscle mass, fat mass-body weight ratio, muscle mass-body weight ratio, body mass index, body fat percentage, and waist-hip ratio. During jumping, the lifting and sinking of the center of gravity's (CG) position and its velocity and acceleration were improved. In case of squatting, the results showed significant improvements in the velocity and acceleration of dynamical characteristics of the CG. Other correlations were observed between changes in body composition and the dynamics of movements. DISCUSSION The research proved that recreational training optimized body composition and improved the characteristics of CG's dynamics. The study suggests considerable connection between body composition and the characteristics of the movements' dynamics. From this point of view, our training program was the most effective in the working age groups.

The effectiveness and quantitative control of the surface transition of multi-walled carbon nanotubes (MWCNTs) was characterized by inverse gas chromatography (iGC). The surface energy profile of carbon nanotubes compatibilized with an olefin-maleic-anhydride-ester-amide (OMAEA)-type coupling agent was determined by a surface energy analyzer (SEA). The surface energetic heterogeneity with energy distributions of dispersive and specific (acid-base) components of the surface energy of the MWCNTs were determined at various surface coverages. The results of the surface energy mapping showed that surface treatment significantly reduced the dispersive surface energy of MWCNTs and increased the specific surface energy. Furthermore, the surface modification enhanced its Lewis basic character and simultaneously decreased the acidic character of MWCNTs. It has been demonstrated that the surface treatment modified the heterogeneity profiles of the energetic surface of the carbonaceous nanomaterials.

The effects of ghrelin on vasopressin and oxytocin secretion were studied in 13–14-day cell cultures of isolated rat neurohypophyseal tissue. The vasopressin and oxytocin contents of the supernatant were determined by radioimmunoassay after a 1- or 2-h incubation. Significantly increased levels of vasopressin and oxytocin production were detected in the cell culture media following ghrelin administration, depending on the ghrelin doses. The oxytocin level proved to be more elevated than that of vasopressin. The increase of vasopressin and oxytocin secretion could be totally blocked by previous administration of the ghrelin receptor antagonist ([D-Lys3]-growth hormone-releasing peptide-6). Application of the ghrelin receptor antagonist after ghrelin administration proved ineffective. The results indicate that vasopressin and oxytocin release is influenced directly by the ghrelin system, and the effects of ghrelin on vasopressin and oxytocin secretion from the neurohypophyseal tissue in rats can occur at the level of the posterior pituitary. Our observations lend support to the view that neurohypophysis contains ghrelin receptors.