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Copyright of Kemija u Industriji is the property of Croatian Society of Chemical Engineers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Kemija u Industriji is the property of Croatian Society of Chemical Engineers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, post-consumer poly(ethylene terephthalate) (PET) bottles were gathered, separated from other materials, and re-extruded. In order to evaluate the effect of re-extrusion on the structure of PET, Fourier transform infrared spectroscopy was utilised. No significant effect of the re-extrusion process on the structure of the PET sample was noticed. Obtained samples were also characterised by differential scanning calorimetry (DSC) in order to determine characteristic thermal transitions of PET. DSC results indicated the influence of re-extrusion; extruded PET started to melt at lower temperatures, and the crystallisation of re-extruded PET took place at significantly higher temperatures in comparison to PET. Likewise, thermogravimetric analysis (TG) was used to evaluate the effect of re-extrusion process on the thermal stability of samples. TG analysis revealed that the re-extrusion process had no effect on the thermal stability of the investigated PET samples. Finally, the activation energy of thermal degradation of the investigated samples was calculated using iso-conversional Flynn-Wall-Ozawa and Friedman method. Consequently, higher activation energies were noticed for the re-extruded PET sample in comparison to the PET bottle sample, which is a good argument in support of PET bottle recycling. [ABSTRACT FROM AUTHOR]

Investigation of the influence of sodium alginate (NaAlg) on the structure and properties of poly(ethylene oxide) (PEO) films cast from aqueous solutions was performed by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), non-isothermal thermogravimetry (TG), and electrochemical impedance spectroscopy (EIS). The research aimed to find the optimal blend for the preparation of a solid polymer electrolyte (SPE) film for lithium-ion batteries (LIB). In PEO/NaAlg blend films, hydrogen bonds are formed between PEO and NaAlg, the blends are miscible, and have a lower content of crystalline phase compared to pure PEO film. The films of the blends are more thermally unstable than the film of pure PEO, and show dielectric properties, but the blend 80PEO/20NaAlg is suitable for the preparation of SPE by addition of lithium salt due to the lowest content of PEO crystalline phase. [ABSTRACT FROM AUTHOR]

The main aim of this paper is to present and evaluate thermomechanical treatment for semi‐solid feedstock production of A380 (AlSi9Cu3(Fe)) aluminum alloy. Equal channel angular pressing (ECAP) is used to heavily deform and refine as cast dendritic microstructure with needle like eutectic appearance. The deformed microstructure is easily changed to globular microstructure by recovery and recrystallization mechanisms during heating at the semi‐solid temperature range which is a crucial factor for quality semi‐solid feedstock preparation. The microstructural evolutions investigations during semi‐solid heating at different holding times is carried out utilizing optical microscope and scanning electron microscope accompanied by energy dispersive x‐ray spectroscopy. Homogeneous distribution of the silicon particles and intermetallic compounds around globular primary aluminum phase is observed. The used approach is appropriate and seems highly promising for preparation of the quality semi‐solid feedstock. [ABSTRACT FROM AUTHOR]

The aim of this work was to prepare poly(3-hydroxybutyrate)/montmorillonite (PHB/MMT) composites on the laboratory press with heating, and to determine the influence of different food simulants on the composites and the filler migration. Analysis of the food simulants after migration testing was conducted with UV/Vis spectroscopy. Due to the established hydrolysis of PHB under the influence of the food simulants, it was impossible to determine the migration of MMT from PHB/MMT composites. Differential scanning calorimetry (DSC) confirmed the degradation of PHB. This research showed the potential of UV/Vis spectroscopy in dealing with the influence of food simulants on polymer composites. [ABSTRACT FROM AUTHOR]

This study examines flank wear and surface ruoghness in up and down hard end milling. After obtaining the mathematical models, it has been carried out a series of numerical simulations with variation of input parameters in order to analyze their influence on flank wear and surface roughness. Additionally, flank wear and surface roughness has been analysed in correlation with the volume of the removed material for different cutting parameters. Observed from the viewpoint of machinability, down hard milling is favorable compared to the up hard milling. [ABSTRACT FROM AUTHOR]

This paper examines the influence of cutting parameters on surface roughness of steel workpiece. The experiments have been carried out in accordance with a design of experiments (DOE). Equation for the surface roughness, as a function of cutting parameters, has been obtained by means of regression analysis. To obtain the minimal value of surface roughness, the equation optimizing was performed by using partial derivations and solving system of equations. The Taguchi method, with orthogonal arrays and signal to noise ratio, has been used to analyse impact of various cutting parameters on surface roughness and to find optimal levels of the cutting parameters. The comparison of results obtained by means of the response surface method and the Taguchi method was performed. [ABSTRACT FROM AUTHOR]