The upstream applications of post-consumer polypropylene (PCPP) demand long-term oxidation stability to prevent deterioration of its properties. This study explores the potential to replace a commercial antioxidant (AO), Irganox 1010 (I1010), with greener alternatives, quercetin and tocopherol. The emphasis was placed on evaluating their influence on thermal stability, including oxidation resistance and degradation behavior during multiple processing cycles. The rPCPP exhibited inferior thermal properties, with an oxidation induction time (OIT) of 1.2 min and an oxidation onset temperature (OOT) of 205 degrees C. Incorporation of the selected individual AOs improved these properties. The combination of quercetin and tocopherol (QT) exhibited the best results, increasing OIT to 43 min and OOT to 260 degrees C. After five reprocessing cycles, the melt flow rate (MFR) values for the QT system remained unchanged, whereas I1010-stabilized and the non-stabilized rPCPP increased by 183% and 376%, respectively. Similarly, the carbonyl index (CI) value increased by four times for rPCPP and two times for I1010, whereas the QT remained nearly unchanged. The observed enhanced stability of QT is attributed to the synergistic effect. This effect was further supported by the DPPH assay. All the findings demonstrate the effectiveness of selected natural AOs, particularly QT, as a sustainable alternative to conventional stabilizers.

Aluminum is a very attractive material for bipolar plates in proton exchange membrane (PEM) fuel cells due to its low weight, excellent thermal and electrical conductivity, as well as good recyclability. However, to achieve the necessary low contact resistance and corrosion stability, a suitable surface coating is needed. In the present study, two different material systems were evaluated, electroless deposited NiP based coatings and high-power impulse magnetron sputter-deposited (HiPIMS) Ti based coatings. The addition of a 100 nm amorphous carbon (a-C) top-layer on the NiP and Ti based coatings was also evaluated. The electrochemical corrosion behavior of the coatings was evaluated in simulated PEM environments. Potentiodynamic and potentiostatic polarization experiments revealed that the HiPIMS Ti coatings performed better than NiP coatings. The addition of the a-C top-layer on the other hand was found to be detrimental to the Ti based coatings resulting in a corrosion current density of 3.6 mu A/cm2. The opposite was observed in the case of the NiP based coatings where the addition of the a-C layer decreases the corrosion current thereby increasing corrosion resistance. Further analysis showed that defects in the coating as well as the presence of a Fe-Si rich particles in the Al substrate were the initiation points for the corrosion attacks to occur.

Gold plated tungsten wires are used in a wide variety of applications ranging from medical devices to high frequency signal transmission. Thin wires place special demands on the plating process and this study aims to understand how surface properties affect the deposition of gold. Tungsten single crystals and wires with different dimensions were therefore studied in alkaline cyanide electrolyte with and without gold cyanide complexes, using electrochemical impedance spectroscopy under stationary conditions. Measurements were made as function of potential and steady-state currents, capacitances and resistances were extracted from the data. The results show that deposition of gold takes place close to the equilibrium potential irrespective of crystal orientation and morphology of tungsten. Concentration dependences show that the deposition rate is first order with respect to the concentration of gold complex and inversely related to the free cyanide concentration. These results confirm that the reaction sequence includes a chemical dissociation step prior to electron transfer. For partially gold covered tungsten wires, the rate of hydrogen evolution was found to be enhanced compared with a bare tungsten wire and pure gold metal, which is explained by the formation of three-phase junctions where water splitting and electron transfer occur at different sites.

The aim of the present work is to recommend future directions for the European surface technology industry to remain relevant and competitive, and, furthermore, to suggest supportive actions stimulating this development. This is done from a pan-European view based on an analysis of the potential of combining dry (typically PVD) and wet (typically electrolytic) coating processes for obtaining optimal functionality. The work has been carried out by a group of European experts representing different sectors and regions. The potential of combining dry and wet processes is illustrated by a number of innovative cases in which experts related to the European Academy of Surface Technology (east) have been engaged. One challenge in combining dry and wet processes is that these processes traditionally are carried out by physicists and chemists, respectively. Few organisations have the combined skills and facilities available. Another reason is that a combined coating system is likely more costly. Therefore, the added value due to increased quality of the combined coating system should exceed the extra costs. When developing combined coatings, the coatings together with the substrate should be considered as a material system to create material solutions that would not be possible without combining dry and wet processes on the substrate.

Från Bakgrund: Syftet med denna studie är att möjliggöra och åskådliggöra en fossilfri värdekedja inom skogsnäringen genom en kartläggning av nuläge för ingående fordon för transport och ingående mobila maskiner i värdekedjan för skogsråvara. Detta täcker aktiviteter i skogen, inom förädling, transport på väg samt utgående logistik. Studien baseras på fordon och mobila arbetsmaskiner i den svenska skogens värdekedjan, men anses vara lika relevant för den norska värdekedjan.

Det finns behov av att beskriva värdekedjan avseende fordon/arbetsmaskiner och nödvändig infrastruktur för att identifiera behov av effektiva, hållbara logistikflöden, tekniklösningar och affärsmodeller.

Studien har avgränsats till mobila maskiner och fordon samt fordonsnära infrastruktur. Stationära maskiner i exempelvis träförädling ingår inte. Studien skall ge förslag på fortsatt fördjupande arbete.

Highlights Molybdenum single crystals and wires exhibit large pseudocapacitances in cyanide solution. Gold deposition takes place after partial reduction of the thin surface oxide. The partially reduced surface oxide may assist gold deposition prior to electrodeposition. Adsorbed intermediates are involved both in the deposition and dissolution of gold. The chemical adhesion of gold on molybdenum is weak and physical binding is a prerequisite.

The aim of this project was to assess the thermal conductivity of polyethylene (PE) filled with carbon black (CB), specifically for geothermal pipes. The project explored the potential modification of PE's thermal conductivity by incorporating recycled textile fibers. Different types of shredded recycled fibers were tested, including two types of polyamide fibers with varying contaminations and one type of polyester fiber. Following several preparation steps, various composite materials were manufactured and compared to bulk PE using various testing methods: Differential Scanning Calorimetry analysis (DSC), mechanical testing (flexural and tensile), and laser flash analysis (LFA). The results revealed alterations in the mechanical properties of the composite materials in comparison to PE filled with CB. The LFA tests demonstrated the effectiveness in reducing polymer thermal diffusivity at higher temperatures, particularly when the material was loaded with recycled polyester fillers.