Higher temperatures and longer treatment times are necessary in a conventional thermal treatment method, which restricts the substrate materials and treatment efficiency. In this paper, the grain ...size and orientation of the coating are regulated by pulsed electric field (PEF) treatment, and the adhesion of the coating is enhanced by reducing the internal stress between the grains. The findings demonstrate that the PEF can change the coating to the close-packed (111) with high conductivity and facilitate the short-range diffusion of N atoms. The effects reduce the concentration of defects and reduce the coating’s internal stress, improving the critical load of the coating. The PEF treatment provides an effective solution for low-temperature and high-efficiency treatment coatings.
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Starch is a versatile and a widely used ingredient, with applications in many industries including adhesive and binding, paper making, corrugating, construction, paints and coatings, chemical, ...pharmaceutical, textiles, oilfield, food and feed. However, native starches present limited applications, which impairs their industrial use. Consequently, starch is commonly modified to achieve desired properties. Chemical treatments are the most exploited to bring new functionalities to starch. However, those treatments can be harmful to the environment and can also bring risks to the human health, limiting their applications. In this scenario, there is a search for techniques that are both environmentally friendly and efficient, bringing new desired functionalities to starches. Therefore, this review presents an up-to-date overview of the available literature data regarding the use of environmentally friendly treatments for starch modification. Among them, we highlighted an innovative chemical treatment (ozone) and different physical treatments, as the modern pulsed electric field (PEF), the emerging ultrasound (US) technology, and two other treatments based on heating (dry heating treatment - DHT, and heat moisture treatment - HMT). It was observed that these environmentally friendly technologies have potential to be used for starch modification, since they create materials with desirable functionalities with the advantage of being categorized as clean label ingredients.
Poly(ethylene 2,5‐furandicarboxylate) (PEF) is an emergent biobased polyester whose chemical structure is analogous to poly(ethylene terephthalate). Pilot‐scale PEF is synthesized through the direct ...esterification process from 2,5‐furandicarboxylic acid and bio‐ethylene glycol. Wide‐angle X‐ray diffraction (WAXD) measurements reveal similar crystallinities and unit cell structures for melt‐crystallized and glass‐crystallized samples. The non‐isothermal crystallization of PEF sample is investigated by means of DSC experiments both from the glass and the melt. The temperature dependence of the effective activation energy of the growth rate is obtained from these data, and the results show that the glass and early stage of the melt crystallization share common dynamics. Hoffman–Lauritzen parameters and the temperature at maximum crystallization rate are evaluated. It is found that the melt‐crystallization kinetics undergo a transition from regime I to II; however, the crystal growth rate from the melt shows an atypical depression at T < 171 °C compared with the predicted Hoffman–Lauritzen theory.
Non‐isothermal crystallization kinetics of a new prospective biobased polymer, poly(ethylene 2,5‐furandicarboxylate) (PEF), whose chemical structure is analogous to poly(ethylene terephthalate) (PET), is undertaken for both melt and glass crystallization by combining isoconversional analysis, the Hoffman–Lauritzen theory, and the Ozawa analysis. Change in the crystallization regimes is highlighted. The temperature at maximum crystallization rate is estimated using measurements and simulations.
The segmental and local dynamics of the bio‐based polyester poly(ethylene‐2,5‐furanoate) (PEF) are investigated by dielectric spectroscopy (DS) at atmospheric pressure as a function of temperature ...and frequency for samples prepared with different degrees of crystallinity. Crystallization significantly alters the segmental process as this is manifested in the dielectric strength and the distribution of relaxation times. Enhanced crystallinity by the different annealing protocols increases the glass temperature of the mobile amorphous fraction. A two‐phase model is adequate in describing the dynamics associated with the β‐process within the glassy state. However, the same model fails in describing the segmental dynamics at and above the glass temperature. The combined differential scanning calorimetry and DS results provide evidence that for samples with a degree of crystallinity of ≈40%, approximately a third of segments are located within the restricted amorphous fraction.
Poly(ethylene furanoate) (PEF) is a fully bio‐based polyester and an alternative to poly(ethylene terephthlate) (PET) with improved barrier properties. The dynamics of PEF pertinent to penetrant diffusion are investigated as a function of the degree of crystallinity by combining differential scanning calorimetry with dielectric spectroscopy. They provide clear evidence that a third of segments are located within the restricted amorphous fraction.
In this work, a TiO2-decorated electrode was fabricated by dip coating activated carbon fibers (ACF) with TiO2, which were then used as a cathode for the photoelectro-Fenton (PEF) treatment of the ...pharmaceutical enalapril, an angiotensin-converting enzyme inhibitor that has been detected in several waterways. The TiO2 coating was found to principally improve the electrocatalytic properties of ACF for H2O2 production via the 2-e- O2 reduction, in turn increasing enalapril degradation by PEF. The effect of the current density on the mineralization of enalapril was evaluated and the highest TOC removal yield (80.5% in 3 h) was obtained at 8.33 mA cm−2, in the presence of 0.5 mmol L−1 of Fe2+ catalyst. Under those conditions, enalapril was totally removed within the first 10 min of treatment with a rate constant k = 0.472 min−1. In contrast, uncoated ACF only achieved 60% of TOC removal in 3 h at 8.33 mA cm−2. A degradation pathway for enalapril mineralization is proposed, based on the degradation by-products identified during treatment. Overall, the results demonstrate the promises of TiO2 cathodes for PEF, a strategy that has often been overlooked in favor of photoelectrocatalysis (PEC) based on TiO2-modified photoanodes.
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•TiO2 coating improved H2O2 cathodic generation on activated carbon fibers (ACF).•TOC removal reached 80.5% after 3 h of photoelectro-Fenton treatment.•Enalapril was totally removed within 10 min with a rate constant k = 0.472 min−1.•Electrocatalysis was the dominant mechanism, followed by photolysis.•First report of enalapril treatment and of its electrochemical degradation pathway.
Calcium is an element that performs many important functions in the human body. A study was conducted on the use of a pulsed electric field (PEF) to enrich cells of Lactobacillus rhamnosus B 442 in ...calcium ions. The highest concentration of calcium ions in bacterial cells (7.30 mg/g d.m.) was obtained at ion concentration of 200 μg/ml of medium and with the use of the following PEF parameters: field strength 3.0 kV/cm, exposure time 10 min, pulse width 75 ms and 20 h of culturing after which bacteria were treated with the field. Cell biomass varied in the range from 0.09 g/g d.m. to 0.252 g/g d.m., and the total number of bacteria ranged from 10 10 CFU/ml to 10 12 CFU/ml. Microscope photographs prove that calcium ions were situated within the cells of the bacteria, and electroporation contributed to an increase in the effectiveness of the ion bioaccumulation process. Samples containing calcium and subjected to electroporation displayed intensive fluorescence. The significance of this research was the possibility of using probiotic bacteria enriched with calcium ions for the production of functional food in subsequent studies.
•The PEF/TiO2 NWs composites were successfully prepared via in-situ polymerization.•The introduction of TiO2 nanowires improved the impact strength of PEF obviously.•The UV and blue light shielding ...of PEF increase with the addition of TiO2 nanowires.•The nanocomposite could kill 98 % of E.coli mostly by exposing to UV light for 30 min.•Furthermore, the elongation at break of nanocomposite reaches 47.69 % at PSR of 2.
As a candidate of fossil-based poly(ethylene terephthalate) (PET), bio-based poly(ethylene 2,5-furandicarboxylate) (PEF) that could be converted from renewable resources has attracted attention from academia and industry. Here, we prepare a series of new type of PEF/TiO2 NWs composites from 2,5-furandicarboxylic acid (FDCA), ethylene glycol (EG), titanium dioxide nanowire (TiO2 NWs, diameter∼100 nm, length∼20 µm) and dipentaerythritol (Di-PE) via in-situ polymerization. The TiO2 nanowires (0.5∼10 wt‰ based on PEF) and Di-PE (3 mol‰ based on FDCA) were added as fillers and extenders. TiO2 nanowires were distributed in the PEF uniformly, shown by SEM. Compared with pure PEF, the Tg and thermal stability of all nanocomposites got improved. And the impact strength of nanocomposites could reach 60 kJ/m2 in contrast to brittle pure PEF. The UV-A and blue-light shielding of nanocomposites increased from 53 % to 98 % and 28 % to 86 %, respectively, and the nanocomposites still maintained good gas barrier properties. Moreover, the antibacterial activity of nanocomposites against E. coli had increased to 98 %, better than that of the PEF/Ag NWs composites. By uniaxial pre-stretching, the tensile modulus and the elongation at break were improved obviously, from 1840 MPa to 5466 MPa and 4 % to 54 % respectively with pre-stretching ratio increasing. Compared to the PET/TiO2 NWs composites, the PEF/TiO2 NWs composites shows batter thermal property and mechanical property. The PEF/TiO2 NWs composites exhibit potential foreground in the packaging application.
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Poly (ethylene 2,5-furandicarboxylate) (PEF) has attracted more attention due to its excellent properties and great potential to be the substitute of the petroleum-based polyethylene ...terephthalate (PET). However, the improvement of toughness and functionality from nano materials were limited. Here, we prepared novel PEF/TiO2 nanocomposites from dimethyl 2,5-furandicarboxylate (DMFD), ethylene glycol (EG), pyromellitic dianhydride (PMDA) and TiO2 nanoparticles via one-pot polycondensation. The optimized PMDA (5‰ mol/mol of DMFD), TiO2 (60 nm, 0.5-10‰ wt./wt. of PEF) or TiO2 (30 nm or 100 nm, 3‰) served as extender, fillers, and comparison, respectively. The Tgs (∼88 °C) and the thermal stability of all nanocomposites were higher than pure PEF. The crystallization rate of the nanocomposites (60 nm-TiO2, 3‰) was improved mostly, and its half-crystallization time (t1/2) decreased to 6.16 min at 160 °C. The impact strength of nanocomposites (60 nm-TiO2, 10‰) could reach to 52.2 × 103 J/m2. Interestingly, the ultraviolet and blue-light shielding of PEF/TiO2 nanocomposites increased from 45.4% to 93.5% and 21.5% to 74.3%, respectively. The antibacterial activity of nanocomposites against E. coli also increased to 83%. The maximum migration of Ti during 35 d was 1.82 µg/g (FDA and EU guidance level are 10 µg/g). PEF/TiO2 nanocomposites shown great potential in industrial production and application.
In this research, we explore the possibility and effectiveness of using laser-induced surface oxidation methods to enhance the durability and effectiveness of PEF (Pulsed Electric Field) systems. ...Despite advantages over thermal pasteurisation, PEF faces challenges like electrode corrosion and biofouling, hindering its adoption. This research introduces laser-induced oxidation to mitigate metal ion release during PEF, directly targeting electrode alteration. Our examination adopts a comprehensive method, integrating Design of Experiments (DoE) parameter sets for PEF trials, morphological analysis, evaluation of metal ion release via Inductively Coupled Plasma Quadrupole Mass Spectrometry (ICP-QMS), waveform capture utilizing a Data Acquisition (DAQ) system, electrochemical assessment via impedance spectroscopy, and examination of oxide layer composition employing X-ray photoelectron spectroscopy. Pulse waveform characteristics shows the intricate relationship between PEF processing parameters with metal ion release, alongside XPS analysis providing insights into surface chemistry. Optimized results show a three-fold reduction in metal ion release post-PEF, with laser-treated samples outperforming untreated stainless steel due to selective surface chemistry alteration, notably an increased Cr/Fe ratio, reducing harmful elements. This study highlights laser-induced oxidation as a practical solution for enhancing PEF electrode performance and reducing metal ion release, addressing key challenges in PEF technology. It advances sustainable food processing, promising extended PEF system lifespan while maintaining efficiency and product quality.
•First practical example of reducing metal ion release in PEF processing via laser-induced electrode surface modification.•Laser processing cuts metal ion release by three times, extending electrode lifespan.•Discovery into the effect of variations in pulse waveform characteristics influence on electrochemical reactions and corrosion.•Reduced nickel and chromium enhance food safety, advancing sustainable food processing.•XPS shows surface chemistry changes, like increased Cr/Fe ratios, boosting corrosion resistance and reducing harmful ion release.
Piper retrofractum Vahl. have the potential to be developed into standardized medicinal ingredients. However, the extraction process of the active compounds in Piper retrofractum Vahl. needs further ...exploration to get the right method. This is necessary because previous studies state that conventional extraction requires a long time, while modern extraction technology has the disadvantage of being difficult to apply in society. Therefore the aim of this study was to obtain the PEF pre-treatment conditions in the extraction process which affected the quality of the Piper retrofractum Vahl. extract obtained. The stages in this study included the pre-treatment of Piper retrofractum Vahl. with PEF at a voltage (T1 = 5000, T2 = 5000, and T3=6000 volt) and an exposure time (W1=240 and W2=480 seconds), and was macerated using 96% ethanol solvent. The results of Piper retrofractum Vahl. extract with PEF pre-treatment produced a thick extract, dark brown color, characteristic odor, and spicy taste with a yield of 10.64±1.67%, water content 6.30±0.18%, total ash content 0.14±0.03%, acid insoluble ash content 0.25±0.01%, essential oil content 3.00±0.00% and piperine content of 40.38±2.44%.
