Low Crystallinity Research Articles

Functionalization of Arabinoxylan in Chitosan Based Blends by Periodate Oxidation for Drug Release Study

AbstractThis article presents the isolation of arabinoxylan (AX) from Plantago ovata seed husk and its oxidation using periodate to create oxidized‐AX (OAX) with distinct functionalities. Utilizing the solution casting method, biocompatible blends of arabinoxylan/chitosan (AX/CS) are prepared at various weight ratios, and their properties are assessed. Fourier transform infrared spectroscopy (FT‐IR), x‐ray diffraction (XRD), and thermogravimetric analysis (TGA) are employed to gauge compatibility and thermal traits of AX and OAX with CS. Solubility tests reveal partial and limited solubility of AX and OAX in distilled water, respectively. OAX displays favorable compressibility and flow rate through Carr's index, Hausner's ratio, and angle of repose analyses. FT‐IR data confirm intermolecular hydrogen bonding between CS′s −NH2− group and OAX′s carbonyl group, with XRD showing low crystallinity. Diclofenac sodium (DC) is loaded as a model drug into AX/CS and OAX/CS blends for release studies in pH 6.8 phosphate buffer. Results exhibit OAX/CS blends with sustained drug release, surpassing AX/CS blends. Among ratios tested, the OAX/CS (1 : 2) blend emerges as a superior excipient, demonstrating enhanced in‐vitro release potential, highlighting oxidized blends′ promise in sustained drug delivery systems.

Changes in Cooking Characteristics, Structural Properties and Bioactive Components of Wheat Flour Noodles Partially Substituted with Whole-Grain Hulled Tartary Buckwheat Flour

The whole-grain, hulled Tartary buckwheat flour (HTBF) with outstanding bioactive functions was prepared, and the effects of partial substitution ratios (0, 30%, 51% and 70%) of wheat flour with HTBF on the characteristics of TB noodles (TBNs) were investigated, mainly including the cooking characteristics, sensory analysis, internal structure, bioactive components, and in vitro starch digestibility. With an increasing replacement level of HTBF, the water absorption index of the noodles decreased, whereas the cooking loss increased. A sensory analysis indicated that there were no off-flavors in all TBN samples. The scanning electron microscope images presented that the wheat noodles, 30% TBNs and 70% TBNs had dense and uniform cross sections. Meanwhile, the deepest color, V-type complexes, and lowest crystallinity (13.26%) could be observed in the 70% TBNs. A HTBF substitution increased the rutin content and the total phenolic and flavonoid contents in the TBNs, and higher values were found in the 70% TBNs. Furthermore, the lowest rapidly digestible starch content (16%) and highest resistant starch content (66%) were obtained in the 70% TBNs. Results demonstrated that HTBF could be successfully applied to make TBNs, and a 70% substitution level was suggested. This study provides consumers with a good option in the realm of special noodle-type products.

Composition, structural, physicochemical and functional properties of dietary fiber from different milling fractions of black rice bran

Black rice bran is a superior dietary fiber (DF) resource. However, the lack of specific distribution and functionality of DF in black rice bran has constrained its refined processing. This study divided black rice bran into five equal bran fractions (BF) by stepwise milling to obtain BF1(outermost layer) to BF5 (the innermost layer). The contents, structure, physicochemical and functional properties of DF in each bran fractions were investigated. The results revealed that the insoluble, soluble and total dietary fiber (IDF, SDF and TDF) contents were 17.52 ± 0.48 to 31.14 ± 0.96, 2.03 ± 0.20 to 3.86 ± 0.01 and 19.57 ± 0.28 to 34.61 ± 1.10 g/100 g dry basis, respectively. Compared to BF1, the TDF content of BF2–BF5 was reduced by 3.90, 3.20, 21.74 and 43.46%, respectively. The main monosaccharides in both IDF and SDF were xylose, glucose, arabinose and galactose. The molecular weight of SDF samples ranged from 17.19 ± 1.95 to 36.32 ± 0.80 kDa. The outer bran fractions (BF1–BF3) IDF exhibited higher water swelling, water retention, oil adsorption capacity, together with cholesterol and sodium nitrite adsorption capacity than those of inner bran fractions (BF4–BF5), owing to their lower crystallinity and well-developed porous structure. These results provide essential data for the development of black rice DF-based food processing with enhanced functional benefits.

The effect of citric acid concentrations on the mechanical, thermal, and structural properties of starch edible films

SummaryThis study investigated the effects of citric acid on the properties of edible tapioca starch films plasticised with glycerol. These films were formed using 5% tapioca (w/w of water); 1%, 3%, 5%, 7% and 9% citric acid (w/w of starch); and 2.2% glycerol (w/w of water). Native starch films formed using 5% tapioca and 2.2% glycerol were used as the control. The properties tested included the degree of crosslinking, thermal stability, crystallinity and mechanical properties. These were evaluated using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR‐FTIR), X‐Ray diffraction (XRD), thermal gravimetric analysis (TGA) and tensile profile analysis (TPA). The FTIR results provided information about the nature of the crosslinking in the films, while TGA showed that increasing the citric acid concentration reduced the physical decomposition temperature of the materials. Films containing 9% citric acid had the highest degree of esterification and crosslinking, while those containing 7% citric acid had the lowest heat‐related weight loss that correlated with the degree of crosslinking. The weight loss among all six samples was the greatest in the temperature range 260 °C–350 °C where a total of 60% weight loss occurred. The XRD results showed that films containing 3% citric acid had the lowest crystallinity while the native starch films had the highest crystallinity. The TPA analyses showed that films containing 5% citric acid had the greatest influence on improving the tensile strength and elastic modulus, while also having the best impact on lowering the elongation. Tensile strength values recorded for films containing 0%, 1%, 3%, 5%, 7% and 9% citric acid were 5.327, 7.813, 8.688, 12.855, 14.549 and 11.614 MPa. Similarly, when citric acid concentration increased from 3% to 5%, the elastic modulus significantly increased from 831.058 to 2255.691 MPa. This study demonstrated that the physicochemical properties of tapioca starch‐based films could be modified by the incorporation of citric acid.

Crystallographic Benchmarking on Diffraction Pattern Profiling of Polymorphs-TiO2 by WPPF for Pigment and Acrylic Paint

At a very low temperature high crystalline phase of TiO2 best-fitted strain anatase was synthesized by peptization which was the prime object of this study. Unresolved parameters were investigated by the X-ray diffraction (XRD) technique employed for lattice parameters, crystallite size, lattice volume, strain, crystal structure, d-spacing and percentage of phase in weight fraction. 54.40 % anatase, 29.10 % brookite and 16.50 % rutile crystalline phase were found by whole powder pattern fitting (WPPF-Rietveld’s refinement) method and lattice volume of anatase 137.150, brookite 267.079 and rutile 62.901 ų as well the crystal strain 0.307, 0.45 and 0.28 % of anatase, brookite and rutile polymorph-TiO2 found respectively. The calculated lattice parameters of the anatase are \(\alpha\)=\(\beta\)=\(\gamma\)= 90.0°; a=b= 3.8056 Å, c= 9.470 Å and predominant (101), (004) and (200) miller indices with diffracted angle (2Ɵ) 25.38, 37.26 and 48.22 observed. The average crystallite size was 7.39 nm which confirmed the formation of nano-crystal-TiO2 due to the highly dispersed on medium. The percentage of strain of the individual polymorphs of TiO2 shows the best fit used for the pigment and acrylic paint.

Surficial engineering of active hydroxyls for ambient formaldehyde oxidation via enhanced Lewis acidity over Zr-doped cryptomelane materials

Lewis acids of solid catalysts have been featured for a pivotal role in promoting various reactions. Regarding the oxidation protocol to remove formaldehyde, the inherent drawback of the best-studied MnO2 materials in acidic sites has eventually caused deficiency of active hydroxyls to sustain low-temperature activity. Herein, the cryptomelane-type MnO2 was targeted and it was tuned via incorporation of Zr metal, exhibiting great advances in not only the complete HCHO-to-CO2 degradation but also cycling performance. Zr species were existent in doping state in the MnO2 lattice, rendering lower crystallinity and breaking the regular growth of MnO2 crystallites, which thereby tripled surface area and created larger volume of smaller mesopores. Meantime, the local electronic properties of Mn atoms were also changed by Zr doping, i.e., more low-valence Mn species were formed due to the electron transfer from Zr to Mn. The results of infrared studies demonstrate the higher possession of Lewis acid sites on ZrMn, and this high degree of electrophilic agents favored the production of hydroxyl species. Furthermore, the reactivity of surface hydroxyls, as investigated by CO temperature programmed reduction and temperature programmed desorption of adsorbed O2, was obviously improved as well after Zr modification. It is speculated jointly with the characterizations of the post-reaction catalysts that the accelerated production of active hydroxyls helped rapidly convert formaldehyde into key intermediate—formate, which was then degraded into CO2, avoiding the side reaction path with undesired intermediate—hydrocarbonate—over the pristine MnO2, where active sites were blocked and formaldehyde oxidation was inhibited. Additionally, Zr decoration could stabilize Lewis acidity to be more resistant to heat degeneration, and this merit brought about advantageous thermal recyclability for cycled application.

Enhanced lanthanum-stabilized low crystallinity metal oxide electrocatalysts with superior activity for oxygen reactions

Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are key electrochemical reactions for the development of rechargeable Zn-air batteries. However, due to the high cost of commercial noble metal-based catalysts and their limited bifunctionality, it is necessary the design of new electrocatalysts. In this study, stable electrocatalysts have been synthesized through a hydrothermal method and further low-temperature thermal treatment. The materials consist of La stabilized low crystallinity Mn and Co metal (hydro-)oxides. The electrocatalytic performance of these materials has been compared with counterparts calcined at higher temperatures. The findings demonstrate that materials synthesized at lower temperatures and with low crystallinity exhibit superior electrocatalytic activity for both ORR and OER. Moreover, the research highlights the favorable influence of the lanthanum cation, which enhances changes of surface morphology and oxidation states of other cations (Mn and Co). Additionally, the positive contribution of the carbon component to electrochemical activity and electrical conductivity has been elucidated. The best electrocatalyst was studied in a rechargeable Zn-air battery with a durability of up to 120 h. They exhibited better stability and performance than the commercial Pt/C + RuO2 catalyst currently used.

Degenerating products of flag varieties and applications to the Breuil–Mézard conjecture

We consider closed subschemes in the affine grassmannian obtained by degenerating e-fold products of flag varieties, embedded via a tuple of dominant cocharacters. For G=GL2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$G= {\ ext {GL}}_2$$\\end{document}, and cocharacters small relative to the characteristic, we relate the cycles of these degenerations to the representation theory of G. We then show that these degenerations smoothly model the geometry of (the special fibre of) low weight crystalline subspaces inside the Emerton–Gee stack classifying p-adic representations of the Galois group of a finite extension of Qp\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\mathbb {Q}}_p$$\\end{document}. As an application we prove new cases of the Breuil–Mézard conjecture in dimension two.

Finite element analysis of the effect of crystallinity on low-velocity impact performance of poly (aryl ether ketone) composites

A new copolymer poly (aryl ether ketone) (PAEK) resin was used as a matrix to prepare carbon fiber (CF) reinforced composites with different crystallinity by slow and rapid cooling. Finite element (FE) models were constructed according to micromechanics, and the progressive damage method based on the three-dimensional (3D) PUCK damage criterion was used to analyze the low-velocity impact damage mechanism of the CF/PAEK composites. The experimental results show that the composites with lower crystallinity have higher impact resistance and smaller impact damage area. In the FE simulated impact damage evolution process, the damage of the impact side is mainly compressive damage of the matrix and the fiber, while that of the impact back side is mainly tensile damage of the matrix. Moreover, due to their high interfacial bonding strength, the main damage modes of rapid-cooled composites with lower crystallinity are severe matrix tensile damage and slight fiber tensile damage in the impact back side. However, the slow-cooled composites show more delamination. In addition, for the damage evolution of compression after impact, the FE simulation shows that fiber compression, matrix tension, matrix compression and delamination expand along the transverse to the compression load. Furthermore, the in-plane damage expansion occurs earlier in the rapid-cooled composites, which also have graver interlaminar damage.

Highly strong carbon fibers through synergistic carbonization process of sulfonated poly(p-phenylene sulfide) and carbon nanotube

This paper presents the fabrication and characterization of high-performance carbon nanotube-polyphenylene sulfide (CNT-PPS) composite fibers. The study begins by dissolving PPS in chlorosulfonic acid (CSA) to create dopes suitable for wet-spinning, enabling the formation of CNT-PPS composite fibers. The presence of PPS, known for its low solubility and high crystallinity, leads to improved mechanical properties and thermal stability after carbonization. The structural evolution of the fibers during heat treatment is examined. The results show that the fibers' tensile strength and modulus increase significantly after carbonization, with the highest tensile strength (6.04 ± 0.50 GPa) achieved by the fiber containing 30 wt% of PPS heat-treated at 1400 °C and the highest tensile modulus (619 ± 44 GPa) achieved by the fiber containing 10 wt% of PPS heat-treated at 2500 °C. The mechanism of radical coupling between CNTs and PPS during de-sulfonation is proposed as a key factor contributing to the enhanced mechanical properties. The study also highlights the benefits of using PPS as a carbon fiber precursor, eliminating the need for costly and time-consuming stabilization processes. Overall, this research offers a novel strategy for producing high-performance and cost-effective carbon nanotube-based carbon fibers with applications in various industries.

Evidence for partial melting and earthquake activity in the crust from a 2-D electrical resistivity model in the vicinity of the Chayu region, southeastern Jiali-Chayu fault, Tibetan Plateau

The southeastern segment of the Jiali-Chayu fault is a prominent strike-slip fault that separates the eastern Lhasa terrane. Its formation and activity are influenced by the subduction of the Indian plate towards the Lhasa terrane and clockwise rotation in the Himalayan Eastern syntaxis region. Notably, the Chayu 1950 Ms 8.6 earthquake, triggered by this fault, remains the largest recorded inland earthquake to date. However, due to a lack of high-precision geophysical evidence, the deep crustal structure of the hypocenter area remains challenging to reconstruct, limiting our understanding of earthquake activity in the region. In this paper, the Magnetotelluric data is consisted of 70 sites spaced 2 km apart. Through a joint inversion of the transverse electric and magnetic modes, we recovered the 2-D resistivity model that is approximately 140 km long and 50 km deep. The resistivity model provides compelling evidence that the presence of magmatic rocks and metamorphic basement is responsible for the high resistivity anomaly. Conversely, the low resistivity anomaly observed in the northern region can be attributed to crustal melting. These results suggest that the variation in earthquake activity between the Gongrigabu fault and Guyu fault can be attributed to the contrasting characteristics of the crustal material. The Gongrigabu fault represents a brittle plate with low water content and high crystallinity, resulting in a distinctive high resistivity anomaly. On the other hand, the Guyu fault corresponds to a molten plate, exhibiting a low resistivity anomaly. We believe that the Chayu earthquake is a typical intraplate earthquake in the Lhasa terrane and its seismogenic fault is a deeper hidden fault located below the Gongrigab fault, challenging the belief held by other scholars that the Gongrigabu fault is solely responsible. We think the Gongrigabu fault is a high-risk zone for severe earthquakes that demands continuous vigilance in the future.

Highly Crystalline Poly(heptazine imide)-Based Carbonaceous Anodes for Ultralong Lifespan and Low-Temperature Sodium-Ion Batteries.

Carbon nitrides with layered structures and scalable syntheses have emerged as potential anode choices for the commercialization of sodium-ion batteries. However, the low crystallinity of materials synthesized through traditional thermal condensation leads to insufficient conductivity and poor cycling stability, which significantly hamper their practical applications. Herein, a facile salt-covering method was proposed for the synthesis of highly ordered crystalline C3N4-based all-carbon nanocomposites. The sealing environment created by this strategy leads to the formation of poly(heptazine imide) (PHI), the crystalline phase of C3N4, with extended π-conjugation and a fully condensed nanosheet structure. Meanwhile, theoretical calculations reveal the high crystallinity of C3N4 significantly reduces the energy barrier for electron transition and enables the generation of efficient charge transfer channels at the heterogeneous interface between carbon and C3N4. Accordingly, such nanocomposites present ultrastable cycling performances over 5000 cycles, with a high reversible capacity of 245.1 mAh g-1 at 2 A g-1 delivered. More importantly, they also exhibit an outstanding low-temperature capacity of 196.6 mAh g-1 at -20 °C. This work offers opportunities for the energy storage use of C3N4 and provides some clues for developing long-life and high-capacity anodes operated under extreme conditions.

Synthesis and Properties of Semicrystalline Poly(ether nitrile ketone) Copolymers.

As a high-performance engineering plastic, polyarylene ether nitrile (PEN) is widely used in many fields. The presence of cyano groups of PEN ensures its good adhesion to other substrates, but the inherent low crystallinity of PEN limits its application. In this work, the poly(aryl ether ketone) segment was introduced into PEN via copolymerization using both 2,6-Dichlorobenzonitrile and 4,4'-Difluorobenzophenone as the starting reagents to prepare poly (ether nitrile ketone) (BP-PENK). The effect of composition and thermal treatment on the crystallization behavior and properties of poly (ether nitrile ketone) were systematically studied. It was found that when the content of DFBP is 30%, the copolymer BP-PENK30 had the best mechanical properties, with a tensile strength of 109.9 MPa and an elongation at a break value of 45.2%. After thermal treatment at 280 °C for 3 h, BP-PENK30 had the highest crystallinity with a melting point of 306.71 °C, a melting enthalpy of 5.02 J/g, and crystallinity of 11.83%. Moreover, with the increase in crystallinity, the dielectric constant and energy density increased after thermal treatment. Therefore, the introduction of poly(aryl ether ketone) chain segments and thermal treatment can effectively improve the crystallization and the comprehensive properties of PEN.

Manipulating the Microenvironment of Single Atoms by Switching Support Crystallinity for Industrial Hydrogen Evolution.

Modulating the microenvironment of single-atom catalysts (SACs) is critical to optimizing catalytic activity. Herein, we innovatively propose a strategy to improve the local reaction environment of Ru single atoms by precisely switching the crystallinity of the support from high crystalline and low crystalline, which significantly improves the hydrogen evolution reaction (HER) activity. The Ru single-atom catalyst anchored on low-crystalline nickel hydroxide (Ru-LC-Ni(OH)2 ) reconstructs the distribution balance of the interfacial ions due to the activation effect of metal dangling bonds on the support. Single-site Ru with a low oxidation state induces the aggregation of hydronium ions (H3 O+ ), leading to the formation of a local acidic microenvironment in alkaline media, breaking the pH-dependent HER activity. As a comparison, the Ru single-atom catalyst anchored on high-crystalline nickel hydroxide (Ru-HC-Ni(OH)2 ) exhibits a sluggish Volmer step and a conventional local reaction environment. As expected, Ru-LC-Ni(OH)2 requires low overpotentials of 9 and 136 mV at 10 and 1000 mA cm-2 in alkaline conditions and operates stably at 500 mA cm-2 for 500 h in an alkaline seawater anion exchange membrane (AEM) electrolyzer. This study provides a new perspective for constructing highly active single-atom electrocatalysts.

A novel hyperbranched polyurethane solid electrolyte for room temperature ultra-long cycling lithium-ion batteries

Low room temperature ionic conductivity of solid polymer electrolytes (SPE) greatly constraints its application in the solid lithium-ion batteries. Hyperbranched polymer with unique topological structure as matrix of SPE is expected to solve this issue due to its low crystallinity and rich functional groups which helps dissociation of lithium salt. Herein, a hyperbranched polyurethane (HPU) solid electrolyte is prepared by the reaction of hyperbranched polyethylene glycol and isophoradione diisocyanate in the presence of lithium salt and ionic liquid for the first time. The obtained HPU1.5-IL1.5 electrolyte possesses a high room temperature ionic conductivity of 0.4 mS cm−1 and a wide electrochemical window of 4.95 V (vs Li/Li+). It is worth noting that the prepared HPU1.5-IL1.5 electrolyte can be adapted to multiple electrodes. Specifically, the assembled LFP half-cell can achieve long cycling up to 1000 cycles at 0.5 C with 83 % capacity retention at room temperature. Notably, the NCM811|HPU1.5-IL1.5|Li cells and LTO|HPU1.5-IL1.5|Li cells can deliver the initial discharge capacity of 148 mAh g−1 at 0.1 C for 160 cycles and the initial discharge capacity of 150 mAh g−1 at 0.2 C for 440 cycles at room temperature, respectively. Meanwhile, the safety of the pouch cell has been confirmed under some extreme conditions.

Manipulating the Microenvironment of Single Atoms by Switching Support Crystallinity for Industrial Hydrogen Evolution

AbstractModulating the microenvironment of single‐atom catalysts (SACs) is critical to optimizing catalytic activity. Herein, we innovatively propose a strategy to improve the local reaction environment of Ru single atoms by precisely switching the crystallinity of the support from high crystalline and low crystalline, which significantly improves the hydrogen evolution reaction (HER) activity. The Ru single‐atom catalyst anchored on low‐crystalline nickel hydroxide (Ru−LC−Ni(OH)2) reconstructs the distribution balance of the interfacial ions due to the activation effect of metal dangling bonds on the support. Single‐site Ru with a low oxidation state induces the aggregation of hydronium ions (H3O+), leading to the formation of a local acidic microenvironment in alkaline media, breaking the pH‐dependent HER activity. As a comparison, the Ru single‐atom catalyst anchored on high‐crystalline nickel hydroxide (Ru−HC−Ni(OH)2) exhibits a sluggish Volmer step and a conventional local reaction environment. As expected, Ru−LC−Ni(OH)2 requires low overpotentials of 9 and 136 mV at 10 and 1000 mA cm−2 in alkaline conditions and operates stably at 500 mA cm−2 for 500 h in an alkaline seawater anion exchange membrane (AEM) electrolyzer. This study provides a new perspective for constructing highly active single‐atom electrocatalysts.

Unified understanding and mitigation of detrimental phase transition in cobalt-free LiNiO2

Ni-enriched layered materials are used as electrode materials of Li-ion batteries for electric vehicle applications. Stoichiometric LiNiO2 with cationic Ni3+/Ni4+ redox is the ideal electrode material, but the gradual loss of capacity at the high voltage region, associated with Ni ion migration, hinders its use for practical applications. Therefore, to improve electrode reversibility of LiNiO2, less abundant Co ions and/or other electrochemically inactive ions, e.g., Al3+ ions, are in part substituted for Ni ions. Nevertheless, a unified understanding of improvement by metal substitution is as yet not established. In this study, the origin causing detrimental phase transition in LiNiO2 is discussed through the detailed analysis on LiNiO2 integrated with nanosized Li3PO4 derived from a metastable and rocksalt LiNiO2–Li3PO4 solid solution sample. LiNiO2 derived from the metastable rocksalt oxide has approximately 6 % anti-site defects, and the particle size growth is suppressed by uniformly dispersed nanosized Li3PO4. In low crystallinity LiNiO2 with partial structural disordering, the Ni ion migration to tetrahedral sites is effectively suppressed because of repulsive electrostatic interaction from Ni ions in Li layers. Moreover, from these findings, non-stoichiometric Li0.975Ni1.025O2 with smaller particle size has been directly synthesized without high-energy milling and Li3PO4 integration, and significant improvement of electrode reversibility is achieved. Electrode reversibility of non-stoichiometric Li0.975Ni1.025O2 is further improved through surface stabilization in a highly concentrated electrolyte solution. The unified understanding of deterioration mechanisms for LiNiO2 offers a new criterion to design Co-free LiNiO2 without metal substitution, leading to full utilization of a reversible capacity for layered materials.

The Effect of Electrospinning Parameters on the Electrospun Polybutylene Adipate Co-Terephthalate (PBAT) Biodegradable Scaffold

Electrospinning is a cost-effective and versatile technique to fabricate continuous fibers ranging from submicron diameter to nanometer diameter. Polybutylene adipate-co-terephthalate (PBAT) has been investigated as a fibrous scaffold because of its low crystallinity, rapid biodegradability, and excellent mechanical properties, particularly for its high toughness and flexibility. However, the potential of the PBAT fibrous scaffold for medical purposes is still limited. PBAT blends with biocompatible polymers have been developed and investigated for tissue engineering applications. Herein, the preliminary research examines the processability of neat PBAT as a fibrous scaffold by varying several electrospinning processing parameters, such as solution concentration, voltage, flow rate, and tip to collector distance. The aim is to obtain continuous, smooth, and bead-free fibers. The electrospun fibers were examined using a scanning electron microscope (SEM) to determine its diameters. The optimum parameters for obtaining a continuous, bead-free PBAT fibrous scaffold were 20% w/v concentration, 19 kV voltage, 2 mL/h flow rate, and a 15 cm distance.

Prediction of absorptivity in Multi-Jet Fusion manufactured polypropylene structures through laser flash and corrected porosity method

For the first time in the literature, this study validates the absorption phenomena in Multi-Jet Fusion (MJF) printed polypropylene (PP) structures through Laser Flash (LFA) and Corrected Porosity (CP) methods. The influence of process parameters such as build height and build orientation was investigated on tensile properties, crystallinity, porosity and thermophysical attributes in MJF printed PP coupons. Results showed that both crystallinity and tensile performance did not significantly vary with either location or build orientation. Interestingly, samples printed in the Z orientation showed a 35% decrease in strain, indicating that Z-oriented MJF coupons were more brittle than the flat samples (XY). Samples printed in Z orientation also possessed higher porosity and relatively lower crystallinity than the XY orientation. However, large deviations within porosity values were an obstacle to determining a suitable build chamber location for manufacturing dense samples. Therefore, a detailed investigation on porosity of printed samples using micro-CT scans and CT image analysis was necessary. Initially, poor contrast was obvious when MJF printed samples were positioned vertically in the micro-CT chamber which was mainly due to high value of horizontal intensity profile (HIP ~ 70%). Contrast in MJF samples improved significantly in the horizontal orientation (HIP ~ 40%). In parallel, the half-time and heat loss were measured in LFA to understand changes in absorption phenomena with height and orientation of the build. A direct correlation was found between LFA half-time and porosity only when the porosity correction method was implemented. Corrected porosity value was found to be inversely proportional to the heat loss of printed PP samples which indicated higher absorption for samples printed in the bottom of build chamber, XY12, whereas lower absorption was observed for less dense Z samples. Finally, heat loss phenomenon was verified using dense reference Pyroceram samples as they possess high diffusivity and low half-time and porosity compared to MJF printed samples. There is a science behind understanding the absorptivity of the MJF process which is related to the complexity of the process and is challenging to address in MJF PP samples when mixed with carbon black. The study showed that accurately determining the level of porosity is the key to validate absorption phenomena within MJF printed coupons. The contributions of this work are the investigation of the light absorption phenomena in MJF printed PP structures, and the establishment of the absorption-porosity correlation. These contributions help to predict the mechanical properties and subsequently the overall quality of the produced parts which can save cost and time in effectively utilising the MJF process.

Catalytic peroxidation of winery wastewater contaminants using activated carbon-supported magnetite nanoparticles

In this study, co-precipitation and hydrothermal synthesis methods were employed to prepare two types of magnetite nanoparticles (MNPs). An activated carbon derived from olive stones (OSAC) was used as MNPs-support. The physicochemical properties of the resulting OSAC-MNPs catalysts were determined using various characterization techniques. A more homogeneous distribution of larger and well-defined MNPs was obtained by hydrothermal synthesis, resulting in a more extensive blockage of the microporous structure of the support. Both catalysts exhibited paramagnetic behavior, but with relatively low magnetization due to the small size and low crystallinity of the Fe3O4 nanoparticles obtained. The catalytic peroxidation performance of OSAC-MNPs was studied using tyrosol (TY) as a model compound, but also real samples of winery wastewater (WW) were used in the optimized operational conditions, including pH, temperature, and doses of catalyst and hydrogen peroxide. The MNPs-based catalyst prepared by co-precipitation performed better in the range of experimental conditions tested because of the higher surface concentration of active phase that is easily accessible to the pollutant and was less prone to deactivation during successive reaction runs. The combination of active materials and optimized process enables to remove up to 92 % TPh, 35 % COD, and 26 % TOC, while the high stability of the samples associated to a low Fe-leaching (0.07 mg L−1) permits the reuse of materials in consecutive cycles.