Crystalline Temperature Research Articles

Bacterial cellulose production through the valorization of waste apple pulp and stale bread

AbstractIn this work, stale bread and waste apple pulp were used as feedstocks for the production of bacterial cellulose (BC). A glucose-rich solution was prepared from stale bread by dilute acid hydrolysis, while an extract comprising fructose and glucose was obtained from the waste apple pulp, which was used for cultivating Komagataeibacter xylinus DSM 2004, either as sole feedstocks or supplemented with Hestrin-Schramm medium. Supplementation significantly improved BC production: 3.38 ± 0.09 g/L for waste apple pulp extract and 2.07 ± 0.22 g/L for stale bread hydrolysate. There was no significant impact on BC chemical structure or fiber diameter, but the biopolymer produced from waste apple pulp extract had slightly higher crystallinity (CI = 59–69%) and lower thermal degradation temperature (Tdeg = 341–350 ℃) than that of the stale bread hydrolysate (CI = 55%; Tdeg = 316–320 ℃). Moreover, supplementation of the waste apple pulp extract led to the preparation of thicker membranes, with higher Young’s modulus, tension, and deformation at break but lower water uptake capacity and lower permeability to O2 and CO2. These results show that waste apple pulp and stale bread are suitable feedstocks for BC production and the cultivation conditions can be adjusted for tailoring the biopolymer’s mechanical and barrier properties to suit different applications.

Biotransformation of microplastics from three-layer face masks by nitrifying-denitrifying consortia

COVID-19 increased microplastics (MP) contamination due to the extensive use of single-use personal protective equipment, particularly three-layer face masks. MP from face masks enter wastewater treatment plants (WWTPs), which were not designed to remove them. We utilized nitrifying-denitrifying microbial consortia and synthetic urban wastewater to evaluate the biotransformation of MP from each layer of three-layer face masks made of polypropylene (PP). The biotransformation carried out by the nitrifying-denitrifying consortia altered the surface of the outer, middle, and inner layers, as a consequence of the chemical modification of the PP-MP structure. Abiotic controls did not show changes on the physicochemical and thermal properties of PP-MP. Biotic tests showed increments in both the carbonyl and hydroxyl indices of the three layers in 42 days. The outer layer showed the greatest degree of biotransformation, which was consistent with morphological changes detected by scanning electron microscopy and in physicochemical properties such as crystallinity, evaporation, and fusion temperature. The nitrifying-denitrifying consortia, which removed 99 % of the total nitrogen from the synthetic urban wastewater, had several genera with proven capacity to biotransform MP such as Cephaloticoccus and Pseudomonas.

Functionalization and Repurposing of Polypropylene to a Thermoset Polyurethane.

Developing effective recycling pathways for polyolefin waste, enabling a move to a circular economy, is an imperative that must be met. Postuse modification has shown promising results in upcycling polyolefins, removing the limitation of inertness, and improving the final physical properties of the recycled material while extending its useful lifetime. Grafting of maleic anhydride groups to polypropylene is an established industrial process that enhances its reactivity and provides a convenient route to further functionalization and upcycling. In this work, maleic anhydride grafted polypropylene was hydroxylated and subsequently cured with a diisocyanate to form a thermoset polyurethane (PU). The crystal structure (unit cell and lamellar structure) of the polypropylene (PP) was preserved in the PU. At room temperature, the PU showed a high modulus due to the crystallization behavior of the PP; upon increasing the temperature above the melting temperature, the modulus decreased to a rubbery plateau, consistent with formation of a network. The resulting PU showed a higher glass transition temperature and lower degree of crystallinity than its PP predecessor due to the crosslinked nature of the polymer. The mechanical integrity of the PU was maintained through several reprocessing cycles due to the melt processability enabled by the presence of a urethane exchange catalyst. This functionalization and upcycling route thus offers a promising alternative to repurposing PP waste in which the creation of melt-processable thermoset polymers expands applications for the materials.

Effect of ethylene oxide and gamma sterilization on surface texture of films and electrospun poly(ε-caprolactone-co-p-dioxanone) (PCLDX) scaffolds

In the field of tissue engineering, synthetic and degradable polyesters like poly(ε-caprolactone) (PCL) and poly(ε-caprolactone-co-p-dioxanone) (PCLDX) are widely used as scaffolds. Our previous research revealed that thermal storage conditions could alter the surface texture of PCL and PCLDX scaffolds, which might influence cell-scaffold interactions in tissue engineering applications. These findings highlighted the importance of multi-scale characterization techniques to identify the scales most sensitive to external changes and the need for personalized surface texture analysis. Sterilization techniques, such as ethylene oxide and gamma radiation, are essential for ensuring the sterility of polymeric medical devices. However, these processes can significantly impact the bulk polymer properties and/or surface texture of the scaffolds, potentially affecting their biocompatibility, safety, and overall performance. Therefore, the influence of sterilization processes on the surface texture of PCLDX films and electrospun nanofibers and to correlate these findings with the thermal and physical properties of the polymer are essential and have been assessed. Our results demonstrated that ethylene oxide maintained the structural integrity and surface texture of PCLDX scaffolds, while gamma irradiation caused a significant reduction in molar mass and increased the number of hills (Shn) and dales (Sdn) on PCLDX samples. Despite these changes, both sterilization methods showed minimal effects on the thermal properties, such as melting temperature and degree of crystallinity, and surface wettability of the scaffolds. This comprehensive surface texture analysis highlights the importance of evaluating feature parameters such as Shn and Sdn for optimizing the performance and biocompatibility of polymeric scaffolds in tissue engineering.

Application of Silica Nanoparticles Improved the Growth, Yield, and Grain Quality of Two Salt-Tolerant Rice Varieties under Saline Irrigation.

Salt stress significantly reduces rice yield and quality and is a global challenge, especially in arid and semi-arid regions with limited freshwater resources. The present study was therefore conducted to examine the potential of silica nanoparticles (SiO2 NPs) in mitigating the adverse effects of saline irrigation water in salt-tolerant rice. Two salt-tolerant rice varieties, i.e., Y liangyou 957 (YLY957) and Jingliangyou 534 (JLY534), were irrigated with 0.6% salt solution to simulate high-salt stress and two SiO2 NPs were applied, i.e., control (CK) and SiO2 NPs (15 kg hm-2). The results demonstrated that the application of SiO2 NPs increased, by 33.3% and 23.3%, the yield of YLY957 and JLY534, respectively, compared with CK, which was primarily attributed to an increase in the number of grains per panicle and the grain-filling rate. Furthermore, the application of SiO2 NPs resulted in a notable enhancement in the chlorophyll content, leaf area index, and dry matter accumulation, accompanied by a pronounced stimulation of root system growth and development. Additionally, the SiO2 NPs also improved the antioxidant enzyme activities, i.e., superoxide dismutase, peroxidase, and catalase activity and reduced the malondialdehyde content. The SiO2 NPs treatment effectively improved the processing quality, appearance quality, and taste quality of the rice. Furthermore, the SiO2 NPs resulted in improvements to the rapid viscosity analyzer (RVA) pasting profile, including an increase in peak viscosity and breakdown values and a reduction in setback viscosity. The application of SiO2 NPs also resulted in a reduction in crystallinity and pasting temperature owing to a reduction in the proportion of B2 + B3 amylopectin chains. Overall, the application of silica nanoparticles improved the quality of rice yield under high-salt stress.

Effects of element specific Co substitution in Ni-Mn-Ga-Fe and accelerated grain growth during heat treatment

The substitution of small amounts of Co and Fe into Ni-Mn-Ga-based ferromagnetic shape memory alloys (FSMAs) is widely recognized for its ability to finely tune their multifunctional properties. This study investigated the effects of the substitution of each of the parent elements, in amounts of Co = 1, 3, and 5 (at.%), on the crystalline structure transformation temperature, microstructure, and magnetic properties of the nominal alloy Ni50Mn25Ga20Fe5. An induction melting technique was used to fabricate a series of 10 alloys with and without Co-substitution. In addition to determining the evolution of its magnetic and structural characteristics, Co-doping has been found to have an unexpected and beneficial effect on the grain microstructure. The findings of the study revealed that the Ni49Co1Mn25Ga20Fe5 alloy exhibited significant grain growth while demonstrating the mixed 10 M + 14 M martensitic crystal structure at ambient temperature. Separating an oriented grain of 1 × 2 mm enabled the experimental demonstration of magnetic field-induced structural rearrangement through twin-domain motion. Varying the levels of Co-substitution and the specific element being substituted allows tuning between the stabilisation of cubic austenite, modulated martensites (10 M or 14 M), or a non-modulated martensite at ambient temperature. Using standard melting facilities to fabricate large grains of polycrystalline ingots with 10 M + 14 M Co-doped Ni-Mn-Ga-Fe actuating elements offers a practical advantage over growing single crystals.

Production of biosurfactant by Bacillus megaterieum using agro-food wastes and its application in petroleum sludge oil recovery.

The objective of this study is to utilize cost-effective renewable substrates derived from agro-food wastes for the production of biosurfactant by Bacillus megaterium, which was isolated from petroleum sludge. Various agro-food waste materials, namely potato peelings (PP), rice cooking water (RW), biscuit by products (BB), carob pods (CP), and eggshells, were evaluated as nutrient sources for bacterial growth compared to a synthetic medium (SM). The results indicate that the medium comprising carob pods, potato peels supplemented with eggshells promoted the growth of the bacteria and the production of Biosurfactants at a rate of 150mg/l and 140mg/l respectively. The biosurfactant exhibited an emulsification index (E24) of 55.23 ± 0.32%, 46.47 ± 3% 43.80 ± 0.4%, 18.33 ± 0.25% and 20 ± 0.11% for PP, CP, SM, BB and RW respectively. The biosurfactant produced from PP had the ability to decrease the surface tension of water from 74 to 39.38 mN/m, with a critical micelle concentration (CMC) of 15mg/L. The chemical characterization of purified biosurfactant was done using Fourier-transform infrared spectroscopy (FTIR) and Thermal gravity (TG), as well as differential scanning calorimetry (DSC) analysis (TG/DSC), revealing the functional groups and thermostability of the biosurfactant. The DSC spectrum for PP biosurfactant showed the highest thermostability with crystalline temperature (Tc) of 150°C and melting point (Tm) of 295°C. The extracted biosurfactant was mixed with petroleum sludge, composed of heavy oil, 40.64 ± 0.19% of extracted oil was obtained after 5h of reaction while using PP based medium.

Physicochemical properties of starch of four varieties of native potatoes

The limited industrial use of indigenous varieties of native potatoes has caused a decrease in its cultivation, restricting it to the self-consumption of the Andean population. The present study analyzed the physicochemical, thermal, and structural properties of the starches extracted from four of these varieties Aq'hu Pukucho, Yurakk Kkachun Wakkachi, Yurac Anca, and Huarmi Mallco, as a potential source of be used in industries such as food, pharmaceutical and, bioplastics. The percentage yield in wet extraction ranged between 14.53 and 20.26 %. The luminosity L* and whiteness index (WI) values were observed in ranges of 90.75–92.71 and 90.05–91.50, respectively. The Finding revealed various techno-functional properties, since the level of amylose varied between 36.29 and 43.97 %, an average zeta potential of −22 mV, and a maximum viscosity between 19,450–14,583 cP. The starches showed consistent thermal behavior since the TGA curves showed three stages with gelatinization temperatures that ranged between 54.9 and 59.75 °C, an enthalpy of 3.60–6.62 J/g, and various shapes of particles such as circular, elliptical, and oval. In conclusion, the relationships between variables such as water absorption index, swelling power, viscosity, crystallinity, enthalpy, and gelatinization temperature reveal different characteristics of each type of starch, which can influence its use.

Wood flour / ceramic reinforced Polylactic Acid based 3D - printed functionally grade structural material for integrated engineering applications: A numerical and experimental characteristic investigation

Recently, efforts have been done to capitalize on the potential of multidisciplinary research in order to produce unique features in polymer technology. To improve its physical and chemical properties for any intended use, the most promising Polylactic acid (PLA) has recently been copolymerized using other polymeric or non-polymeric components. This investigation aims to employ the material extrusion (MEX) process to develop a new functionally grade structural material (FGSM) by alternate layer deposition of wood flour reinforced PLA (WPLA) and ceramic reinforced PLA (CPLA). The mechanical properties of the printed laminates are examined using tensile, compression and three point bend tests. The microscopic investigation is used to assess fracture morphologies. A numerical simulation is also performed using ABAQUS under standardized parametric settings to investigate the mechanical behaviour of the laminates. The experimental and numerical results are consistent, with a deviation about ∼1 %. The tensile, compressive, and flexural strength of the newly developed FGSM are 61.39, 95.4, and 107.8 % higher than those of WPLA printed laminates. Furthermore, the acquired mechanical behaviour results are merely comparable to those of CPLA printed laminates. DSC thermograms demonstrate that FGSM has a better glass transition temperature (66oC) and a cold crystalline temperature (87.63oC), which contributes to its thermal stability. Overall, the newly developed FGSM might be considered a viable alternative, mechanically strong, and less expensive polymer composite material for structural built applications in any engineering and related fields.

Biodegradability of renewable isosorbide and sebacate-based copolyesters

The growing environmental concerns associated with the use of plastics highlight the need to mitigate carbon emissions and environmental pollution via biodegradable plastics development. Herein, biotechnologically accessible and renewable building blocks, namely 1,4-butanediol and sebacic acid, were copolymerized with carbohydrate-derived isosorbide to afford random poly(butylene-co-isosorbide sebacate) with variable isosorbide content. The thermal stabilities of these copolyesters and their biodegradabilities under (non)enzymatic hydrolysis, compost, soil, and marine conditions were examined as functions of isosorbide content. With the increasing isosorbide content, the glass transition temperature increased, whereas the crystallinity and melting temperature decreased. Isosorbide incorporation enhanced hydrolyzability under alkaline and enzymatic conditions, while demonstrating minimal impact under neutral and acidic conditions. The in-compost degradation rate increased with the increasing isosorbide content because of the concomitant decrease in melting temperature and crystallinity. In soil and marine environments, the copolyesters were degraded faster than poly(butylene sebacate). At 30 mol% isosorbide, the degradation extent reached 97.2 and 68.3 % after eight-week degradation in soil and 32-week degradation in a marine environment, respectively. This study is the first to report the biodegradability and degradation mechanisms of poly(butylene-co-isosorbide sebacate) and provides valuable insights into customizing the synthesis of biodegradable plastics to meet the degradation cycle requirements under various environmental conditions.

Ultraviolet encryption information storage using hydrophobic poly(ε-caprolactone)/carbon quantum dot composite film

Luminescent poly(ε-caprolactone)/nitrogen-doped carbon quantum dots (PCL/N-CQDs) film with the function of information protection and encryption was realized based on the fluorescent N-CQDs. The N-CQDs were synthesized from citric acid with urea as a dopant for the enhancement of fluorescent properties. The facilely prepared composite film retained the hydrophobic nature of PCL and achieved the enhanced mechanical property. The appropriate crystallization temperature and degree of crystallinity of PCL provide the film with opaque characteristics at room temperature, rendering it an ideal carrier for carrying information. The information encryption and decryption are achieved through ionoprinting technique, exploiting the ability of Fe3+ ions to quench the fluorescence of N-CQDs, allowing for the encryption of designed information on the film’s surface. With its opaque, hydrophobic, and photoluminescent properties, the PCL/N-CQDs composite film holds significant promise for applications in information encryption.

The δ18O contrast between bulk goethite and water extracted from it does not reliably reveal goethite growth temperature

Goethite (α-FeOOH) contains two structurally-distinct oxygen sites that can potentially be independently interrogated for isotopic composition by analyzing bulk goethite δ18O (δ18Obulk) and the δ18O of water extracted from it (δ18Oextracted). The isotopic contrast between these two components may form the basis of a paleothermometer (Miller et al., 2020). We sought to better understand the behavior of goethite undergoing vacuum dehydroxylation, the key step in this potential paleothermometric technique. A refined method for making these measurements applied to a suite of natural and synthetic goethites revealed that δ18Oextracted is extremely sensitive to extraction temperature and to details of the vacuum environment in which the goethite is dehydroxylated. This sensitivity likely arises from the fundamental mechanism by which evolved water is removed from goethite in vacuum, via nm-wide pores penetrating nascent hematite surrounding dehydroxylating goethite. These pores may provide favorable conditions for back reaction that scrambles the oxygen isotopic composition, and also for kinetic mass fractionation. The character of these pores is known to vary with goethite composition, crystallinity, and extraction temperature. We identified additional sample-specific factors that affect δ18Oextracted. For example, some synthetic goethites undergo dehydroxylation at surprisingly low temperature (<90 °C) in vacuum, under conditions usually used to remove nonstoichiometric water. In addition, some of the synthetic goethites have spectroscopic characteristics suggesting a range of OH bonding environments that complicate the idea that goethite has just two structurally (and potentially isotopically) distinct oxygen sites. Instead, in fine grained or poorly crystalline goethite there may be a continuum of physisorbed water, chemisorbed water, and stoichiometric water that is simultaneously released during vacuum extraction. After investigating a wide range of extraction conditions, we determined that rapid heating to 255 ± 5 °C is optimal for achieving high degrees of water extraction with the least apparent back reaction. When applied to synthetic goethites grown between 5 °C and 70 °C, we found no compelling correlation between synthesis temperature and the contrast between δ18Obulk and δ18Oextracted. Analyses of two natural samples, known to have grown at ∼5 °C and ∼ 25 °C, revealed no significant difference in measured isotopic contrast. Together these observations suggest that goethite has no resolvable formation temperature information encoded in the bulk and extracted water oxygen isotope ratios as interrogated by the method we explored. If there is temperature-dependent isotopic contrast between the two oxygen sites in goethite, the use of the dehydroxylation method appears unable to reliably reveal it.

Thermal and Mechanical Properties of Bio‐Based Polyamide 56/6 Filled with Talc

AbstractPolyamide composites with varying filler concentrations are prepared using the hot melt extrusion method, employing polyamide 56/6 (PA56/6) and modified talc as fillers. Initially, the thermal characteristics of PA56/6 composites (PA56/6‐talc) are examined through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), encompassing parameters such as melting temperature, crystallinity, and decomposition temperature. The hydrophilicity and barrier properties of PA56/6‐talc are assessed using an optical contact angle meter, a water vapor transmission rate tester, and an oxygen transmission rate tester. Furthermore, the mechanical properties of PA56/6‐talc are also scrutinized. The results indicate that PA56/6 exhibits superior hydrophobic, barrier, and mechanical properties, thereby demonstrating its immense potential in garment fabrics and packaging materials.

Design and fabrication of durable poly(3-hydroxybutyrate) (PHB) coating with high adhesion and desirable anti-corrosion performance on Mg alloy for bio-application

To improve the degradation properties of magnesium (Mg) alloy-based temporary implants, a durable polymer coating with high adhesion and desirable anti-corrosion performance is designed in this work. The biodegradable poly(3-hydroxybutyrate) (PHB) with high crystallinity (>60 %) and low glass transition temperature (Tg < 5 °C) is conducted as the protective coating for Mg alloy. The hydrogen evolution rate decreases by 2.56 times with the protection of the PHB coating, while the maximum concentrations (Cmax) of Na+ and Cl− ions penetrated across the PHB film are <0.1 % and 10 % of their total concentrations respectively. Furthermore, a simple approach through the network interdiffusion, hydrogen bonding, and chemical cross-linking is performed to improve the adhesion from 0.19 to 8.36 MPa. The modified PHB coated Mg alloy with a strong interface shows excellent corrosion resistance even after 168 h immersion. The design principle for durable polymer coatings is proposed based on the above results. Moreover, the interfacial bonding is identified by the Density Functional Theory (DFT) computational method. This study demonstrates the prepared PHB coating could act as an ion barrier to supply efficient protection for Mg alloys in vitro and enriches our understanding on the structure-property-performance relationship of polymer coatings.

Physically cross-linked PVA/f-MWCNTs nanocomposite hydrogel with enhanced thermal, mechanical, and dielectric properties

This work offers a new method for the preparation of poly (vinyl alcohol)/f-MWCNTs nanocomposite hydrogel. Employing a physical cross-linking method, fabricated high-strength nanocomposite hydrogel in one step at room temperature without following the traditional repeated freeze-thaw method. Optical microscopy images indicate the uniform dispersion of f-MWCNTs in the PVA matrix with average agglomerate size of 5–6 µm. Morphology investigation showed entangled, more dense network structure after addition of f-MWCNTs. Scissoring of inter chain H-bonding and establishing of intermolecular H-bonding between -OH and -COOH group of PVA and f-MWCNTs examined by ATR-FTIR. Delay in thermal degradation of PVA/f-MWCNTs nanocomposite hydrogel with f-MWCNTs suggested by thermos-gravimetry analysis. Improved melting and crystalline temperature examined by differential scanning calorimetry. PVA/f-MWCNTs nanocomposite hydrogel showed ⁓ 5 and 6 times of modulus and hardness respectively than pristine PVA hydrogel. Oscillatory rheology analysis suggests the robust gel-like network formed upon addition of f-MWCNTs into the PVA matrix. PVA/f-MWCNTs nanocomposite hydrogel showed 13 times dielectric constant than pristine PVA hydrogel along with small dielectric loss investigated by broadband dielectric spectroscopy (BDS). Enhanced thermal, mechanical and dielectric properties make the fabricated PVA/f-MWCNTs nanocomposite hydrogel a potential candidate for the energy storage device and electronics application.

The Effects of Lignin on the Thermal and Morphological Properties and Damage Mechanisms after UV Irradiation of Polypropylene Biocomposites Reinforced with Flax and Pine Fibres: Acoustic Emission Analysis.

This study investigates the impact of lignin on the durability and performance of polypropylene-based biocomposites (PP-flax and PP-pine) under environmental stresses such as UV radiation and moisture. The findings indicate that pine fibres, with their higher lignin content, are significantly more resistant to thermal degradation than flax fibres. Differential scanning calorimetry (DSC) showed that lignin influences crystallinity and melting temperatures across the composites, with variations corresponding to fibre type. Acoustic emissions analysis revealed that increasing the lignin content in pine fibres effectively reduces surface microcracks under UV exposure. Overall, these results underscore the importance of fibre composition in improving the performance and longevity of biocomposites, making them better suited for durable construction applications.

The fate of plastic wraps in constructed wetland: Surface structure and microbial community

The high use of plastic wraps leads to significant environmental pollution. In this study, the surface structure and microbial community evolution of commercially available plastic wraps [polyethylene (PE), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), and polylactic acid (PLA)] in constructed wetlands (CWs) were investigated. The results indicated that all plastic wraps gradually decreased in molecular weight, crystallinity, melting, and crystallization temperatures, whereas a gradual increase was observed in the surface roughness, polymer dispersity index (PDI), carbonyl index (CI) and Shannon index of microorganisms colonizing the CWs. The aging rate of the plastic wrap was in the order: PLA > PVC > PE > PVDC, at the same site in the CWs, and it was in the order: soil surface > plant roots > subsoil, for the same plastic wrap. The diversity of microorganisms colonizing the same plastic wrap was in the order: plant roots > subsoil > soil surface. The Shannon indices of microorganisms on plastic wraps were lower than those in the soil, indicating that the diversity of microorganisms colonizing plastic wraps is limited. Additionally, the microbial community structure on the plastic surface was co-differentiated by the plastic type, placement position in the CWs, and aging time. Significantly different microbial community structures were found on the PVC and PVDC wrap surfaces, revealing that the chlorine in plastics limits microbial diversity. Unclassified members of Rhizobiaceae and Pseudomonadaceae were the dominant genera on the surface of the plastic wraps, suggesting that they may be the microorganisms involved in plastic degradation processes. The study provides valuable perspectives to facilitate a comprehensive understanding of the migration, fate, and environmental risks associated with microplastics (MPs) in wetlands.

Promotion of Processability in a p-Type Thin-Film Transistor Using a Se-Te Alloying Channel Layer.

p-type thin-film transistors (pTFTs) have proven to be a significant impediment to advancing electronics beyond traditional Si-based technology. A recent study suggests that a thin and highly crystalline Te layer shows promise as a channel for high-performance pTFTs. However, achieving this still requires specific conditions, such as a cryogenic growth temperature and an extremely thin channel thickness on the order of a few nanometers. These conditions critically limit the practical feasibility of the fabrication process. Here, we report a high-performance pTFT incorporating a 60-nm-thick highly crystalline Se-Te alloyed channel layer, produced using pulsed laser ablation at room temperature. The Se0.5Te0.5 alloy system enhances crystalline temperature and widens the band gap compared to a pure Te channel. Consequently, this approach results in a field-effect mobility of 3 cm2/V·s, with an on/off current ratio of 3 × 105, a subthreshold slope of 2.1 V/decade, and a turn-on voltage of 6.5 V, achieved through conventional annealing at 250 °C. To demonstrate its applicability in complementary circuit applications, we integrate a complementary-type inverter using a p-type Se0.5Te0.5 TFT and an n-type Al-doped InZnSnO, demonstrating a high voltage gain of 12 and a low static power consumption of 17 nW. This suggests that the Se-Te alloyed channel approach paves the way to a more straightforward and cost-effective process for Te-based pTFT devices and their applications.

Enhancing 3D printability of polyhydroxybutyrate (PHB) and poly(3-hydroxybutyrate-co-3-hydroxy valerate) (PHBV) based blends through melt extrusion based-3D printing

Polyhydroxybutyrate (PHB) and poly (3-hydroxybutyrate-co-3-hydroxy valerate) (PHBV) possess favorable biological properties such as biocompatibility and biodegradability, making them suitable for various applications. However, their utility is limited by a narrow processing window due to low thermal stability and challenges in manipulating filament size during extrusion, attributed to poor melt strength. These issues result in irregularities such as discontinuous flow and incomplete deposition of melted PHB, significantly affecting 3D printing outcomes. To address these concerns, this study explores blending PHB and PHBV with poly (lactic acid) (PLA) and poly (butylene adipate-co-terephthalate) (PBAT) to enhance its processability and printability. Thermal analysis of all blends revealed three distinct degradation steps occurring at approximately 300, 360, and 400ºC, corresponding to PHB or PHBV, PLA, and PBAT, respectively. Moreover, the melting temperatures of PHB, PHBV, PLA, and PBAT were measured around 176, 173, 152, and 121ºC, respectively. It was observed that the polymer blends exhibited lower crystallization temperature and degree of crystallinity compared to PHB or PHBV. Assessing their 3D printability, neat PHB and PHBV filaments experienced fusion issues, poor flow during extrudate deposition, and significant warping, leading to 3D printing failures. In contrast, the blends displayed enhanced flowability and successfully produced high-quality specimens. Scanning electron microscope (SEM) analysis highlighted a phase separation morphology in the blends, showcasing uniform dispersion of PLA and PBAT within the PHB matrix.

Role of processing procedures and molecular weight and their link to quasistatic and fatigue properties of polyamide 6

To expand the scientific base for the usage of the fused layer modelling (FLM) process for the production of polyamide 6 (PA 6) parts, in this work the influence of processing (injection moulding, compression moulding and FLM) and molecular weight on the end-use properties of PA 6 is elucidated. Besides its viscosity, the molecular weight of PA 6 also influences crystallinity and crystallization temperature. The mechanical properties of the fabricated specimens were studied in detail, also in the fatigue range, and analysed focusing on the fusion of interfaces in compression moulding and fused layer modelling. The analysis reveals, that the molecular mobility in the melt (i.e. viscosity and diffusion coefficient) as well as the amount and orientation of interfaces (as determined by the processing procedure) strongly influences the end-use properties. In the case of FLM printed parts, mechanical failure due to quasistatic and fatigue loading essentially depends on the quality of fusion of adjacent layers, which is strongly determined by molecular weight and processing temperature. Generally, a lower viscosity of PA 6 favours fusion of adjacent layers.