Low-temperature Crystallization Research Articles

The Crystallization and Melting Behavior of Neodymium-Based Butadiene Rubber Blends.

This study investigates the influence of poly(butadiene-isoprene) copolymer rubber (BIR) and TDAE oil on the crystallization and melting behavior of neodymium-based butadiene rubber (Nd-BR). The study demonstrates that the melting points of Nd-BR and its blends decrease with lower crystallization temperatures. Below the critical crystallization temperature (Tc,c), the melting behavior shows dual peaks in distinct temperature ranges, which are attributed to different spherulitic sizes. The addition of BIR or TDAE oil lowers the Tc,c, with TDAE oil exerting a more substantial effect. These diluents mainly influence the nucleation temperature and crystallinity level of Nd-BR while having a minimal effect on the crystallization mechanism. A master curve, which overlaps for various samples, is developed by correlating the peak melting temperature (Tm,peak) with the Tc. This curve facilitates a quantitative assessment of the effects of BIR and TDAE oil on Nd-BR, highlighting the greater influence of TDAE oil on the crystalline structure compared with BIR at equivalent mass fractions. By applying the Lorentz equation and multi-peak fitting, a relationship between the melting points and crystallization temperatures is established, enabling the calculation of the equilibrium melting points (Tm0) for different samples. The findings show a reduction in the Tm0 due to the diluents; specifically, the Tm0 is approximately 0 °C for pure Nd-BR, and it decreases to -4.579 °C and -6.579 °C for samples with 50 PHR TDAE oil and 60 wt.% BIR, respectively.

Physico-chemical, sensory and oxidative quality of butter from cows fed 3-nitrooxypropanol

This study aims to investigate the effects of supplementing 3-nitrooxypropanol (3-NOP) to the diet of dairy cows on physico-chemical and sensory properties, as well as oxidative stability of butter. Forty-eight Danish Holstein cows were randomly assigned to control diets or 3-NOP supplemented diets at 60 mg 3-NOP kg−1 feed DM. Compared to control butter, 3-NOP butter had higher proportions of short- and medium-chain fatty acids (FAs) and lower solid fat content, onset crystallization and offset melting temperatures. Sensory analysis revealed minor differences between 3-NOP and control butter, while peroxide values of 3-NOP butter was lower than control butter during storage of 12 weeks. In conclusion, the alterations in FA composition by 3-NOP led to minor changes in physical properties but improved oxidative stability of butter without major changes in sensory characteristics.

Tetragonal phase-free crystallization of highly conductive nanoscale cubic garnet (Li6.1Al0.3La3Zr2O12) for all-solid-state lithium-metal batteries

The synthesis and processing of garnet-type conductors is usually done at temperatures above 1100 °C to reach the high Li-ion conducting cubic phase resulting in micron-sized particles and potential Li-loss, which are unfavorable for further processing and electrode-electrolyte assembly. Here, we tackle this problem and report a novel low-temperature aqueous synthesis route to stabilize the cubic phase of Li6.1Al0.3La3Zr2O12 (c-Al-LLZO) at a temperature as low as 600 °C, while obtaining nano-crystallites at around 100 - 200 nm. Moreover, a dual-reaction mechanism was proposed to describe the process of c-Al-LLZO crystallization. The as-synthesized nanoscale c-Al-LLZO particles facilitate the densification of the solid-state electrolyte (SSE) pellets with less endowed grain boundaries (exhibiting a high relative density of 97.8 %). The ionic conductivity reaches 0.42 mS cm−1 at 21 °C and the low activation energy (half of the published values) is 0.17 eV. The results presented here show that symmetric cells with Li metal exhibit excellent stability at the current density of 0.2 mA/cm2 and 0.5 mA/cm2, and an improved critical current density (CCD) of 2.16 mA/cm2. This work provides a feasible method of low-temperature crystallization of nanoscale cubic garnet SSEs with good performance for the fabrication of stable SSLBs.

Resource Disposal and Products of Fly Ash from Domestic Waste Incineration in Zhejiang Province, China: Migration and Change of Hazardous Heavy Metals

At present, domestic waste incineration fly ash is classified as hazardous waste. The technical hurdle of fly ash detoxification and resource usage must be overcome in order to effectively utilize fly ash resources. In this study, we investigate the migration and transformation of heavy metal contaminants in the course of utilizing domestic waste incineration fly ash resources through the technology pathway of low-temperature pyrolysis, cyclic rinsing, and evaporation crystallization. Firstly, a comparative analysis was conducted on the fly ash (FA), pyrolysis ash (PA), and water-washing ash (WA) resulting from domestic waste incineration, revealing 24 types of metals, 3 types of non-metals, and 8 types of oxides. We observed the variations in heavy metal concentrations as well as the acidity and alkalinity in three types of ash resulting from the regenerated salt (RS) and incineration processes. Moreover, we analyzed the changes in heavy metal levels and acidity and alkalinity of treated saline water (TSW) and industrial brine (IB), which originate from the fly ash treatment process. The study’s results have confirmed that the heavy metal content in RS was below the detection limit following resource treatment. In addition, the regenerated salt product is determined to be a CaO-SiO2-Al2O3-Fe2O3 system, which enables the utilization of fly ash as a valuable resource. Notably, there were significant changes observed in heavy metal content in TSW and IB. Continued attention needs to be paid to the potential risk of environmental contamination from heavy metals and dioxins in FA infiltration. This research will prove beneficial in assessing resource utilization potential of products subjected to environmentally sound incineration fly ash treatment.

Effect of Surface Properties of Nanoparticles on the Crystallization Behavior of Polypropylene/Polypropylene‐g‐Silica Nanocomposites

AbstractIn order to investigate the effect of surface properties of nanoparticles (NPs) on the crystallization behavior of nanocomposite, three kinds of silica (SiO2) NPs are dispersed in isotactic polypropylene (iPP) matrix by solution blending method. Specifically, the poor compatibility between inorganic bare SiO2 NPs and organic PP matrix triggers the formation of aggregates and induces the fractionated crystallization with two crystallization peaks at higher particle loading (Φ), i.e., main crystallization peak (MCP) and low temperature crystallization peak (LCP, always located at 124.0 °C). Once short PP chains (0.9 × 104 g mol−1) are grafted onto the surface of SiO2 NPs, the nanocomposites with all Φ only exhibit a single MCP which is attributed to the strong interfacial interaction. With the increase of grafting chain length (9 × 104 g mol−1), the more stretched conformation of grafting chains can provide numerous heterogeneous nucleation sites and significantly accelerate the crystallization rate of PP chains near the surface of SiO2 NPs, which lead to the formation of an extra high temperature crystallization peak (HCP, almost kept constant at 133.0 °C). The occurrence of various crystallization peaks implies that the surface properties of nanoparticles play a vital role in the nucleation ability of nanoparticles.

Study of flashlamp annealing to promote crystallization of indium tin oxide thin films

The use of flashlamp annealing as a low-temperature alternative or supplement to thermal annealing is investigated. Flashlamp annealing and thermal annealing were conducted on 100 nm thick indium tin oxide (ITO) films deposited on glass to compare the properties of films under different annealing methods. The ITO samples had an average initial sheet resistance of 50 Ω/sq. After flashlamp annealing, the sheet resistance was reduced to 33 Ω/sq only, while by thermal annealing at 210 °C for 30 min, a sheet resistance of 29 Ω/sq was achieved. Using a combination of flashlamp annealing and thermal annealing at 155 °C for 5 min, a sheet resistance of 29 Ω/sq was achieved. X-ray diffraction analysis confirmed that flashlamp annealing can be used to crystallize ITO. Flashlamp annealing allows for low-temperature crystallization of ITO on a time scale of 1–3 min. Through electrical and optical characterizations, it was determined that flashlamp annealing can achieve similar electrical and optical properties as thermal annealing. Flashlamp offers the method of low-temperature annealing, which is particularly suitable for temperature sensitive substrates.

A mixed valence decanuclear cerium-oxo cluster CeIII4CeIV6 for efficient photocurrent response

Cerium-oxo clusters with mixed valence exhibit distinctive redox properties due to cerium ions switch between +3/+4 valence states. However, the design and synthesis of these clusters present formidable challenges, resulting in limited availability of such species, often necessitating the use of both CeIII and CeIV reactants. Herein, we successfully obtained a mixed valence cerium-oxo cluster CeIII4CeIV6(µ3-O)4(µ4-O)4(acac)14(CH3O)6(CH3OH)2 (CeIII4CeIV6, Hacac = acetylacetone) through low-temperature crystallization only using the trivalent cerium salt. The coexistence as well as the distribution of Ce ions in different valence states have been determined from a multifaceted analysis. In addition, the stability of the synthesized cluster was confirmed by the HRESI-MS study through redissolution of the single crystal sample in fresh methanol. Importantly, Importantly, this study reveals the mechanism for the generation of +4 valence state. Under alkaline conditions, the presence of trace oxygen and the involvement of acetylacetone ligand facilitated the partial oxidation of CeIII to CeIV. The cluster CeIII4CeIV6 has strong ultraviolet absorption and long visible light absorption. As the electrode precursor, CeIII4CeIV6 showed clear photocurrent response and high photocurrent intensity due to CeIII/CeIV redox reaction.

Effect of aluminum content on plasma resistance and contamination particle generation in yttrium aluminum oxide coatings

Yttrium aluminum oxide (YAO) has garnered interest due to its ability to protect the interior parts of process chambers from the corrosive effects of fluorine-based plasma. This ability is attributed to its low melting point, which enhances the internal bonding capabilities of the atmospheric plasma spray (APS) method. We explored the resistance of YAO coatings, with varying yttrium-to-aluminum content ratios, to fluorine-based plasma. These coatings were applied using the APS method and subsequently subjected to NF3/O2 gas. Our results revealed that a higher Al content ratio resulted in a decreased number of defects within the coating, which also led to selective etching at the initial Al2O3-rich sites, primarily creating relatively weak Al-F bonds and smaller particles. In particular, selecting an appropriate yttrium-to-aluminum content ratio significantly reduced the coating defects and enhanced the etch rate compared to coatings with a higher yttrium content ratio. This improvement was attributed to the balanced presence of Al-F and Y-F bonds. Furthermore, for coatings rich with the yttrium aluminum garnet (YAG) phase, the resistance to fluorine-based plasma was primarily influenced by the thickness of the APS-Y2O3 layer. This layer, used to augment adhesion to parts, relies on the low-temperature crystallization features of YAG. The findings of this study offer valuable insights for optimizing YAG coating in dry-etching processes requiring high-density APS coatings.

Synthesis of a water-stable CsPbBr3 perovskite for selective detection of mercury ion in water.

By using the method of low-temperature crystallization, CsPbBr3 perovskite nanocrystals (PNCs) coated with trifluoroacetyl lysine (Tfa-Lys) and oleamine (Olam) were synthesized in aqueous solution. The structure of the CsPbBr3 PNCs was characterized by many methods, such as ultraviolet (UV)-visible absorption spectrophotometer, fluorescence spectrophotometer, transmission electron microscopy (TEM), and X-ray diffraction (XRD) pattern. The fluorescence emission of the CsPbBr3 PNCs is stable in water for about 1 day at room temperature. It was also found that the fluorescence of the PNCs could be obviously and selectively quenched after the addition of mercury ion (Hg2+ ), allowing a visual detection of Hg2+ by the naked eye under UV light illumination. The fluorescence quenching rate (I0 /I) has a good linear relationship with the addition of Hg2+ in the concentration range 0.075 to 1.5 mg/L, with a correlation coefficient (R2 ) of 0.997, and limit of detection of 0.046 mg/L. The fluorescence quenching mechanism of the PNCs was determined by the fluorescence lifetime and X-ray photoelectron spectroscopy (XPS) of the PNCs. Overall, the synthesis method for CsPbBr3 PNCs is simple and rapid, and the as-prepared PNCs are stable in water that could be conveniently used for selective detection of Hg2+ in the water environment.

Constructing Intrapenetrated Hierarchical Zeolites with Highly Complete Framework via Protozeolite Seeding.

Creation of intrapenetrated mesopores with open highway from external surface into the interior of zeolite crystals are highly desirable that can significantly improve the molecular transport and active sites accessibility of microporous zeolites to afford enhanced catalytic properties. Here, different from traditional zeolite-seeded methods that generally produced isolated mesopores in zeolites, nanosized amorphous protozeolites with embryo structure of zeolites were used as seeds for the construction of single-crystalline hierarchical ZSM-5 zeolites with intrapenetrated mesopores (mesopore volume of 0.51 cm3 g-1 ) and highly complete framework. In this strategy, in contrast to the conventional synthesis, only a small amount of organic structure directing agents and a low crystallization temperature were adopted to promise the protozeolites as the dominant growth directing sites to induce crystallization. The protozeolite nanoseeds provided abundant nucleation sites for surrounding precursors to be crystallized, followed by oriented coalescence of crystallites resulting in the formation of intrapenetrated mesopores. The as-prepared hierarchical ZSM-5 zeolites exhibited ultra-long lifetime of 443.9 hours and a high propylene selectivity of 47.92 % at a WHSV of 2 h-1 in the methanol-to-propylene reaction. This work provides a facile protozeolite-seeded strategy for the synthesis of intrapenetrated hierarchical zeolites that are highly effective for catalytic applications.

Constructing Intrapenetrated Hierarchical Zeolites with Highly Complete Framework via Protozeolite Seeding

AbstractCreation of intrapenetrated mesopores with open highway from external surface into the interior of zeolite crystals are highly desirable that can significantly improve the molecular transport and active sites accessibility of microporous zeolites to afford enhanced catalytic properties. Here, different from traditional zeolite‐seeded methods that generally produced isolated mesopores in zeolites, nanosized amorphous protozeolites with embryo structure of zeolites were used as seeds for the construction of single‐crystalline hierarchical ZSM‐5 zeolites with intrapenetrated mesopores (mesopore volume of 0.51 cm3 g−1) and highly complete framework. In this strategy, in contrast to the conventional synthesis, only a small amount of organic structure directing agents and a low crystallization temperature were adopted to promise the protozeolites as the dominant growth directing sites to induce crystallization. The protozeolite nanoseeds provided abundant nucleation sites for surrounding precursors to be crystallized, followed by oriented coalescence of crystallites resulting in the formation of intrapenetrated mesopores. The as‐prepared hierarchical ZSM‐5 zeolites exhibited ultra‐long lifetime of 443.9 hours and a high propylene selectivity of 47.92 % at a WHSV of 2 h−1 in the methanol‐to‐propylene reaction. This work provides a facile protozeolite‐seeded strategy for the synthesis of intrapenetrated hierarchical zeolites that are highly effective for catalytic applications.

Mullite crystallization in zirconia incorporated aluminosilicate ceramics prepared from novel monophasic liquid precursor

This paper deals with the synthesis of a series of zirconoaluminosiloxane (ZAS) as monophasic liquid precursors in toluene for zirconia/mullite ceramics. Precursors are synthesized by the zirconium modification of aluminosiloxane. The effect of zirconium incorporation in the aluminosilicate network is studied by FTIR, NMR, and TG/DTA analysis. 29Si and 27Al clearly indicates that zirconium is chemically bonded to the aluminosilicate network and the network connectivity increases with increase in zirconium content. 27Al NMR also reveals the progressive distortion of octahedral symmetry of AlO6 due to zirconium incorporation, validating the insertion of Zr through Al–O–Zr bonds where Al is four coordinated. These observations attest the monophasic nature and the chemical homogeneity of the synthesized precursors, which is the main factor contributing to the low temperature crystallization of ceramic phases. Ceramic conversion studies of the precursors confirmed the formation of crystalline zirconia/mullite ceramic phases at a low temperature of 900 °C. The XRD and microstructure analysis by SEM/EDX indicated that the mullite crystallization can be controlled by zirconia incorporation. This effect is discussed in terms of the occupancy of zirconia either as intra-granular or inter-granular particles. The zirconia concentration for maximum crystallization of mullite is optimized.

Separation and recovery of zinc from blast furnace dust via coordination leaching of Cl− and hydrolysis of NH4+

Blast furnace dust (BFD) is a by-product of iron-making process, a typical hazardous waste containing abundant recyclable components. In this study, a NH4Cl cooperative coordination leaching method was proposed for the selective separation and recovery of zinc from BFD. The thermodynamic analysis results revealed that ZnO and ZnSO4 from BFD can be converted to zinc-chlorine coordination compounds (ZnCli2−i, i = 1,2,3,4) in the cooperative actions of NH4+ and Cl− ions. The experimental results showed that the leaching efficiency of zinc reached 85.64% while iron and carbon was enriched from 46.76% to 57.96% under the optimal experimental conditions. The leaching residue with a total content 2.53% of Zn, Cl, K and Na can be returned to sintering for the recovery of iron and carbon. Moreover, the XRD, SEM-EDS and chemical phase analysis results of BFD and residue demonstrated that a small amount ZnO, ZnS and ZnFe2O4 were not leached and remained in the leaching residue. Additionally, a novel method of low-temperature crystallization was adopted to recover zinc from filtrate. The crystallization efficiency of zinc reached 80.96% and the obtained crystal was confirmed to be special Zn(NH3)2Cl2. Thus, this work not only achieved the separation and recovery of zinc from BFD, but also solved the disposal problem of leaching residue and crystallization solution, providing a guidance for the resource utilization of hazardous BFD.

Thermomechanical Properties of High Oleic Palm Oil Assessed Using Differential Scanning Calorimetry, Texture Analysis, Microscopy, and Shear Rheology.

Standard Palm Oil (SPO) is widely used as a food ingredient partially due to its unique thermophysical properties. However, the American Heart Association recommends a saturated fat consumption of <5% of the caloric intake per day. The OxG Palm hybrid yields oil known as "palm oil with a higher content of oleic acid" (HOPO), with <35% SFA and >50% oleic acid. Characterizing novel high oleic oils is the starting point to find processes that can functionalize them such as oleogelation. This study compared the thermophysical properties of HOPO to SPO using Differential Scanning Calorimetry, shear rheology, polarized light microscopy, and texture analysis to characterize the differences between these oils. HOPO had a lower onset crystallization temperature (Δ7 °C) and its rheological behavior followed similar trends to SPO; however, large viscosity offsets were observed and were correlated to differences in crystallization temperatures. The maximum peak force of SPO was an order of magnitude higher than that of HOPO. Overall similar trends between the oils were observed, but differences in firmness, crystal morphology, and viscosity were not linearly correlated with the offset in crystallization temperature. This study quantified differences between these oils that will better enable industry to use HOPO in specific applications.

Tailoring the Nucleation and Crystallization Rate of Polyhydroxybutyrate by Copolymerization.

In the polyester family, the biopolymer with the greatest industrial potential could be poly(3-hydroxybutyrate) (PHB), which can be produced nowadays biologically or chemically. The scarce commercial use of PHB derives from its poor mechanical properties, which can be improved by incorporating a flexible aliphatic polyester with good mechanical performance, such as poly(ε-caprolactone) (PCL), while retaining its biodegradability. This work studies the structural, thermal, and morphological properties of block and random copolymers of PHB and PCL. The presence of a comonomer influences the thermal parameters following nonisothermal crystallization and the kinetics of isothermal crystallization. Specifically, the copolymers exhibit lower melting and crystallization temperatures and present lower overall crystallization kinetics than neat homopolymers. The nucleation rates of the PHB components are greatly enhanced in the copolymers, reducing spherulitic sizes and promoting transparency with respect to neat PHB. However, their spherulitic growth rates are depressed so much that superstructural growth becomes the dominating factor that reduces the overall crystallization kinetics of the PHB component in the copolymers. The block and random copolymers analyzed here also display important differences in the structure, morphology, and crystallization that were examined in detail. Our results show that copolymerization can tailor the thermal properties, morphology (spherulitic size), and crystallization kinetics of PHB, potentially improving the processing, optical, and mechanical properties of PHB.

Preparation of LiFe0.99Mn0.01PO4 Cathode Material with Lower Fe-Li Antisite via Wet-Lithiation Following by Tavorite-Olivine Phase Transition

Mn doping is widely used to improve the kinetic properties of LiFePO4 cathode materials. In this work, we synthesized LiFe0.99Mn0.01PO4 cathode material by a novel phase transition from the tavorite LiFePO4OH structure to the olivine LiFePO4 structure at 600 °C. A lower crystallization temperature not only results in a looser lattice for LiFePO4 material but also prevents crystal growth in higher temperatures and shortens the ion diffusion path. Experiments reveal that Mn doping can further broaden the lattice on this basis and thus ameliorate the Li+ diffusion property. The Density-Functional Theory (DFT) calculations not only support the above argument, but also predict that the LiFePO4 cathodes obtained from LiFePO4OH-to-LiFePO4 phase transition own lower Fe-Li antisite concentration (due to the high Fe-Li antisite formation energy of pre-lithiated precursor LiFePO4OH). As a result, the obtained LiFe0.99Mn0.01PO4 yields a discharge capacity close to the theoretical capacity of 169.2 mAh g−1 at a low rate of 0.2 C, 142.9 mAh g−1 at a high rate of 10 C and a capacity retention of 97.8% till 1000 cycles at 1 C. These findings indicate that the LiFePO4OH enabled by prelithiation in liquid provides a new idea for realizing substitution-modified LiFePO4 with optimal electrochemical performance.

In-situ growth of LiFePO4 with interconnected pores supported on carbon nanotubes via tavorite-olivine phase transition

Lithium iron phosphate (LiFePO4) has gained significant attention as a promising cathode material for lithium-ion batteries due to its excellent stability and safety characteristics. However, its relatively low electrical conductivity restricts its practical application in high-power devices. In this study, we propose a novel approach to improve the electrochemical performance of LiFePO4 cathodes by introducing carbon nanotubes (CNT) through an in-situ growth process. Firstly, CNT serve as nucleation sites for the growth of FePO4, which subsequently attaches and grows in situ on CNT, resulting in the precipitation of CNT/FePO4. Subsequently, pre-lithiation is performed to synthesize CNT/LiFePO4OH, which ensures efficient mass transfer and uniform reaction achieved by wet chemical lithiation process. Eventually,The improved lattice perfection of CNT/LiFePO4 is obtained through the tavorite-olivine phase transition at a low crystallization temperature, allowing for more favorable ion diffusion pathways. Furthermore, in conjunction with the uniform incorporation of CNT to enhance the overall conductivity of the composite, the presence of intrinsically interwoven pores entwined amidst a bedrock of LFP nanoparticles is unveiled. These intricately connected pores function as conduits, promoting the seamless diffusion of electrolyte across the composite structure. This, in turn, augments the interfacial engagement between the cathode and electrolyte, propelling a surge in electrochemical reactivity and harnessing a heightened level of electrochemical efficacy, thereby amplifying the overall electrochemical performance and efficiency. Electrochemical tests demonstrate that the CNT/LiFePO4 cathodes exhibit significantly prominent rate capability with 143.0 mAh g-1 at a rate of 20C, and remarkable cycling stability with a retention rate of ∼97.0% under 1000 cycles at 1C. The in-situ growth of CNT/LiFePO4 offers a simple and scalable approach for the modification of LiFePO4 cathodes, enabling the practical utilization of this promising material in high-performance lithium-ion batteries.

Flexible, high strength and low thermal conductivity of a novel high entropy oxide ceramic fiber membranes

Single-component oxide fibers encounter various issues, including grain transition growth and mechanical property degradation at high temperatures, which restrict their potential usage for high-temperature applications. The unique properties of high-entropy materials, including lattice distortion, sluggish diffusion, and cocktail effects, can effectively maintain small grains and excellent mechanical properties even in extreme conditions. Therefore, developing high-entropy oxide fibers provides a dependable solution to address the issues associated with single-component fibers. This paper successfully obtained the (Zr0.2Hf0.2Ti0.2Gd0.2Y0.2)O2-δ (ZHTGY) high-entropy oxide fibers by commencing from molecular design. Compared to other high entropy oxide materials, ZHTGY fibers exhibit a low crystallization temperature of 700 °C and exceptional high-temperature stability with no phase changes observed from RT to 1500 °C. In addition, the ZHTGY fiber membranes exhibit a density of merely 33 mg·cm−3, a tensile strength of 2.73 MPa@1000 °C, excellent flexibility, knot-free and fold-free properties, as well as the ability to bend freely even in environments with butane flame or liquid nitrogen. The ZHTGY fiber membranes have excellent thermal insulation properties due to their ultra-low density and high-temperature structural stability. With a thermal conductivity of only 25.7 mW·m−1K−1, an 8 mm thick sample laminated with these fiber membranes can reduce the temperature of a 1370 °C heat source to just 320 °C. The fiber membranes maintain good flexibility and strength even after heat treatment at 1200 °C for 50 h and 1400 °C for 180 s. This study provides a novel approach for preparing high-entropy oxidation fibers, thereby enabling the development of lightweight high-temperature thermal protection materials.

Defining the physical properties of blends of acetyl‐triacylglycerols derived from transgenic oil seeds

AbstractAcetyl‐TAG are unusually structured triacylglycerols (TAG) that possess an acetate group at their sn‐3 position. Acetyl‐TAG have different physical properties compared to regular TAG, including lower viscosity and improved cold temperature properties, making acetyl‐TAG useful for different applications, including as a diesel replacement. These unusual TAG molecules can be synthesized in the seeds of transgenic plants through the expression of diacylglycerol acetyltransferase (DAcT) enzymes isolated from different Euonymus species. In this study, the kinematic viscosity as well as the crystallization and melting behavior of blends of acetyl‐TAG and regular TAG were examined to define goals for acetyl‐TAG synthesis in transgenic plants. Even small amounts of regular TAG when blended with acetyl‐TAG had a disproportionate effect on the viscosity of mixture. This effect of regular TAG in increasing kinematic viscosity was more pronounced at lower temperatures. Under slow cooling conditions, the two different TAGs and their blends possessed two main crystallization events with different degree of separation of the thermal transition, and the lower crystallization temperature decreased with increasing amounts of acetyl‐TAG in the blend. At higher cooling rates, one broad and tailed crystallization peak was observed. Heating thermograms indicate similar polymorphic behavior of the blends and a general peak shift to lower transition range with increasing acetyl‐TAG compared to the two pure lipids. This information about the viscosity and thermal properties of blends of TAG and acetyl‐TAG will provide useful targets for engineering higher levels of acetyl‐TAG in transgenic seeds.

Silver substituted cobalt zinc ferrites as magnetic antimicrobials

Silver-substituted cobalt zinc ferrite series, CoxAg0.5-xZn0.5Fe2O4 (x = 0.4, 0.3, 0.2, 0.1), is synthesized using the citrate gel method, wherein ferrite formation is achieved at 600 °C. The low-temperature crystallization results in agglomerated and porous ferrites. In this sample preparation methodology, as the silver content in the series increases, metallic silver deposits at the grain boundaries, and vacancies are created at the octahedral sites. With a further increase in silver content, the magnitude of magnetic properties decreases. Antimicrobial activity increases and further decreases with an increase in silver content. The composition Co0.4Ag0.1Zn0.5Fe2O4 exhibits both magnetic and antimicrobial behaviour. These materials can potentially be beneficial in the manufacture of removable antimicrobial agents for water purification and drug delivery systems.