Decrease In Crystallization Temperature Research Articles

Thiourea crystal growth kinetics, mechanism and process optimization during cooling crystallization

In the cooling crystallization process of thiourea, a significant issue is the excessively wide crystal size distribution (CSD) and the abundance of fine crystals. This investigation delves into the growth kinetics and mechanisms governing thiourea crystals during the cooling crystallization process. The fitting results indicate that the crystal growth rate coefficient, kg, falls within the range of 10–7 to 10–8 m·s–1. Moreover, with decreasing crystallization temperature, the growth process undergoes a transition from diffusion-controlled to surface reaction-controlled, with temperature primarily influencing the surface reaction process and having limited impact on the diffusion process. Comparing the crystal growth rate, G, and the diffusion-limited growth rate, Gd, at different temperatures, it is observed that the crystal growth process can be broadly divided into two stages. At temperatures above 25 °C, 1/qd approaches 1, indicating the predominance of diffusion control. Conversely, at temperatures below 25°C, 1/qd increases rapidly, signifying the dominance of surface reaction control. To address these findings, process optimization was conducted. During the high-temperature phase (35–25 °C), agitation was increased to reduce the limitations posed by bulk-phase diffusion in the crystallization process. In the low-temperature phase (25–15 °C), agitation was reduced to minimize crystal breakage. The optimized process resulted in a thiourea crystal product with a particle size distribution predominantly ranging from 0.7 to 0.9 mm, accounting for 84% of the total. This study provides valuable insights into resolving the issue of excessive fine crystals in the thiourea crystallization process.

Contrasting magma chemistry in the Candelaria IOCG district caused by changing tectonic regimes

Iron oxide-copper-gold (IOCG) deposits are a vital source of copper and critical elements for emerging clean technologies. Andean-type IOCG deposits form in continental arcs undergoing extension, and they have a temporal relationship with magmatism although they do not exhibit a close spatial relation with the causative intrusions. The processes required to form IOCG deposits and their potential connections to iron oxide–apatite (IOA)-type mineralization remain poorly constrained, as well as the characteristics of magmatism linked to both deposit types. Here we combine zircon U–Pb geochronology with zircon trace element geochemistry of intrusive rocks associated with the Candelaria deposit, one of the world’s largest IOCG deposits, to unravel distinctive signatures diagnostic of magmatic fertility. Our results reveal a marked transition in the geochemistry of intrusions in the Candelaria district, characterized by changes in the redox state, water content and temperature of magmas over time. The oldest magmatic stage (~ 128–125 Ma), prior to the formation of the Candelaria deposit, was characterized by zircon Eu/Eu* ratios of 0.20–0.42, and redox conditions of ΔFMQ − 0.4 to + 1.0. The earliest magmatic stage related to the formation of Fe-rich mineralization at Candelaria (118–115 Ma) exhibits low zircon Eu/Eu* ratios (0.09–0.18), low oxygen fugacity values (ΔFMQ ~− 1.8 to + 0.2) and relatively high crystallization temperatures. In contrast, the youngest stage at ~ 111–108 Ma shows higher zircon Eu/Eu* (~ 0.37–0.69), higher oxygen fugacity values (ΔFMQ ~ + 0.4 to + 1.3) and a decrease in crystallization temperatures, conditions that are favorable for the transport and precipitation of sulfur and chalcophile elements. We conclude that Candelaria was formed through two distinct ore-forming stages: the first associated with a reduced, high temperature, water-poor magma developed under a low tectonic stress, followed by a more oxidized, water-rich, and low temperature magmatic event related to a compressional regime. The first event led to Fe-rich and S-poor IOA-type mineralization, while the second event with geochemical signatures similar to those of porphyry copper systems, generated the Cu- and S-rich mineralization. This late stage overprinted preexisting IOA mineralization resulting in the formation of the giant Candelaria IOCG deposit.

Facile synthesis of an Ni/LaAlO3 – Perovskite via an MOF gel precursor for the dry reforming of methane

A simple strategy to prepare the pure perovskite phase of lanthanum aluminate (LaAlO3) by calcination of a highly porous, dry MOF precursor gel has been developed. This study demonstrates that the structural and textural properties, such as specific surface area, pore volumes and pore sizes, of precursor-like metal–organic gels (MOG) (MOG-Al-La) based on metal–organic framework (MOF) structures can be modulated by optimizing the solvothermal treatment time. The perovskite obtained after solvothermal treatment at 120 °C for 12 h and calcination at 750 °C maintained the mesoporous characteristics of the MOF precursor, with a small particle size due to the decrease in crystallization temperature. These properties in the support allowed a good dispersion of the active Ni sites, low reducibility, and a strong interaction between them and the support, thus suppressing sintering under the severe catalytic reaction conditions evaluated (GHSV = 120,000 cm3/g·h) for the dry reforming of methane. The resulting MOX-(12 h)-LaAlO3-750-Ni catalyst gave a CH4 average conversion of 75% and CO2 average conversion of 80% after 20 h of reaction. The improved stability of the catalyst was attributed to suppression of the formation of the dense network of carbon filaments that can stress and subsequently fracture the support, cause attrition of the catalyst granules and hinder diffusion of the reactants both through the pores of the support and the interparticle spaces.

Valorization of Agricultural Waste Lignocellulosic Fibers for Poly(3-Hydroxybutyrate-Co-Valerate)-Based Composites in Short Shelf-Life Applications.

Biocircularity could play a key role in the circular economy, particularly in applications where organic recycling (composting) has the potential to become a preferred waste management option, such as food packaging. The development of fully biobased and biodegradable composites could help reduce plastic waste and valorize agro-based residues. In this study, extruded films made of composites of polyhydroxybutyrate-co-valerate (PHBV) and lignocellulosic fibers, namely almond shell (AS) and Oryzite® (OR), a polymer hybrid composite precursor, have been investigated. Scanning electron microscopy (SEM) analysis revealed a weak fiber-matrix interfacial interaction, although OR composites present a better distribution of the fiber and a virtually lower presence of "pull-out". Thermogravimetric analysis showed that the presence of fibers reduced the onset and maximum degradation temperatures of PHBV, with a greater reduction observed with higher fiber content. The addition of fibers also affected the melting behavior and crystallinity of PHBV, particularly with OR addition, showing a decrease in crystallinity, melting, and crystallization temperatures as fiber content increased. The mechanical behavior of composites varied with fiber type and concentration. While the incorporation of AS results in a reduction in all mechanical parameters, the addition of OR leads to a slight improvement in elongation at break. The addition of fibers improved the thermoformability of PHBV. In the case of AS, the improvement in the processing window was achieved at lower fiber contents, while in the case of OR, the improvement was observed at a fiber content of 20%. Biodisintegration tests showed that the presence of fibers promoted the degradation of the composites, with higher fiber concentrations leading to faster degradation. Indeed, the time of complete biodisintegration was reduced by approximately 30% in the composites with 20% and 30% AS.

4D printable maleated poly(styrene-b-ethylene/butylene-b-styrene) / Poly(ethylene-co-vinyl acetate) thermoplastic elastomer blends; effects of blend composition on shape memory and mechanical properties

Shape memory polymers are attracting attention in materials science with their responsive properties and their application areas are gradually developing. By adapting these materials to the additive manufacturing process, four-dimensional (4D) printing technology has been developed. In this study, novel thermo-responsive shape memory polymer blends were prepared for high temperature applications from commercially available polymers using maleated poly(styrene-b-ethylene/butylene-b-styrene) (SEBS-g-MA) and poly(ethylene-co-vinyl acetate) (EVA) and their applicability in three-dimensional (3D) printing was explored. The presence of SEBS-g-MA led to an increase in the degree of crystallization and glass transition temperature of EVA, accompanied by a decrease in crystallization temperature. As the EVA content increased, the blend morphology transitioned from droplet to co-continuous structure. Higher EVA content resulted in an increase in Young's modulus, but a decrease in tensile strength. Nevertheless, these blends exhibited exceptional elongation at break, surpassing 1200%. The blend comprising 70 wt% SEBS-g-MA and 30 wt% EVA demonstrated a synergistic effect, yielding the highest values for elastic modulus, creep resistance, and storage modulus. Furthermore, the blend with 60 wt% SEBS-g-MA and 40 wt% EVA exhibited optimal shape memory performance, achieving a shape fixing ratio of 93.1% and a shape recovery ratio of 98.7%. The conducted analyses demonstrated that the shape recovery of the produced blends could be adjusted according to temperature, and the blends were able to consistently replicate the shape memory effect across multiple cycles. A filament was manufactured for a 3D printer from the blend of 60 wt% SEBS-g-MA and 40 wt% EVA. Using this filament, 4D models having complex geometries were successfully printed. The produced models were able to maintain their temporary shapes to a significant degree. When triggered by heat, these models rapidly returned to their original shapes within a very short period.

Effect of Fluorosilicone Rubber on Mechanical Properties, Dielectric Breakdown Strength and Hydrophobicity of Methyl Vinyl Silicone Rubber.

Silicone rubber (SIR) is used in high-voltage insulators because of its insulation, and excellent hydrophobicity is very important in harsh outdoor environments. To enhance the hydrophobicity and low-temperature resistance of silicone rubber, methyl vinyl silicone rubber and fluorosilicone rubber (FSIR) blend composites with different ratios were prepared. The samples were characterized and analyzed using scanning electron microscopy, tensile testing, dynamic mechanical analysis and static contact angle testing. The results showed that after blending, SIR and FSIR were well compatible. FSIR had higher elastic modulus and reduced the tensile strength to some extent in SIR/FSIR composites. The addition of a small amount of FSIR made its crystallization temperature decrease from -30 to -45 °C, meaning that the low-temperature resistance was significantly improved. The breakdown strength of SIR/FSIR composites can still be maintained at a high level when a small amount of FSIR is added. The contact angle of the composites increased from 108.9 to 115.8° with the increase in FSIR content, indicating the enhanced hydrophobicity. When the samples were immersed in water for 96 h, the hydrophobicity migration phenomenon occurred. The static contact angle of the samples with less FSIR content had a weaker decreasing trend, which illustrated that the hydrophobicity was maintained at a high level.

Effect of Cr2O3 Content on the Viscosity and Crystallization Properties of Continuous Casting Mold Slag

Herein, the effect of Cr2O3 on the crystallization and flow behavior of CaO–SiO2–Al2O3–Na2O–CaF2 continuous casting mold slags is investigated. The viscosity in the slag at 1200–1500 °C is measured by the rotating cylinder method and a quantitative relationship between the viscosity and the Raman structure Q3/Q2 is constructed. The time–temperature–transformation and continuous cooling transformation diagrams for various slags are obtained using a single hot‐thermocouple technique. The results show that with the crystallization temperature decreases, it can be observed that the crystal growth mode gradually changes from 3D spherical and 2D massive to 1D needle‐like. The study finds the transition from network modifier to network forming agent in the slag for Cr2O3 content from 0 to 3 wt%. The Cr2O3 added to 1–2 wt% decreases the viscosity and promotes crystallization. The viscosity increases and the crystallization is inhibited when the content of Cr2O3 increases to 3 wt%. Meanwhile, when Cr2O3 is added to 3 wt%, the Cr2O3 crystalline phase precipitates except for the main crystalline phase 2CaO·SiO2.

Viscosity, crystallization temperature, phase composition, and structure of the low-basicity СаО–SiO2–B2O3–Cr2O3–Аl2O3–МgO slag system

The influence of B2O3 on viscosity, crystallization temperature, phase composition, and structure of fluorine-free slags of the СаО–SiO2–B2O3–2 % Cr2O3–3 % Аl2O3–8 % МgO system in the range of boron oxide content from 0 to 6% and basicity (B = CaO/SiO2 ) equal to 1.0 is studied by vibrational viscometry, phase composition thermodynamic modeling in combination with raman spectroscopy. It is found that boron oxide-free slag has the simplest structure, as indicated by the average amount of bridging oxygen BO equal to 0.73, and has a higher viscosity compared to boron-containing slags of 0.85‒0.60 Pa•s in the temperature range of 1400‒1450°C, and crystallization temperature of 1402°C. This is due to the high proportion of high-temperature compounds in the formed slag. The introduction of 2 to 6% boron oxide complicates the structure of the slag, which is accompanied by an increase in the average amount of bridging oxygen BO to 0.98 and 1.28, respectively. The resulting four-coordination structural elements [BO4], [CrO4] and [AlO4] are embedded in the silicon-oxygen lattice of the slag and complicate it, which increases the degree of polymerization. However, the formation of low-melting eutectics CaO•B2O3 and 2CaO•B2O3 after introduction of 2 and 6% boron oxide, despite the complexity of the structure of the formed slags, leads to a decrease in crystallization temperature to 1346 and 1265°C, an increase in the degree of slag superheating and a decrease in its viscosity to 0.9 and 0.55 Pa•s already at 1350°C. Thus, the addition of boron oxide to slag, despite the structure complication of the formed oxide system, leads to an increase in the liquid mobility of the slag due to the formation of a high proportion of low-temperature phases and a decrease in the proportion of medium- and high-temperature phases and a lower binding energy of boron with oxygen compared to silicon

Accelerated Laboratory Weathering of Polypropylene/Poly (Lactic Acid) Blends.

To solve the pollution problems that result from polypropylene (PP), suitable biopolymers such as poly (lactic acid) (PLA) were selected to blend with PP. Since PP/PLA blends are often exposed to the natural environment, it is necessary to study the photodegradation behavior of PP/PLA blends. In this paper, PP/PLA blends with different compositions were prepared by extrusion and subjected to the accelerated laboratory weathering equipment. The effects of compatibilizers on the degradation behavior of PP/PLA blends were also studied. The weatherability of PP/PLA blends was studied through weight loss, optical microscope, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results revealed that PP is easy to degrade than PLA during accelerated laboratory weathering. PP/PLA blends are susceptible to the accelerated laboratory weathering process, and PP-rich and PLA-rich blends reduce the weathering resistance. Moreover, the results indicate that the initial degradation temperature, melting temperature, and crystallization temperature decrease after weathering related to the decreased thermal stability of PP/PLA blends. For instance, the initial degradation temperature of PP/PLA8.2 reduces from 332.2 °C to 320.2 °C. Moreover, the compatibilized sample is generally more resistant to weathering conditions than the uncompatibilized one due to the higher compatibility of PP and PLA.

Dislocation mechanism of Ni47Co53 alloy during rapid solidification

Dislocations and other atomic-level defects play a crucial role in determining the macroscopic properties of crystalline materials, but it is extremely difficult to observe the evolution of dislocations due to the limitations of the most advanced experimental techniques. Therefore, in this work, the rapid solidification processes of Ni47Co53 alloy at five cooling rates are studied by molecular dynamics simulation, and the evolutions of their microstructures and dislocations are investigated as well. The results show that face-centered cubic (FCC) structures are formed at the low cooling rate, and the crystalline and amorphous mixture appear at the critical cooling rate, and the amorphous are generated at the high cooling rate. The crystallization temperature and crystallinity decrease with cooling rate increasing. Dislocations are few at the cooling rates of 1 × 1011 K/s, 5 × 1012 K/s, and 1 × 1013 K/s, and they are most abundant at the cooling rates of 5 × 1011 K/s and 1 × 1012 K/s, in which their dislocation line lengths are both almost identical. There appear a large number of dislocation reactions at both cooling rates, in which the interconversion between perfect and partial dislocations is primary. The dislocation reactions are more intense at the cooling rate of 5 × 1011 K/s, and the slip of some dislocations leads to the interconversion between FCC structure and hexagonal close packed (HCP) structure, which causes the twin boundaries (TBs) to disappear. The FCC and HCP are in the same atomic layer, and dislocations are formed at the junction due to the existence of TBs at the cooling rate of 1 × 1012 K/s. The present research is important in understanding the dislocation mechanism and its influence on crystal structure at atomic scales.

Decrease in crystallization temperature of β-Ga2O3 in nanowire structure

We have found that Ga2O3 nanowires (NWs) become β-type at about 600 °C, which is much lower than 900 °C known for bulk and thin films. The raw NWs were chemically synthesized at 70 °C in a flask. When the NWs were heat-treated at 400 °C or lower, ε-Ga2O3 was formed, and when heat-treated at 600 °C or higher, β-Ga2O3 was formed. The phase transition from ε-type to β-type occurred at around 500 °C during the temperature rise. Chemical synthesis and heat treatment was found to be low-cost methods for producing β-Ga2O3 NWs, which is expected to be applied to high-speed transistors and high-efficiency sensors.

Breakage behaviour and functionality of spray-dried agglomerated model infant milk formula: Effect of proteins and carbohydrates content

This study explored the effect of protein content (whey protein and casein) and carbohydrate content (lactose, sucrose, and maltodextrin) on the breakage behaviour and its influence on spray-dried agglomerated model infant milk formula. Whey protein powders were bigger in particle size, weaker in structural strength, and marginally more irregular in shape, which resulted in better rehydration properties but more breakage than pure casein powders. Similarly, sucrose samples had better rehydration properties and higher glass transition temperatures but suffered more breakage than maltodextrin and pure lactose powders because of their bigger particle size. The influence of proteins on breakage was greater than that of carbohydrates. Breakage changed the physical and structural properties of powders, especially for whey protein and sucrose samples, which caused the deterioration of rehydration properties and the decrease in crystallization temperatures. From the perspective of particle breakage, unwanted dairy powder breakage could be controlled by changing powder formulations.

Crystallization behavior and mechanical properties of high strength mica-containing glass-ceramics from granite wastes

The high-strength mica-containing glass-ceramics were prepared from granite wastes by bulk crystallization. The influences of SiO2/Al2O3 molar ratio (S/A = 7.72, 9.62, 12.58, 17.82 and 29.67) on the crystallization behavior, microstructure, mechanical properties and machinability of glass-ceramics were investigated. The results demonstrated that the polymerization degree of the glass network decreased with the S/A ratio increasing, which further caused the decrease in glass transition temperature and crystallization temperatures. The increase in the S/A ratio promoted the precipitation of diopside, hectorite, kalsilite and tainiolite in glass-ceramics when the samples were heated at 750 °C, while inhibiting the precipitation of forsterite. For the glass-ceramics crystallized at 800 and 900 °C, the main crystalline phases transformed from diopside, forsterite, and nepheline to diopside, kalsilite, and tainiolite, with the S/A ratio increasing. As the SiO2 gradually replaced Al2O3, the morphology of crystals changed from lamellar to granular, while the mean size of crystals reduced. The Vickers-Hardness values of glass-ceramics crystallized at 800 and 900 °C ascended with S/A ratio rising, and the values were above 6.30 GPa. The bending strength of most glass-ceramics is stable between 90 and 140 MPa, among which the maximum bending strength is 133.28 ± 14.81 MPa. The fracture toughness of the glass-ceramic crystallized at 800 and 900 °C declined, while that at 700 °C increased with a larger S/A ratio. Glass-ceramics after heat-treated at 900 °C with S/A ratio of 9.62 had the largest fracture toughness of 3.28 ± 0.15 MPa m1/2. In preliminary tests of machinability, glass-ceramic after heat-treated at 900 °C with S/A ratio of 9.62 showed better results.

Characterization of the incorporated SiO2 co-doped with Sr2+ and Tb3+ phosphors into PLA polymer matrix

SiO2 :0.4% Sr2+, x% Tb3+ (0 ≤ x ≤ 0.5) nanophosphor powders were prepared by sol-gel method. The powder samples were dispersed into the PLA polymer matrix through melt mixing method and compression molding to prepare the nanophosphor polymer composite. X-ray diffraction (XRD) patterns showed broad peaks with the position of the peaks shifting and more separating with an increase in Tb3+ concentration. The transmission electron microscope (TEM) images showed darker patches with the introduction of the nanophosphor, which indicates the incorporation of phosphor particles into PLA polymer. Differential scanning calorimeter (DSC) results revealed that the composites show an increase in the cold crystallization temperature (Tcc) and slight decrease in the glass transition temperature (Tg) as compared to the PLA. Thermogravimetric analysis (TGA) results showed that the thermal stability of the composites show an initial decrease with the incorporation of the fillers, but they become more thermally stable with higher Tb concentration in the fillers. Ultraviolet visible spectroscopy (UV–vis) results showed the decrease in transmittance for the composite compared to the PLA polymer. The photoluminescence (PL) results showed that the incorporation of the Sr2+doped SiO2 only affected the luminescence intensity, while co-doping with the incorporation of the Sr2+ and Tb3+ ions induced the emissions peaks at 487, 543, 582 and 621 nm, which could be attributed to the 5D4 → 7F3, 7F4, 7F5, and 7F6 transitions of Tb3+, respectively. The main aim of this study was to fabricate the light emitting polymer-based material.

Magma hybridization and crystallization in coexisting gabbroic and granitic bodies in the mid-crust, Akechi district, central Japan

Petrological and geochemical features of gabbros and fine-grained mafic rocks (mafic microgranular enclaves; MMEs) in the Inagawa Granite of the Ryoke Plutonic Complex were investigated to assess the interactions between coexisting mafic and silicic magmas, and the petrogenetic relationships between the MMEs and surrounding gabbros. The MMEs exhibit mingling textures that imply the coexistence of mafic and silicic magmas that did not undergo complete mixing, but the geochemical compositions of the MMEs require substantial hybridization and homogenization. The gabbroic rocks exhibit disequilibrium textures and mineral compositions, such as quartz–hornblende ocellar textures and patchy plagioclase crystals with bimodal anorthite contents. These textures and compositions record an abrupt decrease in crystallization temperature and mechanical mixing between crystallizing gabbroic mush and silicic (granitic) melt. Geochemical variations of the gabbroic rocks can be explained by hybridization and fractional crystallization (HFC) processes between crystallizing gabbroic mush and granitic melt. Extrapolation of the mixing trend to a basaltic composition suggests that the primitive mafic end-member was a low-K basaltic magma. Given that HFC yields magnesian andesite by the addition of a small amount of silicic melt to a primitive mafic end-member, the compositional modification of mafic magmas by magma mixing might be an essential process in the formation of andesitic magma in arc crust.

Investigation of Polycaprolactone/Carboxymethyl Cellulose Scaffolds by Mechanical and Thermal Analysis

The objective of this work was to learn more about three-dimensional porous scaffolds made from biomaterial based on polycaprolactone (PCL) containing different amounts of carboxymethyl cellulose (CMC) nanoparticles. Composite material samples containing 0, 2, 6.5, 11, 15.5, and 20% w/w of CMC and PCL/CMC scaffolds were prepared with the use of the salt particle leached technique. The mechanical properties were evaluated with the compressive strength analysis method. The studied temperature range started at very low temperatures and ended at crosslinking temperatures. It was evaluated using the thermal analysis methods of Differential Scanning Calorimetry (DSC) in the range 0ºC-200ºC. The results revealed that the compressive modulus of blended PCL/CMC scaffold was higher than the one of pure PCL scaffold (582.2±106.2 kPa for pure PCL scaffold and 612.2±296 kPa for blended scaffold which contained 20% of CMC). For DSC analysis, in addition to the 15.5% w/w CMC PCL/CMC composite scaffold, other proportions of composite materials showed a decrease in crystallization temperature. The crystallinity of PCL-20% CMC was higher than that of PCL scaffolds.

Morphological Evolution from Open Cells to Reticulated Structures in Moderately Branched Polybutylene Terephthalate Foamed Using Supercritical CO2

A simple and feasible method is proposed to fabricate thermoplastic reticulated foams, which are commercially valuable materials applied in the areas of environmental protection, impact absorption, and tissue engineering. The key to achieving the evolution from open‐cell (OC) foam to reticulated foam is to match the melt strength of the polymer with the driving force of the cell growth. Therefore, herein, a small amount of triglycidyl isocyanurate (TGIC) containing three epoxy groups reacts with linear polybutylene terephthalate (PBT) to form a branched structure to finely control the melt strength. The crystallization temperature and crystallization rate decrease with the formation of branched PBT. Based on these findings, a cooling batch foaming method is designed and applied at different foaming pressures to prepare reticulated foams. As the TGIC content decreases from 0.2 to 0.05 phr, closed cells, conventional OCs, reticulated cells, and collapsed cells are observed in turn. Reticulated PBT foams with an OC content of 91.1% and a volume expansion ratio (VER) of 17.5 are formed in the PBT/TGIC0.15 sample in optimum foaming conditions. In addition, conventional OC foams with an OC content of 95.1% and VER of 34.3 are also obtained in PBT/TGIC0.2 sample.

Electric field-induced crystallization of ferroelectric hafnium zirconium oxide

Ferroelectricity in crystalline hafnium oxide thin films is strongly investigated for the application in non-volatile memories, sensors and other applications. Especially for back-end-of-line (BEoL) integration the decrease of crystallization temperature is of major importance. However, an alternative method for inducing ferroelectricity in amorphous or semi-crystalline hafnium zirconium oxide films is presented here, using the newly discovered effect of electric field-induced crystallization in hafnium oxide films. When applying this method, an outstanding remanent polarization value of 2P_{mathrm{R}} = 47 upmuC/cm^{2} is achieved for a 5 nm thin film. Besides the influence of Zr content on the film crystallinity, the reliability of films crystallized with this effect is explored, highlighting the controlled crystallization, excellent endurance and long-term retention.

Effects of crystallization temperature on the characteristics of sugar crystals in date fruit syrup as measured by differential scanning calorimetry (DSC), polarized microscopy (PLM), and X-ray diffraction (XRD).

Characteristics of sugar crystals are important for developing set-syrup due to their contribution to the desired mouth feel when consumed. Two types of set-syrup (i.e. seeds with and without) were developed by storing the syrup at -20, 4 and 15°C. The melting temperatures (onset and peak), and enthalpy of set-syrup without seeds (SN) were 30.2°C, 74.6°C and 42.2kJ/kg respectively. In the case of SN, enthalpy decreased with the decrease of crystallization temperature (P < 0.05), while there was insignificant change in the case of set-syrup with seeds (SW) (P > 0.05). Polarized Light Microscopy (PLM) images showed that finer crystals were formed in the cases of set-syrups (i.e. SN and SW) as the storage temperature was decreased. X-ray diffraction (XRD) analysis showed the formation of different polymorphic sugar crystals. Crystallization temperatures at 4 and -20°C can be used to produce finer crystals with varied polymorphic characteristics.

Utilization of Talc as a Nucleating Agent in Poly(Lactic Acid) and Poly(Butylene Succinate) Blend

In this paper, poly(lactic acid) (PLA) was modified with poly(butylene succinate) (PBS) and talc to obtain PLA formulation with good toughness and high crystallization rate. PBS was added as a toughening agent at 40wt% and talc was added as a nucleating agent from 2 to 10wt%. Experimental results showed that both the tensile modulus and strength of PLA significantly decreased with the presence of PBS. Both values were found to notably increase with talc concentration and reached the maximum value at 8wt%. The tensile elongation at break was found to remarkably increase with PBS blending. However, it was linearly dropped with talc addition. Thermal test results also indicated the faster crystallization rate with the decreased crystallization temperature (Tc) and increased degree of crystallinity (Xc), by more than four times, when talc was added at least 4wt%. The isothermal crystallization half-time (t1/2) was applied to provide the data for injection molding process. The results showed that neat PLA required more than 25 min to obtain its half crystallinity. Minimum t1/2 of 3.45 min was obtained when talc was added to PLA/PBS at 8wt%. Heat distortion temperature (HDT) was also found to increase from 56.8 (neat PLA) to 97.2°C (8wt% talc). Based on the experimental results, the optimum talc concentration was 8wt% which provided the highest crystallization rate and thermal stability. The practical application of this formulation is for the biodegradable injection molding products.