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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. [ABSTRACT FROM AUTHOR]

The performance of sustainable polymers can be modified and enhanced by incorporating functional groups in the backbone of the polymer chain that increases intermolecular interactions, thus impacting the thermal properties of the material. However, in-depth studies on the role of intermolecular interactions on the crystallization of these polymers are still needed. This work aims to ascertain whether incorporating functional groups able to induce intermolecular interactions can be used as a suitable systematic strategy to modify the polymer thermal properties and crystallization kinetics. Thus, amide and additional ester groups have been incorporated into aliphatic polyesters (PEs). The impact of intermolecular interactions on the melting and crystallization behavior, crystallization kinetics, and crystalline structure has been determined. Functional groups that form strong intermolecular interactions increase both melting and crystallization temperatures but retard the crystallization kinetics. Selecting appropriate functional groups allows tuning the crystallinity degree, which can potentially improve the mechanical properties and degradability in semicrystalline materials. The results demonstrate that it is possible to tune the thermal transitions and the crystallization kinetics of PEs independently by varying their chemical structure. [ABSTRACT FROM AUTHOR]

In this work, a series of K 2 O–MgO–B 2 O 3 –P 2 O 5 (KMBP) glasses were prepared by the melt-quenching method and the glass-ceramics were prepared by the one-step heat treatment. The thermal, structural, physical and optical properties, as well as the crystallization behaviour of the KMBP system, were investigated in detail using characterization techniques such as DSC, XRD, SEM, FTIR, transmittance spectroscopy and microhardness. As indicated by DSC, the thermostability and glass-forming ability were gradually enhanced through the partial substitution of K 2 O by MgO. XRD showed that the main crystalline phases of the glass-ceramics (GC) were gradually converted from the P –Mg–K–O based crystalline phases to the P –Mg–O based and the P –Al–O based crystalline phases. The SEM results indicated that tiny grain-like crystals were successfully precipitated from the parent glasses after heat treatment. The deconvoluted FTIR spectra results showed a gradual conversion of the [BO 3 ] and [PO 3 ] units towards the [BO 4 ] and [PO 4 ] units with the increase of the MgO contents. The increase in the degree of glass network polymerization was the essential reason for the increment in the microhardness of the parent glasses. The microhardness of GC featured a trend concordant with the crystallinity of the crystalline phases. The values of metallization criteria (M C) between 0.34 and 0.45, as well as the higher values of third-order nonlinear polarizability (χ (3)) and nonlinear refractive index (n nl) are indicative of the good suitability of the KMBP glasses for the nonlinear optical applications. [ABSTRACT FROM AUTHOR]

In the present study, the fatty acid composition (FAC), triacylglycerol (TAG) composition, crystallization, and melting behaviors of mango kernel fats (MKFs) extracted from seven Ivorian mango varieties—Amelie (AM), Kent (KT), Palmer (PR), Keitt (KI), Brooks (BR), Dadiani (DI), and Djakoumankoun (DN)—were characterized by complementary techniques: pNMR, DSC, polarized light microscopy, and X-ray diffraction. Regardless of the variety, Ivorian MKF is rich in stearic (St) and oleic (O) fatty acids. (72–84% of the total FA), with three main TAGs: StOSt (23.9–45.8%), StOO (15.5–25.8%), and StLSt (10.4–12.5%). Their crystallization onset temperature (Tco) ranged from 15 to 20 °C. All samples showed complete melting around 35 °C, except DN (~ 38 °C). The β-polymorph appeared to be the most predominant and stable polymorph for the seven MKFs. The thermal properties investigated were linked to monounsaturated and triunsaturated triacylglycerol content, indicating the significant influence of chemical composition. The fine analysis of the results allows the seven Ivorian varieties to be divided into four groups, based on both their physical properties and thermal behavior, and the StOSt wealth: hard high-StOSt fat (DN), half-hard medium-StOSt fat (DI, BR), soft low-StOSt fat (KT, PR, KI), and very-soft very-low-StOSt fat (AM). The seven investigated mango varieties from Ivory Coast might offer a wide range of applications in food, pharmaceutical, and cosmetic industries. [ABSTRACT FROM AUTHOR]

Glass foams and glass-ceramic foams exhibit great potential in thermal insulation of buildings, consequently reducing the necessity for heating or cooling, and ultimately contributing to energy saving. In this study, we prepared glass-ceramic foams utilizing silicate glass as starting material and CaCO 3 as foaming agent through a thermochemical process. Foams with varying degrees of relative crystallinity were produced by controlling temperature and duration of isothermal heat treatment. The foaming mechanism in the glass-ceramics was discussed by analyzing how the heat flow, mass, and volume evolve within the powder mixture during dynamic heating. The crystallization in glass did not show any clear trend on the compressive strength of glass foams. On the other hand, the thermal conductivity of the glass-ceramic foams increases with increasing relative crystallinity. The calculated solid thermal conductivity exhibited a minimum at low relative crystallinity (<20 %). These findings are crucial for designing high performance glass-ceramic foams for thermal insulation, potentially also for fabricating glass-ceramic foams using waste glasses. [ABSTRACT FROM AUTHOR]

A fundamental understanding of crystallization behavior is essential for the processing of both virgin and recycled polymers. This research delves into the crystallization characteristics and non‐isothermal crystallization kinetics of recycled polyethylene terephthalate (rPET) and its blends with poly butylene terephthalate (PBT), which have been modified using epoxy‐based multifunctional chain extenders (CE). The preparation of rPET/PBT blends involved a twin‐screw extruder, with varying weight ratios and different CE concentrations. Differential scanning calorimetry was employed to perform crystallization analysis on the samples. The results underscore the profound impact of blend composition on the thermal characteristics of the system, with CE exerting only a marginal influence. The glass transition temperatures (Tg) of the two polymers were measured at 49 and 79°C. During blending, the Tg values demonstrated variations relative to the proportions but did not adhere to the Fox equation. Furthermore, PBT was found to enhance the crystallization tendencies of rPET, resulting in an increase in relative crystallinity from 11% to 36%. Notably, the crystallization rate of PBT at 0.40 min−1 exceeded that of rPET at 0.36 min−1. PBT minimally affected the crystallization rate constant of rPET‐dominant blends, while rPET significantly reduced the crystallization rate in PBT‐dominant blends. [ABSTRACT FROM AUTHOR]

This study investigated the effects of mechanical recycling on the crystallization, mechanical, thermal, and rheological properties of recycled high‐density polyethylene (rHDPE), as well as vHDPE/rHDPE pellets and films made by different compositions. The results confirmed the presence of contaminants in rHDPEs, and the crystalline diameter of rHDPE is smaller than that of virgin high‐density polyethylene (vHDPE), with diameters ranging from 0.60 to 0.72 μm. The content of 75 wt% vHDPE in rHDPE film could repair the defects of crystalline morphology to approximate that of vHDPE films and significantly improve the elongation at break. The temperature required for the transition from crystalline to amorphous state of rHDPE film was 2°C lower than that of vHDPE, and the crystallization time and crystallinity declined compared to that of vHDPE. For rheological performance, the apparent shear viscosity and melt fluidity of rHDPE were worse than those of vHDPE. The blending of low rHDPE with vHDPE is a feasible option not only to reduce plastic waste but also to maintain acceptable properties of the blend composition. [ABSTRACT FROM AUTHOR]

This paper is dedicated to studying the effect of replacing molybdenum with vanadium on the tendency to amorphisation, structure, and thermal properties of high-entropy alloys of the (Fe0.25Ni0.25Co0.25Cr0.125Mo0.125‑xVx)100‑yBy system, where x = 0; 0.0625; 0.125 and y = 17–25. The alloy structure was analyzed using X‑ray diffraction, scanning and transmission electron microscopy methods. Thermal properties were determined by differential scanning calorimetry. It was found that the replacement of molybdenum with vanadium leads to the formation of crystalline particles of complex nitrides (V, Cr, Mo)(N, B) in the ribbon structure. The dependences of the characteristic alloy temperatures have been established. Molybdenum replacement with vanadium was shown to stabilize the supercooled liquid in alloys with completely amorphous structure. [ABSTRACT FROM AUTHOR]

The glass composition (70-x)PbO-(30-y)B2O3-(x+y)AlF3, where x and y ranges from 0 to 20 mol%, were prepared using the conventional melt-quenching-annealing technique. The structural and thermal properties of the glasses were comprehensively analyzed using techniques like Differential Thermal Analysis (DTA), Dilatometry, Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). XRD confirmed the amorphous, non-crystalline structure of the glasses. The glass network was found to be composed of structural units such as PbO4, BO4, BO3 and AlO6 using FTIR spectroscopy. FTIR analysis revealed significant structural changes, including the transformation of BO4 to BO3 units and the increase in non-bridging bonds, particularly with higher AlF3 content. DTA was instrumental in determining characteristic temperatures, such as the glass transition, melting, and peak crystallization temperatures, along with glass stability parameters (ΔT, Hr, Tgr) for all samples. The study found that the addition of AlF3 led to a decrease in these characteristic temperatures when replacing B2O3, but an increase when replacing PbO. Variations in the density and thermal expansion of the lead borate glass were observed upon the addition of AlF3, decreasing when substituting for PbO and increasing when substituting for B2O3. These findings provide insights into the properties of oxyfluoride glasses, paving the way for future optimization in their composition for varied applications. [ABSTRACT FROM AUTHOR]

The physicochemical properties of anhydrous milk fats (AMF) often change according to different regions and seasons, inevitably affecting dry fractionation. This study analyzed the differences in the fraction yields and physicochemical characteristics of four AMFs from different sources. The results showed that single-stage dry fractionation conducted at 25 °C easily separated AMFs into liquid fractions (L25) and solid fractions (S25) via pressure filtration, both producing satisfactory yields. Moreover, all L25s exhibited few crystals with good fluidity at 25 °C, while S25s presented as semi-solids supported by β crystal networks with a certain hardness and plasticity. However, four AMFs displayed fractionation efficiency variation, while the thermal differences among them showed no obvious correlation with those among their fractions. Generally, more trisaturated triglycerides with 48 to 54 carbon atoms in the AMF increased the S25 yield and decreased the slip melting points (SMP) of both fractions.

The main purpose of this work is to present the effect of long-chain branching and specific α-nucleation on the optical properties, crystallization and supermolecular structure of polypropylene (PP). Commercially available α-nucleating/clarifying agent 1,3;2,4-bis(3,4-dimethylbenzylidene)sorbitol (Millad 3988) was mixed into linear PP and long-chain branched PP (LCB-PP) in the concentration of 0.2 wt%. For the study of polymorphic composition, crystallinity, and crystallization process under isothermal conditions in the temperature range of 130–150 °C, differential scanning calorimetry and wide-angle X-ray scattering were used. Although the used nucleating/clarifying agent appears to have a slight effect on the optical properties of long-chain branched polypropylene, it does not appear to affect the crystallization kinetics significantly. LCB-PP exhibited self-nucleation, favored over nucleation by a specific nucleating agent.

Cerium is a well-known surrogate to trivalent and tetravalent actinides and has been investigated to explore the structural and thermal characteristics of simulated radwaste-loaded material systems. The solubility and distribution of CeO 2 into a sodium niobium phosphate glass have been explored with the objective of developing a host matrix for radioactive waste immobilization. Niobium phosphate glasses of (100-x) (40Na 2 O–20Nb 2 O 5 –40P 2 O 5)-xCeO 2 (x = 0, 1, 3, 5, 8, and 10 mol%) compositions are prepared by melt-quenching method and are characterized by X-ray diffractometry (XRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and scanning electron microscopy (SEM). This study summarises the influence of cerium ion incorporation on the structure, thermal stability, and formation of crystalline phases of the niobium phosphate glass. The various glass stability parameters, such as Hruby (K H), Weinberg (K W), and Lu–Liu (K LL) parameters are estimated to assess the stability of the glass melt against devitrification in the supercooled region. The spectroscopic analysis ascertains the presence of metaphosphate and pyrophosphate networks as primary structural building units in the glass. However, the Raman analysis demonstrates the influence of CeO 2 on the network linkages arising from the corner-sharing of NbO 6 octahedrons and Nb–O–P bonding in the glass. The CeO 2 loading is optimized up to 8 mol% into the base 40Na 2 O–20Nb 2 O 5 –40P 2 O 5 glass matrix without precipitation of any crystalline phase. The glasses are heat treated to obtain glass-ceramics embedded with the crystalline phases, namely, monazite CePO 4 , NbOPO 4 , NaNbO 3 , and niobium phosphate bronze Na 6 Nb 8 (PO 4) 5 O 15. The microanalysis of these glass ceramics shows that the CeO 2 is more aggregated inside the niobium phosphate bronze framework than in the bulk at a higher temperature. It is also observed that the surface crystallization process is a prevalent mechanism for the crystallization of glasses on heating at crystallization onset temperature. [ABSTRACT FROM AUTHOR]

This study explores the impact of different levels of halloysite nanotubes (HNT) and d-isomer on the non-isothermal crystallization behavior of the polylactic acid (PLA). The processing conditions, thermal flow, molecular orientation and the presence of nanofillers can affect the crystallinity and properties of PLA. In this work, PLA-based nanocomposite filaments were produced and their crystallization kinetics was studied. The data obtained through experiments, using differential scanning calorimetry at various cooling rates, were analyzed employing the Jeziorny and Mo models. And the activation energy of crystallization was determined by the Friedman method. The results showed that the growth of PLA crystals is three-dimensional, the HNT can accelerate the crystallization process, and crystallization occurs at higher temperatures in the presence of flow. The activation energy increased with addiction of more HNT in the nanocomposite. The study also found that the d-isomer has a more significant influence on the crystallization of PLA than HNT, which can inhibit crystal formation in some cases. These findings provide insights into the factors that can influence the properties of PLA nanocomposites and how they can be optimized. [ABSTRACT FROM AUTHOR]

Biodegradable poly (lactic acid) (PLA) as a great substitute for petroleum-based plastics was widely used to reduce environmental pollution resulted by greenhouse gas emissions. However, the practical application range of PLA was limited due to the inherently poor crystallization, mechanical and heat resistance properties. In this context, a heterogeneous nucleating agent (HNA) was incorporated into PLA matrix to address the problems mentioned above. The effects of HNA on the crystallization kinetics of PLA were explored by Avrami method. Isothermal and nonisothermal crystallization kinetics of PLA/HNA systems containing various HNA contents (0–0.75 wt.%) proved that HNA could generate the heterogeneous nucleation of PLA matrix and effectively improve its crystallization rates. The t1/2 of PLA/HNA-0.75 composite decreased to 2.35 min compared with 34.12 min for pure PLA at isothermal temperature of 135 °C. The crystallinity of PLA/HNA-0.75 composite was enhanced by 42.1% in contrast with pure PLA. The "shish-kebab" structure of PLA/HNA composites containing various HNA contents (0.25–0.75 wt.%) was observed by polarized optical microscope as the concentration of HNA exceeded 0.375 wt.%. PLA/HNA-0.75 composite possessed the highest unnotched izod impact strength (33.6 kJ/m2), notched izod impact strength (4.3 kJ/m2) and heat deformation temperature (73.2 °C). In general, a feasible method was proposed for preparation of PLA with excellent mechanical and heat resistance properties through this work. [ABSTRACT FROM AUTHOR]

Macromolecule entanglements are common in polymers. The first part of this review describes their influence on the properties of entangled polymers. Then, methods for reducing the entanglement density of macromolecule chains are discussed. It has been shown that research on partially disentangled polymers has provided a lot of new information about the relationship between the entangled state and properties of polymers. This research concerns, among others, mechanical and thermal properties and the crystallization process. A special disentangled polymer case, ultra-high-molecular-weight polyethylene, is also discussed. The results of research on polymer composites in which macromolecules were disentangled via processing and composites were produced using already disentangled polymers are presented in particular detail. It has been indicated that such composites and blends of disentangled polymers are promising and will probably be intensively researched in the near future. [ABSTRACT FROM AUTHOR]

The thermal properties and alignment of crystallinity of materials in thin films play crucial roles in the performance and reliability of various devices, especially in the fields of electronics, materials science, and engineering. The slight variations in the molecular packing of the active layer can make considerable differences in the optical and thermal properties. Herein, we aim to investigate the tuning of the physical properties of a blended thin film of n-type small organic molecules of perylene-3,4,9,10-tetracarboxylic acid (PTCA-SMs) with the mixing of the p-type polymer poly(3-hexylthiophene) (P3HT). The resulting thin films exhibit an enhanced surface crystallinity compared to the pristine material, leading to the formation of long crystallites, and these crystallites are thermally stable in the solid state, as confirmed by X-ray diffraction (XRD), atomic force microscopy (AFM), and thermal analysis using variable-temperature spectroscopic ellipsometry (VTSE) and differential scanning calorimetry (DSC). We believe that the crystalline structure of the obtained P3HT/PTCA-SMs blends is a combination of edge-on and face-on orientations, which enable the potential use of this material as an active layer in organic electronics. [ABSTRACT FROM AUTHOR]

We have developed an analytical method to quantitatively analyze differential scanning calorimetry (DSC) experimental data. This method provides accurate determination of thermal properties such as equilibrium melting temperature, latent heat, change of heat capacity which can be performed automatically without intervention of a DSC operator. DSC is one of the best techniques to determine the thermal properties of materials. However, the accuracy of the transition temperature and enthalpy change can be affected by artifacts caused by the instrumentation, sampling, and the DSC analysis methods which are based on graphical constructions. In the present study, an analytical function (DSCN(T)) has been developed based on an assumed Arrhenius crystal size distribution together with instrumental and sample-related peak broadening. The DSCN(T) function was successfully applied to fit the experimental data of a substantial number of calibration and new unknown samples, including samples with an obvious asymmetry of the melting peak, yielding the thermal characteristics such as melting and glass transition temperature, and enthalpy and heat capacity change. It also allows very accurate analysis of binary systems with two distinct but severely overlapping peaks and samples that include a cold crystallization before melting. [ABSTRACT FROM AUTHOR]

Chalcogenide glasses are unquestionably one of the most popular materials known for their phase change property. Phase change materials (PCM) have a key role in the field of photonics, memory devices, imaging, etc. With an aim to study the worth of ternary Sb10Se90-xGex (x = 0, 19, 21, 23, 25, 27) and quaternary Sb10Se65Ge25-yIny (y = 0, 3, 6, 9, 12, 15) chalcogenide systems as PCM, the composition variation and effect of dopants on the thermal properties of two systems has been probed. The thermal stability of two glass systems has been investigated using criteria such as the S parameter, fragility index, and rate constants at glass transition and crystallization temperatures. The mechanism of the phase change phenomenon occurring in the glasses has been studied using the Avrami index. [ABSTRACT FROM AUTHOR]

In this study, the semi-aromatic poly (decamethylene terephthalamide) acid (PA10T) and an array of PA10T/1010 with various copolymerization content of the third monomer 1,10-decanedioic acid (DCA) were synthesized using a productive one-step melt polycondensation method. Importantly, the addition of DCA's effect for PA10T on crystallization behaviors, thermal properties, and mechanical performances were extensively investigated. Additionally, the results of DSC demonstrate that all the melting temperature of PA10T/1010 copolyamides are significantly lower than PA10T by introducing the third monomer DCA, and the heat stability has been not significantly affected according to the results of TGA, suggesting the improvement of processing properties. Besides, compared with PA10T, the bending modulus, breaking elongation, tensile strength, and izod impact strength of PA10T/1010-1 all increase obviously, when the feed ratio of DCA and terephthalic acid (PTA) is 10:90. Thus, introducing bio-based DCA for copolymerization is a promising method to enhance both the processing and mechanical properties of PA10T. [ABSTRACT FROM AUTHOR]

A range of industrial propylene‐based elastomers (PBEs) were investigated to disclose the relationship between the ethylene/propylene sequences distribution and the performance. The results of carbon‐13 nuclear magnetic resonance and Raman spectroscopy indicated that the majority of propylene sequences existed as isotactic polypropylene (iPP) segments and the stochastic insertion of ethylene sequences mainly in the form of ethylene–propylene (EP) segments. In this case, the amorphous EP chain segments joined by iPP crystals served as physical cross‐linking points, while the completeness of iPP crystallines was disturbed by the presence of ethylene sequences. Eventually, the ratios of imperfect short crystalline were gradually raised with the increasing ethylene contents, and even noncrystalline when the ethylene contents were higher than 15%. Accordingly, the features of these short crystalline networks played a decisive role of the mechanical properties of these PBEs. It was revealed that the higher contents of PPP segments led to more stiffness of PBEs. Therefore, the excessive insertion of ethylene sequences negatively affected the crystallization and mechanical performances of PBEs, and the optimal ethylene content was about 10%–15%. Additionally, in the case of similar molecular sequences, low‐molecular weight had adverse effect on strength or stiffness. [ABSTRACT FROM AUTHOR]

The anti‐moisture absorption and thermal properties of bio‐based polyamide 56 (PA56) were improved by adding heat‐resistant agents to expand its application in the automotive field. Two macromolecular heat‐resistant agents, p(N‐(4‐F‐phenylmaleimide)‐alt‐styrene) (PFS) and p(N‐(4‐F‐phenylmaleimide)‐alt‐triallyl isocyanurate) (PFT), were synthesized via precipitation polymerization, and their effects on the thermal properties, mechanical properties, and anti‐moisture absorption of PA56 were studied. Compared with PA56, the heat deflection temperature of PA56/PFS and PA56/PFT composites was improved by 11.9% and 21.2%, with their anti‐moisture absorption increasing by 14.6% and 15.5%, respectively. This is due to the crystallization of PA56 has been promoted and its more complete crystal structure has been obtained. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) is a biodegradable polyester, but its low crystallization rate and excessive embrittlement limit its application. Decanedioic acid 1,10‐bis (2‐benzoylhydrazide) (TMC‐300) as an effective nucleating agent of PLA will induce PLA epitaxial crystallization and improve the crystallization rate of PLA. This article studied the promoting behavior of TMC‐300 with different contents in composite systems on PLA crystallization. The results showed that with the increase of TMC‐300 content, the crystallinity can be significantly increased, up to 22 times, and t1/2 significantly decreases. Meanwhile, with the addition of TMC‐300, the typical spherical crystal morphology of PLA gradually became attached to TMC‐300 fibrous crystal morphology. In terms of mechanical properties, the tensile strength reached its maximum at 0.5 wt% of TMC‐300 content, increasing from 60.60 MPa (PLA) to 74.59 MPa (0.5‐TMC‐300), an increase of 23.09%. At this time, due to the reduction in spherical crystal size, the elongation at break also increased significantly. However, the thermal stability of PLA composites deteriorated with the increase of nucleating agent content due to the low thermal decomposition temperature of TMC‐300 itself, and the Tmax decreased from 372°C (PLA) to 353°C (5‐TMC‐300), a decrease of 19°C. [ABSTRACT FROM AUTHOR]

In this work, the effect of uniaxial stretching on the crystallization and melting behaviors, miscibility, crystal structure, and mechanical properties of neat poly(L-lactide) (PLLA) and miscible PLLA/poly(vinyl acetate) (PVAc) blends was investigated. Stretching process could generate remarkable influence on thermal properties of neat PLLA and PLLA/PVAc blend. With stretching ratio increasing, macromolecular chains orientation and crystallization were promoted, resulting in a decrease in cold crystallization temperature and an increase in glass transition temperature, and a significant increase in crystallinity. In addition, after stretching process PVAc still inhibited the crystallization of PLLA. PLLA/PVAc blends were completely miscible blend system which had only one glass transition temperature before and after stretching process, and phase separation did not occur after stretching process. When stretch ratio increased, amorphous PVAc had greater influence on the tanδ transition peak and storage modulus increased markedly, which was benefit to the improvement of heat resistance. The α′ crystal form was produced in blends after stretching process. Stretching process with moderate stretch ratio can be utilized to improve the mechanical properties of PLLA with simultaneous enhancement of tensile strength, fracture strain and stiffness. The findings in this work provide an insightful understanding of the effect of stretching process on miscible PLLA blend and the improvement of toughness, which will facilitate the large-scale practical application of PLLA. [ABSTRACT FROM AUTHOR]

Bioactive glasses (BGs) are promising materials for bone regeneration due to their ability to bond with living bone tissue. However, thermal stability and mechanical properties of BGs need improvement for better clinical performance. In this paper, we present an overview of the influence of different ions on the sintering and crystallization of BGs. Specifically, this review focuses on the impact of thermal treatments on the crystallization of 45S5 and other significant BG compositions. Potential applications of these thermally treated BGs, such as scaffolds, BG-based composites, and thermally sprayed coatings, are explored. Moreover, the substitution of ions has been investigated as a method to enhance the thermal properties of BGs. Notably, zinc, potassium, and strontium have been studied extensively and have demonstrated promising effects on both the thermal and the mechanical properties of BGs. However, it is important to note that research on ion inclusion in BGs is still in its early stages, and further investigation is necessary to fully comprehend the effects of different ions on sintering and crystallization. Therefore, future studies should focus on optimizing the ion substitution method to improve the thermal, mechanical, and even biological properties of BGs, thereby enhancing their potential for various biomedical applications. [ABSTRACT FROM AUTHOR]

Novel heavy-metal oxide glasses with different compositions, specifically (80-x)PbO– xBi2O³–10B2O3–10SiO2, where x ranges from 0 to 60 mol%, were synthesized using a conventional melt-quenching technique. The amorphous nature of these glasses was confirmed through X-ray diffraction analysis. Additionally, infrared spectra were obtained for the prepared samples to explore their structural characteristics. Differential thermal analysis was performed to investigate the characteristic temperatures of the glasses, including the glass transition temperature, melting temperature, onset crystallization temperature, and peak crystallization temperature. The addition of Bi2O3 shifts the characteristic temperatures to higher values and affects the crystallization process and phases formed. Parameters like ΔT, KH, and KSP are used to evaluate and quantify glass stability. Dilatometric measurements demonstrated that substituting PbO with Bi2O3 in the glass composition resulted in an increase in glass transition temperature and dilatometric softening temperature, as well as a decrease in the coefficient of thermal expansion. Furthermore, we determined the density and calculated the molar volume of the samples. These findings deepen our understanding of the thermal behavior, glass stability, and structure-property relationships in lead borosilicate glasses with Bi2O3, facilitating the development and customization of glass compositions with desired thermal and physical characteristics for specific applications. [ABSTRACT FROM AUTHOR]

Bio-based semi-aromatic poly (decamethylene terephthalamide) acid (PA10T) and a series of poly (decamethylene terephthalamide/hexamethylene terephthalamide) (PA10T/6 T) were synthesized by an efficient one-pot melt polymerization reaction. The chemical structures of the obtained samples were evaluated by fourier infrared spectroscopy (FT-IR). And the influence of addition of 1,6-hexanediamine (HAD) for copolyamides PA10T/6 T on melting points, thermal behaviors, crystallization performances, and mechanical characteristics of PA10T and PA10T/6 T were also analyzed thoroughly. The thermal analysis demonstrates that PA10T/6 T possess excellent thermal stability, and the melting temperatures can be tuned effectively by adding a suitable copolymerization content of the third monomer HAD to improve the processing properties appropriately. POM and XRD were used to research the crystallization behaviors showing that the addition of HAD did not alter the crystalline structure of PA10T essentially. Mechanical properties such as bending modulus and tensile strength of PA10T/6 T remarkably improved with increased HAD content. Moreover, this work provides an approach for preparing plant-derived semi-aromatic copolyamides PA10T/6 T, and these copolyamides exhibit outstanding processing performances, wider processing temperature range, high thermal stability, adjustable mechanical characteristics, and excellent comprehensive properties. [ABSTRACT FROM AUTHOR]

In this work, the thermal stability of a BaO–CaO–SiO 2 –B 2 O 3 glass sealant, named "H", was investigated by differential scanning calorimetry (DSC). The crystallization behavior of glass H as the sealant matrix was investigated by a combination of experimental X-ray diffraction (XRD) analysis and thermodynamic simulation with the FactSage package. A good agreement was found between the Rietveld refinement of XRD experiments and the FactSage simulation. Particular attention was also given to the influence of the Sr 2 SiO 4 filler added to the glass matrix "H" on the thermal expansion and microstructures of glass-Sr 2 SiO 4 composites by means of dilatometry and scanning electron microscopy (SEM). The reinforced 20 wt% Sr 2 SiO 4 composite (HS2S20) showed excellent properties and, thus, its joining performance was investigated using SrTi 0.75 Fe 0.25 O 3-δ (STF25) and Aluchrom as promising oxygen transport membrane (OTM) and counterpart, respectively. The joining behaviors were investigated by comparing different joining temperatures. 920 °C is the best joining temperature for HS2S20 sealant. [ABSTRACT FROM AUTHOR]

The ytterbium-aluminate microspheres with yterbium-aluminium garnet composition doped by 0.25, 0.5, 0.75, 1.0, 3.0 and 5.0 mol.% of Er 2 O 3 were prepared by combination of sol-gel method and flame synthesis. The prepared systems were mostly X-ray amorphous with the presence of traces of ytterbium-aluminium garnet phase (YbAG), and ytterbium oxide. The thermal analysis of prepared systems shows crystallization of the prepared systems in the temperature interval 914–984 °C in one or two steps, depending on the Er content. Ytterbium aluminate garnet was found to crystallize as the prevailing phase in all heat-treated samples. An almost pure red up-conversion photoluminescence emission with the intensity influenced by the Er 2 O 3 content was observed in prepared systems. [ABSTRACT FROM AUTHOR]

Through isoconversional analysis of differential scanning calorimetry data, thermally induced processes of glass transition and crystallization in Cux(As2Se3)100-x chalcogenide glasses (x =1, 5, 10, and 15 at.%) were investigated. The characteristic values of activation energy and its changes during the processes were calculated using the advanced isoconversional method developed by S. Vyazovkin as well as isoconversional forms of Kissinger and Moynihan relations. The results showed the variation of the activation energy with the extent of conversion. The activation energy values are slightly changing with the increase of Cu content from 1 to 5 at.%, while more significant changes are detected after a further increase of Cu content up to 15 at.%. The crystallization processes of As2Se3 in composition with 1 at.% of Cu and CuAsSe2 and Cu3AsSe4 in composition with 10 at.% of Cu were analyzed. Isoconversional analysis showed that crystallization is a complex process and that the apparent activation energy of crystallization of As2Se3 and CuAsSe2 structural units decreases with the extent of conversion increase. [ABSTRACT FROM AUTHOR]

The aim of the study was to study the effect of cheap bio-based monomer 2,5-thiophenedicarboxylic acid on poly(butylene furandicarboxylate). Bio-based copolyesters were successfully synthesized by two-step melt polycondensation using 2,5-thiophenedicarboxylic acid (TDCA), 2,5-furandicarboxylic acid (FDCA) and 1,4-butanediol (BDO). Compared with FDCA, the price of TDCA is lower. The main purpose of this study is to add different amounts of TDCA to reduce the cost of polyester and to investigate the effect of TDCA on the properties of poly(butylene furandicarboxylate) (PBF). It can be determined that the expected copolymers were indeed synthesized by FTIR and 1H NMR spectra. DSC and WAXD results suggested that PBFTF27, PBFTF51 and PBFTF77 show isodimorphism behaviors. Because the angle between two carboxyl groups in TDCA is larger than that of FDCA, and the electronegativity of sulfur atom is weaker than that of oxygen atom, the glass transition temperature decreases due to the increase in the flexibility of the chain with the increase in TDCA. Compared with PBF, the toughness of poly(butylene 2,5-thiophenedicarboxylate) (PBTF) and copolyesters increased significantly. Poly(butylene furandicarboxylate-co-butylene 2,5-thiophenedicarboxylate) can be used in the packaging applications. [ABSTRACT FROM AUTHOR]

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Polycarbonate (PC) foam is a versatile material with excellent properties, but its low thermal stability limits its application in high-temperature environments. The aim of this study was to improve the thermal stability of PC foam by adding glass fibers (GF) and to investigate the effect of GF on PC crystallization behavior and PC foam cell morphology. This study was motivated by the need to improve the performance of PC foams in various industries, such as construction, automotive, and medical. To achieve this goal, PC/GF composites were prepared by extrusion, and PC/GF composite foams were produced using a batch foaming process with supercritical carbon dioxide (SC-CO2) as the blowing agent. The results showed that the addition of GF accelerated the SC-CO2-induced crystallization stability of PC and significantly increased the cell density to 4.6 cells/cm3. In addition, the thermal stability of PC/GF foam was improved, with a significant increase in the residual carbon rate at 700 °C and a lower weight loss rate than PC matrix. Overall, this study highlights the potential of GF as a PC foam reinforcement and its effect on thermal and structural properties, providing guidance for industrial production and applications. [ABSTRACT FROM AUTHOR]

Charge transport in electrostatically doped poly[benzimidazobenzophenanthroline]‐BBL thin films in a field‐effect transistor geometry were investigated in the temperature range 150 K < T < 370 K. At low temperatures activation and hopping transport mechanisms dominated, while phonon scattering dominated at high temperatures. The activation energies (EA) were found to lie in the range 140 meV < EA < 400 meV implying the existence of deep traps within the polymer bandgap of 1.8 eV. Two quasi‐linear dependencies of EA on the gate voltage (Vg) were observed with EA decreasing as Vg increased. An unexpected "metallic‐like" transport characteristic appeared for T > 335 K which depended on Vg. Enhanced electron delocalization combined with increased carrier density could be responsible for this "metallic‐like" behavior. Our results show that the existence of deep traps with multiple energy distributions, combined with increased carrier density led to the unusual temperature dependence of charge transport observed in BBL. [ABSTRACT FROM AUTHOR]

The structural and thermal properties of sodium niobium phosphate glass are studied to analyse its suitability for immobilizing long-lived radioactive waste from nuclear reprocessing plants. Two series of sodium niobium phosphate glasses such as (A) xNb2O5–(50−x)Na2O–50P2O5 and (B) xNb2O5–(50−x/2)Na2O–(50−x/2) P2O5 (x = 0, 10, 20, 30, 40 mol.%) are prepared by the conventional melt–quenching technique. The influence of the incremental addition of Nb2O5 on the structural and thermal properties of the above two series is investigated. The FTIR and Raman spectra of these glasses revealed that the number of [NbO6] octahedral chain increases with Nb content and dominates as the major structural unit over the number of PO4 tetrahedra unit. The glass transition temperature (Tg), crystallization temperature (Tc) and melting temperature (Tm) are measured by using a differential scanning calorimeter (DSC). Other thermal stability parameters such as Hruby (KH), Angell (KA), Saad–Poulain (KSP) and Weinberg (KW), the total relaxation time of transformation and fragility are evaluated and compared between different composition of glasses. For both series A and B, the glass transition temperature increases with Nb content, suggesting the formation of a larger number of P–O–Nb or Nb–O–Nb linkages compared to the PO4 tetrahedra, resulting in a more rigid network. This is confirmed by Raman spectra which show an increase in the number of Nb–O–Nb bonds with Nb content. The major crystalline phases formed by devitrifying these glasses are identified by XRD and are found to be mainly NaPO3, NbOPO4, Na2Nb6P4O26 and Na4Nb8P4O32. [ABSTRACT FROM AUTHOR]

This work is a first attempt to study the crystallization behavior of ethylene-vinyl alcohol copolymer with 44 mol% of ethylene units (EVOH44) and to observe the supermolecular structures developed during its crystallization. Thermal analysis has evidenced a very fast crystallization and the formation of different crystal populations during isothermal crystallization. In-situ wide-angle X-ray scattering experiments using a synchrotron radiation source have shown a unique orthorhombic morphology, independently of the crystallization conditions. Small spherulites (with an average radius of about 1 μm) were observed using polarized optical microscopy and confirmed by typical four-leaf patterns obtained by small-angle light scattering. In-situ atomic force microscopy has revealed stacked lamellae growing from common centers to form small spherulitic entities. Finally, studies of isothermal crystallization have evidenced the existence of partial crystallization (especially at high crystallization temperatures) and the need for higher undercooling to complete crystallization.

Polyhedral oligomeric silsesquioxane POSS nanoparticles can be applied as reinforcing additives modifying various properties of biodegradable polymers. The effects of aminopropylisobutyl POSS (amine-POSS), trisilanolisooctyl-POSS (HO-POSS) and glycidyl-POSS (Gly-POSS) on the viscoelastic, thermal properties and crystallization of biodegradable poly(ε-caprolactone) PCL were studied. The analysis of the viscoelastic properties at ambient temperature indicated that aminopropylisobutyl POSS (amine-POSS) and glycidyl-POSS (Gly-POSS) enhanced the dynamic mechanical properties of PCL. The increase in the storage shear modulus G′ and loss modulus G″ was observed. The plasticizing effect of trisilanolisooctyl POSS (HO-POSS) due to the presence of long isoctyl groups was confirmed. As a result, the crystallization of PCL was facilitated and the degree of crystallinity of χc increased up to 50.9%. The damping properties and the values of tan δ for PCL/HO-POSS composition increased from 0.052 to 0.069. The TGA results point out the worsening of the PCL thermal stability, with lower values of T0.5%, T1% and T3%. Both HO-POSS and Gly-POSS facilitated the relaxation of molten PCL. The presence of Gly-POSS influenced the changes that occurred in the viscoelastic properties of the molten PCL due to the thermo-mechanical degradation of the material; a positive impact was observed. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) has shown two different crystalline structures, namely a and a' when cooled down from the melt state. However, a-PLA has shown significant improvement in the barrier and mechanical properties of PLA. Although the effect of some nucleating agents on phase transformation of the PLA has been determined in the past, this is the first attempt, the effect of the starch nanocrystals on the formation of polymorphic crystal structure of PLA was evaluated. In this framework, the effect of lactic acid grafted starch nanocrystals (SNCs-g-LA) concentrations on the phase transition, and crystallization behavior of PLA/SNCs-g-LA nanocomposites at different isothermal crystallization temperatures (Tc) were studied. The results indicate that SNCs-g-LA nanoparticles promote the degree of crystalline transition to yield the highly crystalline ordered a-PLA. Further, the half-time crystallization (t1/2) of PLA composites was calculated by the Avrami equation. The t1/2 of PLA was minimum by adding 5 wt% SNCs-g-LA nanoparticles, and it decreased from 10.4 to 3.9 min. The growth rate of the spherulite morphology of PLA composites showed a significant improvement in the crystalline structure of PLA/SNCs-g-LA (5 wt%) nanocomposites as well. Finally, small angle X-ray scatting (SAXS) analysis showed that the inclusion of 5 wt% grafted SNCs resulted in the increment of the long period (Lac) as well as crystal layer thickness (Lc). [ABSTRACT FROM AUTHOR]

Effects of annealing temperature (Ta: 80–140°C) and time (ta: 3‐30 h) on the crystalline phase transition in poly(lactic acid) (PLA) were studied by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). In the DSC curves, the sample annealed at Ta = 80°C with time interval (ta: 10–30 h) demonstrates a peculiarly small exothermal peak (Texo) around 130°C, just prior to the melting point, corresponding to the disorder‐to‐order (α'‐to‐α) phase transition, while the sample annealed at temperature (Ta: 90–110°C) shows a double melting behavior considered as the α'‐α phase transition. Towards low temperatures, the glass modulus Eg reported by DMA thermograms, shows an important increase (~30,000 MPa) at Ta = 80°C for ta = 3 h, due to the extremely high self‐nucleation density in low‐crystallized PLA materials. After a sharp drop to 3600 MPa at Ta = 110°C, a marked improvement of Eg (15,900 MPa) is observed around Ta = 120°C for all samples, regardless of time ta. This interesting effect (improvement of Eg in the range Ta = 100–120°C) can be correlated with the grow of crystallinity in the same domain of Ta, and the α'‐α phase transition Ta (Ta: 90–110°C) determined by the double Tm melting DSC peak, which is confirmed by the increase of Tg for Ta = 90–110°C. [ABSTRACT FROM AUTHOR]

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Covalent adaptable networks (CANs) exhibit recyclability such as reprocessing, but it's a challenge to address the contradiction between reprocessing rate and performance. Here, pendent aliphatic chain anhydride monoesters are innovatively introduced into epoxy CANs based on transesterification, which efficiently accelerates the reprocessing without sacrificing thermal and mechanical properties. The transesterification rate is raised on account of the flexible aliphatic chain‐promoted segment movement and dynamic transfer auto‐catalysis. When the carbon number reflecting the length of the pendent chain is 12, the epoxy CAN exhibits the fastest stress relaxation or reprocessing. Computation via molecular dynamics simulation demonstrates that the increased segmental mobility from the pendent aliphatic chains contributes to enhanced reprocessability. Interestingly, the crystallization of the pendent aliphatic chains maintains or even improves the thermal and mechanical properties. Thus, introducing a flexible and crystallizable aliphatic side chain is an innovative and efficient approach to accelerate dynamic reactions and network arrangement while improving performance. [ABSTRACT FROM AUTHOR]

In this work, poly(ethylene glycol) (PEG)/boron nitride nanosheets (BNNS) masterbatch was prepared by freeze-drying their ultrasonically homogenized aqueous suspension, followed by melt-mixing with poly(lactic acid) (PLA) to fabricate the nanocomposites. The effect of PEG and BNNS on the crystallization behavior of PLA was investigated. The dynamic mechanical properties, thermal conductivity and thermal stability of the nanocomposites were also evaluated. It was found that, under quiescent conditions, PEG and BNNS had a synergistic effect on accelerating the nonisothermal crystallization of PLA. Unexpectedly, under injection molding conditions, the combination of PEG and BNNS had a negative effect on PLA crystallization. This can be ascribed to the plasticizing effect of PEG, which relaxes the orientation of PLA chains and retards flow-induced crystallization. Dynamic mechanical analysis (DMA) showed that the presence of BNNS enhanced the heat resistance of PLA only when PLA was crystallized, while further incorporation of PEG had a negative effect. Nevertheless, simultaneous use of PEG and BNNS had a synergistic effect on enhancing the thermal conductivity of PLA. [ABSTRACT FROM AUTHOR]

Gum acacia (GA) based gel electrolyte was cross-linked with polyvinyl alcohol (PVA) in the presence of different concentrations of NaOH salt for the preparation of stable, biodegradable and saprophyte-free gel matrix, and characterized them with ionic conductivity, pH, FTIR and TGA studies. The maximum ionic conductivity (σ = 4.39 mS/cm at 30 °C) has been observed for GA-PVA based gel electrolyte containing lower concentration of NaOH salt and the analyte reaches toward neutral pH region as compared to acidic nature of gum acacia-based gel electrolyte in deionized water having ionic conductivity of 4.99 mS/cm at 30 °C. Physical cross-linking for better jellification has been analyzed through FTIR and thermogravimetric analysis (TGA). FTIR spectra of GA-PVA based gel electrolyte indicate the stability of the gel matrix at nearly neutral pH region and undergo complex decomposition with the influence of higher salt concentrations. Thermal stability and thermal behavior of gel electrolytes were investigated under non-isothermal conditions by thermogravimetric analysis and differential thermogravimetry (DTG), and the obtained results exhibit variations in the glass transition temperature (Tg) suggesting the miscibility of the compositions and also support the existence of compatibility of such system. Gel electrolyte with suitable composition indicates better stability near neutral pH region and small change in ionic conductivity over the temperature range of 10–70 °C make them suitable and applicable for many solid-state ionic device applications. [ABSTRACT FROM AUTHOR]

Blend oils composed by leaf lard (LL) and cottonseed oil stearin (COS) were prepared and the thermal property, microstructure and crystallization of these blends were investigated in the present study. Solid fat content (SFC), thermal behaviors, triacylglycerols composition, crystal structure and morphology of the LL and COS blends were determined by pulsed nuclear magnetic resonance (pNMR), differential scanning calorimetry (DSC), high-performance liquid chromatography (HPLC), X-ray diffractometer (XRD) and polarized light microscope (PLM), respectively. SFC profiles and iso-solid diagrams indicated that SFCs of all blends were almost close to the weighted averages of the fat components at temperatures beyond 20°; however, below 20°, SFCs of blends exhibited higher than those of the weighted averages of the fat components. With the content of COS increasing, palmitic acid and linoleic acid in the blends increased, while stearic acid and oleic acid decreased; monounsaturated-disaturated (USS) and triunsaturated (UUU) glycerides in the blends enhanced, while monosaturated-diunsaturated (UUS) glycerides declined. The melting temperature of the blends decreased with the increase of COS content. The crystal forms in LL were ß' and ß, and the packing pattern was double and triple chain length (2L and 3L). With COS in blends increasing, ß' form crystals and 3L pattern reduced. Polarized light micrographs showed that the number of crystal particles in the blends raised with the increase of COS content, meanwhile, the grainsize of the sample gradually decreased. Visual appearances of the blends indicated that blending LL with COS could efficiently reduce the graininess of LL. The addition of COS had a significant effect on the crystallization behavior of LL. LL presented one-step crystallization at 10° and 20°, while COS showed two-step crystallization at 10° and one-step crystallization at 20°. However, the blends exhibited obvious two-step crystallization at 10°, one-step or slight two-step crystallization at 20°. [ABSTRACT FROM AUTHOR]

In this paper, the properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) PHBV/bio-based engineering polyester elastomer (BEPE) compounds were studied through analyzing their rheological properties, crystallization properties, mechanical properties, thermal properties, and microstructure. The results indicated that the number of PHBV spherulites increased along with a decrease in their size due to the hydrogen bonding, chain entanglement, and similar main chain structures between PHBV and BEPE, resulting in better compatibility and dispersion. When 30 wt% BEPE was added, the compounds achieved maximum elongation at break and impact strength, increasing by 589.2% and 149.4%, respectively, compared to pure PHBV. The crystallinity of the compounds decreased with the addition of BEPE, and their impact fracture surface tended to be rough along with a "brittle-ductile" transition according to the morphological observation. [ABSTRACT FROM AUTHOR]

Currently, it is still a huge challenge to prepare high performance eco-friendly poly(lactic acid) (PLA) with high thermal stability, good processability, excellent crystallization behavior, good transparency and highly-efficient fire safety. In this paper, a novel bio-based nucleation agent N-(furan-2-ylmethyl)- P , P -diphenylphosphinic amide (FPPA) was prepared and used for the fabrication of fire safety PLA/FPPA composites. The chemical structure of FPPA was measured by FTIR, NMR and MS. Further, the crystallization behavior, thermal stability, fire safety and mechanical properties of PLA/FPPA composites were performed by TGA, DSC, polarization microscope, LOI, UL94, cone calorimeter, DMA and, SEM, Raman, GC–MS, and TGA-FTIR. The results showed that the multifunctional FPPA not only had a high thermal stability and was a good nucleation agent for PLA. Moreover, only loading of 3 wt% FPPA increased the LOI of PLA from 19.0 to 33.8 % with UL-94 V-0 classification. Furthermore, the heat release rate and total heat release values of PLA/3%FPPA composite reduced by 6.3 % and 15.3 % in cone-calorimeter test. Such high fire safety was mainly attributed to specific fire safety radicals due to thermal degradation of FPPA to interrupt composites burning in gas phase. Besides, transparency and mechanical properties were almost not changed because of low loading of FPPA in PLA. This multifunctional bio-based fire-retardant for PLA with good comprehensive performance promises broad application in engineering electronics, automobiles, 3D printing and construction materials. [ABSTRACT FROM AUTHOR]

Carbon nanotube/continuous carbon fiber–reinforced poly(etherketoneketone) (CNT/CCF/PEKK) prepreg tapes were prepared by the wet powder impregnation method, and then the prepreg tapes were molded into laminates. The effects of carbon nanotubes on the mechanical properties, conductivity, thermal conductivity and crystallinity of the composites were studied by universal testing machine, thermal conductivity and resistivity tester, dynamic mechanical analyzer (DMA) and differential scanning calorimeter (DSC). The results show that when the content of carbon nanotubes is 0.5 wt% (relative to the mass of PEKK resin, the same below), the flexural strength and interlaminar shear strength of the laminates reach the maximum, which are increased by 15.99% and 18.16%, respectively, compared with the laminates without carbon nanotubes. The results of conductivity and thermal conductivity show that the higher the content of carbon nanotubes, the better the conductivity and thermal conductivity of the material. DSC results show that the addition of CNT promoted the crystallization of PEKK in the material and decreased the cold crystallization of PEKK. DMA results show that the deformation resistance of the material can be improved by adding an appropriate amount of CNT and the bonding between CF and PEKK can be enhanced, while excessive CNT destroys this phenomenon. [ABSTRACT FROM AUTHOR]

Polypropylene (PP)−poly(ethylene oxide) (PEO) nanocomposites were prepared by tensile drawing of PP films in water–ethanol solutions containing PEO with molecular masses of 4, 20, and 200 kDa via environmental crazing (EC). EC of PP films is accompanied by the development of nanoporous structure, which is loaded with the PEO component. The content of PEO in the PP − PEO nanocomposites can achieve 40%. Crystallization of PEO within the nanoporous PP matrix proceeds under the conditions of the confined space: as a result, the degree of crystallinity and melting temperature of PEO are markedly reduced. This effect appears to be more pronounced as the molecular mass of PEO increases. The direction of orientation of the PEO crystalline lamellae also depends on the molecular mass of PEO. The prepared PP‐PEO composites with new thermophysical properties of PEO can be used as gas‐separation membranes as well as in microelectronics and electrochemical devices. [ABSTRACT FROM AUTHOR]

Basalt fiber can be used as a reinforcing phase to improve the mechanical properties of wood thermoplastic composites. The purpose of this study was to use differential scanning calorimetry to study the effect of the addition of basalt fiber and wood flour on the non-isothermal crystallization kinetics of high-density polyethylene (HDPE)-based composites. The Avrami method and Avrami–Ozawa method were adopted to describe the non-isothermal crystallization process, and Gaussian model was used to calculate the surface activation energy. This study showed that the addition of basalt fiber and wood flour significantly changed the crystallinity of wood flour/high-density polyethylene (HDPE)/basalt fiber three-phase composites. The apparent activation energy of the three-phase composites was calculated using Gaussian multi-peak simulations, and the trend of the conversion rate was modeled. In addition, basalt fiber and wood flour, as nucleating agents, had the ability to accelerate the crystallization of wood flour/high-density polyethylene (HDPE)/basalt fiber three-phase composites without changing the crystallization mechanism of these composite materials. [ABSTRACT FROM AUTHOR]

A cost-effective solution for the synthesis of high-porosity TiO2 aerogels, which can be used as a mesoporous perovskite network charge-carrier material during the manufacture of solar cells, is described. The effects of the synthesis parameters (precursor (titanium (IV) isopropoxide (TIP) and tetrabutyl orthotitanate (TBOT)), additional solvent exchange (n-hexane (nH), cyclohexane (CH), and diethyl ether (DE)), subcritical drying (800 mbar vacuum, 70 °C, 8 h), aging, and calcination on the aerogel's structure have been investigated. Methods of XRD, FT-IR, BET, Raman, STA, SEM, UV–vis, and thermal conductivity measurements were applied to find out the relation between the synthesis conditions and the properties of the synthesized aerogels. Amorphous aerogels are polydispersed systems with the highest probability of pore diameter from 0.5 to 15 nm. An nH-exchanged, aged aerogel synthesized from the precursor TIP shows the highest diameter of pores. After calcination, the aerogels tend to crystallize into an anatase phase and the size of the crystallites depends on the precursor's nature. Calcination leads to a significant increase in both the apparent and true density of the aerogels, and it also results in an increase in porosity and thermal conductivity. [ABSTRACT FROM AUTHOR]