Wrinkling prediction and controlling for the hot stamping of plain weave CF/PEEK prepreg in the molten state

Conductive media in which ions carry charge through a solution are foundationally important to batteries, supercapacitors, and ionotronic devices. Shifts in ion mobility imposed by physical changes in the solution can dynamically impact the conductivity of the medium. This paper reports a class of temperature-responsive phase-change organogels in which a polymer network is formed within salt solutions in organic solvents with melting points between room temperature and 100 °C. The conductivity in the molten state (up to ∼10-4 to 10-3S/cm) exceeded that in the frozen state by over 10000-fold and remained stable after holding at 90 °C for 3 h or over 100 freezing/melting cycles. A diverse range of salts can be used, and the conductivity/temperature relationship can be tuned by selecting or mixing solvents with different melting points. Depending on the solvent composition, these phase-change organogels can either produce approximately digital (binary) thermal responses to function as switches or respond continuously as analog temperature sensors or other transducers. An advantage of this strategy over prior literature is that the identity of the charge carrier and the phase behavior of the solvent can be tuned independently, presenting a wide design space for electrolyte materials whose conductivity responds to temperature.

Boron oxide (B2O3) has recently emerged as a promising metal-free catalyst for the oxidative dehydrogenation (ODH) of methane, with remarkable selectivity for formaldehyde (HCHO) and carbon monoxide (CO) at 823 K. Since B2O3 melts at ∼725 K, the ODH reaction is likely to proceed in its molten state. In 2023, ab-initio molecular dynamics simulations by Rousseau and co-workers revealed that molten B2O3 comprises of 8-, 6-, 4-membered cyclic B-O-B sites and a B-B site. So herein, we carried out a detailed DFT-based mechanistic investigation for CH4 oxidation across these structural motifs with 1O2 and 3O2. Due to the multireference character of 1O2 and its associated species, CASSCF/NEVPT2 methodology was employed. Among all motifs, the B-B site exhibits superior catalytic activity toward HCHO formation (36.6kcal mol-1), while cyclic B-O-B sites require significantly higher activation barriers (∼ 50 to 78kcal mol-1). Orbital analysis reveals that electron transfer in cyclic B-O-B sites originates from oxygen lone-pair located in the ring, while at the B-B site, it originates from σ(B-B) bond. In addition, CO formation is thermodynamically more favorable than CO2, consistent with existing experimental observations. Overall, these mechanistic insights offer a foundation for designing efficient, metal-free methane oxidation catalysts.

We present the synthesis and characterization of a viologen-based molten poly(ionic liquid), VPIL(TFSI), and its application to electrochromic (EC) devices. VPIL(TFSI) was obtained as a highly viscous liquid with a glass transition temperature of −23 °C, enabling its use in a molten state without additional solvent. Electrochemical analysis by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) of neat VPIL(TFSI) revealed a unique conduction mechanism: while ionic conductivity is dominated by the counter-anion (TFSI) migration, charge transport during redox cycling involves electron hopping between viologen units. Diffusion coefficient analysis indicated that electron hopping is slower than counter-anion migration, suggesting that the reorientation of viologen moieties, rather than ion migration, determines the transport kinetics. An EC device was fabricated using an equimolar mixture of VPIL(TFSI) and a ferrocene-based RAIL as cathodic and anodic components, respectively, without any supporting electrolyte. The device exhibited distinct coloration with strong absorption bands at 530 and 890 nm, attributed to π-dimerization of reduced viologen species, along with high contrast and coloration efficiency comparable to theoretical values. These findings demonstrate the potential of molten poly(ionic liquids) as promising redox-active media for solvent-free and durable electrochromic devices.

An electrochemical system; utilizing the sodium in the molten state, and carbon dioxide and oxygen gas mixture as the reactant species; to produce electrical energy has been formulated to predict the standard-state open-circuit voltage as a function of thecell temperature. The cell open-circuit voltage as a function of temperature can be predicted for the non-standard states of the species taking part in the overall cell reaction. In addition, the developed formulation is capable of predicting the following:The cell operational voltage, electric power density, and efficiency of the cell to deliver electric power density as a function of the cell geometric current density:For the case of the cell operation as a batch electrochemical reactor, the provided formulation can predict the open-circuit cell voltage as a function of the cell temperature, pressure, the overall reaction extent and the initial composition of the cell cathode-side reactant mixture. The rates of the reactant-species consumption and product-species production can also be predicted at a given cell geometric current density.Some examples of the computed data presented in the form of plots are given below.(1)The cell open-circuit voltage decreases from 3.26 to 2.95 volt for the increase in the cell temperature from 100 to 300°C.(2)For the cell with the solid electrolyte (sodium beta-alumina solid electrolyte) of 10𝜇𝑚thickness, the decrease in the cell operational voltage is of the order of 3𝑚𝑉at 200°Cfor the cell current range of 10𝑡𝑜100𝑚𝐴∙𝑐𝑚𝑔𝑒𝑜𝑚−2.(3)At the cell temperature of 200°C,𝑃𝑃0=4,the electric power density increases from about 0.033to 0.327𝑊∙𝑐𝑚−2over the geometric current range of 10to 100𝑚𝐴∙𝑐𝑚𝑔𝑒𝑜𝑚−2.(4)The efficiency to deliver electric power ranges from 99.98to 99.80over the geometric current density of range of 10to 100𝑚𝐴∙𝑐𝑚𝑔𝑒𝑜𝑚−2for the cell with the solid electrolyte thickness of 10𝜇𝑚at 200°Cand 𝑃𝑃0=4

Plastic waste from fossil-derived polymers remains a major environmental challenge, driving interest in biopolymers and enzyme-enabled end-of-life strategies. This review synthesizes current understanding of how polymer structure and thermal state govern enzymatic degradability, with emphasis on semicrystalline architectures and state-dependent accessibility. Within the Keller-Flory two-phase framework, crystalline lamellae embedded in an amorphous matrix dictate water/enzyme diffusion, chain mobility, and hydrolysis kinetics. Enzymatic attack preferentially initiates in amorphous regions, producing characteristic biphasic behavior as amorphous domains erode faster than crystalline regions, leading to crystallinity enrichment and subsequent slowing of degradation. Thermal transitions further modulate this balance: near or above Tg, segmental mobility and free volume rise, accelerating hydrolysis if enzymes remain stable; above Tm, chain mobility is maximal, but enzyme stability typically limits feasibility. Processing and architecture also strongly influence outcomes: annealing increases crystallinity and slows mass loss, quenching suppresses crystallization and hastens degradation, random copolymerization disrupts packing and lowers Tm, while block copolymers often degrade selectively by domain. Recent advances expand the operational window toward rubbery or near-molten states for low-melting aliphatic polyesters (e.g., PCL, PLGA, PEG-b-PLA), leveraging thermophilic/engineered hydrolases (cutinases, PETases, lipases, carboxylesterases) with demonstrated stability at 60-90 °C. Emerging strategies-including enzyme thermostabilization, AI-guided design, disulfide grafting, smart encapsulation, and in-situ enzyme embedding-enable self-degradation of materials and accelerate inside-out depolymerization under mild triggers. Integrating thermal analysis with polymer morphology and enzyme engineering offers a path to programmable, circular end-of-life for biopolymers, translating fundamental structure-property-reactivity relationships into practical enzymatic recycling and reduced environmental impact.

Chemical recycling is one of the most prominent techniques that enables monomer recovery for plastics like polyethylene terephthalate (PET), which ultimately reduces the dependency on virgin material inputs. In this study, 40 deep eutectic solvents (DESs) were pre-screened using COSMO-RS to identify the best solvent for chemical recycling of PET. Quantitative evaluation was performed based on activity coefficients (γ) to assess solute–solvent interactions. Qualitatively, the sigma profile and sigma potential were analyzed to understand the polarity and affinity of each DES component. This study experimentally validated the two top-performing DESs based on COSMO-RS output. The DES formed by combining thymol with phenol (Thy/Phe (1:2)) achieved 100% PET degradation and 94.5% terephthalic acid (TPA) recovery from post-consumer PET in just 25 min. The rapid dissolution of PET into molten state accelerated the hydrolysis reaction, leading to efficient monomer recovery. The second DES, tetrabutylammonium bromide/sulfolane (TBABr/Sulf (1:7)), attained 93.7% PET degradation and 94% TPA recovery. The PET-to-solvent ratio used in this study was 0.75, while the PET-to-DES ratio in the mixture was only 0.15, the lowest reported for DES-assisted hydrolysis to date. Characterization of the recycled TPA confirmed a purity level comparable to its virgin grade, as verified by FT−IR analysis. This study presents two important outcomes. First, the use of COSMO-RS for DES selection provides a strong rationale for solvent choice in targeted reactions and processes. Second, the use of appropriate DES in this study helps reduce key parameters associated with depolymerisation process, including reaction time, temperature, and catalyst consumption.

Additive manufacturing, as an innovative manufacturing technology compared to traditional subtractive manufacturing, offers greater design freedom and rapid prototyping capabilities. Material Extrusion (MEX), the most widely applied branch within additive manufacturing (AM), operates on the core principle of heating thermoplastic polymers or composite materials to a molten state, then depositing them layer by layer through a nozzle to form the final shape. However, the inherent contradiction between printing speed and build quality remains the key bottleneck limiting its widespread adoption. Desktop Material Extrusion techniques like Fused Filament Fabrication (FFF) offer high precision but require extended printing times. Meanwhile, industrial-scale Big Area Additive Manufacturing (BAAM) processes achieve high deposition rates yet suffer from insufficient accuracy. This paper systematically reviews the primary application domains of additive manufacturing technologies, elucidating their process flows and classification systems. Building upon this foundation, it systematically analyzes the contradiction and coupling relationship between high precision and high deposition speed in Material Extrusion technologies from aspects including hot-end flow, system thermal management, vibration, and printing parameters. It provides a reference for the subsequent design and optimization of high-precision, high-speed Material Extrusion (MEX) printers.

This study investigates the influence of chain length on the crystalline structure and thermodynamic behavior of side-chain polyhedral oligomeric silsesquioxane (POSS)-containing homopolymers. A series of precisely synthesized POSS-containing polymers with exact chain lengths was prepared using precision chemistry. Comprehensive characterization revealed that the covalent attachment of crystalline POSS cages to the polymer backbone confined their crystallization to a 2D lattice, fundamentally distinct from the chain-folding mechanism of conventional polymers. Polarized optical microscopy confirmed the absence of birefringence during crystallization, consistent with this constrained geometry. Differential scanning calorimetry demonstrated that the melting temperature systematically increased with longer chain lengths, attributed to reduced configurational entropy in the molten state, but remained invariant with isothermal crystallization temperature for each sample. Crystal structure analysis confirmed identical interlamellar spacing and crystalline packing across different chain lengths, supporting a model where POSS cages form crystalline bilayers sandwiching the incompatible polyester backbone layer. These findings provide robust experimental validation for the 2D lattice crystallization model in POSS-containing polymers and establish precise molecular design as a key strategy for tailoring the hierarchical organization and thermal properties of hybrid nanocomposites.

As an emerging photovoltaic technology, perovskite solar cells (PSCs) suffer from inherent instability, which limits their commercial viability. Conventional encapsulation methods can improve the stability of sensitive materials in PSCs through isolation. This work describes a strategy to improve the stability of PSCs by introducing sucrose material during the encapsulation process. After solidifying from the molten state, sucrose binds tightly at the interface and generates compressive strain within the device. This compressive strain method can effectively mitigate light‐induced degradation, inhibit ion migration, and improve the stability of the device for long‐term operation. Compared to the unencapsulated and paraffin‐encapsulated controls, the sucrose‐encapsulated PSCs retain 98.6% of their initial efficiency after 1200 h of storage in the dark (20 ± 5°C, 10% RH) and exhibit superior performance under accelerated light–dark cycling. This simple method, based on a widely available material, provides a promising solution for enhancing the durability and commercial potential of PSC technology.

In this study, a novel multifunctional composite comprising polyvinyl alcohol (PVA), microcrystalline cellulose (MCC), sulfur, and vanadium dioxide (VO2) was successfully synthesized through a solvent-free melt intercalation method. The process involved dispersing MCC/S-VO2 material within a PVA matrix in the molten state, enabling homogeneous mixing and effective interfacial integration, and subsequently calcining the mixture at 300°C. Calcination preserved the monoclinic phase of VO2 and enhanced the composite's porosity through thermal decomposition of PVA and MCC, resulting in uniformly distributed active phases within black, granular adsorbents. X-ray diffraction (XRD) confirmed the sustained integrity of the crystalline monoclinic VO2 phase. X-ray photoelectron spectroscopy (XPS) detected the elements carbon, oxygen, sulfur, and vanadium, along with carbonized polyvinyl alcohol (PVA), all exhibiting distinct spectral characteristics that point to strong interfacial interactions within the composite. Scanning and transmission electron microscopy (SEM and TEM) revealed a porous, layered architecture with VO2 nanosheets uniformly distributed throughout the carbon-rich matrix. Continuous fixed-bed column experiments were conducted under varying operational parameters, including bed heights, initial methylene blue (MB) concentrations, and flow rates. The composite demonstrated exceptional adsorption efficiency, achieving a peak capacity of 47.7 mg g-1 under optimal conditions (bed height: 0.5cm, MB concentration: 20 mg L-1, flow rate: 1 mL min-1, column diameter: 1cm). Breakthrough curve analysis confirmed the validity of the BDST model for performance prediction (R2 > 0.9), whereas the Thomas and Yoon-Nelson models exhibited lower correlation coefficients (R2 < 0.9), suggesting reduced applicability under the tested parameters. Notably, the adsorbent retained over 83.6% of its initial adsorption capacity after four regeneration cycles, underscoring its structural resilience and recyclability. The adsorption mechanism for MB onto the synthesized composite was attributed to π-π interactions, hydrogen bonding, and electron donation from the amine groups of MB to vanadium sites. This study, for the first time, demonstrates the use of solid PVA in a solvent-free melt intercalation process to fabricate polymer-inorganic hybrid adsorbents, offering a novel and eco-friendly strategy for advanced wastewater treatment.

Homogeneous radiation crosslinking of ultra-high molecular weight polyethylene in molten state

Aluminum-silicon (Al-Si)-coated steel is a mainstay material for manufacturing ultrahigh strength automotive parts through hot stamping. The coating protects the blanks from oxidation and decarburization as the steel is austenitized in a furnace. It also reacts with the steel to form solid Al-Fe-Si intermetallic phases that provide long-term corrosion protection. However, the coating extends the required heating times due to its high reflectance, and, in its molten state, it can also impregnate the furnace rollers, leading to their failure. This work demonstrates a strategy to avoid these issues by depositing an Fe-rich layer on the Al-Si coating. The introduction of a second Fe source both increases the blank's ability to absorb thermal irradiation and introduces a secondary mechanism that accelerates the reactions that convert the metallic coating into the intermetallic layer. Cross-sectional Raman microscopic mapping reveals that the intermetallic phases grow from the steel/coating interface into the Al-Si coating only after the binary phase θ (Al13Fe4) converts to η (Al5Fe2) at 620 °C. With the Fe-rich overlayer, however, speciation maps show that the coating can be converted completely to solid-state intermetallic phases at temperatures only slightly above the Al-Si melting point. This strategy provides a promising new method to mitigate furnace roller contamination in industrial hot stamping manufacturing lines.

Molten beryllium and uranium containingfluoride salts, such asNaF-BeF2-UF4-ZrF4 and NaF-BeF2 are examples of fuel solvent and heattransfer salts used in molten salt reactor designs. To observe thebehavior of these salts and to ascertain the mechanisms behind theformation of ionic complexes present in their molten state, this workused high temperature rheology and hydrostatic density methods tomeasure thermophysical properties. Similar to modeling literature,two regions of viscosity were identified: one below 60 molar percentageof complex forming cations, where it is hypothesized that viscosityis driven by the diffusion of small ionic fragments, and one abovewhere it is hypothesized the degree of polymerization of the complexingcation and network formation drives the increase in viscosity.

The varying stoichiometry of the lithium amide–imideammoniadecomposition catalyst under working conditions was ascertained bycalculating the gas release events in the ammonia decomposition experiments.Rather than varying smoothly between amide and imide, the gas releasesshowed evidence of a molten state with a majority of amide stoichiometrybefore converting at temperatures above 460 °C to a solid witha majority of imide stoichiometry. At higher temperatures, there wasindirect evidence of nitride hydride groups being formed within thecatalyst structure.

On the use of ethylene carbonate as a green solvent in mobile phases.

Solid-liquid phase change materials (PCMs) possess green and reversible thermal storage characteristics, but their application is limited by liquid leakage in the molten state and the low thermal conductivity of solid-liquid PCMs. Biochar (BC), with its inherent porous architecture and abundant surface functionalities, was synthesized through K2FeO4 activated carbonization of straw, a representative agricultural residue, demonstrating exceptional potential as a sustainable matrix material. After loading polyethylene glycol, the composite PCMs were obtained (BC/PEG). The research focused on investigating the effects of carbonization temperature and K2FeO4 on the structural properties of biochar. The results indicated that when the carbonization temperature is 800 °C and the proportion of K2FeO4 is 1:1, the specific surface area of BC reaches 1463.85 m2/g. The BC/PEG has excellent heat storage performance, with a loading rate as high as 74.8% and a melting enthalpy of 120.7 J/g. While maintaining a high loading rate, BC/PEG800-1 exhibited a thermal conductivity of 0.449 W/(m·K), representing a 38.6% enhancement over that of pure PEG. The findings suggest that biochar derived from K2FeO4 activated biomass effectively addresses PCM leakage and low thermal conductivity. This material exhibits promising potential for energy storage systems, offering a novel strategy to enhance thermal performance in PCMs.

The strength-toughness trade-off in polymer glasses presents a fundamental challenge, as enhancing one property typically compromises the other. Moreover, efforts to enhance mechanical performance often lead to increased melt viscosity, which in turn hinders processability. Here, we demonstrate that incorporating single-chain nanoparticles (SCNPs) breaks this trilemma by simultaneously enhancing strength, toughness, and processability. Through a combined experimental and molecular dynamics simulation approach, we reveal that SCNPs with higher glass transition temperature than the matrix not only increase yield strength but also delay and homogenize crazing, leading to dramatically improved toughness in the glassy state. Importantly, the SCNPs reduce melt viscosity in the molten state, countering the conventional trend of viscosity increase in nanocomposites. This triple enhancement establishes a universal framework for designing high-performance polymer glasses that transcend traditional material property limitations.

Biodegradable thermoplastic cassava starch/poly(butylene succinate) blends with citric acid: Characterization and evaluation of properties.

CO2 solubilities in low-density polyethylene (LDPE) in its molten state over high temperatures and pressures conditions