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Fabrication of hollow MgO granules via freeze granulation as a filler for lightweight thermal interface materials

Rokhyeon Kim, Yunha Lee, Joo-Hwan Han, Chee-Sung Park & Jungho Ryu

Abstract

With the improvement in the performance of electric vehicles (EVs), heat generation by the battery increases, potentially leading to a number of issues; thus, the thermal management of high-performance secondary batteries is crucial. Thermal interface materials (TIMs) are polymer composites constituting high-thermal-conductivity fillers homogeneously dispersed in a polymer matrix. The thermal conductivity of TIMs is strongly affected by the thermal properties, size, shape, and content of the filler. As the weight of an EV directly impacts its fuel efficiency, new fillers with high thermal conductivity, low density, and cost-effectiveness must be developed for next-generation EVs. In this study, freeze granulation was used to fabricate highly thermally conductive, lightweight hollow MgO granules for low-density TIMs. Hollow MgO granules were fabricated by dispersing polymethyl methacrylate (PMMA) microbeads in a Mg(OH)₂ slurry, freeze-granulating the slurry, and removing PMMA through sintering to create hollow MgO spherical-shaped granules. The heating rate during PMMA removal, the PMMA microbead content, and the solid content of the Mg(OH)₂ in the slurry were adjusted to fabricate ideal hollow spherical-shaped granules. A TIM made with spherical hollow MgO granules (average diameter of 15–20 µm) fabricated through freeze granulation showed approximately 1% lower density and about 9% higher thermal conductivity than a TIM with solid MgO granules.

Keywords:

MgO
Hollow granule
Thermal interface material
Freeze granulation
Thermal conductivity

An Innovative Formulation Development Approach of Sustained Release Matrix Tablet: A Review

S Gokulakrishnan, K B Ilango, R Kalyan, R Samyuktha, A Subash, K Subhashini

Abstract

This review delves about the various manufacturing process/ method of the sustained release matrix tablet & the methods are direct compression, wet granulation, dry granulation, foam granulation, freeze granulation, nanosponge, sintering method, 3D Printing. These all method possesses distinctive traits & unique benefits. The choice of process depends upon the specific formulation, desired tablet characteristic and production scale. In these methods, the solid medicaments are distributed throughout the porous matrix formed by the polymer which controls the medicament releasing & there is a presence of a novel strategy for prolonging drug release is the disintegration-controlled matrix, which maintains release for up to 24 hours by regulating the tablets breakdown rate. This review also discusses about the formulation of sustained release matrix tablet by using Quality by Design (QbD) & their dissolution patterns is indirectly detected by using the AI tool. Keywords: Sintering, Nano sponge, 3-D Printing, DCMT (Disintegration Controlled Matrix Tablet), Sustained-Release, Artificial intelligence.

Keywords:

Freeze granulation, dry granulation, foam granulation, wet granulation, nanosponge

Development of spray freezer for production of freeze granulations

DARSHAN M B , ABHIJIT KAR , DEBABANDYA MOHAPATRA

Abstract

Spray freezer is an essential component of spray freeze drying (SFD) technique to produce microspheres during encapsulation. In this study, a lab scale spray freezer unit was developed to produce freeze granulations, which could be used for encapsulation of bio-pigments and other useful bio-active compounds. The components of spray freezer were spray nozzle, freezing chamber, magnetic stirrer, feed reservoir, homogenizer, peristaltic pump, air compressor, liquid nitrogen tank and hose fittings. The maltodextrin ‘MD’ solution (10%) was atomized into liquid nitrogen using spray freezer to produce freeze granulations and these granulations were freeze dried to obtain spray freeze dried maltodextrin (SFDMD) particles. The produced SFDMD particles were characterized and compared with classical freeze dried maltodextrin (FDMD) particles to evaluate the performance of spray freezing unit. The drying period for producing maltodextrin granules in SFD and freeze drying (FD) technique was between 12 to 24 and 36 to 48 hr, and their % moisture absorption was found to be 2.37 and 2.17%, respectively. The SFD technique produced microspheres of maltodextrin with particle size ranging from 2 to 60 μm, whereas FD technique produced irregular macro-size flakes. The morphological studies revealed that SFD microstructure particles had smooth surface and freeze dried particles had rough surface; however, porous appearance was observed in both samples. There were no significant differences in colour values; however, the flow properties of SFDMD particles were relatively better than FDMD particles. The developed spray freezer can be used for production of freeze granulations during SFD technique.

Systematic investigation of thermal process parameters on the morphology of spray-freeze-dried powders

Annika Rautenberg, José Ignacio Vázquez-Olvera, Paul Bühlbecker, Alf Lamprecht

Abstract

Hypothesis: During spray freeze drying (SFD), vitrification, recrystallization, and polymorphic transitions govern particle morphology and mechanical integrity. We hypothesize that with control over freezing temperature, annealing relative to the glass transition of the maximally freeze-concentrated matrix (Tg’), and drying temperature it is possible to modulate ice growth, molecular mobility, and solid-state transformations, thereby enabling the production of advanced materials via freeze-casting droplets with designable properties.

Experiments: A full-factorial design was conducted using lactose, mannitol, and trehalose. Formulations were frozen at temperatures above or below water’s glass transition, annealed under four conditions (no annealing, annealing above or below Tg’, and extended times), and dried either near or above Tg’. Resulting powders were analysed regarding ice formation mechanism, solid state composition and morphological behaviour.

Findings: Mannitol displayed pronounced process-dependent polymorphism, which is driven by annealing and temperature during sublimation. Lactose and trehalose remained amorphous throughout. Annealing above Tg’ promoted viscous flow within the vitrified matrices, producing partial particle fusion and reduced mechanical stability. Variations in recrystallization and Ostwald ripening during annealing systematically altered surface area and pore architecture. This connects annealing to sintering mechanisms, electrical conductivity and mechanical stability of micrometre sized spheres. Across all conditions, SFD consistently yielded spherical, low-density particles, yet the interplay of vitrification and phase transitions generated distinct microstructural outcomes.

Keywords:

Freeze-casting; Polymorphs, annealing; Powder design; Spray-freeze-drying.

SPRAY FREEZE DRYING FORMATION OF DRY POWDER COMPOSITIONS

Inventors:
BUCKLAND, Justin
CHATURBEDY, Piyush
TAYLOR, Steve
WENBAN, Nathan
COUPLAND, George

Abstract

The present invention relates to dry powder compositions, methods, apparatus and systems for manufacture of the same. In particular, the present invention relates to a system for producing a dry powder composition including a vacuum chamber depressurised by a vacuum pump and a spray head assembly configured to introduce a liquid formulation into the vacuum chamber, wherein the spray head assembly is ultrasonically stimulated during introduction of the liquid formulation into the vacuum chamber to initiate breakup of the liquid formulation into liquid droplets within the vacuum chamber. The present invention further relates to dry powder compositions comprising lyophilised aggregates produced with such apparatus.

Hybrid materials for wastewater treatment: synergistic coupling of Neochloris oleoabundans and TiO₂ nanoparticles

Ilaria Zanoni, Sara Amadori, Andrea Brigliadori, Anna Luisa Costa, Simona Ortelli, Pierluigi Giacò, Costanza Baldisserotto, Simonetta Pancaldic and Magda Blosi

Abstract

In this work, we combined microalgae’s sorptive properties with titania-based nanoparticles’ photocatalytic capabilities to develop technologies applicable to wastewater treatment while also providing valuable insights into the innovation of adsorption technologies. The coupling of Neochloris oleoabundans biomass with an inorganic nanophase enables the formation of hybrid materials integrating heavy metal adsorption with photocatalytic action. To prepare the samples, we employed a water-based colloidal method followed by a spray freeze granulation treatment. The preparation process was followed by comprehensive physicochemical characterization from the wet precursors to the final hybrid granules. Key performance indicators, including adsorption and photocatalytic activity, were assessed using two model contaminants: copper ions (for heavy metal adsorption) and Rhodamine B (for photocatalysis). The results revealed a synergistic effect of the hybrid nanomaterials, significantly enhancing the Cu²⁺ adsorption capacity of the biomass, which increases from 30 mg g⁻¹ to 250 mg g⁻¹ when coupled with the inorganic phase and is likely due to the supporting and dispersing role of the inorganic nanoparticles on the biomass. The adsorption experimental values followed the Freundlich isothermal model and pseudo-second-order kinetic model, indicating that the adsorption occurred primarily through a multimolecular layer adsorption process, consistent with chemisorption mechanisms. The photocatalytic performance of the inorganic counterpart was preserved when coupled with the microalgae, with TiO₂–SiO₂/biomass achieving complete Rhodamine B degradation within 1 hour.

Keywords:

Spray freeze granulation

Spray Freeze Drying Equipment Unlocking Growth Potential: Analysis and Forecasts 2025-2033

Key Insights

The spray freeze drying equipment market is experiencing robust growth, driven by increasing demand across various sectors, including pharmaceuticals, biotechnology, and food processing. The market size in 2025 is estimated at $500 million, projected to grow at a Compound Annual Growth Rate (CAGR) of 8% from 2025 to 2033. This growth is fueled by several key factors. Advancements in spray freeze drying technology, leading to improved product quality, higher yields, and reduced processing times, are significantly impacting market expansion. Furthermore, the rising prevalence of biologics and the increasing demand for stable and high-quality pharmaceuticals are major drivers. The pharmaceutical industry, in particular, is adopting spray freeze drying for the production of heat-sensitive drugs and vaccines, boosting market demand. Growing investments in research and development, coupled with the rising adoption of advanced analytical techniques for process optimization, further contribute to market expansion.

Several restraints exist, however. High initial investment costs associated with spray freeze drying equipment can hinder adoption, particularly among small and medium-sized enterprises. Also, the complex process and the requirement for specialized expertise in operating and maintaining this equipment pose challenges. Despite these restraints, the market is segmented by equipment type (lab-scale, pilot-scale, and industrial-scale), application (pharmaceuticals, food, and others), and region (North America, Europe, Asia Pacific, and the Rest of the World). Companies such as Meridion, GEA, IMA Group, Pilotech, and others are key players shaping the market landscape through technological innovation and strategic partnerships. The competitive dynamics are characterized by ongoing efforts to enhance equipment performance, expand product offerings, and increase market penetration. The long-term outlook remains positive, driven by ongoing technological advancements, increasing demand for high-quality products, and growing investments in the healthcare and food industries.

Keywords:

Spray freeze drying equipment

Beyond Traditional Methods: Novel Granulation Approaches for Enhanced Functionality in Pharmaceuticals

Ch. Niranjan Patra*, Supriyo Satapathy, Shuvendu K Dinda, Sudarsan Behera, Sashank S Hota, Goutam K Jena and Sanjiv K Panda

Abstract

Granulation, a cornerstone process in many industries, has seen significant advancements in recent years. This abstract explores these novel techniques, highlighting their potential to improve the functionality and efficiency of granule production.The traditional wet and dry granulation methods are addr essed, outlining their limitations, such as solvent usage and challenges with moisturesensitive materials. The abstract then delves into innovative approaches that address these limitations. Techniques like pneumatic granulation, reverse granulation, foam granulation, steam granulation, and moisture-activated dry granulation (MADG) are discussed, emphasizing their advantages. Foam granulation offers improved binder distribution and reduced water requirement, while steam granulation eliminates organic solvents and promotes faster drying. Improved granule properties, including folowability, compressibility, and controlled release characteristics, are highlighted. Additionally, the reduction of solvent usage and drying times translates to increased environmental sustainability and production efficiency.The abstract concludes by emphasizing the ongoing development of novel granulation techniques. It underscores the potential of these advancements to revolutionize various industrial processes, particularly in the pharmaceutical industries, by ensuring the production of high-quality granules with improved functionality and at a reduced environmental cost.

Keywords:

moisture-activated dry granulation, freeze-drying

Full Density Powder Metallurgical Cold Work Tool Steel through Nitrogen Sintering and Capsule-Free Hot Isostatic Pressing

Anok Babu Nagaram, Giulio Maistro, Erik Adolfsson, Yu Cao, Eduard Hryha and Lars Nyborg

Abstract

Vanadis 4E (V4E) is a powder metallurgical cold work tool steel predominantly used in application with demand for wear resistance, high hardness, and toughness. It is of interest to have a processing route that enables full density starting from clean gas-atomized powder allowing component shaping capabilities. This study presents a process involving freeze granulation of powder to facilitate compaction by means of cold isostatic pressing, followed by sintering to allow for capsule-free hot isostatic pressing (HIP) and subsequent heat treatments of fully densified specimens. Citation: Nagaram, A.B.; Maistro, G.; Adolfsson, E.; Cao, Y.; Hryha, E.; Nyborg, L. Full Density Powder Metallurgical Cold Work Tool Steel through Nitrogen Sintering and Capsule-Free Hot Isostatic Pressing. Metals 2024, 14, 914. https://doi.org/ 10.3390/met14080914 Academic Editor: Andreas Chrysanthou Received: 17 June 2024 Revised: 31 July 2024 Accepted: 2 August 2024 Published: 12 August 2024 Copyright: © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). The sintering stage has been studied in particular, and it is shown how sintering in pure nitrogen at 1150 ◦C results in predominantly closed porosity, while sintering at 1200 ◦C gives near full density. Microstructural investigation shows that vanadium-rich carbonitride (MX) is formed as a result of the nitrogen uptake during sintering, with coarser appearance for the higher temperature. Nearly complete densification, approximately 7.80 ± 0.01 g/cm3, was achieved after sintering at 1200 ◦C, and after sintering at 1150 ◦C, followed by capsule-free HIP, hardening, and tempering. Irrespective of processing once the MX is formed, the nitrogen is locked into this phase and the austenite is stabilised, which means any tempering tends to result in a mixture of austenite and tempered martensite, the former being predominate during the sequential tempering, whereas martensite formation during cooling from austenitization temperatures becomes limited.

Keywords:

cold work tool steel; freeze granulation; sintering; capsule-free hot isostatic pressing; full densification

Advances in Spray-Drying and Freeze-Drying Technologies for the Microencapsulation of Instant Tea and Herbal Powders: The Role of Wall Materials

Júlia Mazár, Krisztina Albert ,Zoltán Kovács , András Koris, Arijit Nath and Szilvia Bánvölgyi

Abstract

The microencapsulation of tea and herbal extracts is gaining considerable attention in the food industry, particularly in the production of instant powders. This review examines the application of spray-drying and freeze-drying technologies for the encapsulation of bioactive compounds, focusing on the role of wall materials. Over the past two decades, carbohydrate-based (e.g., maltodextrin), gum-based (e.g., gum Arabic), and protein-based (e.g., whey protein isolate) materials have been widely used due to their impact on sensory properties, stability, protection of bioactive compounds, and other critical attributes of encapsulated products. Despite their widespread use, these materials have distinct advantages and limitations, such as cost, availability, and compatibility with different extracts. This review provides a comprehensive analysis of their physical and chemical properties, examines alternative and emerging wall materials (e.g., beta-cyclodextrin, sodium alginate, and inulin), and highlights the potential of combining different materials to optimise encapsulation outcomes. It also identifies current research gaps and future directions to improve the efficacy and quality of encapsulated tea and herbal powders.

Keywords:

microencapsulation; spray-drying; freeze-drying; wall material; core material; instant herbal powder; instant tea powder