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The abradable coating is one of the significant stator components in aero-engine，which protects the rotating blade and casing by abrading itself and improves the engine performance by reducing the gap between the rotor and stator. In this study，taking the addition-type silicone resin as the matrix，the effect of diameter and stacking density of glass hollow/solid microspheres on the processability of abradable coating was investigated. Moreover，the effect of glass microsphere type and content was illustrated using a self-designed wear tester simulating the working conditions of stator in aero-engine. The results show that the silicone resin reinforced by H-type （size distribution 20–820 um） hollow glass microspheres exhibits excellent surface quality，flowability and comprehensive performance. The suitable preparation technology of abradable coatings was developed by glass microsphere selection，content controlling，tool design and infusion parameters optimizing. The as-prepared glass microsphere/silicone abradable composite is successfully applied and verified in aero-engine stator component.

Polymer matrix syntactic foams made of hollow glass microspheres (HGMs) and epoxy resin are widely used in underwater vehicles providing buoyancy due to their advantages of low density and high mechanical strength. When HGMs is strong enough, surface modification of HGMs is an effective method to improve the compressive strength of syntactic foams. However, the effects of different surface modifiers on the physical properties of HGMs and the compressive strength of syntactic foams have rarely been systematically studied. It is of great significance to enhance the interfacial strength of syntactic foams. Herein, the T40 HGMs was treated by different modifiers (HCl, NaOH, Li2SiO3, Me3SiONa, KH550, KH560, KH570, and Volan), physical properties of modified HGMs were studied, including true density, angle of repose, isostatic compressive strength, specific surface area, and contact angle. Furthermore, the effects of modified HGMs on the compressive strength of syntactic foams were also studied. The results showed that the compressive strength depend largely on the interface bonding between HGMs and resin matrix. This work can provide some references for mechanical property reinforcement of syntactic foams with high filling ratio and plenty of interface zones.

Cement-based sensors have attracted considerable attention due to their potential for self-sensing applications, particularly in the realms of structural health monitoring and traffic management, as they eliminate the need for external sensors. However, the performance of these sensors can be adversely affected by various environmental factors, with water ingress being a particularly critical concern that can destabilize their piezoresistive sensing capabilities. In this study, hollow glass microspheres (HGM), recognized for their superhydrophobic properties, were incorporated into cement-based sensors to improve their piezoresistive sensing stability under conditions of water ingress. Carbon nanotubes (CNT) were employed as the conductive filler, and the hybrid effects of CNT and HGM were systematically investigated using a range of characterization techniques. The study experimentally assessed the impact of HGM on the compressive strength, electrical resistivity, and water absorption characteristics of the cementitious composites. Furthermore, the enhancement in sensing performance due to HGM was evaluated with respect to sensitivity, linearity, and stability under both monotonic and cyclic loading scenarios. The experimental findings revealed that while HGM initially reduces water absorption, this effect diminishes over prolonged periods of water exposure. Additionally, HGM prevents CNT-based conductive networks from water ingress, thereby improving sensing stability after water exposure. Consequently, the utilization of HGM is anticipated to enhance the sensing stability of cement-based sensors under water ingress conditions.

To investigate the compression properties and failure mechanisms of syntactic foams, two different resin matrices and three types of hollow glass microspheres (HGMs) were used to prepare syntactic foams with different properties. Results showed that the compression strength of syntactic foams increases with the increase in the compression strength of HGMs or resin matrix. Low-strength HGMs will be the first to break down as a source of cracks under stress. When the stress value exceeds the compression strength of the matrix, the matrix will deform and break, leading to the overall destruction of syntactic foam. High-strength HGMs not only act as a lightweight filler but also act as a reinforcing phase to improve the strength of the syntactic foam. The matrix located at the interface will experience initial cracking when subjected to stress, becoming the origin of subsequent cracks. Consequently, the weaker part between the HGMs and the matrix will be the initial point of failure, resulting in the formation of a crack source. The failure of the matrix will ultimately result in the complete destruction of the syntactic foam.

Polycarbonate (PC) composites are often used in the production of high value-added products, but it is necessary to improve its environment stress cracking condition in the presence of pre-strain and soluble solvents. In this work, the effect of weight reduction and strengthening is realized by introducing microstructures and hollow glass microspheres (HGMs) into the PC composites. It is found that the addition of HGMs can reduce the melt viscosity and [T.sub.g] value of the composite materials, which will change the foaming behavior of PC/HGMs composites. Besides, the effect of different content of HGMs and foaming temperature on the foaming behavior of PC/HGMs composite foams are studied. The PC/HGMs composite foams exhibit a typical structure of both large and small cellular pores, because of the existence of hollow beads and cellular structures. Moreover, compared to the neat PC foam, the tensile strength as well as the flexural strength of the composite foams are significantly increased by 110.9% and 364.7%, respectively. Furthermore, the as-prepared PC/HGMs composite foams have low thermal conductivity (lower than 0.07W/mK), which can effectively insulate heat propagation. Highlights * Hollow glass microsphere can reduce melt viscosity and [T.sub.g] of composites. * The mechanical properties of composite foams have been greatly improved. * Composite foams exhibit excellent thermal stability due to their microstructure. KEYWORDS composites, foams, microstructure, polycarbonates, 1 | INTRODUCTION As the king of commercial engineering plastic, polycarbonate (PC) has become an important raw material for high-value-added products, such as 5G communications, translucent construction facades, aircrafts, and [...]

This study aimed to investigate the immunomodulatory effect of two different forms of phosphate-based glass microspheres (solid and porous), on human macrophages. Human THP-1 monocytes were converted to M0 macrophages after being treated with 100 ng/mL phorbol 12-myristate 13-acetate for 48 h. The differentiated cells were analysed for the CD14 marker using flow cytometry. The adhesion, spreading, and viability of M0 macrophages grown directly or indirectly (extracts) at varying concentrations of solid and porous glass microspheres (GMs) were analysed via phase contrast microscopy, confocal microscopy, and XTT assay. The expression of IL-8, IL-1β, IL-6, IL-10, TNF-α, and IL-12p70 cytokines was investigated using flow cytometry. The conversion to M0 macrophages was confirmed by their adherent nature, increased granularity, and CD14 expression. The results showed that both solid and porous GMs or extracts favored the attachment, spreading, and proliferation of macrophages in a comparable manner to cells grown in a normal tissue culture medium. Only the higher concentration of porous GMs (10 mg/mL) changed the morphology of M0 macrophages and increased the expression of IL-1β and IL-8 pro-inflammatory cytokines; this could be related to the fast degradation nature of porous GMs. Of the six cytokines analysed, M0 macrophages grown directly or indirectly with GMs only expressed IL-1β, IL-10, and IL-8. Accordingly, solid microspheres may have advantages as regenerative agents due to their controlled degradation.

In this article, the surface modification methods of hollow glass microspheres and their applications in coatings were briefly introduced. The latest research progress in thermal insulation coatings, fireproof coatings, wave-absorbing coatings and anticorrosive coatings was summarized, and the future direction of the application of hollow glass microspheres in coatings was prospected. [ABSTRACT FROM AUTHOR]

This study focuses on improving the mechanical properties of sandwich composites by developing epoxy-based sandwich composite panels with hollow glass microspheres/nanoclay hybrid core and banana fiber facesheets for structural applications. The mechanical performance of sandwich composite panels made with hollow glass microspheres (HGM)/nanoclay hybrid core with banana fibers face-sheet composites panel is investigated in this work. The HGM content of the core was varied from 1 wt% to 3 wt% in the sandwich composites panel, while the nanoclay content of the core was varied from 1 wt% to 5 wt% in each of the HGM-filled series of the sandwich composite panel, these sandwich composite panels were fabricated using a conventional resin casting method. In this investigation, the mechanical, water absorption, and buoyancy behavior are thoroughly studied and the findings revealed better improvement at the sandwich composites with hybrid core formulation with banana fiber facesheets than the sandwich composites without hybrid core formulation. This demonstrates that banana fiber with epoxy resin has a limited amount of strength when used without a hybrid core but delivers better performance when HGM and clay particles are mixed as the hybrid core because of excellent interfacial adhesion between the hybrid core and the matrix. The improved mechanical properties could suggest that this material may be suitable for application in industries where sandwich structures that are lightweight with good mechanical properties are required. This study showed a new area of sandwich structure development by enhancing mechanical properties using hybrid core and banana fibers.

The presence of residual carbon in powder precursors prepared using the sol-gel method can pose significant challenges in producing ceramics and glasses of high quality. In the case of glass, carbon dioxide formation during the glass-melt heating process leads to bubble/pore formation, while in the case of ceramics, residual carbon can significantly impair its optical properties. The present study aims to identify the reasons for the persistence of residual carbon in YAG and YAG ⁺ Al₂O₃ (YAGA) precursor powders prepared by the sol-gel Pechini method, even under high-temperature conditions exceeding 1400 °C. The study seeks to provide insights to aid in the development of strategies that mitigate the impact of residual carbon on the quality of ceramics and glasses produced using sol-gel techniques. It was found that even after the annealing of the precursor at a temperature of 1200 °C for two hours, a small amount of carbon remains in the precursor powder. The X-ray diffraction (XRD) analysis of the YAGA precursor powders showed that the crystallisation of alumina was delayed and began at 1200 °C. The amount of α-alumina, which corresponds to its actual addition, was identified at a temperature of 1500 °C. Additionally, as the alumina crystallises, the carbon is released from the precursor which is the reason for microspheres blowing in the flame, even when the precursor was burnt out at a temperature of 1400 °C.