Large-Scale Fabrication of Boron Nitride Nanosheets and Their Utilization in Polymeric Composites with Improved Thermal and Mechanical Properties

Recent advanced thermal interfacial materials: A review of conducting mechanisms and parameters of carbon materials

Recent advancements in material technologies have promoted the development of various preparation strategies and applications of novel polymer–nanoclay composites. Innovative synthesis pathways have resulted in novel polymer–nanoclay composites with improved properties, which have been successfully incorporated in diverse fields such as aerospace, automobile, construction, petroleum, biomedical and wastewater treatment. These composites are recognized as promising advanced materials due to their superior properties, such as enhanced density, strength, relatively large surface areas, high elastic modulus, flame retardancy, and thermomechanical/optoelectronic/magnetic properties. The primary focus of this review is to deliver an up-to-date overview of polymer–nanoclay composites along with their synthesis routes and applications. The discussion highlights potential future directions for this emerging field of research.

A Review of the Synthesis and Applications of Polymer–Nanoclay Composites

Diamond is a metastable allotrope of carbon. Monocrystalline diamond with particle size less than 100 nm (designated as nanodiamond) has been widely studied during the past decades. Nanodiamonds have recently attracted attention owing to their exceptional mechanical and optical properties, tunable surface structure, and high specific surface area. The specific core-shell structure and abundant functional groups on its surface endow it with a variety of functional applications. Their excellent physical properties enable their application as ideal fillers in reinforcing polymer composites, resulting in superior mechanical properties, thermal stability, thermal conductivity and tribological properties. In addition to polymer composites, nanodiamonds and its composites are also widely used in sensors, optical computing, and quantum computing. As nanoscale materials, nanodiamonds and its composites are also used in electrical energy storage, wastewater treatment and bioapplications. Due to its superior biocompatibility and low cytotoxicity, nanodiamonds and its composites are now becoming crucial in biological applications. In this study, the properties of nanodiamonds and their application in polymer composites, electronics, energy, environmental areas and biological areas were analyzed.

A critical review of nanodiamond based nanocomposites: Synthesis, properties and applications

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A comprehensive review on mechanical, electromagnetic radiation shielding, and thermal conductivity of fibers/inorganic fillers reinforced hybrid polymer composites

This research focused on evaluating the thermal and physical properties of a composite reinforced with nanodiamonds and epitaxial boron nitride in an epoxy matrix. Nanodiamond-attached exfoliated hexagonal boron nitride nanoplates were fabricated using 4,4′-methylene diphenyl diisocyanate as the coupling agent. The morphology and structure of boron nitride (BN), exfoliated hexagonal BN nanoplates (EBN), and nanodiamond-attached EBN nanoplates (NDEBN) were determined. Epoxy composites were fabricated by in-situ polymerization and reinforced with various concentrations of either EBN or NDEBN nanoplates. These composites exhibited high thermal stability and high thermal conductivity, attributed to the exceptional thermal stability and thermal conductivity inherent in nanodiamond materials. In addition, inserting nanodiamond particles between BN layers prevented the BN nanosheet from forming agglomerates. We also found that nanodiamond particles improved dynamic mechanical properties by acting as a crack pinning role, which could restrict the molecular mobility of the epoxy.

Thermal conductivity and thermo-physical properties of nanodiamond-attached exfoliated hexagonal boron nitride/epoxy nanocomposites for microelectronics

Enhancing the heat and load transfer efficiency by optimizing the interface of hexagonal boron nitride/elastomer nanocomposites for thermal management applications

Amine-terminated macromolecular chain (ATBN) were covalently grafted on expanded graphite (EG) surface using 4,4′-methylene diphenyl diisocyanate as coupling agent. The functionalization result of the amine-terminated EG (AEG) was demonstrated by various analysis techniques. The AEG was incorporated into the epoxy (EP) matrix to form EP/AEG nanocomposites by interlayer polymerization in the EG interval layers. The grafted ATBN chains on the AEG surfaces can not only enhance the interfacial adhesion of the filler and EP matrix, but can also act as hardener to react with the EP chains covalently to further toughen the fabricated EP nanocomposites. The thermal stability, thermal conductivity, thermos-mechanical, and rheological properties of the EP/AEG nanocomposites were comprehensively studied. The results showed that the novel-designed AEG can significantly enhance the thermal conductivity of the EP composites. Moreover, the as-designed composites show superior thermal stability and thermo-physical properties, making them potentially useful as thermal management materials in electronic devices.

Interlayer polymerization in amine-terminated macromolecular chain-grafted expanded graphite for fabricating highly thermal conductive and physically strong thermoset composites for thermal management applications

Herein, we investigated polyacrylonitrile (PAN)-based porous activated carbon sorbents as an efficient candidate for CO2 capture. In this research, an easy and an economical method of chemical activation and carbonization was used to generate activated PAN precursor (PAN-C) adsorbents. The influence of various activators including NaOH, KOH, K2CO3, and KNO3 on the textural features of PAN-C and their CO2 adsorption performance under different temperatures was examined. Among the investigated adsorbents, PANC-NaOH and PANC-KOH exhibited high specific surface areas (2,012 and 3,072 m2 g-1), with high microporosity (0.82 and 1.15 cm3 g-1) and large amounts of carbon and nitrogen moieties. The PAN-C activated with NaOH and KOH showed maximum CO2 uptakes of 257 and 246 mg g-1 at 273 K and 163 and 155 mg g-1 at 298 K, 1 bar, respectively, which was much higher as compared to the inactivated PAN-C precursor (8.9 mg g-1 at 273 K and 1 bar). The heat of adsorption (Qst) was in the range 10.81-39.26 kJ mol-1, indicating the physisorption nature of the CO2 adsorption process. The PAN-C-based activated adsorbents demonstrated good regeneration ability over repeated adsorption cycles. The current study offers a facile two-step fabrication method to generate efficient activated porous carbon materials from inexpensive and readily available PAN for use as CO2 adsorbents in environmental applications.

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A Role of Activators for Efficient CO2 Affinity on Polyacrylonitrile-Based Porous Carbon Materials.

Activated carbon (AC) was synthesized with various weight ratios of manganese dioxide (MO) through a simple hydrothermal approach. The electrochemical performance of the synthesized activated carbon/MnO2 composites was investigated. The effect of the activated carbon/MnO2 (AM) ratio on the electrochemical properties of the activated carbon/MnO2 composites and the pore structure was also examined. The results show that the specific capacitance of the activated carbon material has been improved after the addition of MO. The as-synthesized composite material exhibits specific capacitance of 60.3 F g−1 at 1 A g−1, as well as stable cycle performance and 99.6% capacitance retention over 5000 cycles.

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Jang Rak Choi

Papers

Thermal conductivity and thermo-physical properties of nanodiamond-attached exfoliated hexagonal boron nitride/epoxy nanocomposites for microelectronics

Enhancing the heat and load transfer efficiency by optimizing the interface of hexagonal boron nitride/elastomer nanocomposites for thermal management applications

Interlayer polymerization in amine-terminated macromolecular chain-grafted expanded graphite for fabricating highly thermal conductive and physically strong thermoset composites for thermal management applications

A Role of Activators for Efficient CO2 Affinity on Polyacrylonitrile-Based Porous Carbon Materials.

Activated Carbon/MnO2 Composites as Electrode for High Performance Supercapacitors