Cross-Linking-Filler Composite Materials of Functionalized Hexagonal Boron Nitride and Polyrotaxane Elastomer

Abstract

This study demonstrates cross-linking-filler composites in which covalent bonds between the fillers and polymer chains act as the main cross-linking points for the development of flexible and thermally conductive materials. Cross-linking-filler composites are fabricated using functionalized hexagonal boron nitride (hBN) fillers and polyrotaxane, called slide-ring polymers. The hBN particles modified with a carbon layer were produced by plasma processing in hydroquinone aqueous solution and functionalized with isocyanate groups. As the functionalized hBN provides cross-linking points for polyrotaxane, the cross-linkingfiller composites can reduce cross-linking agents among polyrotaxane and exhibit considerable flexibility. Young's moduli of the cross-linking-filler composites are much lower than those of previously reported polyrotaxane composites while retaining their toughness. These values are relatively close to those of unfilled polyrotaxane elastomers, despite containing hBN fillers with a content of 50 wt %. Thus, the cross-linking-filler composites exhibit a combination of flexibility and thermal conductivity, which few hBN/elastomer composites have achieved.

Cyclodextrins‐Based Polyrotaxanes: From Functional Polymers to Applications in Electronics and Energy Storage Materials

“…It's noteworthy that while polyrotaxanes typically form topological cross-linking structures with polymers at the molecular level in gel and elastomer systems, their application extends to batteries and flexible electronic devices, demonstrating that the slide-ring effect can be effectively utilized and regulated at micro and nano scales. [133] As mentioned above, the successful applications in engineering polymers, electronics and energy storage materials achieved the first step in industrialization of CDs-based polyrotaxanes. Hence, the environmental impact of these materials, including aspects of biodegradability and sustainability should be taken into consideration.…”

“…The sliding behavior of cyclodextrins during stretching enabled the MXene to form a strong resistance to structural defect formation. It's noteworthy that while polyrotaxanes typically form topological cross‐linking structures with polymers at the molecular level in gel and elastomer systems, their application extends to batteries and flexible electronic devices, demonstrating that the slide‐ring effect can be effectively utilized and regulated at micro and nano scales [133] …”

Size reduction and water dispersibility improvement of hexagonal boron nitride particles by femtosecond laser irradiation in water

“…In this process, the discharge plasma indirectly affects hBN particles; it initially acts on the solvent or solvent vapor, and then the generated active species chemically interact with hBN. Consequently, this approach has led to defect formation in fillers [8], improved dispersion of fillers in composites and water [9], and enhanced mechanical properties of composite materials [9][10][11]. Moreover, physical effects induced by discharge plasma, such as the exfoliation of hBN particles, have been reported [12].…”