Self-assembled supramolecule for synthesizing highly thermally conductive Cellulose/Carbon nitride nanocomposites with improved flame retardancy

• Published in: Journal of colloid and interface science Vol. 608; no. Pt 3; pp. 2560 - 2570
• Main Authors: Zhang, Hangzhen, Wu, Kun, Jiao, Enxiang, Liu, Yingchun, Shi, Jun, Lu, Mangeng
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.02.2022
• Subjects: Carbon Nitride; Cellulose; Cellulose Nanofiber; Electrical Insulation; Flame Retardancy; Nanocomposites; Nanofibers; Nitriles; Supramolecule; Thermal Conductivity; Cellulose Nanofiber; Supramolecule; Electrical Insulation; Thermal Conductivity; Carbon Nitride; Flame Retardancy
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2021.10.177

[Display omitted] •A strategy focused on precursor selection was proposed to achieve high thermal conductivity.•Additional modifications for cellulose matrix or carbon nitride filler were not required.•Resultant cellulose/carbon nitride films showed obvious improvement on flame retardancy.•The application of carbon nitride for thermal management was further expanded. The fabrication of polymer composites with excellent thermal conductivity typically involves complex matrix or fillers modifications. This study proposed a simple technique based on precursor selection for obtaining highly thermally conductive cellulose nanofiber (CNF)/supramolecule-synthesized carbon nitride (SCN) composites. Fourier-transform infrared tests demonstrated the construction of hydrogen bonds between CNF and SCN; a highly ordered structure and relatively compact in-plane stacking were confirmed via scanning electron microscopy and X-ray diffraction characterizations. Consequently, the resultant CNF/SCN composites exhibited remarkable in-plane thermal conductivity of 11.83 ± 0.41 W m−1 K−1 at 30 wt% SCN content, which was attributed to the significantly reduced interfacial phonon scattering. It also showed evident improvements in electrical insulation and flame retardancy compared with the pure CNF film, where the volume resistivity, peak heat release rate, and total heat release were remarkably enhanced by 1242% and reduced by 59.9% and 15.8%, respectively. Further analysis of char residuals revealed a relatively dense surface, high concentration of carbon materials, and a high degree of graphitization, indicating that the char residual functioned as a robust physical barrier to effectively inhibit combustion. This study provides a facile approach to achieving high-efficiency improvements in thermal conductivity and flame retardancy, and simultaneously facilitating broader applications of carbon nitride in thermal management.