Pyrene-Functionalized Alkali Lignin to Disperse Hydroxylated Boron Nitride Nanosheets in Cellulose Nanofibers for Thermal Management

High-thermal-conductivity (A) nanocomposites have been thought to resolve thermal management issues in electronic development. However, use of these is still challenging due to the easy aggregation of micro/nanofillers in a matrix. Here, a high-efficiency, low-cost, environmental strategy was developed wherein pyrene-functionalized alkali lignin (AL-PPBA) dispersants were employed to disperse hydroxylated boron nitride nanosheets (BNNS) by x-x conjugation in a cellulose nanofiber (CNF) solution, following which a nanocomposite film was prepared via the vacuum-assisted self-assembly method. Experimental and simulation results show that an efficient interfacial interaction between AL-PPBA and BNNS was achieved successfully and a stable aqueous dispersion solution was obtained. The as-prepared nanocomposites thus show A as high as 18.27 W m-1 K-1 with the loading of 10.4 vol % of BNNS and superior anisotropy. A potential thermal management capability was demonstrated when using nanocomposites as heat sink components for light-emitting diode (LED) chips. This study provides a route to promote the dispersity of micro/nanofillers via a noncovalent cross-linking strategy and address heat management issues.

Automated summary

A high-efficiency, low-cost, environmental strategy was developed to disperse hydroxylated boron nitride nanosheets in a cellulose nanofiber solution, using pyrene-functionalized alkali lignin as dispersants. The resulting nanocomposites exhibited high thermal conductivity and superior anisotropy. Potential thermal management capability was demonstrated when using these nanocomposites as heat sink components for LED chips. This study addresses the challenge of aggregating micro/nanofillers in a matrix and provides a route to promote their dispersity via a noncovalent cross-linking strategy.