Reinforcing Poly(ethylene) with Cellulose Nanocrystals

The fabrication of nanocomposites of low-density polyethylene (LDPE), one of the world's most widely used polymers, and cellulose nanocrystals (CNCs), which represent the world's most abundant bio-based nanofiller, is reported. While the hydrophobic polymer and the hydrophilic filler seem to be intrinsically incompatible, this article shows that it is possible to kinetically trap homogeneous nanocomposites by a templating approach. An organogel is first prepared by exchanging the solvent of an aqueous CNC dispersion against acetone, impregnating the resulting organogel, in which the CNCs form a percolating network with a hot LDPE solution in toluene, and compression-molding the resulting materials into thin films. At a filler content of 7.6% v/v, the resulting materials display a three- to four-fold increase in strength and stiffness compared with the neat LDPE, which confirms that the CNC network could be largely maintained. It is also possible to reprocess these nanocomposites and dilute them with LDPE using conventional melt-processing techniques.