Collaborative Research: Stronger than Glass Fibers, Stiffer than SteelWires: A New Perspective into the Mechanics of Cellulose Nanocrystals

Reza Shahbazian-Yassar, Michigan Technological University, DMR 1100806

Intellectual Merit: Cellulose nanocrystals (CNCs) are highly crystalline organic polymers that can be extracted from natural materials. They are stiffer than aluminum and theoretical calculations place their tensile strength at 7500 MPa, higher than glass fibers or steel. However the properties of individual nanotubes are difficult to measure due to their small dimensions and lack of miniaturize devices with capability for sensitive force, electrical and thermal measurements.

We successfully showed that the mechanical properties of interphase in cellulose nanocrystal (CNC) composites could be quantitatively characterized and the correlation with the size of CNCs could be mapped. The peak force tapping mode in atomic force microscope (AFM) was used to characterize deformation, adhesion, and modulus gradient of the interphase region in poly(vinyl alcohol) (PVA)-poly(acrylic acid) (PAA)-cellulose nanocrystal (CNC) composites. It is shown that interphase thickness is higher for CNCs with larger diameter.

Broader Impact: A news article about our cellulose work is published at www.nanotechweb.org We also have had 3 published journal articles:(1) A. Pakzad, et al., Journal of Materials Research, 27 (2012), 528-536.(2) A. Pakzad, et al., Nanotechnology, 23 (2012), 085706.(3) A. Pakzad, et al., Composites Science and Technology, 72 (2012) 314–319

In addition, the PI taught the concept of cellulose nanocrystals and their mechanical properties in two lectures of MEEM 5130-Nanotechnology course.

Collaborative Research: Stronger than Glass Fibers, Stiffer than SteelWires: A New Perspective into the Mechanics of Cellulose Nanocrystals

Reza Shahbazian-Yassar, Michigan Technological University, DMR 1100806