9:00 AM. 368. Rheological Exploration of the Role of Microgel Polymer Network Structure and Interparticle Interactions on the Brittility of Granular PEG Hydrogel Biomaterials.Victor Rivera-Llabres, PhD1, Jiye Lee1, John Brownridge1, Simon Rogers, PhD1, Brendan Harley2 1University of Illinois Ubana-Champaign, 2University of Illinois at Urbana Champaign