Isotactic polypropylene (iPP) melts are industrial semicrystalline polymers whose processing typically involves strong shear flows. The study of the rheological response iPP melts, well beyond linear viscoelastic limit, is limited by edge fracture, which manifests in rotational rheometers. In this work, we used a reflection polariscope under to detect onset rate at fracture observed for various...

We report on the synthesis and the mechanical characterization of an alginate-collagen fibril composite hydrogel. Native type I collagen fibrils were used to synthesize the fibrous composite hydrogel. We characterized the mechanical properties of the fabricated fibrous hydrogel using tensile testing; rheometry and atomic force microscope (AFM)-based nanoindentation experiments. The results show...

Using rheometry and light scattering, we have studied the viscoelasticity of gels formed by the kinetically arrested phase separation in an emulsion-polymer mixture; to prevent the gels from collapsing under their own weight, we have used an isopycnic solvent. At constant osmotic pressure (set by the polymer concentration) and droplet volume fractionsφ well above the gelation transition, we fin...

The knowledge of brain tissue mechanical properties is a critical issue in the head injury biomechanics research field. Due to experimental limitations, brain tissue has been characterized in vitro, whereas its actual in vivo behavior remains poorly known. We propose the use of Magnetic Resonance Elastography as a non invasive, non destructive tool for measuring the viscoelastic properties of b...

A combination of sensitive rotational rheometry and surface rheometry with a double-wall ring were used to identify the origins of the viscosity increase at low shear rates in protein solutions. The rheology of two high molecular weight proteins is discussed: Bovine Serum Albumin (BSA) in a Phosphate Buffered Saline solution and an IgG1 monoclonal antibody (mAb) in a formulation buffer containi...

The co-assembly of mutually complementary, but self-repulsive oligopeptide pairs into viscoelastic hydrogels has been studied. Oligopeptides of 6, 10, and 14 amino acid residues were used to investigate the effects of peptide chain length on the structural and mechanical properties of the resulting hydrogels. Biophysical characterizations, including dynamic rheometry, small-angle X-ray scatteri...

Natural and synthetic hydrogel scaffolds exhibit distinct viscoelastic properties at various length scales and deformation rates. Laser Speckle Rheology (LSR) offers a novel, non-contact optical approach for evaluating the frequency-dependent viscoelastic properties of hydrogels. In LSR, a coherent laser beam illuminates the specimen and a high-speed camera acquires the time-varying speckle ima...

The purpose of this paper is to demonstrate how the general problem interconversion between parallel and orthogonal superposition protocols can be treated using kernels in a Fréchet series expansion about base viscometric flow. Such differ from expanded rest history which are encountered theory Green–Rivlin materials simple fluid Coleman Noll, that nonlinear response material captured at first ...