The Transient Flow of the PET‐PEN‐Montmorillonite Clay Nanocomposite

Abstract

Polyethylene terephthalate (PET) and polyethylene 2, 6 naphthalene dicarboxylate (PEN) nanocomposites were prepared by an extrusion process with organic‐modified montmorillonite clay. The steady‐state viscosity of all blends diminished as compared to the system with no clay added. A rheological study was conducted to know more about the complex structure formed by the polymer matrix‐clay interactions. Instantaneous stress relaxation curves are presented for the PEN, PEN‐PET and PET‐PEN‐1phr clay systems. A Fourier Transform (FT) frequency response was obtained from the relaxation curves and compared to the linear oscillatory data, which lead to an extended frequency region. The results were modeled by a rheological equation of state which accounts for the formation‐destruction dynamics of the microstructure during flow. Relaxation time spectra are presented and compared for both rheological tests, namely, instantaneous stress relaxation and linear oscillatory flow. Additional studies using scanning electron microscopy (SEM) are presented, which reveal the presence of a slip layer in capillary flow for the system with added clay.

Linear oscillatory dynamics of flexoelectric membranes embedded in viscoelastic media with applications to outer hair cells

“…The resonance properties: (i) frequency, (ii) power, (iii) elasticmembrane energy, and (iv) resonance ratio were computed using eqns. (43,(46)(47)(48)(49). The value of the dimensionless numbers and parametric functions (22)(23)(24) were chosen in order to satisfy the mathematical and physical requirements given by eqn.…”

“…All these parameters can be estimated from rheological and membrane experiments in steady and unsteady state [46][47][48][49][50][51][52]. Equations (14-16a-f) describe an electro-viscoelastic system with three phases, two viscoelastic liquids and one elastic membrane.…”

Rheological of chocolate-flavored, reduced-calories coating as a function of conching process

“…The results obtained from the rheometric tests were modeled using a multimode Maxwell model (Calderas et al 2009;Macosko and Larson 1994) algorithm. The multimode Maxwell model was expressed in terms of elastic moduli G', and viscous G'', as indicated by Eqs.…”

PET-MMT and PET-PEN-MMT Nanocomposites by Melt Extrusion

“…For a mono modal model ( ) 1 i = , the BMP [Bautista et al 1999Soltero 1999Escalante et al 2007;Calderas et al 2009;Herrera et al 2009Herrera et al , 2010 model is defined by the following equations: …”

“…In addition, the model reproducing the complete flow curve for a shear thinning and shear-thickening fluid, i.e. a Newtonian plateau at low and high shear rates, an intermediate power-law region and non-vanishing normal-stress differences; it also gives a reasonable description of the elogational and complex viscosity with finite asymptotic value and mono-exponential relaxation stress relaxation and start-up curves, thixotropy and shear banding flow [Soltero et al 1999;.Bautista et al 1999;, Escalante et al 2003Calderas et al 2009]. …”