Research on Polymer Viscous Flow Activation Energy and Non-Newtonian Index Model Based on Feature Size

Abstract

The viscous flow activation energy and non-Newtonian index properties of polymer based on feature size were studied through a series of experiments on the rheological properties of amorphous polymer polymethyl methacrylate (PMMA), semi-crystalline polymer polypropylene (PP), and crystalline polymer high-density polyethylene (HDPE) using capillary die with hole diameters of φ0.3 mm, φ0.5 mm, φ1.0 mm, and φ2.0 mm. The results show that the viscous flow activation energy of PMMA decreases with the feature size under microscopic scale. And the viscous flow activation energy of PP and HDPE increases with hole diameters of the die. Under macroscopic scale, the difference in viscous flow activation energy of all polymer materials is significantly reduced with hole diameters of the die. For the non-Newtonian index of the three polymer materials, it decreases with the feature size under the microscopic scale while it increases or does not change with the feature size under the macroscopic scale. At the same time, for different high polymer materials, the viscous flow activation energy model (SVAE model) and non-Newtonian index model (SNNE model) based on feature size were established. Finally, the accuracy and effectiveness of the SVAE model and the SNNE model are verified by comparing with the traditional model and reference data. The viscous flow activation energy and non-Newtonian index values of the polymer material can be calculated conveniently and accurately.

Improved melt strength and processability of impact copolymer polypropylene by introducing long‐chain branching via reactive extrusion with “ene” functionalized dendrimer

“…Since E a is not dependent on the change in molecular weight or PDI, an increase in its value can be credited to the reduction in segmental motion due to a high degree of entanglement in the prepared branched ICP sample. [49,50] As discussed before, the rheological response is highly dependent on the molecular structure and degree of branching of the polymer. The estimation of the extent of branching is important information as it influences the polymer's melt elasticity, shear thickening, and thinning behavior.…”

Azide Polyether with a Highly Flexible Main Chain as Energetic Materials

“…As can be seen from the figure, with an increase in temperature, the mobility of molecular chains is enhanced, and the viscosity of PADOL-1 decreases at a given shear rate. The relationship between the viscosity of a polymer melt and temperature can be described by the Arrhenius equation: η ( T ) = K normale E η / R T where η is the viscosity; K is the material constant, which can be obtained from the fitting curve of η 0 to T (Figure S11), K = η 0 ( T → ∞), E η is the viscous activation energy with units of J mol –1 , R = 8.314 J mol –1 K –1 is the gas constant, and T is the temperature.…”

“…As can be seen from the figure, with an increase in temperature, the mobility of molecular chains is enhanced, and the viscosity of PADOL-1 decreases at a given shear rate. The relationship between the viscosity of a polymer melt and temperature can be described by the Arrhenius equation: 28…”

Controlling the Processability and Stability of Supramolecular Polymers Using the Interplay of Intra- and Intermolecular Interactions

“…The results show that polymers with higher DPs result in lower activation energies, while no significant trend was observed upon increasing the content of UPy-urea grafts (5 to 10 mol %) (Figure E). Interestingly, the absolute activation energy values seem to be comparable to averaged values for UPy dissociation and viscous flow of conventional polymers, arguably indicating the presence of a synergistic process. However, in-depth mechanistic studies would be required to support this hypothesis.…”