Visco- and plastoelastic fracture of nanoporous polymer sheets

Abstract

We study the dependence of the fracture surface energy on the pulling velocity for nano-porous polypropylene (PP) sheets to find two components: the static and dynamic ones. We show that these terms can be interpreted respectively as plastoelastic and viscoelastic components, as has been shown for soft polyethylene (PE) foams in a previous work. Considering significant differences in the pore size, volume fraction and Young's modulus of the present PP and previous PE sheets, the present results suggest a universal physical mechanism for fracture of porous polymer sheets. The simple physical interpretation emerging from the mechanism could be useful for developing tough polymers. Equivalence of Griffith's energy balance in fracture mechanics to a stress criterion is also discussed and demonstrated using the present experimental data.

Influence of PVB Interlayer Mechanical Properties on Laminated Glass Elements Design in Dependence of Real Time-Temperature Changes

“…To determine the mechanical properties of viscoelastic materials [ 22 ], it is necessary to combine elastic behavior governed by Hooke’s law and viscous behavior governed by Newton’s law [ 23 ]. During the static test, two approaches are carried out: creep test and stress relaxation test ( Figure 2 ).…”