Abstract
A series of tensile relaxation tests is performed on isotactic polypropylene in the
sub-yield and post-yield regions at room temperature. Constitutive equations are
derived for the time-dependent response of a semicrystalline polymer at isothermal
loading with small strains. Adjustable parameters in the stress–strain relations
are found by fitting experimental data. It is demonstrated that the growth of the
longitudinal strain results in an increase in the relaxation rate in a small interval of
strains in the sub-yield domain. When the strain exceeds some critical value which
is substantially less than the apparent yield strain, the relaxation process becomes
strain-independent.
sub-yield and post-yield regions at room temperature. Constitutive equations are
derived for the time-dependent response of a semicrystalline polymer at isothermal
loading with small strains. Adjustable parameters in the stress–strain relations
are found by fitting experimental data. It is demonstrated that the growth of the
longitudinal strain results in an increase in the relaxation rate in a small interval of
strains in the sub-yield domain. When the strain exceeds some critical value which
is substantially less than the apparent yield strain, the relaxation process becomes
strain-independent.
| Originalsprog | Engelsk |
|---|---|
| Publikationsdato | 2002 |
| Antal sider | 20 |
| Status | Udgivet - 2002 |