However, a master curve cannot be drawn for the viscosity of polymers for which temperature causes chemical aging like postcondensation or thermo-hydrolytic degradation.
4] recently used a relatively simple experimental approach to consider rheological changes of PA 12, which were initiated by processing conditions and caused by postcondensation.
The effect of thermally initiated postcondensation or degradation was measured in oscillatory shear, whereas a frequency scan was repeated more than one time with the same sample.
The results show that in vacuum atmosphere aging is more severe than in nitrogen atmosphere as post-crystallization effects and postcondensation
effects are not reduced by simultaneous degradation effects by auto-oxidation.
a copolymeric interfaciel layer is f ormed, acting as a compatibilizer; (ii) an additional stage can be included ensuring molecular weight upgrading via solid state postcondensation
(27, 29) when A and B are recycled polycondensates (e.
Yet at the drying temperature of 210[degrees]C, one observes a further weight loss after the equilibrium value, which may possibly be due to postcondensation
in the solid state .