This is because of the molecular relaxation
occurred at relatively high pretreatment temperature.
This complicated phenomenon is one of the motivations for starting this study, to investigate molecular relaxation
changes occurring in a polymer during weathering as an explanation to supplement chemical degradation for these observations.
g] when a reaction or molecular relaxation
is going on and separates decomposition from crosslinking.
Molded EPS patterns shrink with time due to molecular relaxation
of the stresses in the cell walls and equilibration of the gas composition in each cell with the surrounding air," according to the authors.
Relatively fast molecular relaxation
in the melt or solution state hinders orientation of macromolecules by adopting the entropically favorable random coil conformation.
Work in this paper explores the effect of temperature of the weathering environment, and how it affects the polymer molecular relaxation
Shrinkage results from the gas composition in each cell coming into equilibrium with the surrounding air and from molecular relaxation
In the glassy state the molecular relaxation
engages cooperative movements in larger scales than the liquid-like state .
Several dielectric studies on the molecular relaxation
behavior of PP are available (18-20).
This was considered to be due to molecular relaxation
occurring which reduces the orientation for subsequent crystallization.
4a obtained in dry PA66 show at least three well-identified molecular relaxation
processes, namely [gamma], [beta], and [alpha] (in order of increasing temperature) (28-30).
The shear-thinning at the low frequency region can be assigned to the molecular relaxation
at the crystalline interfaces and is related to the double melt peak phenomenon of PEEK.