Research Information System
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING, vol.49, pp.10787-10803, 2024 (SCI-Expanded)
A numerical simulation of the film blowing process is performed. The Phan–Thien and Tanner (PTT) constitutive equations
with quiescent and flow-induced crystallization effects are considered with proper boundary and initial conditions. The PTT
model is employed both for molten and crystallized polymer. Modeling of crystallization is done with nested Schneider rate
equations and the Kolmogorov–Avrami model. The current model can predict the shape and size of the bubbles, as well as their
temperature, stress, space filling and morphological changes for given process conditions. The study focuses on investigating
the impact of process conditions on the mechanical response of the blown film, as well as on the morphological structure of
the crystallizing molten polymer. It is observed that the axial stress increases at a faster rate compared to the circumferential
stress with increase in draw ratio. The trend is reversed for increasing blow-up ratios. Increasing the draw ratio does not
result in significant improvement in the quiescent contribution to the crystalline structure, but it leads to a decrease in the
flow-induced contribution. Increasing blow-up ratio leads to increase in total space filling and the flow-induced component
of the crystalline structure. Finally, three heat transfer coefficients chosen from the literature are compared. It is observed
that the model choice is not critical for higher draw ratio values, but for low and moderate values, detailed investigations are
required. The presented model enables accurate prediction of both the morphological structure and mechanical properties of
semicrystalline polymers in a film blowing process