ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 5, pp. 871−878. © Pleiades Publishing, Ltd., 2015.
Rheological Modeling of Polymeric Films
B. V. Berdyshev
, I. V. Skopintsev
, H. Hosseini
, and B. Shirkavand Hadavand
Department of Chemical Equipment, Moscow State University of Mechanical Engineering,
ul. B. Semenovskaya 38, Moscow, 107023 Russia
Department of Chemical Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran
Laboratory of Polymer Chemistry, Faculty of Chemistry, University of Helsinki,
Fabianinkatu 33, P.O. 3, Helsinki, Finland
Institute for Color Science and Technology, Department of Resin and Additives, Tehran, Iran
Received May 18, 2015
Abstract—The equations in this paper determine the kinetics of elastic deformation in polymeric ﬁ lms under
loading to the point of destruction. The rheological model indicates that the destruction of polymeric ﬁ lms is
characterized by relaxation time, initial stress and the level of limited deformation. These results make it possible
to determine the critical time and allow prediction of the performance of this product. The destruction of poly-
meric ﬁ lms can be calculated from the results presented herein and only requires evaluation of the accumulated
elastic deformation for each discrete load. The period of time after which the accumulated elastic deformation
from discrete loading reaches a critical value provides a theoretical estimate of product life. This paper proposes
a reasonable agreement between experimental data and model prediction.
Most polymer ﬁ lm is used to produce bags. These
bags are used for packaging, storage and transportation
of products. American and European patent applications
relating to the production of plastic shopping bags
date back to the early 1950s, but these were primarily
composite constructions with handles ﬁ xed to the bag
in a secondary manufacturing process. The modern
lightweight shopping bag is the invention of Swedish
engineer Sten Gustaf Thulin. The popularity of polymer
bags can be traced to their convenience, light weight and
capacity to be reused for other purposes.
Creep and destruction in polymer ﬁ lms has become a
major concern during loading because of the viscoelastic
nature of the polymer matrix, in which degradation is
time-dependent upon the modulus. It has been shown
that under uniaxial extension the rupture of polymer ﬁ lm
can be categorized as dependent upon the applied load,
molecular structure and the environment [1−3]. Typically,
these bags are not durable. Most users have experienced
sudden tearing of a loaded bag. This fairly frequent
occurrence has prompted assessment of the efﬁ ciency of a
bag under force loading for the duration of its use [4−10].
In-service bag rupture most often occurs near the handle.
It is the most loaded section of the bag and experiences
maximum tensile stress (Fig. 1). Overhead bag handles
consist of two slit strips on each side of the bag that are
. The pressed ﬁ lm evenly redistributes
the load acting on the width of the ﬁ lm (Fig. 1, section b).
The most loaded section is A (Fig. 1) and this is the area
where the handles rupture. These are usually overhead
handles or other structures in areas immediately adjacent
to them, where the polymeric ﬁ lm material experiences
deformation in a horizontal direction. In reality, these
deformed areas of material correspond to the kinematics
of pure shear [11−15].
The text was submitted by the authors in English.