Investigation of the migration behavior of polyisobutylene with various molecular weights in ethylene/α‐olefin copolymer blown stretch films for improved cling properties |
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| Authors: | Mirko Rennert Steffen Fiedler Michael Nase Matthias Menzel Sandra Günther Jörg Kressler Wolfgang Grellmann |
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| Affiliation: | 1. Department of Materials Science, Center of Engineering Science, Martin‐Luther University Halle‐Wittenberg, Haale/Saale, Germany;2. Chemistry Department, Physical Chemistry of Polymers, Martin‐Luther‐University Halle‐Wittenberg, Halle/Saale, Germany;3. Department of Engineering, University of Applied Science Hof, Faculty of Engineering, Hof, Germany;4. Business Unit Biological and Macromolecular Materials, Fraunhofer Institute for Mechanics of Materials IWM, Halle (Saale), Germany |
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| Abstract: | High retention forces are the basic requirements on stretch films for agricultural or pallet wrapping of goods and significantly influenced by cling properties (autohesion) that are essential for a reliable load stability during transportation and storage. Low molecular weight polyisobutylene (PIB) has tacky properties and is immiscible with polyethylene. Blended with ethylene/α‐olefin copolymers in coextruded stretch films, PIB can migrate to the film surfaces and cause cling properties. Cling and adhesion forces were investigated using the mechanical cling test, atomic force, and scanning electron microscopy and infrared spectroscopy. The molecular weight of the PIB as well as density and crystallinity of the matrix material have strong influences on migration kinetics and therefore, on the cling forces. Cling forces increase with increasing aging time, having a maximum after 2 weeks of production. The following slight decrease of the cling force might be correlated with a beginning degradation process of the UV sensitive PIB. Polyisobutylene with higher molecular weight diffuses slower through a linear low density polyethylene (LLDPE) matrix than lower molecular weight PIB, but can cause higher cling forces on the film surfaces. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40239. |
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| Keywords: | films packaging adhesives polyolefins copolymers |
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