Impact of resin density and short-chain branching distribution on structural evolution and enhancement of tensile modulus of MDO-PE films

Dixit Guleria; Shouren Ge; Ludwig Cardon; Sylvie Vervoort; Jaap den Doelder

Polymer Testing (Oct 2024)

Impact of resin density and short-chain branching distribution on structural evolution and enhancement of tensile modulus of MDO-PE films

Dixit Guleria,
Shouren Ge,
Ludwig Cardon,
Sylvie Vervoort,
Jaap den Doelder

Affiliations

Dixit Guleria: Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O Box 513, 5600 MB, Eindhoven, the Netherlands; Centre for Polymer and Material Technologies (CPMT), Department of Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 130, 9052, Zwijnaarde, Belgium
Shouren Ge: Dow Analytical Sciences, Lake Jackson, TX, 77566, USA
Ludwig Cardon: Centre for Polymer and Material Technologies (CPMT), Department of Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 130, 9052, Zwijnaarde, Belgium
Sylvie Vervoort: Dow Benelux B.V., Packaging and Specialty Plastics R&D, P.O. Box 48, 4530 AA, Terneuzen, the Netherlands
Jaap den Doelder: Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O Box 513, 5600 MB, Eindhoven, the Netherlands; Dow Benelux B.V., Packaging and Specialty Plastics R&D, P.O. Box 48, 4530 AA, Terneuzen, the Netherlands; Corresponding author. Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O Box 513, 5600 MB, Eindhoven, the Netherlands.

Journal volume & issue: Vol. 139
p. 108560

Abstract

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This research explores the potential of PE-based mono-material flexible packaging as a sustainable alternative to traditional designs, emphasizing its efficient mechanical recyclability. Typically, non-PE materials are used in the outer layers of multilayer flexible packaging to ensure adequate stiffness and barrier properties. The stiffness of PE films can be significantly improved through the machine direction orientation (MDO) process. Our study investigates the influence of key polyethylene (PE) resin parameters, specifically, resin density and short-chain branching (SCB) distribution, with indications of molecular weight on lab-scale MDO film stretching and its subsequent effects on mechanical properties. We processed 5 distinct PE resins and blends in a lab-scale setup to produce compression molded base sheets and further MDO-PE films, characterizing them using shear rheology, GPC, DSC, and iCCD analyses. Tensile testing provided insights into the mechanical characteristics, while X-ray scattering (SAXS and WAXS) and AFM studies analysed structural evolution and morphology. Uniaxial stretching notably enhanced the tensile modulus of MDO-PE films along the machine direction, particularly in higher density blends, comparable to conventionally used polymers. Challenges related to extremely high-density base sheets led to localized stretching and breakage. Certain resin compositions exhibited unique molecular architecture, facilitating enhanced tensile modulus and axial stiffness. Our study offers insights into the microstructural changes and surface morphology of MDO-PE films, underscoring the potential use of stiffness-enhanced MDO-PE films as outer layers in PE-based flexible packaging designs.

Published in Polymer Testing

ISSN: 0142-9418 (Print); 1873-2348 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Chemical technology: Polymers and polymer manufacture
Website: https://www.journals.elsevier.com/polymer-testing

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