Oriented Tapes of Incompatible Polymers Using a Novel Multiplication Co-Extrusion Process.

Area of Science:

• Materials Science
• Polymer Science
• Composite Materials

Background:

• Developing advanced polymer composites with enhanced mechanical properties is crucial for various industrial applications.
• Polypropylene (PP) and high-density polyethylene (HDPE) are widely used polymers, but their incompatibility limits direct composite formation.
• Novel processing techniques are needed to create strong interfaces between dissimilar polymers.

Purpose of the Study:

• To develop a novel co-extrusion process for creating continuous tapes of polypropylene (PP) and high-density polyethylene (HDPE).
• To investigate the structure-property relationships of the resulting PP/HDPE composite tapes.
• To evaluate the mechanical performance and interfacial interactions of the oriented composite tapes.

Main Methods:

• Utilized a novel multiplication co-extrusion process to produce PP/HDPE tapes.
• Characterized the tape structure using Atomic Force Microscopy (AFM).
• Performed orientation processing at 130 °C and analyzed mechanical properties (modulus, tensile strength) at various draw ratios.

Main Results:

• The co-extrusion process resulted in co-continuous PP and HDPE domains (200-500 nm) with a large contact interface.
• AFM revealed strong interfacial interactions between the incompatible PP and HDPE domains.
• Oriented tapes showed significantly increased modulus (approx. 10 GPa) and tensile strength (approx. 540 MPa) at a draw ratio of 25.
• The oriented tapes demonstrated superior stiffness and strength compared to commercial tapes without fibrillation.

Conclusions:

• The novel co-extrusion process successfully created a fiber-like PP/HDPE composite structure with enhanced interfacial adhesion.
• Epitaxial crystallization and large interfacial area enabled high-degree orientation, leading to superior mechanical properties.
• The resulting oriented PP/HDPE tapes offer a promising alternative to conventional materials due to their enhanced performance and processing stability.