Effects of Polymer Properties on Solid-State Shear Pulverization: Thermoplastic Processability and Nanofiller...

Area of Science:

• Polymer Science and Engineering
• Materials Science
• Mechanochemistry

Background:

• Solid-state shear pulverization (SSSP) is an advanced polymer processing technique utilizing twin-screw extrusion and continuous cooling.
• Low-temperature mechanochemistry in SSSP alters macromolecular architecture and morphology, impacting material properties.
• A fundamental understanding of SSSP's mechanochemical effects on polymer structure and properties is lacking.

Purpose of the Study:

• To systematically investigate the processing-structure-property relationships of 10 thermoplastic polymers subjected to SSSP.
• To correlate neat polymer characteristics with their response to SSSP mechanochemical pulverization and nanocomposite compounding.
• To elucidate how SSSP parameters influence structural changes and dictate system properties.

Main Methods:

• Systematic processing-structure-property investigation of 10 thermoplastic polymers using consistent SSSP.
• Analysis of structural, mechanical, and thermal characteristics of neat polymers and their response to SSSP.
• Correlation of SSSP parameters (specific mechanical energy, screw temperature) with polymer properties (glass transition temperature, toughness, crystallinity, thermal diffusivity).

Main Results:

• Mechanochemical engagement is favored by specific mechanical energy > 4 kJ/g, average screw temperature > 20 °C, glass transition temperature < 50 °C, and toughness > 40 MPa.
• Chain scission occurs during SSSP, with molecular weight reduction <10% for most polymers.
• SSSP processing parameters directly influence structural changes like molecular weight reduction and filler dispersion, affecting melt viscosity and thermal stability.

Conclusions:

• Elucidated processing-structure-property relationships provide a foundation for tailoring SSSP.
• The study enables targeted molecular structure alterations and performance improvements in polymers via SSSP.
• SSSP offers a versatile method for modifying polymer systems for specific applications.