Low Density Nanocellular Polymers Based on PMMA Produced by Gas Dissolution Foaming: Fabrication and Cellular...

Area of Science:

• Materials Science
• Polymer Science

Background:

• Nanocellular polymers offer unique properties due to their fine cellular structure.
• Polymethylmethacrylate (PMMA) is a versatile polymer suitable for various applications.

Purpose of the Study:

• To determine optimal processing conditions for producing low-density nanocellular PMMA.
• To investigate the relationship between processing parameters, cellular structure, and material properties.

Main Methods:

• Gas dissolution foaming technique using CO₂ as the blowing agent.
• Optimization of foaming temperature (40-110 °C) and time (1-5 min) while maintaining constant CO₂ uptake (31% by weight).
• Characterization of cellular structure (cell size, cell density) and relative density.

Main Results:

• Achieved relative densities between 0.45 and 0.25 with cell sizes of 200-250 nm and cell densities exceeding 10¹⁴ cells/cm³.
• Optimal foaming temperatures ranged from 80-100 °C with a foaming time of 2 min for lowest densities.
• Established a clear processing-cellular structure relationship.

Conclusions:

• Low-density nanocellular PMMA can be successfully produced by optimizing gas dissolution foaming parameters.
• The cellular structure significantly influences the glass transition temperature due to polymer confinement in cell walls.
• This confinement is a key factor contributing to the enhanced properties of nanocellular polymers.