Micronization as a solution for enhancing the thermal insulation of nanocellular poly(methyl-methacrylate) (PMMA)

• Published in: Polymer (Guilford) Vol. 261; p. 125397
• Main Authors: Sánchez-Calderón, Ismael, Bernardo, Victoria, Cuadra-Rodríguez, Daniel, Martín-de-León, Judith, Rodríguez-Pérez, Miguel Ángel
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 18-11-2022
• Subjects: Nanocellular powder; poly(methyl-methacrylate); Thermal conductivity; Nanocellular powder; poly(methyl-methacrylate); Thermal conductivity
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2022.125397

This work shows a route to reduce the thermal conductivity of nanocellular poly(methyl-methacrylate) (PMMA). This approach is based on micronizing to replace the continuous solid phase by a discontinuous one. PMMA powders with densities of 147–195 kg/m3, formed by particles of 100 μm with nanometric cells inside them, are produced by milling. Micronization allows increasing the overall porosity maintaining the cell size. Results prove that after milling it is possible to obtain open cell nanoporous PMMA powders with thermal conductivity below that of the bulk materials (15% reduction). The reduction is not only due to a density decrease, but a result of the new structure of the powder material. The discontinuity of the solid phase and the increase in radiation extinction are the key factors allowing this improvement. This route is confirmed as a promising alternative to enhance the performance of nanocellular polymers.
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•Production and characterization of open cell nanoporous powders by micronization.•Micronization allows reducing the thermal conductivity of nanocellular polymers.•The solid structure factor is reduced due to the contact-points between particles.