Amorphous Polymers’ Foaming and Blends with Organic Foaming-Aid Structured Additives in Supercritical CO2, a Way to Fabricate Porous Polymers from Macro to Nano Porosities in Batch or Continuous Processes

Molecules

Michel Dumon¹  Margaux Haurat¹ 

[1] Laboratoire de Chimie des Polymères Organiques (LCPO), UMR 5629, Bordeaux INP/ENSCBP, University Bordeaux, CNRS, 16 avenue Pey-Berland, CEDEX, F-33607 Pessac, France;

关键词: polymer foam;    nanostructuration;    batch-foaming;    PMMA;    MAM;    core-shell particles;   

DOI  :  10.3390/molecules25225320

来源: DOAJ

【 摘 要 】

Organic polymers can be made porous via continuous or discontinuous expansion processes in scCO₂. The resulting foams properties are controlled by the interplay of three groups of parameters: (i) Chemical, (ii) physico-chemical, and (iii) technological/process that are explained in this paper. The advantages and drawbacks of continuous (extrusion, injection foaming) or discontinuous (batch foaming) foaming processes in scCO₂, will be discussed in this article; especially for micro or nano cellular polymers. Indeed, a challenge is to reduce both specific mass (e.g., ρ < 100 kg·m⁻³) and cell size (e.g., average pore diameter ϕ_average^pores < 100 nm). Then a particular system where small “objects” (coreshells CS, block copolymer MAM) are perfectly dispersed at a micrometric to nanometric scale in poly(methyl methacrylate) (PMMA) will be presented. Such “additives”, considered as foaming aids, are aimed at “regulating” the foaming and lowering the pore size and/or density of PMMA based foams. Differences between these additives will be shown. Finally, in a PMMA/20 wt% MAM blend, via a quasi one-step batch foaming, a “porous to nonporous” transition is observed in thick samples. A lower limit of pore size (around 50 nm) seems to arise.

【 授权许可】

Unknown