2024-03-28T21:50:27Zhttp://uvadoc.uva.es/oai/requestoai:uvadoc.uva.es:10324/407182021-06-24T07:47:36Zcom_10324_31661com_10324_952com_10324_894com_10324_1158com_10324_931col_10324_31662col_10324_1242
00925njm 22002777a 4500
dc
Bernardo García, Victoria
author
Martín de León, Judit
author
Laguna Gutiérrez, Ester
author
Catelani, Tiziano
author
Pinto Sanz, Javier
author
Athanassiou, Athanassia
author
Rodríguez Pérez, Miguel Ángel
author
2018
Nanostructured polymer blends with CO2-philic domains can be used to produce nanocellular materials with controlled nucleation. It is well known that this nanostructuration can be induced by the addition of a block copolymer poly(methyl methacrylate)-poly(butyl acrylate)-poly(methyl methacrylate) (MAM) to a poly(methyl methacrylate) (PMMA) matrix. However, the effect of the block copolymer molecular weight on the production of nanocellular materials is still unknown. In this work, this effect is analysed by using three types of MAM triblock copolymers with different molecular weights, and a fixed blend ratio of 90 wt% PMMA and 10 wt% of MAM. Blends were produced by extrusion. As a result of the extrusion process, a non-equilibrium nanostructuration takes place in the blends, and the micelle density increases as MAM molecular weight increases. Micelle formation is proposed to occur as result of two mechanisms: dispersion, controlled by the extrusion parameters and the relative viscosities of the polymers, and self-assembly of MAM molecules in the dispersed domains. On the other hand, in the nanocellular materials produced with these blends, cell size decreases from 200 to 120 nm as MAM molecular weight increases. Cell growth is suggested to be controlled by the intermicelle distance and limited by the cell wall thickness. Furthermore, a theoretical explanation of the mechanisms underlying the limited expansion of PMMA/MAM systems is proposed and discussed.
Polymer, Volume 153, 26 September 2018, Pages 262-270
0032-3861
http://uvadoc.uva.es/handle/10324/40718
10.1016/j.polymer.2018.08.022
262
270
Polymer
153
Understanding the role of MAM molecular weight in the production of PMMA/MAM nanocellular polymers