Microcellular low-density nanocomposite foams nucleated by carbon-based nanofillers – processing, properties and foaming behaviour
The demand for energy-efficient houses has led to greater demand by the building and construction industry for polymeric foam materials with superior thermal insulation properties. The prerequisite for this is the preparation of microcellular or, better still, nanocellular low-density foams. Attaining the aforesaid goal comes of course with several challenges concerning the selection of the right foam base material, nucleating agents, processing conditions and processing techniques.
This work outlines a systematic approach to realize low-density foams based on polystyrene (PS), poly(methyl methacrylate) (PMMA) and blends of polystyrene/poly(methyl methacrylate) (PS/PMMA) by incorporating carbon-based fillers such as carbon black, thermally-reduced graphite oxide and talc (inorganic filler) as cell-nucleating agents. The foaming experiments were performed via batch-process and foam extrusion methods.
Low-density foams with high volume expansion ratios were realized, especially via blending of PS with PMMA. The CO2 -philic (the high affinity of PMMA to carbon dioxide due to the presence of carbonyl oxygen) property of PMMA was exploited to realize the cell densities and nucleation densities of 1010 cells/cm3 . Microcellular-extruded PMMA foams that have mean cell sizes of approximately 7 µm at a target density of 190 kg/m3 were achieved with TRGO filler. Also, the extruded low-density foams realized respectively with PS and PMMA revealed homogeneous cell microstructures and the cell size distributions followed a Gaussian distribution. The thermal conductivity value of extruded PS/TRGO nanocomposite foams were found to be superior to neat polystyrene foams (reference material) and Styrodur® C (a commercially-available extruded polystyrene foam from BASF) by 8 % and 3 %, respectively.Lesen Sie die deutsche Zusammenfassung auf Kunststoffe.de
Nanocellular foam, microcellular foam, cell nucleation, thermal conductivity, Knudsen-effect, nanofiller, polystyrene, poly(methyl methacrylate), blend
Institute / chair: Lehrstuhl für Polymere Werkstoffe der Universität Bayreuth
Technical consultant for expert services: Prof. Dr.-Ing. Volker Altstädt, Prof. Dr. Hans-Werner Schmidt
Publication year: 2019
Provider: Wissenschaftlicher Arbeitskreis Kunststofftechnik (WAK) / Kunststoffe.de
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