Kinked Bisamides as Efficient Supramolecular Foam Cell Nucleating Agents for Low-Density Polystyrene Foams with Homogeneous Microcellular Morphology

Titelangaben

Klose, Bastian ; Kremer, Daniel ; Aksit, Merve ; van der Zwan, Kasper P. ; Kreger, Klaus ; Senker, Jürgen ; Altstädt, Volker ; Schmidt, Hans-Werner:
Kinked Bisamides as Efficient Supramolecular Foam Cell Nucleating Agents for Low-Density Polystyrene Foams with Homogeneous Microcellular Morphology.
In: Polymers. Bd. 13 (2021) Heft 7 . - No. 1094.
ISSN 2073-4360
DOI der Verlagsversion: https://doi.org/10.3390/polym13071094

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Abstract

Polystyrene foams have become more and more important owing to their lightweight potential and their insulation properties. Progress in this field is expected to be realized by foams featuring a microcellular morphology. However, large-scale processing of low-density foams with a closed-cell structure and volume expansion ratio of larger than 10, exhibiting a homogenous morphology with a mean cell size of approximately 10 mu m, remains challenging. Here, we report on a series of 4,4 `-diphenylmethane substituted bisamides, which we refer to as kinked bisamides, acting as efficient supramolecular foam cell nucleating agents for polystyrene. Self-assembly experiments from solution showed that these bisamides form supramolecular fibrillary or ribbon-like nanoobjects. These kinked bisamides can be dissolved at elevated temperatures in a large concentration range, forming dispersed nano-objects upon cooling. Batch foaming experiments using 1.0 wt.% of a selected kinked bisamide revealed that the mean cell size can be as low as 3.5 mu m. To demonstrate the applicability of kinked bisamides in a high-throughput continuous foam process, we performed foam extrusion. Using 0.5 wt.% of a kinked bisamide yielded polymer foams with a foam density of 71 kg/m(3) and a homogeneous microcellular morphology with cell sizes of approximate to 10 mu m, which is two orders of magnitude lower compared to the neat polystyrene reference foam with a comparable foam density.