Comprehensive Analysis of the Influence of Expanded Vermiculite on the Foaming Process and Selected Properties of Composite Rigid Polyurethane Foams

Mateusz Barczewski; Maria Kurańska; Kamila Sałasińska; Joanna Aniśko; Joanna Szulc; Izabela Szafraniak-Wiza; Aleksander Prociak; Krzysztof Polaczek; Katarzyna Uram; Karolina Surmacz; Adam Piasecki

doi:10.3390/polym14224967

Comprehensive Analysis of the Influence of Expanded Vermiculite on the Foaming Process and Selected Properties of Composite Rigid Polyurethane Foams

Polymers (Basel). 2022 Nov 16;14(22):4967. doi: 10.3390/polym14224967.

Affiliations

¹ Institute of Materials Technology, Poznan University of Technology, Piotrowo 3, 61-138 Poznan, Poland.
² Department of Chemistry and Technology of Polymers, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland.
³ Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw, Poland.
⁴ Central Institute for Labour Protection-National Research Institute, Department of Chemical, Biological and Aerosol Hazards, 00-701 Warsaw, Poland.
⁵ Faculty of Chemical Technology and Engineering, Bydgoszcz University of Technology, Seminaryjna 3, 85-326 Bydgoszcz, Poland.
⁶ Institute of Materials Engineering, Faculty of Materials Engineering and Technical Physics, Poznan University of Technology, Piotrowo 3, 61-138 Poznan, Poland.

Abstract

This article presents the results of research on obtaining new polyurethane (PUR) foams modified with thermally expanded vermiculite. The filler was added in amount of 3 wt.% up to 15 wt.%. The additionally applied procedure of immersion the non-organic filler in H₂O₂ was performed to increase the exfoliation effect of thermally treated mineral and additional oxidation the surfaces. The effect of fillers on foaming process, cell structure, thermal insulation, apparent density, compressive strength, thermal properties, and flammability are assessed. The foaming process of PUR foams modified with vermiculite was comparable for all systems, regardless of the content of the filler. A slight increase in reactivity was observed, confirmed by a faster decrease in dielectric polarization for the system with modified vermiculite by H₂O₂. The modification of the reference system with the vermiculite increased the content of closed cells from 76% to 91% for the foams with the highest vermiculite content. Coefficient of thermal conductivity of reference foam and foams modified with vermiculite was in the range 24-26 mW/mK. The use of vermiculite up to 15 wt.% did not influence significantly on mechanical properties and flammability, which from an economic point of view is important because it is possible to reduce the cost of materials by introducing a cheap filler without deteriorating their properties.

Keywords: PUR; polyurethane foams; rigid foams; thermal insulation; vermiculite.

Grants and funding

The results presented in this paper were partially funded with grants for education allocated in Poznan University of Technology by the Ministry of Science and Higher Education in Poland executed under the subject of No 0513/SBAD/4774.