Sunflower Oil as a Renewable Resource for Polyurethane Foams: Effects of Flame-Retardants

Magdalene A Asare; Prashant Kote; Sahilkumar Chaudhary; Felipe M de Souza; Ram K Gupta

doi:10.3390/polym14235282

Sunflower Oil as a Renewable Resource for Polyurethane Foams: Effects of Flame-Retardants

Polymers (Basel). 2022 Dec 3;14(23):5282. doi: 10.3390/polym14235282.

Authors

Magdalene A Asare^{1

2}, Prashant Kote^{1

2}, Sahilkumar Chaudhary^{1

2}, Felipe M de Souza^{1

2}, Ram K Gupta^{1

2}

Affiliations

¹ Department of Chemistry, Pittsburg State University, 1701 S. Broadway Street, Pittsburg, KS 66762, USA.
² National Institute for Materials Advancement, Pittsburg State University, 1204 Research Road, Pittsburg, KS 66762, USA.

Abstract

Currently, polyurethane (PU) manufacturers seek green alternatives for sustainable production. In this work, sunflower oil is studied as a replacement and converted to a reactive form through epoxidation and oxirane opening to produce rigid PU foams. Confirmatory tests such as Fourier-transform infrared spectroscopy (FT-IR), gel permeation chromatography (GPC), and hydroxyl value among others were performed to characterize the synthesized polyol. Despite the versatility of rigid PU foams, they are highly flammable, which makes eco-friendly flame retardants (FRs) desired. Herein, expandable graphite (EG) and dimethyl methyl phosphonate (DMMP), both non-halogenated FR, were incorporated under different concentrations to prepare rigid PU foams. Their effects on the physio-mechanical and fire-quenching properties of the sunflower oil-based PU foams were elucidated. Thermogravimetric and compression analysis showed that these foams presented appreciable compressive strength along with good thermal stability. The closed-cell contents (CCC) were around 90% for the EG-containing foams and suffered a decrease at higher concentrations of DMMP to 72%. The burning test showed a decrease in the foam's flammability as the neat foam had a burning time of 80 s whereas after the addition of 13.6 wt.% of EG and DMMP, separately, there was a decrease to 6 and 2 s, respectively. Hence, our research suggested that EG and DMMP could be a more viable alternative to halogen-based FR for PU foams. Additionally, the adoption of sunflower polyol yielded foams with results comparable to commercial ones.

Keywords: bio-based polyol; dimethyl methyl phosphonate; epoxidation; expandable graphite; sunflower oil.

Grants and funding

The authors are grateful to the National Institute of Standards and Technology (NIST award number 70NANB20D146) and the U.S. Economic Development Administration (US-EDA award number 05-79-06038) for providing research infrastructure funding.