Flexural and flammability evaluation of a new bio-based polyurethane foam with alumina trihydrate

Abstract

Flexural and flammability evaluation of a new bio-based polyurethane foam (PUF) with alumina trihydrate (ATH) added as flame retardant were carried out. The PUF was obtained from a blend of vegetable oils. Flexural behavior of the polyurethane with different mass fractions of flame retardant (ATH) was investigated according to ASTM D790-17. Flammability tests were performed according to ASTM D3801-20 and ASTM D635-14 for the vertical and horizontal positions, respectively. The ATH addition influenced the flexural strength of the tested specimens, showing mean values for pure PUF and PUF with 50% of ATH were very close, but the highest value was obtained for PUF with 20% of ATH. Besides, the maximum strain value under flexural load was substantially reduced as the ATH mass increased, which was 11.4% for pure PUF and 3.38% for PUF with 50% of ATH. The flexural modulus increased with ATH incorporation up to 40% mass fraction. The obtained values for pure PUF, PUF with 40% of ATH and PUF with 50% of ATH specimens were 30.63 ± 1.95 MPa, 73.01 ± 2.82 MPa, and 62.16 ± 2.30 MPa, respectively. In addition, flammability test results presented better responses as the amount of ATH increased. PUF with 40% of ATH received V-2 classification, and PUF with 50% of ATH obtained HB classification. Therefore, the results for PUF with the addition of ATH show that the new bio-based material can be designed by using different mass fractions. Thus, this material becomes very useful for many types of applications, such as furniture and automobile industries, as well as sandwich structures and building constructions.