No 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.

The adsorption and removal performance of CMC-based 4-aminophenazone and doped MWCNTs NC was investigated CV and BG dyes. The results demonstrate the excellent potential of A-PH-CMC/MWCNTs nanocomposites as a material for CV and BG dye removal.

In this work the moisture diffusion process and the influence of moisture on mechanical properties (critical strain energy release rate in mode I (GIC), flexural modulus and ultimate flexural strength) of GRP pipes was assessed. The research was performed on specimens conditioned in two different environments, water at room temperature and water at 50°C. In this case it was verified that the water diffusion can be well described by the Fick’s second law. The critical strain energy release rate in mode I, GIC, shows a decrease between 5% and 10% when conditioned in water. The temperature of the conditioning does not have so much influence on the GIC values. The conditioning either in water at room temperature or at 50°C has an influence on the flexural modulus and strength of the pipes in the hoop direction, between 10% and 20%, respectively. The longitudinal modulus was more significantly affected by the conditioning in water at 50°C with a 30% decrease.