Manufacturing and characterization of sustainable macroporous glass foams

Abstract

This work produced glass foams from soda-lime glass bottles, bentonite, and alumina by the replica method. Compositions with different contents of bentonite (5, 10, 15, and 20 wt%) were prepared and heat-treated at 800 °C. In the alumina-added compositions, 50 wt% of the bentonite was replaced by the alumina. The influences of the content of bentonite (binder) and alumina addition were evaluated through the physical-mechanical properties. The results showed that the alumina did not promote a significant effect on physical and mechanical properties in most glass foams; the exception was the sample with 20 wt% bentonite+alumina, which presented better physical properties (lower linear shrinkage and density and greater porosity) when compared to its equivalent sample (without alumina). Foams with 5% of bentonite or bentonite+alumina showed higher linear shrinkage indexes and high densification. Samples with 15% of bentonite or bentonite+alumina showed the best combination of properties: higher porosity (79.2% and 80.2%), water absorption (58.8% and 59.7%), lower shrinkage index (25.5% and 29.4%), and good flexural strength (0.69 and 0.45 MPa).