No abstract

Silica aerogels have attracted increasingly more attention due to their extraordinary properties and their existing and potential applications in a wide variety of technological areas. Materials that promote bone-tissue formation at their surface and bond to osseous tissues when implanted are called bioactive, such as pseudowollastonite particles. In this work, the synthesis of aerogels with pseudowollastonite particles was performed. The synthesis involved the preparation of an alcogel by a two step sol-gel route followed by ambient pressure drying. To promote a higher bioactivity the obtained aerogels were then biomimetically treated using simulated body fluids, SBF and 1.5 SBF. A high bioactivity was demonstrated by FT-IR, SEM, EDS, and XRD. The in vitro biocompatibility was assessed by testing cytotoxicity using rat osteoblasts cultures. The results obtained indicate that these materials are highly potential aerogels for bone tissue regeneration.

The effect of using a compatibilizer, such as maleic anhydride grafted polyethylene (PEgMA), on the flame retardancy and mechanical (tensile) properties of HDPE nanocomposites with silane modified Mg(OH)2 was studied. The silane modification of Mg(OH)2 was confirmed by FTIR. Filler dispersion was characterized by scanning electron microscopy in transmission mode (STEM) and the effect of filler on mechanical properties was also evaluated. The flame retardant properties were evaluated by flammability tests (Underwriters Laboratory – UL‐94) and cone calorimeter. The mechanism by which the use of PEgMA compatibilizer improves the flame retardancy of HDPE/Mg(OH)2 was studied. Through the simultaneous TGAIR analysis, it was found that when using PEgMA, the flame retardant properties of HDPE/Mg(OH)2 are modified, due to the generation of volatile compounds in the thermal decomposition.