Impact of unmodified (PGV) and modified (Cloisite20A) nanoclays into biodegradability and other properties of (bio)nanocomposites

Abstract

The production of bionanocomposites using nanoclays are in constant development to improve the mechanical, gas barrier and thermal properties, and the biodegradability of the polymeric materials. In this study, two different nanoclays: non-treated (hydrophilic sodium-montmorillonite nanoclay - PGV) and treated with organo-modification (montmorillonite nanoclay - Cloisite 20A) were incorporated (2%wt.) into PBAT [poly(butylene adipate-co-terephthalate)] by melting process. The composites properties were evaluated by SEM/EDS, XRD, mechanical properties, contact angle, TGA, and aerobic biodegradation (Sturm test). The SEM/EDS showed the presence of sodium in PGV, which characterize it as sodic montmorillonite, while the Cloisite 20A, as montmorillonite organo-modified, by the high occurrence of carbon percentage. The patterns of X-ray diffraction (XRD), about the d-spacing of the bionanocomposites, indicates high intercalation of the matrix with nanoclay Cloisite 20A and a decrease in the crystallinity index. The elasticity modulus of the bionanocomposites had a slight increase, while maximum elongation was decreased, corroborating with the intercalation, as seen in XRD results. The contact angle results have shown high hydrophilicity for PBAT/PGV, by the presence of sodium ions. Besides, an increase in thermal stability for PBAT/Cloisite 20A was observed. However, the CO2 produced during the degradation of the PBAT/PGV was higher than PBAT/Cloisite20A only at the beginning of the process. Besides, better exfoliation of nanoclay Cloisite 20A in PBAT promoted an increase in the biodegradation process rate. Therefore, these properties can contribute to possible soil stabilizer application, hitching surface hydrophilicity, and good biodegradability, by its water retention ability.