Biodegradation behavior of starch-PVA films as affected by the incorporation of different antimicrobials

The effect that the incorporation of different antimicrobial substances into S-PVA films had on their disintegration and biodegradation process was analysed. To this end, starch, PVA and S-PVA films containing different concentrations of neem oil, oregano essential oil and silver nanoparticles were submitted to composting conditions in order to determine the disintegration and biodegradability percentages for 73 and 45 days, respectively. Additionally, thermogravimetric and structural analyses were also carried out throughout the composting period. The biodegradation and disintegration behavior of S-PVA films was intermediate between S and PVA films. The addition of neem and oregano essential oils slightly affected the biodegradation and disintegration profile of starch-PVA films, enhancing both disintegration and biodegradation levels. So, the presence of these antimicrobials did not compromise the compostable and biodegradable character of the starch-PVA blend films. Nevertheless, the biodegradation capacity of films containing 9.8% silver species was seriously affected, reaching values of only 58% after 45 days of composting, despite their high disintegration capacity. Thus, lower silver concentrations are recommended in order to avoid possible alterations in compost microbial activity.