Eco-compatible cassava starch films for fertilizer controlled-release.

As an attempt to tackle the environmental issues derived from the use of non-degradable plastic and fertilizers overuse, such as irreversible soil pollution, this work focuses on the development of a fertilizer controlled-release, bio-based and biodegradable composite films for agricultural applications. Cassava starch and bagasse composite materials containing urea as active compound and plasticizer were prepared to achieve this purpose, analyzing their properties and stability during storage. Moreover, their biodegradation rate and urea release in soil were also assessed. Films were based on cassava starch with cassava bagasse particles as reinforcing agent and urea contents ranging from 0 to 50 wt% with respect to starch content. Urea proved to be an effective plasticizer of the matrix and films became more flexible with storage time. In addition, the material biodegradation rate in soil increased with urea content. Films with 50 wt% urea content showed a total weight loss of 57% and 95% release of the active compound after 15 days. The results indicate that this approach is adequate for the design of eco-compatible starch-based composite materials for urea dosage in soil based on cassava starch and bagasse.