Water dependent Upcycling of nanocompartment polymeric films

Author(s)

Izabella Wyne Inacio Alves Caetano

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Química
• Defense date: 2022-10-06

Examining board members

Liliane Maria Ferrareso Lona; Rosana Lopes Lima Fialho; Ana Rita Morales

• Advisor: Liliane Maria Ferrareso Lona

Abstract

This work reports a new and easy approach for fabricating nanoparticles and compartmentalized films with potential use in the agricultural area. Pesticides are important for the protection of agricultural products; however, they can cause many diseases in living beings. A sustainable solution is to replace synthetic pesticides with natural products, such as essential oils, but they usually have the disadvantage of rapid degradation in sunlight. To protect these compounds, encapsulation is a great alternative; however, choosing the best encapsulating agent is challenging, because they cannot be aggressive or negatively impact the environment. In this work, neem oil (used as a case study) was encapsulated by the simple emulsion/solvent evaporation technique in nanoparticles of Ecovio, a commercial blend of poly (acid lactic) (PLA) and poly (butylene adipate-co-terephtalate) (PBAT) already used in agriculture, adopting the poly (vinyl alcohol) PVA as surfactant. The aqueous dispersions produced, which had a particle diameter of around 370 nm, were used to produce compartmentalized films by the casting method, which were able to quickly return to the aqueous dispersion form if placed in contact with water, maintaining the same particles diameter of the original dispersion. Poly(vinyl alcohol) (PVA) acted as a surfactant or polymer matrix depending on the hydration of the surrounding medium (wet or dry conditions), and allowed the polymeric film to be reused (upcycling) and also give the possibility of disposal in soils. The nanoparticles in aqueous dispersion showed stability over 9 months, while the films demonstrated improved mechanical performance (an increase of 54% in the elastic modulus, 88% in the elongation at break, and 62% in the tensile strength). Furthermore, it was possible to observe that the addition of neem oil up to a certain concentration (0.5 g ang 1.0 g) caused an increase in the thermal stability of the material and a reduction in transmittance in both UV-vis spectra, at UVA 320-400 nm and UVB 280-320 nm wavelengths (AU)

• FAPESP's process: 20/02050-9 - Encapsulation of neem oil in PLGA nanoparticles
• Grantee: Izabella Wyne Inacio Alves Caetano
• Support Opportunities: Scholarships in Brazil - Master