Banca de QUALIFICAÇÃO: LAYS FURTADO DE MEDEIROS SOUZA KATAOKA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : LAYS FURTADO DE MEDEIROS SOUZA KATAOKA
DATE: 28/07/2023
TIME: 14:00
LOCAL: Plataforma Microsoft Teams
TITLE:

ENVIRONMENTAL ANALYSIS AND EFFECT OF PLASTIFIERS ON THE PROPERTIES OF NANOCOMPOSITE FILMS FROM REGENERATED CELLULOSE AND SILVER NANOPARTICLES

KEY WORDS:

conductive films, regenerated cellulose, plasticizers, silver nanoparticles, life cycle assessment

PAGES: 75
BIG AREA: Engenharias
AREA: Engenharia Mecânica
SUMMARY:

The demand for inorganic polymers has contributed to a growing environmental impact. In this context, conductive regenerated cellulose films are a promising alternative for applications in electronic devices. However, these films may have structural challenges that can compromise their performance, and the addition of plasticizers is a possible solution to improve the physical properties of these materials. In addition, despite being renewable, it is important to emphasize the need to assess the environmental impacts related to these materials, as they involve the use of various chemical reagents and demand high energy. Therefore, the objective of this work is to develop conductive regenerated cellulose films with the addition of silver nanoparticles (AgNP) and plasticizers and their technical and environmental properties in order to obtain environmentally friendly conductive flexible devices. To obtain the films, bleached cellulose extracted from jute fiber was used. The cellulose dissolution occurred in aqueous NaOH solution and the films were regenerated in water. The methodology involved the addition of 15% wt.% of Sorbitol and Glycerol as plasticizers for the films. Furthermore, in order to make the films conductive, the AgNP were synthesized from sodium borohydride and silver nitrate and incorporated into the nanocomposites with 0.5% wt.%. Regenerated cellulose films (RCFs) were produced with and without addition of AgNP for comparison purposes. AgNP were characterized by Transmission Electron Microscopy (TEM). All films were characterized by Ultraviolet-Visible Spectroscopy (UV-Vis), Thermal Analysis (TG/DTG), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The nanocomposite films were also characterized by Sheet Strength by the Vander Pauw Method. In order to environmentally assess the nanocomposite film production process a cradle-to-gate Life Cycle Assessment (LCA) will be developed for the production of 1 kg of film, considering the impact categories of global warming potential, acidification, eutrophication, use of water and energy. Results by TEM analysis revealed an average AgNP size of 9.0 nm. The incorporation of plasticizer and AgNP reduced the initial and final decomposition temperature of the films. The thermal stability of the nanocomposites was around 197 °C to 220 °C. RCF and RCF - AgNP films exhibited dense structure characteristic of regenerated cellulose films. The SEM showed the morphology of the films, where it was seen that the films obtained a homogeneous dispersion of the plasticizers in the matrix, without aggregation of the constituents. With the incorporation of AgNP, there was a color change in the nanocomposite films, with a decrease in transmittance in relation to RCFs without this component. The plasticized nanocomposite with the highest transmittance was RCF - Sorbitol - AgNP. The plasticized nanocomposites obtained a significant improvement in conductivity due to the incorporation of these components, changing from the range of 10-2 to 10-1 in relation to the non-plasticized nanocomposite. The CMC plasticizer provided better conductivity values in the nanocomposite, followed by glycerol and then sorbitol.

COMMITTEE MEMBERS:
Externo à Instituição - DANIEL PASQUINI - UFU
Externo à Instituição - LEONARDO FONSECA VALADARES - EMBRAPA
Interno - 2245668 - MARIO BENJAMIM BAPTISTA DE SIQUEIRA
Presidente - 1720225 - SANDRA MARIA DA LUZ
Externa ao Programa - 2115160 - SIMONE MONTEIRO E SILVA - null