Banca de DEFESA: RAFAELA REIS FERREIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : RAFAELA REIS FERREIRA
DATA : 03/12/2021
HORA: 14:00
LOCAL: On line
TÍTULO:

BIODEGRADABLE FILMS CONTAINING NANOCELLULOSE AND NANOCAPSULAS OF ESSENTIAL OILS FOR ACTIVE PACKAGING

PÁGINAS: 132
GRANDE ÁREA: Outra
ÁREA: Multidisciplinar
RESUMO:

The packaging market is an indicator of society's consumption, and after their use, they have caused significant environmental impacts due to their accumulation in the form of urban solid waste. Biodegradable packages are alternatives to replace those made by commodity polymers, as they have shorter decomposition times after use. Among the biodegradable polymers, poly(adipate-co-butylene terephthalate) (PBAT), a highly flexible copolymer, is already used in the packaging industry. However, it has limitations in its mechanical, thermal, and antimicrobial properties. Thus, this dissertation aims to develop biodegradable polymeric films of PBAT/Nanocellulose/active agents [chitosan nanocapsules with essential oils (EO)] for possible use in biodegradable packaging with antimicrobial activity. Cellulose nanostructures (NC) were obtained from eucalyptus residues after alkaline treatment, followed by mechanical grinding (1, 2, 3, and 4h) and high-intensity ultrasound (10, 20, and 30 min). Chitosan nanocapsules (NQ) containing essential oils (NQOE) of cassia cinnamon (NQC) or rosewood (NQPr) were prepared by the ionic gelling technique between chitosan (Qs) and sodium tripolyphosphate (TPP). Biodegradable films were produced with the incorporation of nanocellulose (NC) (2%, by mass) and different concentrations of NQOE (0, 1, 3, and 5%, by mass) by the casting method. The prepared NC were characterized by structural, dimensional, thermal, and morphological properties, while the NQOE by morphological, thermal, physicochemical, and biological properties, and finally, the active films were analyzed by thermal, morphological, and biological properties. The best condition for obtaining the NC samples was when the eucalyptus was ground for 2h and submitted to 20 min of ultrasound, resulting in particles with more homogeneous dimensions, more crystalline, and electrostatic and thermal stability. The NQOE have monodisperse sizes, between 100 to 150 nm, and present irregular shapes with a spherical tendency. These showed biological activity due to the synergistic antibacterial efficiency between chitosan and the essential oil, with inhibition against E. coli. and B. subtilis. The films showed excellent thermal stability and increased mechanical properties compared to the original films. These results were corroborated by the crystallinity of the film, indicating that the fibers and nanocapsules promoted a nucleation effect during film formation. The results of water vapor permeability and contact angle showed that the EO's hydrophobicity impacted the film's surface properties. The antimicrobial activity of the films was evaluated against E. coli, and inhibition of bacterial growth was observed for all films containing EO. These results show a promising application to extend the shelf life of food products in new formulations and using environmentally friendly materials. The films showed potential for application in food packaging, an alternative to environmental problems related to conventional packaging.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1671275 - DERVAL DOS SANTOS ROSA
Membro Titular - Examinador(a) Interno ao Programa - 1760410 - JEVERSON TEODORO ARANTES JUNIOR
Membro Titular - Examinador(a) Externo à Instituição - LEONARDO GONDIM DE ANDRADE E SILVA
Membro Suplente - Examinador(a) Interno ao Programa - 1676364 - JULIANA MARCHI
Membro Suplente - Examinador(a) Externo à Instituição - RODRIGO LAMBERT ORÉFICE - UFMG
Membro Suplente - Examinador(a) Externo à Instituição - HELIO WIEBECK