Banca de QUALIFICAÇÃO: GABRIELE POLÉZI

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : GABRIELE POLÉZI
DATE: 24/10/2023
TIME: 09:00
LOCAL: on line
TITLE:

PREPARATION AND CHARACTERIZATION OF HYBRID FOAMS OF FUNCTIONALIZED CELLULOSE AND CARBON BLACK WITH POTENTIAL APPLICATION AS ANTISTATIC PACKAGING

PAGES: 60
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Química de Interfaces
SUMMARY:

Conductive polymeric foams are widely used as packaging to protect electrical components sensitive to electrostatic discharge. These products are usually made of polymers derived from petroleum and have extremely low degradation rates. As a potential solution, cellulose, a biodegradable biopolymer widely available in nature, has been explored as an alternative material to produce more environmentally friendly foams. In this work, cationic cellulose fibrils, isolated from sugarcane bagasse, were used to efficiently disperse carbon black (CB) in water and produce conductive foams by freeze-drying method. The cationic cellulose fibrils were obtained by cationization reaction with glycidyl trimethylammonium chloride (GTMAC) in glucose:GTMAC molar ratio of 1:10 and characterized by conductometric titration, zeta potential, spectroscopy of X-ray excited photoelectrons (XPS) and scanning electron microscopy (SEM). The CB was added to the cationic cellulose in an aqueous medium, producing colloidally stable dispersions due to the good electrostatic interaction between the positive charges on the surface of the fibrils and delocalized π electrons from the CB aromatic rings. CB was added to the cationic cellulose in concentrations of 1, 5, 10, 20, and 30 wt% for manufacturing foams with static dissipative properties. (concerning the mass of dry cellulose). The mechanical and electrical properties of the foams were analyzed by compression tests and measurements of electrical resistance by the method of two probes, respectively. The results demonstrated that the foams become more resistant with the increasing concentration of CB, presenting compression modules in the range of 0.51 to 1.06 MPa. Hybrid foams filled with 1 and 5 wt% of CB showed electrical resistivity of about 107 Ω.cm, while higher CB contents promoted lower resistivities (104 to 102 Ω.cm). The good interactions between cationic cellulose fibrils and CB favored the formation of stable aqueous dispersions and foams with good mechanical and electrical properties. The cationic cellulose/CB hybrid foams produced in this study proved to be new conductive porous materials promising for practical electrical applications, including antistatic packaging.

COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 035.297.869-42 - RUBIA FIGUEREDO GOUVEIA - UFABC
Membro Titular - Examinador(a) Externo ao Programa - 2347767 - MATHILDE JULIENNE GISELE CHAMPEAU
Membro Titular - Examinador(a) Externo à Instituição - FABIO ROBERTO PASSADOR - UNIFESP
Membro Suplente - Examinador(a) Interno ao Programa - 050.966.059-22 - MURILO SANTHIAGO - CNPEM
Membro Suplente - Examinador(a) Interno ao Programa - 1761120 - DANILO JUSTINO CARASTAN
Membro Suplente - Examinador(a) Externo à Instituição - DENISE FREITAS SIQUEIRA PETRI - USP