Banca de QUALIFICAÇÃO: JOAO JOSE MELO DOS SANTOS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : JOAO JOSE MELO DOS SANTOS
DATA : 22/07/2019
HORA: 14:00
LOCAL: Sala de aulas do PPGCEM
TÍTULO:

EFFECT OF CHEMICAL ACTIVATION OF CELLULOSE WHISKERS ON THERMAL AND MECHANICAL PROPERTIES OF PLA / CNC NANOBIOCOMPOSITES

PALAVRAS-CHAVES:

nanocomposites, cellulose nanocrystals, poly (lactic acid), dicumyl peroxide, torque rheometer.

PÁGINAS: 73
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
ESPECIALIDADE: Polímeros, Aplicações
RESUMO:

Polymeric nanocomposites and biodegradable nano reinforcement are a promising alternative to replace conventional composites with environmental advantages such as biodegradability, as well as good processability and mechanical and thermal properties suitable for several applications. A great challenge in the processing of nanocomposites is to avoid the formation of reinforcing phase aggregates, for example nanofibers within the polymer matrix, which causes defects and, consequently, the reduction of properties of the final product. In this research, nanocomposites of poly (lactic acid) (PLA) and cellulose nanocrystals (CNC) using dicumyl peroxide crosslinking agent (DCP) and lactic acid compatibilizer (LA) associated with the tin octoate catalyst (Sn(Oct)2) and the triphenylphosphine base (P(C6H5)3). In the proposed approach, the compatibilizer in the reactive system during the extrusion forms a low molar polymer by in situ polymerization, which combined with the crosslinking agent favors the formation of reactive points on the surface of the PLA, as well as of the CNC. These reactive points, fundamental in the grafting process between the PLA/CNC, were investigated by means of Fourier transform infrared spectroscopy (FTIR) and the CNC distribution in the PLA matrix was evaluated by emission scanning electron microscopy field (MEV- FEG). The results of thermal analysis indicated that the addition of CNC associated with the compatibilizers agents improved the thermal stability over the pure polymer. SEM images of the nanocomposites’ fracture surface allow to verify that the CNCs were incorporated in the form of individualized fibers and coated by the matrix phase. The nanocomposites with and without dicumyl peroxide (DCP) with the addition of lactic acid (AL) at 1% m/m presented the best mechanical properties when compared to other formulations and to pure PLA, but formulations PCAL1_0,0045 (PLA + CNC + AL) and PCDAL1_0,0045 (PLA + CNC + DCP + AL) presented the highest values of elasticity modulus, with emphasis on the formulation PCAL1_0,0045 that obtained higher elasticity modulus and tensile strength.

MEMBROS DA BANCA:
Externa à Instituição - AMELIA SEVERINO FERREIRA E SANTOS - UFPB
Interno - 1300987 - CARLOS ALBERTO PASKOCIMAS
Presidente - 1202134 - JOSE DANIEL DINIZ MELO
Interna - 1755267 - MARIA CAROLINA BURGOS COSTA DO NASCIMENTO