Banca de DEFESA: RANNIER MARQUES MENDONCA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : RANNIER MARQUES MENDONCA
DATA : 28/09/2018
HORA: 08:30
LOCAL: Sala de aulas do PPGCEM
TÍTULO:

CURE KINETICS OF POLYESTER WITH THE ADDITION OF CUPUACU SHELL POWDER

PALAVRAS-CHAVES:

Polyester, Cure Kinetics, Cupuacu, Caffeine.

PÁGINAS: 122
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
ESPECIALIDADE: Polímeros, Aplicações
RESUMO:

The growing awareness of environmental issues and the consequent increasingly rigid international legislation in this area have attracted the interest of researchers to the development of materials containing components derived from renewable sources. Among vegetable resources with potential application in the industrial area, cupuaçu (Theobroma grandiforum), a fruit native to the Amazon region, offers pulp and seeds used in the production of food products. In this process, the shell is usually discarded in landfills. This material has in its composition organic compounds that can affect the curing kinetics of polymer resins, with potential to be used as a cure accelerator or retardant. The objective of this research was to study the effect of the chemical compounds present in the cupuaçu fruit shell on the curing kinetics of polyester resins. Laser granulometry, Scanning Electron Microscopy (SEM), thermogravimetry, Differential Scanning Calorimetry (DSC), tensile tests, Dynamic-Mechanical Analysis (DMA), reaction kinetics and phytochemistry analyses were performed. Polymers were produced with the addition of 0.5, 1.0, 2.0 wt.% of vegetable material. According to the results obtained from the kinetic studies by the temperature sweep method, the temperature of the beginning of the cure reaction was shifted to higher values as the percentage of vegetal material was increased, indicating a delay of the reaction process. The vegetable-based additive also affected the degree of conversion throughout the curing process of the unsaturated polyester resin. The activation energies of the reactions were increased with the increase in content of the vegetable material. Using the isothermal method, it was observed that the partition phases of the raw extracts of the shell also affected the curing process of the polymer resin, suggesting more than one reagent molecule in the vegetable material. The addition of the vegetable material did not affect the thermal properties - glass transition temperature and degradation temperature – or mechanical properties - tensile strength and modulus of elasticity - of the cured polyester resin. Chromatographic fractionation of phases of the vegetable material allowed the isolation of caffeine from the ethyl acetate phase, which was identified by mass spectrometry and comparison by High performance liquid chromatography (HPLC) with the standard substance. Its structural characteristic explains its interference in the healing process of the pericarp, delaying the process. In summary, the results of this research demonstrate that cupuaçu pericarp can be used as a curing retardant of the unsaturated polyester resin without any significant effect in its mechanical and thermal properties. 

MEMBROS DA BANCA:
Interno - 2042234 - ANA PAULA CYSNE BARBOSA
Externo à Instituição - CECILIA VERONICA NUNEZ
Presidente - 1202134 - JOSE DANIEL DINIZ MELO
Externo à Instituição - LAURA HECKER DE CARVALHO - UFCG
Externo ao Programa - 1149440 - ROSANGELA DE CARVALHO BALABAN