Estudo comparativo entre ps/ß-caroteno e ps/ácido oléico com ps/óleo de buriti (mauritia flexuosa) e preparação e caracterização dos materiais ps/óleo de açaí (euterpe oleraceae mart)

by Pereira, Nizamara Simenremis

Abstract (Summary)
Polymeric materials are used in many segments of life and therefore the interest of researchers in the production of new polymers with new applications. Among the most widely used polymers, it is the polystyrene (PS) a thermoplastic resin. Despite of to offer many properties that justify its use, the PS does not have optical properties. The addition of vegetable oils such as buriti and acai oil promoter the appearance of optical properties in the PS. The main objective of this work is to add ß-carotene and oleic acid, main constituents of buriti oil in the PS at concentrations 2, 5, 8, 15 and 45 % followed by the of investigation the materials by comparing of with PS/buriti oil. In addition, work is proposed to study the PS modified with acai oil. All materials were prepared and characterized by thermal analysis (TG/DTG, DSC and TMA), DRX, SEM, PL. The PS/acai oil materials were also analyzed by PAS. The results indicated that ß-carotene and oleic acid reduce the thermal stability of the PS and are responsible for the decrease in T of the PS. DRX analysis gnot detected changes in the amorphous regions of the polymer. On the other hand, the micrographs revealed differences between the surfaces of mixtures and the PS. The ß-carotene showed greater dispersion in PS while oleic acid is encapsulated in polymeric matrix, as the buriti oil. The materials PS/ß-carotene 15 and 45 % were PL between 550 and 950 nm, while the samples with 2, 5 and 8% of ß-carotene and PS/oleic acid did not exhibited PL in this region of the spectrum. The modification of the PS with acai oil resulted in materials less flexibles with T below of the PS and greater thermal stability. The acai oil and gthe Chl showed similar spectra of PL with emission in the region of 670 to 675 nm and 715 to 730nm. The materials of PS/acai oil exhibited the same emission, proving the incorporation of oil in the matrix of the PS. Analyses by PAS, of the PS/acai oil revealed absorption of low intensity, and these are contributions of Chl present in the vegetable oil. However, it was observed that the Chl undergoes a process of degradation in the polymeric matrix, promoting change in the color and material reduction in their optical properties.
This document abstract is also available in Portuguese.
Bibliographical Information:

Advisor:Sílvia Cláudia Loureiro Dias; Maria José Araújo Sales; Maria Marcia Murta; Artemis Marti Ceschin

School:Universidade de Brasília

School Location:Brazil

Source Type:Master's Thesis

Keywords:fisico quimica óleo de buriti beta caroteno ácido oléico açaí poliestireno


Date of Publication:04/07/2008

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