RESUMO O objetivo desta pesquisa foi estudar a viabilidade, com relação à resistência à tração, da utilização da folha de buriti como reforço em compósitos com fibras contínuas unidirecionais em matriz polimérica. Como matriz, foram utilizadas as resinas de poliéster isoftálico, de poliéster ortoftálico e de epóxi. Analisou-se a resistência à tração da fibra, das resinas e dos compósitos confeccionados com cada polímero. Testes de arrancamento foram realizados para verificar a adesão da fibra nas resinas usadas como matriz. Foi feita uma caracterização da fibra através de microscopia óptica e com microscópio eletrônico de varredura (MEV), além da determinação de sua densidade. Quanto à estrutura, observou-se que as fibras possuem uma lacuna central entre as faces adaxial e abaxial e que há um enrolamento da fibra. Os ensaios de arrancamento mostraram que houve maior adesão entre a fibra da folha de buriti e a matriz de epóxi, com um comprimento crítico lc = 1,0 mm, seguido pela matriz de poliéster isoftálico, com lc = 2,8 mm, e pela matriz de poliéster ortoftálico, com lc = 26,8 mm. A fibra apresentou resistência à tração variando entre 100,8 MPa e 224,1 MPa. Verificou-se que a resistência à tração das fibras é maior para diâmetros menores. Entre as resinas estudadas, a de epóxi foi a que apresentou maior resistência média à tração (60,5 MPa), seguido pela de poliéster isoftálico (34,5 MPa) e pela de poliéster ortoftálico (27,7 MPa). Testes com os compósitos criados mostraram que a matriz de epóxi é a mais promissora quanto à resistência à tração, seguida pela matriz de poliéster isoftálico. A matriz de poliéster ortoftálico apresentou valores de resistência bem abaixo da demais. Conclui-se que a fibra da folha de buriti apresentou um bom potencial para a produção de compósitos leves e resistentes.

ABSTRACT The objective of this research was to study the viability, with respect to tensile strength, of using buriti leaf as reinforcement in composites with unidirectional continuous fibers in polymeric matrix. As matrix, isophthalic polyester, orthophthalic polyester and epoxy resins were used. The tensile strength of fiber, resins and composites confectioned with each polymer was analyzed. Pullout tests were performed to verify fiber adhesion with the resins used as matrix. The fiber was characterized by optical microscopy and using a scanning electron microscope (SEM) in addition to determining its density. Regarding the structure, it was observed that the fibers have a central gap between the adaxial and abaxial faces and that there is a winding of the fiber. The pullout tests showed that there was greater adhesion between the buriti leaf fiber and the epoxy matrix, with a critical length lc = 1.0 mm, followed by the isophthalic polyester matrix, with lc = 2.8 mm, and the matrix of orthophthalic polyester with lc = 26.8 mm. The fiber presented tensile strength ranging from 100.8 MPa to 224.1 MPa. It was found that the tensile strength of the fibers is higher for smaller diameters. Among the resins studied, epoxy showed the highest average tensile strength (60.5 MPa), followed by isophthalic polyester (34.5 MPa) and orthophthalic polyester (27.7 MPa). Tests with the composites created showed that the epoxy matrix is the most promising as tensile strength, followed by the isophthalic polyester matrix. The orthophthalic polyester matrix presented resistance values much below the others. It was concluded that the buriti leaf fiber presented a good potential for the production of light and resistant composites.

Abstract Lafoensia pacari A. St. Hill has been used in traditional medicine as an anti-ulcerogenic and anti-inflammatory. Although there is an ethnopharmacological indication for cancer treatment, only a few studies have demonstrated its possible anticancer activity. Thus, the aims of this study were: (1) to evaluate the antineoplastic effect of L. pacari ethanolic extract (LPE) in lung carcinoma cells, (2) to determine the mode of action of LPE and (3) to identify the substances present in LPE. Human and murine lung cancer cell lines were grown in vitro and treated with different concentrations of LPE. Cell cycle and caspase-3 activity assays were performed in order to verify the mode of action. LC-ESI-MS screening was performed to detect the compounds present in LPE. LPE showed a dose-dependent cytotoxic effect, where neoplastic cells were more sensitive than non-neoplastic. The LPE induced sub-G1 cell cycle arrest in cancer cells suggesting cell death, which was confirmed as apoptosis by the activation of caspase-3. The LC-ESI-MS analysis indicated a high level of procyanidins, which could be responsible for the antineoplastic effect of LPE. Thus, we concluded that a Lafoensia pacari extract, rich in procyanidins, is cytotoxic against lung cancer cells through activation of caspase-3-dependent apoptosis.