Perfumes: uma proposta de contextualização para o ensino de Química

Anais do II Seminário Seminário Estadual PIBID do Paraná: tecendo saberes / organizado por Dulcyene Maria Ribeiro e Catarina Costa Fernandes — Foz do Iguaçu: Unioeste; Unila, 2014Neste trabalho apresentamos uma proposta de aula de química, na qual, serão tratados os conceitos de solubilidade, concentração e preparo de soluções a partir da preparação de um perfume. Este trabalho foi desenvolvido por bolsistas do projeto PIBID Química da Universidade Tecnológica Federal do Paraná – Campus Apucarana. A atividade será desenvolvida com os alunos do Colégio Estadual Padre José de Anchieta, nas turmas de terceiros anos do ensino médio. O método envolve a discussão histórica do uso e da fabricação de perfumes. As técnicas de fabricação serão discutidas juntamente com os conceitos químicos e problematizadas com o intuito de motivar a curiosidade dos alunos. Serão utilizados materiais de fácil obtenção, o que permite a realização dos experimentos por qualquer instituição escola

ß-Cyclodextrin: Disperse yellow 211 complexes improve coloristic intensity of polyamide dyed knits

Dyes are complex molecules that can sometimes cause damage to the aquatic environment and harm human health. They are often not completely removed from effluent by the usual treatments; therefore, efforts have been made to increase their exhaustion from dyeing through chemical and physical processes. In this context, the use of ß-cyclodextrin (ß-CD) as dyeing auxiliary agent promotes the reduction of harmful products, also increasing the color intensity of the fabric. In this paper, ß-CD was used as a complexing agent to dye polyamide (PA) using the dye C.I. Disperse Yellow 211 (DY211) in order to improve dye exhaustion and color intensity using the ß-CD:DY211 complex. The conventional dyeing process and ß-CD:DY211 dyeing process by exhaustion were compared, and adsorption kinetics, isotherms, and the coloristic intensity were evaluated. The chemical shifts in the FTIR spectra and the thermal stability evidenced the formation of the ß-CD:DY211 complex. Regarding dyeing kinetics and isotherm, the pseudo-first-order model was the most appropriate to describe the process, while Nernst isotherm was the one that best represented the adsorption results. Categorically, the samples dyed with the ß-CD:DY211 complex obtained higher coloristic intensity in comparison with the conventional process. With this evidence, it is possible to conclude that cyclodextrin is a suitable replacement for environmentally harmful textile aides without adding further steps into the dyeing process or the need for additional equipmentPostprint (author's final draft