Banca de QUALIFICAÇÃO: RAFAEL CESAR LIMA VALE

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : RAFAEL CESAR LIMA VALE
DATE: 31/08/2026
TIME: 09:00
LOCAL: google meet
TITLE:

Sustainable coating of cotton with crajiru extract applied by foam

KEY WORDS:

Crajiru; natural dyes; foam application; cotton; textile finishing.

PAGES: 135
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Tecnologia Química
SPECIALTY: Têxteis
SUMMARY:

This study evaluated the foam application of crajiru (Fridericia chica) extract on a cotton textile substrate, considering different extract concentrations and extraction media, as well as the characteristics of the foam formed, color development, and color fastness properties. Crajiru was collected in the municipality of Jardim do Seridó, Rio Grande do Norte, Brazil, and subsequently dried and processed to obtain the plant material in powder form. Solutions were prepared at concentrations of 25, 50, and 100 g/L using water, a water–alcohol mixture, and alcohol as extraction media. The extractions were carried out under heating and agitation, followed by filtration. For foam application, an adaptation of the stirring system available in the laboratory was developed using a whisk (fouet) coupled to a motor, allowing air incorporation and foam formation. The cotton samples were subjected to extract application by spatula spreading and subsequently to thermal treatment. The samples were visually evaluated, and reflectance spectrophotometric analyses were performed, including color strength calculation according to the Kubelka–Munk model, colorimetric characterization using the CIELAB system, and washing and rubbing fastness tests. The results demonstrated that increasing the extract concentration favored the development of color intensity, with the 100 g/L sample exhibiting the highest visible radiation absorption, the highest K/S values, and the greatest chroma. However, this condition also showed greater color change after washing and higher transfer of coloring material in the washing and rubbing tests. The 50 g/L concentration presented a more balanced performance, with high rubbing resistance and lower color transfer to the adjacent fabric during the washing test. It is concluded that the foam application of crajiru extract shows potential for use on cotton substrates, with the 50 g/L concentration standing out as the most balanced condition between color development and fastness properties under the experimental conditions studied.

COMMITTEE MEMBERS:
Presidente - 1150673 - IRIS OLIVEIRA DA SILVA
Interna - 2614285 - KESIA KARINA DE OLIVEIRA SOUTO SILVA
Externo à Instituição - BRENNO HENRIQUE SILVA FELIPE - UFSC