Banca de QUALIFICAÇÃO: CARLA LAIZE DOS SANTOS CRUZ COSTA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : CARLA LAIZE DOS SANTOS CRUZ COSTA
DATE: 05/11/2021
TIME: 14:00
LOCAL: meet.google.com/peo-hojm-foi
TITLE:

DEVELOPMENT OF A THERMOCHROMIC PROPERTY POLYETHYLENE FILAMENT FOR TEXTILE APPLICATIONS

KEY WORDS:

HDPE, Thermochromic pigments, aditives, extrusion, filament.

PAGES: 46
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Tecnologia Química
SPECIALTY: Têxteis
SUMMARY:

The objective of this work was to develop a continuous filament of high density polyethylene (HDPE) with thermochromic property, for application in textile materials. For this, two thermochromic pigments, in orange and purple, both with color change at a temperature of 31 ° C, were mixed with HDPE during the extrusion process to obtain a filament by means of melt spinning, with the proportions used of 0.5%, 1.0% and 2.0% wt% of pigment. The defined micrographs of the thermochromic pigment powders differentiated that the material exhibited a spherical morphology. To identify the pigment activation and a color change, the powders were taken at the activation temperature and images involved in a digital camera with the color difference at 21°C and 45°C. After the extrusion mixing process, specimens were injected of pure HDPE and pigment-additivated HDPE and carried out as preliminary characterizations before the fabrication of the filaments. When comparing the injected specimens of pure HDPE and the other mixtures of HDPE and pigments for the three proportions used, the results of the melt index (MFI) analysis had increasing values, contrary to the results of the Shore D hardness analysis, which decreased, such behavior infers that the proportions of thermochromics used promoted an increase in the mobility of the polymeric chains of HDPE, which may have influenced a change in viscosity and an increase in MFI values, in addition to the reduction of values in the Shore D hardness test indicates that the addition of the pigment resulted in a more flexible polymer matrix, these characteristics being important during melt spinning. Scanning electron microscopy (SEM) fitted micrographs of the injected specimens unaltered that the pigments maintained a preserved spherical structure, maintaining their protected function. The images presented by digital camera, changed the color change of pure HDPE from beige to orange and purple, as well as a color change to yellow and blue, respectively, when they were subjected to thermochromic activation temperature, with the color change being reversibly and the proportion of 0.5% the easier visual perception of color variation when the sample was subjected to pigment activation temperature.

BANKING MEMBERS:
Presidente - 1639676 - EDSON NORIYUKI ITO
Interno - 2239386 - JOSE IVAN DE MEDEIROS
Externa à Instituição - JUCIKLÉCIA DA SILVA REINALDO - UFRN