Banca de DEFESA: GRAZIELLE ROZENDO DE CERQUEIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : GRAZIELLE ROZENDO DE CERQUEIRA
DATE: 16/02/2022
TIME: 09:00
LOCAL: Google Meet
TITLE:

Smart polyurethane films modified with poly(N-vinylcaprolactam)

KEY WORDS:

Dressings, polyurethane, thermo-responsive polymers, PNVCL, gamma radiation, grafting and polymerization.

PAGES: 64
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

Smart polymeric materials or systems, sensitive to external stimuli, have been
considered for numerous applications in the biomedical area, such as controlled drug release and
biomolecules adsorption. Poly(N-vinyl caprolactam) is a thermoresponsive polymer, with a critical
temperature close to the temperature of the human body, which has stood out for being biocompatible,
non-toxic and low cost compared to other smart polymers. One of the possible applications for this
polymer is in the manufacture of smart dressings, which favor the proliferation and adhesion of proteins
and cells in the hydrophobic state, below their critical solubility temperature (LCST), and which, when
heated above the LCST, can promote the detachment of the cells, facilitating the removal of the dressing
without damaging the new tissue formed. In the present work, films of thermoplastic polyurethane (TPU),
already traditionally used in dressings, were superficially modified by grafting and polymerization of NVCL
via gamma radiation at doses of 5 and 20 kGy. Pure polymer poly(N-vinyl caprolactam) (PNVCL) was
also produced by gamma radiation at the same dosages. The materials developed were characterized
physicochemically by the techniques of Fourier transform infrared spectroscopy (FTIR), thermogravimetry
(TGA) and differential scanning calorimetry (DSC). The critical transition temperature (LCST) was
determined by measuring the contact angle, through the cloud point method, and by DSC. The FTIR
results confirmed the polymerization of the monomer, as well as the grafting of the PNVCL on the TPU.
The thermograms (TGA) and its derivative (DTG) showed that at a higher irradiation dose there was a
decrease in thermal stability, possibly favored by the degradation effect in the presence of oxygen. The
evaluation of the LCST by the cloud point revealed that the homopolymers showed the first signs of
turbidity around 30ºC, while for the grafted samples the value was up to 7ºC lower. The measurements of
the contact angle of the homopolymers confirmed the higher hydrophilicity of the polymer below its LCST
and lower water wettability above the LCST. The present work contributes to the development of
innovative smart dressings with potential application in the biomedical area.

BANKING MEMBERS:
Externa à Instituição - ALINE BRUNA DA SILVA
Interna - 2330165 - MARIA GORETI CARVALHO PEREIRA
Presidente - 1283002 - YEDA MEDEIROS BASTOS DE ALMEIDA