Polímeros: Ciência e Tecnologia
https://revistapolimeros.org.br/article/doi/10.1590/0104-1428.1604
Polímeros: Ciência e Tecnologia
Scientific & Technical Article

Influência de estabilizantes na degradação foto-oxidativa de filmes de compósitos de SWy-1/poli(óxido de etileno)

Influence of stabilizers on photo-oxidative degradation of SWy-1/poly (ethylene oxide) composite films

Lombardo, Patrícia Coelho; Poli, Alessandra Lima; Schmitt, Carla Cristina

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Resumo

Compósitos de poli(óxido de etileno) (PEO) com argila montmorilonita SWy-1 e estabilizantes (2-hidroxibenzofenona e tinuvin 770) foram preparados pelo método de intercalação em solução. Os filmes obtidos foram expostos a irradiação UV, e os produtos da fotodegradação foram monitorados por FTIR (Fourier Transform Infrared Spectroscopy, ou Espectroscopia no infravermelho por transformada de Fourier) e SEC (Size Exclusion Chromatography, ou cromatografia de exclusão por tamanho). O PEO puro apresentou maior coeficiente de degradação, kd, comparado com as demais amostras. O sistema que apresentou o menor valor para o coeficiente de degradação (kd = 1,9×10–6 mol g–1 h-1) foi o compósito de PEO/5%SWy-1 com 0,25% de tinuvin 770. Nesse caso, a estabilização da matriz de PEO pode ser atribuída à argila juntamente com o tinuvin 770. A argila dispersa e absorve a irradiação UV, e o tinuvin age como estabilizante do tipo HALS (do inglês hindered amine light stabilizer, ou estabilizantes à luz tipo aminas impedidas).

Palavras-chave

poli(óxido de etileno), montmorilonita, fotoestabilizantes, degradação foto-oxidativa.

Abstract

Poly(ethylene oxide) (PEO) with SWy-1 montmorillonite and stabilizers (2-hydroxybenzophenone and tinuvin 770) composites were prepared by intercalation in solution method. The films of the composites were exposed to UV irradiation. The photodegradation products were monitored by FTIR (Fourier Transform Infrared Spectroscopy) and SEC (Size Exclusion Chromatography) method. The PEO pure showed higher degradation rate coefficients, kd, compared to the others samples. The system that showed the lowest value for the degradation rate coefficients (kd = 1.9×10–6 mol g –1 h –1) was the PEO/SWy-1 5% composite with 0.25% of tinuvin 770. In this case, the stabilization of the PEO matrix can be attributed to clay associated with tinuvin 770. The clay scatters and absorbs UV irradiation and tinuvin acts as a stabilizer of the HALS (hindered amine light stabilizers) kind.

Keywords

poly(ethylene oxide), montmorillonite, photostabilizers, photooxidative degradation.

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