Biological Oxidative Mechanisms for Degradation of Poly(lactic acid) Blended with Thermoplastic Starch

Autor(es)

Rodrigues, Carlos A. ^[1] ; Tofanello, Aryane ^[2] ; Nantes, Iseli L. ^[2] ; Rosa, Derval S. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed ABC, Ctr Engn Modelagem & Ciencias Sociais Aplicadas C, BR-09210580 Sao Paulo - Brazil

^[2] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210170 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ACS SUSTAINABLE CHEMISTRY & ENGINEERING; v. 3, n. 11, p. 2756-2766, NOV 2015.
• Citações Web of Science: 17

Resumo

In the present study, poly(lactic acid) (PLA) and their blends with 5%/wt and 10%/wt thermoplastic starch (TPS) were submitted to degradation in simulated soil. To investigate the mechanisms involved in the degradation, we also submitted the samples to degradation by tert-butyl hydroperoxide, myoglobin, and peroxide-activated myoglobin. The samples were analyzed by Fourier-transformed infrared spectrometry (FTIR), scanning electronic microscopy (SEM), contact angle analysis, and mass loss measurement. The FTIR results indicated a weak interaction between the two components (PLA and starch) in the blend's amorphous structure. However, the corresponding SEM images showed that TPA increased ridges and roughness at the material surface associated with an increase of wettability evidenced by contact angle analysis. Consistently, TPS favored degradation of the material both in the simulated soil and pro-oxidant model systems. In the simulated soil, the occurrence of TPS hydrolysis provided glucose, a biological fuel, that contributed to the growth of the microorganisms. The similar degradation patterns observed in mimetic pro-oxidant biological systems and soil suggest that oxidative reactions catalyzed by heme proteins from biological sources as well as the presence of peroxides and transition metal traces in the original materials have a significant contribution to PLA and PLA/TPS degradation. (AU)

• Processo FAPESP: 12/13445-8 - Compósitos biodegradáveis - Preparação e Avaliação
• Beneficiário: Derval dos Santos Rosa
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 12/07456-7 - Estudos por citometria de fluxo de mecanismos de morte e proteção celular promovida por compostos porfirinóides, fenotiazinas e teluranas associadas a nanoestruturas: montagem de uma sala multiusuário de biologia celular
• Beneficiário: Iseli Lourenço Nantes Cardoso
• Modalidade de apoio: Auxílio à Pesquisa - Regular