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Preparation, characterization, and biodegradation of PS:PLA and PS:PLA:OMMT nanocomposites using Aspergillus niger
Author(s) -
Shimpi Navinchandra G.,
Borane Mahesh,
Mishra Satyendra
Publication year - 2014
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.22658
Subject(s) - materials science , biodegradation , aspergillus niger , nanocomposite , fourier transform infrared spectroscopy , thermal stability , thermogravimetric analysis , montmorillonite , polylactic acid , composite material , polymer , absorption of water , polystyrene , nuclear chemistry , lactic acid , degradation (telecommunications) , chemical engineering , organic chemistry , chemistry , biochemistry , biology , bacteria , engineering , genetics , telecommunications , computer science
Poly(lactic acid) (PLA) was synthesized using l ‐lactic acid by condensation polymerization. Polystyrene (PS) and surface modified montmorillonite (OMMT) was used for the preparation of PS:PLA composites and PS:PLA:OMMT nanocomposites. The composite materials prepared had varying amount of PLA (10–30%) and OMMT (0.5–5 phr). These composites were subjected to degradation in minimal medium using the fungi Aspergillus niger ( A. niger ) under controlled conditions. Scanning electron microscopy (SEM) showed the growth of microorganism on the polymer surface and fracture within the polymer matrix as a result of degradation. Fourier transform infra red spectroscopy (FTIR) was further used to determine the mechanism leading to biodegradation. It was found that the biodegradation of both PS:PLA and PS:PLA:OMMT took place mainly via break down and utilization of ester group, as can be seen from disappearance of absorption peak of ester group and simultaneous appearance of a typical IR absorption of microbial mass at 1450 cm −1 . The thermal stability of PS:PLA:OMMT nanocomposites was found to increase with increasing concentration of OMMT, as observed from thermo gravimetric analysis (TGA), while mechanical property was found to be decreased after degradation at 30% of PLA and 5 wt% of OMMT content. Change in extracellular protein content, biomass production and % degradation with respect to time (up to 28 days) were studied and correlated to evaluate the effectiveness of A. niger in biodegradation of the composites. POLYM. COMPOS., 35:263–272, 2014. © 2013 Society of Plastics Engineers