Poly(lactic acid) (PLA) was synthesized using condensation polymerization of L-lactic acid using a controlled ultrasonic cavitation technique. Polystyrene (PS) was used to prepare the PS:PLA and PS:PLA:organically modified montmorillonite (OMMT) composites. PS was dissolved in benzene (10:90) and kept overnight for dissolution. Meanwhile, surface modification of montmorillonite was done using a column chromatography technique and referred to as OMMT. The d-spacing was found to be 22 Å after modification due to sufficient column length and diameter with good retention time during ion exchange. PLA and OMMT were kept in hot air oven at 100 o C for 30 min to remove the moisture. The mixtures of 10%, 15%, 20%, 25%, and 30% of PS:PLA:OMMT were subjected to ultrasonic irradiation (50 Hz) for homogenization and to form a biodegradable polymer nanocomposite sheet (5 × 5 cm 2 ). The amount of OMMT loading was from 0.5-5 mass%. These composites were subjected to degradation in minimal medium using Pseudomonas aeruginosa bacteria at controlled conditions, and the polymer is a major source of carbon. The degradation was confirmed using scanning electron microscopy, extracellular protein content change, biomass production, and % degradation with respect to time (up to 28 days) after incubation.
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
Phanerochaete chrysosporium species was used to study the degradation of polymeric composites of (a) isotactic polypropylene (iPP) and (PLA) (iPP/PLA), and (b) iPP/PLA filled with calcium carbonate nanoparticles (nCaCO 3 ). PLA was synthesized using L-lactic acid under the controlled ultrasound cavitation technique, dried and used for composite preparation. Meanwhile, the synthesis and subsequent surface modification of nCaCO 3 was done using the ultrasound cavitation technique. Owing to ultrasound cavitation, a reaction mixture is dispersed uniformly but at the same time strong electrostatic force of attraction is developed over the surface of nCaCO 3 particles, which forms the agglomeration of particles. The deagglomeration as well as charge nullification was achieved using surface modification of CaCO 3 nanoparticles with triethoxy vinyl silane (TEVS) under controlled stirring. The sheets of iPP/PLA and iPP/PLA/nCaCO 3 were prepared at normal condition and subjected to a degradation study in minimal medium using P. chrysosporium microorganism up to 28 days. The growth of microorganism and fractures inside the polymer matrix before and after degradation was observed using a scanning electron microscope. Changes in extracellular protein content, biomass production, and percent degradation with respect to time of incubated samples have also been studied. It was found that the iPP/PLA/nCaCO 3 (5 phr) and iPP/PLA (at 30% PLA) composites show an increment in degradation. The presence of nCaCO 3 leads to faster degradation of iPP/PLA/nCaCO 3 nanocomposites, which decreases the mechanical property by 30% of PLA and 5 wt% of nCaCO 3 content. C 2016 Wiley Periodicals, Inc. Adv Polym Technol 201 , , 21691; View this article online at wileyonlinelibrary.com.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.