Showing 5 results for Bionanocomposite
Volume 5, Issue 3 (12-2021)
Abstract
Research subject: Biodegradable compounds with high mechanical and thermal properties are one of the intersting research topics. Polylactic acid is an aliphatic polyester with high biodegradability and flexibility. It, however, suffers from several weaknesses such as high permeability to water vapor and gases, low glass transition temperature, poor thermal stability and brittleness which can be improved by the incorporation of nano-scale fillers giving rise to bionanocomposites. The aim of this study was to investigate the effect of the simultaneous incorporation of cellulose nanocrystals and nanosilver on the mechanical, thermal and water vapor permeability behavior of polylactic acid-based films.
Research approach: Polylactic acid films and their bionanocomposites containing different levels of cellulose nanocrystals (0.01, 0.03 and 0.05 g) and nanosilver (0.01 g) were prepared by solution casting method. To improve compatibility and miscibility of the polymer, cellulose nanocrystals were reacted with acetic anhydride and modified. FTIR spectroscopy, tensile test, thermal properties (DSC), migration test and antibacterial properties were used to study the properties of the samples. The water vapor permeability of the samples were also measured.
Main results: The addition of cellulose nanocrystals, increased the glass transition temperature (Tg) and melting point (Tm) of the samples. The presence of cellulose nanocrystals increased the tensile strength and modulus of elasticity of the bionanocomposite relative to pure polylactic acid. With the addition of cellulose nanocrystals, permeability was reduced by about 25%. As the amount of cellulose nanocrystals increased, the swelling and water absorption of the samples increased significantly. The migration rate of the samples also decreased after the addition of nanocellulose.
Volume 13, Issue 51 (7-2016)
Abstract
The main functions of the packages are: Physical protection, barrier protection, convenience and information. Tendency to minim process food products, quality, safety and preventing of food born disease and strict requirements in relation to consumer health caused ways to use antimicrobial agents in food packaging and prevent the development of microorganism growth. Active packaging is one the methods of efficient packaging, that protect safety and quality of foods. The material of these packages is a suitable base for adding a wide range of different combinations such as antimicrobial agents to them. Pursuant to this, movie bionanocomposite films of Bitter vetch seed’s protein with zinc oxide nanoparticles to produce an antimicrobial packages with %5 w/w of Bitter vetch protein isolate and 0.25, 1 and 2% zinc oxide nanoparticles. Glycerol was used as plasticizer. The mechanical and barrier properties of bionanocomposite films assessment and determined that the addition of zinc oxide nanoparticles as an antimicrobial agent to the protein film caused a sharp decrease of oxygen permeability through the films. The rate of water vapor permeability of bionanocomposite films decreased comparing with control film. The results indicated that lower levels concentrations of nanoparticles cause better functional properties of bionanocomposites films because of fewer particles coagulation. Effect of nanoparticles on the mechanical properties, tensile strength and modulus of elasticity were increased, but elongation of the film was reduced.
Narges Rakhshan, Mohammadreza Mansournia, Fereshteh Jookar Kashi,
Volume 15, Issue 3 (6-2024)
Abstract
The aim of present research is development of a simple green approach to produce Ag/AgCl nanocomposites using bacterial strains Bacillus haynesii and Bacillus halotorans, nominated at PN14F and B3, respectively, via an extracellular process. The bacterial strains PN14F and B3 were isolated from the soil and wastewater samples, using dilution and direct cultivation method. The Ag/AgCl nanocomposites were synthesized from the reaction of silver(I) nitrate solution and supernatant under completely sterile conditions in the presence of light. Moreover, a series of controlled experiments were provided to optimize some reaction conditions such as substrate concentration, PH, substrate volume, bacterial volume, the presence of glucose as an electron donor and silver(I) nitrate as inducer. The products were characterized using various techniques such as UV-Vis, XRD, FT-IR, FE-SEM and EDX. The resulting bionanocomposites (Ag1 and Ag2), with an average particle size of 30 and 22.3 nm, were efficient heterogeneous catalysts for reducing para-nitrophenol to para-aminophenl. Further, it was demonstrated their activity as the antibacterial properties against gram positive and negative bacteria. The results showed that the Ag2 sample with reducing time of 15 min is a more efficient catalyst than the Ag1 nanocomposite, which can be attributed to the smaller size of the Ag2 nanoparticles.
Volume 15, Issue 80 (10-2018)
Abstract
Using biodegradable polymers are one the best solutions to overcome the pollution of the environment by Petroleum-based polymers. Biopolymers as environmental friendly packaging materials were studied extensively. The aim of this research was to study the properties of the bionanocomposites of alyssumm homolocarpum seed gum reinforced with nano zinc oxide (1, 3 and 5%). Functional properties such as water content, water solubility and water vapor permeability were significantly decreased by incorporation of nano particles. Also, most of the UV light was adsorbed at 5% of nano particles. Tensile strength and Young module were increased and elongation at break was decreased. The anti-microbial effect was tested against E. coli using agar diffusion method and this effect was increased by increasing the nano particle contents. The obtained results suggest that nanobiocomposites based on nano zinc oxide and alyssumm homolocarpum seed gum has the potential to use as an active packaging material for packaging industries.
Volume 18, Issue 111 (4-2021)
Abstract
The objective of this study was to investigate the synergistic effect of nano titanium dioxide (TiO2-N) and Mentha piperita essential oil (MEO) on the equilibrum moisture sorption isotherm and microbial growth rate of Staphylococcus aureus of cassava starch film. For this purpose, cassava starch biocomposite film with the addition of 1, 3 and 5% TiO2-N and 1, 2 and 3% MEO, and glycerol as a plasticizer were obtained by the casting method. The equilibrium moisture absorption isotherm and antibacterial activity of prepared nanobiocomposite films against Staphylococcus aureus were examined. The obtained results demonstrated that by addition of nanoparticles and essential oil to the starch biocomposites, the equilibrium moisture absorption isotherm curve was shifted to lower moisture content. The microbial tests stated that the pure cassava starch film (control) showed no antibacterial activity against the Staphylococcus aureus and the antibacterial activity significantly increased with increasing concentration of both TiO2-N and MEO in the starch films (p<0.05). However, the antibacterial activity of TiO2-N nanoparticles was higher than MEO. Addition of TiO2-N and MEO increased lag phase and decreased log phase in microbial growth curve. Finally, according to the obtained results in this study, it can be concluded that incorporation of TiO2-N and MEO combination improved the antibacterial activity of cassava starch biocomposites against Staphylococcus aureus and these bionanocomposite films can be used for packaging and extending the shelf life of food products.
