scholarly journals Biodegradable Poly(butylene adipate-co-terephthalate) Antibacterial Nanocomposites Reinforced with MgO Nanoparticles

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 507
Author(s):  
Xionggang Wang ◽  
Lingna Cui ◽  
Shuhong Fan ◽  
Xia Li ◽  
Yuejun Liu

Antibacterial packaging materials can reduce the microbial contamination of food surfaces. In this study, magnesium oxide (MgO) nanoparticles were synthesized and then coated with cetrimonium bromide (CTAB). CTAB-modified MgO (MgO@CTAB) was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis. Then, different loadings of MgO@CTAB were mixed with poly(butylene adipate-co-terephthalate) (PBAT) by melt compounding. The results showed that the addition of MgO@CTAB deteriorated the thermal stability of PBAT due to MgO serving as a catalyst to promote the thermal degradation of PBAT. In addition, MgO@CTAB could serve as a nucleating agent to improve the crystallinity of PBAT. With the optimal 3 wt% of MgO@CTAB, the tensile strength of PBAT/MgO@CTAB increased from 26.66 to 29.90 MPa, with a slight enhancement in elongation at break. SEM observations and dynamical rheological measurements revealed that aggregation occurred when the content of MgO@CTAB exceeded 5 wt%. The presence of MgO@CTAB endowed PBAT with antibacterial properties. The bacterial inhibition zone increased with the increasing content of MgO@CTAB. In addition, MgO@CTAB had a better antibacterial efficiency against Gram-positive bacterial S. aureus than Gram-negative bacterial E. coli.

2020 ◽  
Author(s):  
Leyla Mojtabavi ◽  
Amir Razavi

AbstractIn this work, we studied the effects of copper incorporation in the composition of bioactive glass. Three different glass compositions were synthesized with 0, 3, and 6 mol% of copper addition. X-Ray Diffraction (XRD) patterns confirmed that an amorphous microstructure was obtained for all three glass compositions. Results from Differential Thermal Analysis (DTA) showed that the copper addition in the glass lowers the glass transition temperature, from 646°C to 590°C when added at 6 mol%. X-ray Photoelectron (XPS) survey and high-resolution scans were performed to study the structural effects of copper addition in the glass. Results indicated that the incorporation of copper changes the ratio of bridging to non-birding oxygens in the structure. Glasses were further analyzed for their structure with Nuclear Magnetic Resonance (NMR) spectroscopy, which indicated that copper acts as a network modifier in the glass composition and copper-containing glasses show a less connected microstructure. Antibacterial efficacy of the glasses was analyzed against E. coli and S. epidermis. Copper-containing glasses showed a significantly higher inhibition zone compared to control glass. The glass with 6 mol% copper, exhibited inhibition zones of 9 and 16mm against E. coli and S. epidermis bacteria, respectively.


Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2389 ◽  
Author(s):  
Sun Jong Kim ◽  
Hyo Won Kwak ◽  
Sangwoo Kwon ◽  
Hyunho Jang ◽  
Su-il Park

In this study, poly(butylene sebacate-co-terephthalate) (PBSeT) was successfully synthesized using various ratios of sebacic acid (Se) and dimethyl terephthalate (DMT). The synthesized PBSeT showed a high molecular weight (Mw, 88,700–154,900 g/mol) and good elastomeric properties. In particular, the PBSeT64 (6:4 sebacic acid/dimethyl terephthalate mole ratio) sample showed an elongation at break value of over 1600%. However, further increasing the DMT content decreased the elongation properties but increased the tensile strength due to the inherent strength of the aromatic unit. The melting point and crystallization temperature were difficult to observe in PBSeT64, indicating that an amorphous copolyester was formed at this mole ratio. Interestingly, wide angle X-ray diffraction (WAXD) curves was shown in the cases of PBSeT46 and PBSeT64, neither the crystal peaks of PBSe nor those of poly(butylene terephthalate) (PBT) are observed, that is, PBSeT64 showed an amorphous form with low crystallinity. The Fourier-transform infrared (FT-IR) spectrum showed C–H peaks at around 2900 cm−1 that reduced as the DMT ratio was increased. Nuclear magnetic resonance (NMR) showed well-resolved peaks split by coupling with the sebacate and DMT moieties. These results highlight that elastomeric PBSeT with high molecular weight could be synthesized by applying DMT monomer and showed promising mechanical properties.


2013 ◽  
Vol 829 ◽  
pp. 294-298 ◽  
Author(s):  
Mehrdad Rashidzadeh

High purity Cadmium (Cd) metal was used as raw material and placed in a microwave susceptor. an evaporation/oxidation process occurs under exposure to microwave in less than 2 minutes. Then, Evaporated cadmium reacted with oxygen and cadmium oxide was collected on the inner surface of a glassy container that was placed a few centimeters above the susceptor. Morphological and structural information of As-synthesized CdO nanopowder, were investigated via SEM and X-ray diffraction (XRD) spectroscopy. The antibacterial activities of different concentration of the CdO nanoparticles were tested by treating Escherichia coli (Gram negative) cultures with CdO nanoparticles. The Study indicates that cadmium oxide nanoparticles show effective antibacterial activity toward the gram-negative bacterium E. coli. Electrochemical properties of as-synthesized powder were investigated via linear and two vertex cyclic voltammetery in the presence of ethanol, a pair of Oxidation/reduction peaks were achieved.


2021 ◽  
Author(s):  
Amalanathan.M ◽  
Aravind.M ◽  
Sony Michael Mary.M ◽  
Razan A. Alshgari ◽  
Asma A. Alothman ◽  
...  

Abstract In this work, jasmine flower derived activated carbon were successfully synthesized by hydrothermal carbonization process at the different annealing temperature. The Crystallinity, phase, structural, morphological and optical properties of activated carbon were investigated using X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Transmission electron microscope (TEM), and UV-visible spectroscopy analysis. The graphitic phase of carbon was obtained from the XRD pattern. Surface morphology reveals irregular-shaped nanoparticles. The photodegradation of methylene blue (MB) was carried out under the visible light irradiation technique to study its photocatalytic activity. The activated carbon obtained at 400oC, 500oC and 600oC shows a photocatalytic degradation efficiency of 86%, 90%, and 94%, respectively. Antibacterial activity of activated carbon was examined against S. Aureus (MTCC-737) and E-Coli (MTCC- 443) microbial pathogens, and their potent antibacterial activity was examined from the zone of inhibition layer.


2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Galo Cárdenas-Triviño ◽  
María J. Saludes-Betanzo ◽  
Luis Vergara-González

The nanotechnology is considered as a tool to overcome antibiotic-resistant infections. The aim of this study was to investigate the antibacterial properties of quantum dots (QDs) of Au, Ag, and Cu supported in chitosan against Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 29213), and Salmonella Typhi (ATCC 9993) strains. The QDs were synthesized by the method (Chemical Liquid Deposition, CLD) using 2-ethoxyethanol as solvent (1×10−3 M approximate dispersion concentration). Then, NPs supported in chitosan were synthesized by solvated metal atom dispersion (SMAD) in two concentrations, labelled [A] and [B] (0.05 and 0.1 g/L) for each metal with chitosan resulting in an average size of Au 10±2.0, Ag 6±1.3, and Cu 10±2.4 nm, respectively. Several other techniques were performed such as TEM, SEM/EDX, TGA, DSC, and FT-IR for characterizing QDs. The antibacterial assay was performed with 8 agents on cultures of E. coli, S. aureus, and S. Typhi by disk diffusion, broth macrodilution, and determining death curve to the most sensitive pathogen. The antibacterial effect of the nanoparticles was compared using the diameter of growth inhibition zone by agar disk diffusion and through the minimal inhibitory concentration (MIC) and minimal bactericide concentration (MBC) obtained by macrodilution in batch culture with an initial inoculum of 5×105 CFU/mL. The highest bactericidal effect was obtained with nanoparticles of Au, Ag, and Cu (0.1 g/L) with MIC and MBC of 200 and 400 mg/mL, respectively. The greatest bactericidal effect considering the three pathogens turned out to be Ag QDs (0.05 and 0.1 g/L). A bactericidal effect of metal nanoparticles is affected mainly by the electronegativity, the concentration of nanoparticles, and the bacterial age culture.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1039 ◽  
Author(s):  
Nanxi Zhang ◽  
Hui Cao

To enhance the antibacterial activity of natural rubber latex foam (NRLF), chitin was added during the foaming process in amounts of 1–5 phr (per hundred rubber) to prepare an environmentally friendly antibacterial NRLF composite. In this research, NRLF was synthesized by the Dunlop method. The swelling, density, hardness, tensile strength, elongation at break, compressive strength and antibacterial activity of the NRLFs were characterized. FTIR and microscopy were used to evaluate the chemical composition and microstructure of the NRLFs. The mechanical properties and antibacterial activity of the NRLF composites were tested and compared with those of pure NRLF. The antibacterial activity was observed by the inhibition zone against E. coli. NRLF composite samples were embedded in a medium before solidification. The experimental results of the inhibition zone indicated that with increasing chitin content, the antibacterial activity of the NRLF composites increased. When the chitin content reached 5 phr, the NRLF composite formed a large and clear inhibition zone in the culture dish. Moreover, the NRLF–5 phr chitin composite improved the antibacterial activity to 281.3% of that of pure NRLF against E. coli.


2020 ◽  
Vol 7 (1) ◽  
pp. 13 ◽  
Author(s):  
Tina Modjinou ◽  
Davy Louis Versace ◽  
Samir Abbad Andaloussi ◽  
Valérie Langlois ◽  
Estelle Renard

Biocompatible and biodegradable bacterial polyesters, poly(hydroxyalkanoates) (PHAs), were combined with linalool, a well-known monoterpene, extracted from spice plants to design novel antibacterial materials. Their chemical association by a photo-induced thiol-ene reaction provided materials having both high mechanical resistance and flexibility. The influence of the nature of the crosslinking agent and the weight ratio of linalool on the thermo-mechanical performances were carefully evaluated. The elongation at break increases from 7% for the native PHA to 40% for PHA–linalool co-networks using a tetrafunctional cross-linking agent. The materials highlighted tremendous anti-adherence properties against Escherichia coli and Staphylococcus aureus by increasing linalool ratios. A significant decrease in antibacterial adhesion of 63% and 82% was observed for E. coli and S. aureus, respectively.


2017 ◽  
Vol 751 ◽  
pp. 270-276 ◽  
Author(s):  
Warot Prasanseang ◽  
Chaval Sriwong ◽  
Kittisak Choojun

Ag-natural rubber (Ag-NR) hybrid sheets were successfully prepared with a very simple and low cost method. In this method, silver nanoparticles (AgNPs) were firstly synthesized by a rapid and green microwave-assisted using polyvinylpyrroridone (PVP) media. The effect of PVP weight ratios towards the size of AgNPs was also investigated. Then, Ag-NR hybrid sheet samples were prepared by latex mixing-casting method using concentrated natural rubber (NR) latex with the synthesized AgNPs colloids. The characteristic absorption, particles sizes and shapes of the obtained AgNPs were examined through UV-vis, TEM and SAED. Also, the prepared Ag-NR sheet samples were characterized using XRD, FT-IR, SEM and EDS techniques. It was found that the particles sizes of all the synthesized AgNPs had spherical-like shape, and the mean sizes were increased from 29.7 to 90.4 nm upon increasing PVP contents. EDS results showed the AgNPs were well-dispersed and impregnated into the rubber matrix. Moreover, the antibacterial properties of the prepared Ag-NR sheets were tested by agar disk-diffusion method with Gram-positive and Gram-negative bacteria as Staphylococcus aureus(S. aureus) and Escherichia coli(E. coli), respectively. The results showed that the hybrid sheets exhibited excellent antibacterial properties against these bacteria, in which the zones of inhibition were also dependent on the synthesized AgNPs by utilizing the different amounts of PVP.


2012 ◽  
Vol 182-183 ◽  
pp. 259-264
Author(s):  
Jia Wei Duan ◽  
Qiang Dou

In this study polypropylene (PP) composites containing β-nucleating agent (NT-C) and talc filler were prepared by melt compounding. The melting and crystallization behavior, morphology and mechanical properties of the composites were studied by means of differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), polarized light microscopy (PLM) and mechanical tests. The results indicate that talc suppresses the formation of β phase, but promotes the formation of α phase. The Izod notched impact strength and tensile strength of β-PP/talc composites are superior to those of PP/talc composites, indicating an outstanding balance of stiffness and toughness of β-PP/talc composites.


2013 ◽  
Vol 1547 ◽  
pp. 135-140 ◽  
Author(s):  
Yarilyn Cedeño-Mattei ◽  
Myrna Reyes ◽  
Oscar Perales-Pérez ◽  
Félix R. Román

ABSTRACTThe present work focuses on the development of a reproducible and cost-effective size-controlled synthesis route for nanoscale MgO and the preliminary assessment of its bactericide capacity as a function of crystal size. Nanoscale MgO was produced through the thermal decomposition of Mg-carbonate hydrate precursor (hydromagnesite) synthesized in aqueous phase. The exclusive formation of the MgO phase, with an average crystallite size between 7 and 13 ± 1 nm, was evidenced by X-Ray Diffraction and HRTEM analyses. Fourier Transform – Infrared spectroscopy confirmed the evolution of the precursor into the desired MgO structure. The bactericidal tests were conducted by measuring the optical density at 600 nm of E. coli in presence of MgO nanoparticles of specific sizes. MgO nanocrystals with average crystallite sizes of 13nm inhibited bacterial growth up to 35% at 500 mg MgO/L. The mechanism of inhibition could be attributed to the formation of superoxide species on the MgO surface.


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