scholarly journals Evaluation of the Thermal and Morphological Properties of γ-Irradiated Chitosan-Glycerol-Based Polymeric Films

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1783
Author(s):  
Waheed A. Al-Masry ◽  
Sajjad Haider ◽  
Asif Mahmood ◽  
Mujeeb Khan ◽  
Syed Farooq Adil ◽  
...  
Keyword(s):  
Composite Films ◽  
Exothermic Peak ◽  
Thin Layers ◽  
Polymeric Films ◽  
Endothermic Peak ◽  
Morphological Properties ◽  
Γ Irradiation ◽  
Casting Technique ◽  
Γ Rays ◽  
Two Peaks

Industry-sponsored research has intensified to find suitable substitutes for synthetic polymers. For this purpose, biopolymers are promising materials that are extracted from renewable resources. However, there are areas of concern (biopolymers are mostly brittle in the dry state) that require further research before they are used in advanced applications. To overcome this, plasticizers are often added to biopolymers to enhance their physicochemical properties. In this study, chitosan (CH)-glycerol (GL)-based polymeric films were prepared by a simple drop-casting technique, and the influence of a plasticizer (GL) on the properties of chitosan films was analyzed. Additionally, the as-prepared samples were irradiated with γ-rays (60Co γ rays with a dose of 102 kGy) to study the effect of γ-irradiation on the properties of polymeric composites. To achieve this, different samples were prepared by varying the amount of GL. FT-IR analysis revealed the interruption of hydrogen bonding in chitosan by the incorporation of GL. This led to the chain-spreading of CH, which ultimately increased the flexibility of the composite films (CH-GL). The DSC of the CH film showed two peaks: one endothermic peak below 100 °C (due to water vapor) and a second exothermic peak that appeared between 130 and 360 °C (degradation of the amino group). Plasticization of CH films with GL was confirmed by DSC, where the exothermic degradation was converted into an endothermic peak. Depending upon the amount of GL, γ-irradiation considerably affected the chemical structure of CH by breaking the carbohydrate and pyranose rings; this led to a decrease in the crystallinity of the composite films. The changes studied in the DSC and TGA analysis complemented each other. γ-irradiation also affected the morphology of the films, which changed from smooth and homogeneous to roasted structures, with random swelling on the surface of the films. This swelling reflected the degradation of the surfaces into thin layers. Considering the changes that occurred in the films post-γ-irradiation, it can be inferred that the irradiation dose of 102 kGy is sufficient to degrade as-prepared biopolymer composites.

Characterization of Nostoc muscorum NCCU-442 Derived Poly-3- hydroxybutyrate (PHB) and Polyethylene Glycol (PEG) Blends

2020 ◽  
Vol 10 (3) ◽  
pp. 200-207
Author(s):  
Sabbir Ansari ◽  
Tasneem Fatma
Keyword(s):  
Thermal Properties ◽  
Polyethylene Glycol ◽  
Morphological Properties ◽  
Morphological Alteration ◽  
Nostoc Muscorum ◽  
Microbial Culture ◽  
Polymer Science ◽  
Mixed Microbial Culture ◽  
Scanning Calorimetry ◽  
Casting Technique

Background: Poly-3-hydroxybutyrate (PHB) has attracted much consideration as biodegradable biocompatible polymer. This thermoplastic polymer has comparable material properties to polypropylene. Materials with more valuable properties may result from blending, a common practice in polymer science. Objective: In this paper, blends of PHB (extracted from cyanobacterium Nostoc muscorum NCCU- 442 with polyethylene glycol (PEG) were investigated for their thermal, tensile, hydrophilic and biodegradation properties. Methods: Blends were prepared in different proportions of PHB/PEG viz. 100/0, 98/2, 95/5, 90/10, 80/20, and 70/30 (wt %) using solvent casting technique. Morphological properties were investigated by using Scanning Electron Microscopy (SEM). Differential scanning calorimetry and thermogravimetric analysis were done for thermal properties determination whereas the mechanical and hydrophilic properties of the blends were studied by means of an automated material testing system and contact angle analyser respectively. Biodegradability potential of the blended films was tested as percent weight loss by mixed microbial culture within 60 days. Results: The blends showed good misciblity between PEG and PHB, however increasing concentrations of plasticizer caused morphological alteration as evidenced by SEM micrographs. PEG addition (10 % and above) showed significant alternations in the thermal properties of the blends. Increase in the PEG content increased the elongation at break ratio i.e enhanced the required plasticity of PHB. Rate of microbial facilitated degradation of the blends was greater with increasing PEG concentrations. Conclusion: Blending with PEG increased the crucial polymeric properties of cyanobacterial PHB.

scholarly journals Antimicrobial Active Bioplastics Using Triangular Silver Nanoplate Integrated Polycaprolactone and Polylactic Acid Films

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1132
Author(s):  
Eduardo Lanzagorta Garcia ◽  
Olivia A. Attallah ◽  
Marija Mojicevic ◽  
Declan M Devine ◽  
Margaret Brennan Fournet
Keyword(s):  
Polylactic Acid ◽  
Scale Up ◽  
Composite Films ◽  
Antimicrobial Properties ◽  
Morphological Structure ◽  
Antimicrobial Effect ◽  
Solvent Casting ◽  
Local Surface Plasmon Resonance ◽  
Casting Technique ◽  
Triangular Silver Nanoplates

An innovative antimicrobial technology for plastic surfaces is presented. We report the synthesis and scale-up of triangular silver nanoplates (TSNPs) and their integration into polycaprolactone (PCL) and polylactic acid (PLA) polymers through a solvent-casting technique. The TSNPs have a high geometric aspect ratio and strong local surface plasmon resonance (LSPR) response, which provides an effective tool for monitoring their integrity during processing and integration with the biodegradable plastics. An aqueous-based seed-mediated chemical method was used to synthesize the TSNPs, and characterisation was carried out using TEM and UV (Ultraviolet)-VIS (Visible) spectroscopy to measure LSPR profiles. The UV-VIS spectra of silver seeds and TSNPs exhibited characteristic peaks at 395 and 600 nm respectively. Synthesized TSNPs were coated with thiol-terminated polyethylene glycol (SH-PEG) and transferred into chloroform in order to effect compatibility with PCL and PLA. TSNP/PCL and TSNP/PLA composite films were prepared by solvent casting. The morphological structure, thermal, mechanical, and antimicrobial properties of the TSNP-incorporated composite films were evaluated. Results showed the TSNP-treated films had a rougher surface than the bare films. Insignificant changes in the thermal properties of TSNP-treated films compared to bare ones were also observed, which indicated the thermal stability of the composite films. The tensile strength and antimicrobial properties of the composite films were increased after TSNP incorporation. TSNP/PCL and TSNP/PLA films exhibited improved antimicrobial activity against Escherichia coli and Staphylococcus aureus with antimicrobial effect (AE) values ranging between 0.10 and 0.35. The obtained results and demonstrated TSNP production scalability validate the TSNP treated PCL and PLA films as a composite material with desirable antimicrobial effect for wide-ranging surface applications.

scholarly journals Ammonia Gas Sensing Characteristic of P3HT-rGO-MWCNT Composite Films

2021 ◽  
Vol 11 (15) ◽  
pp. 6675
Author(s):  
Tran Si Trong Khanh ◽  
Tran Quang Trung ◽  
Le Thuy Thanh Giang ◽  
Tran Quang Nguyen ◽  
Nguyen Dinh Lam ◽  
...  
Keyword(s):  
Response Time ◽  
Gas Sensor ◽  
Gas Sensing ◽  
Composite Films ◽  
Weight Ratio ◽  
Film Surface ◽  
Relative Sensitivity ◽  
Ammonia Gas ◽  
Casting Technique ◽  
Multi Walled Carbon Nanotubes

In this work, the P3HT:rGO:MWCNTs (PGC) nanocomposite film applied to the ammonia gas sensor was successfully fabricated by a drop-casting technique. The results demonstrated that the optimum weight ratio of the PGC nanocomposite gas sensor is 20%:60%:20% as the weight ratio of P3HT:rGO:MWCNTs (called PGC-60). This weight ratio leads to the formation of nanostructured composites, causing the efficient adsorption/desorption of ammonia gas in/out of the film surface. The sensor based on PGC-60 possessed a response time of 30 s, sensitivity up to 3.6% at ammonia gas concentration of 10 ppm, and relative sensitivity of 0.031%/ppm. These results could be attributed to excellent electron transportation of rGO, the main adsorption activator to NH3 gas of P3HT, and holes move from P3HT to the cathodes, which works as charge “nano-bridges” carriers of Multi-Walled Carbon Nanotubes (MWCNTs). In general, these three components of PGC sensors have significantly contributed to the improvement of both the sensitivity and response time in the NH3 gas sensor.

Identification of Amber and the Copal under Heat Pressurized Process

2012 ◽  
Vol 554-556 ◽  
pp. 2112-2115
Author(s):  
Hui Li ◽  
Xuan Wang ◽  
Yong Zhu ◽  
Qin Ren
Keyword(s):  
Chemical Properties ◽  
Peak Position ◽  
Exothermic Peak ◽  
Endothermic Peak ◽  
Scanning Calorimetry ◽  
Natural Resin ◽  
Before And After ◽  
Artificial Heat ◽  
Physical And Chemical ◽  
And Chemical Properties

Amber and copal belong to the natural resin, which are similar and transitional in the physical and chemical properties. The artificial heat-pressurized treatment is contributed to the polymerization of the natural copal, and turns into green, yellow-green and deep orange-yellow copal. It is very difficult to identify amber from the heat- pressurized treatment copal only based on the gemological parameters.The thermal behavior of amber and the copal before and after heat-pressurized treatment were analyzed by means of differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy(FTIR) and nuclear magnetic resonance(NMR). The results show that amber exists an evident endothermic peak around 123~132°C, and copal reveals an obvious endothermic peak at about 174~178°C, and the heat pressurized treatment copal occurs a clear exothermic peak around 150~152°C. The differences between endothermic or exothermic transition and peak position reveal occurring thermal oxidation or the bond breaking or the melting, which are of great significance in the identification.

OPTICAL AND ELECTRICAL PROPERTIES OF ARGON ION BEAM IRRADIATED PVA/Ag NANOCOMPOSITES

2017 ◽  
Vol 24 (03) ◽  
pp. 1750038 ◽  
Author(s):  
A. M. ABDEL REHEEM ◽  
A. ATTA ◽  
T. A. AFIFY
Keyword(s):  
Silver Nanoparticles ◽  
Electrical Properties ◽  
Ion Beam ◽  
Composite Films ◽  
Band Gap Energy ◽  
Dielectric Measurement ◽  
Optical And Electrical Properties ◽  
Structure Property ◽  
Casting Technique ◽  
Argon Ion

In this work, PVA/Ag nanocomposites films were prepared using solution casting technique, these films were irradiated with Argon ion beam to modify the structure. The main objective of the study is to enhance the optical and electrical properties of the polymer nanocomposites films by irradiation. The conventional characterization techniques such as UV–Visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR), transmission electron microscope (TEM) and dielectric measurement are employed to understand the structure–property relations. FTIR analysis of these composite films shows chemical changes and a significant impact on them can be observed after irradiation. After doping, the XRD data shows silver nanoparticles formation in the PVA polymer. The band gap energy of samples is decreased with increases in the concentration of silver nanoparticles and ion beam fluence, which gives clear indication that ion beam irradiation induced defects are formed in the composite systems. The electrical conductivity, dielectric loss [Formula: see text] and dielectric constant [Formula: see text] are increased with increasing ion beam fluence and Ag dopant concentration.

scholarly journals Hepatic Gene Expression Changes in Rats Internally Exposed to Radioactive 56MnO2 Particles at Low Doses

2021 ◽  
Vol 43 (2) ◽  
pp. 758-766
Author(s):  
Bakhyt Ruslanova ◽  
Zhaslan Abishev ◽  
Nailya Chaizhunussova ◽  
Dariya Shabdarbayeva ◽  
Sholpan Tokesheva ◽  
...  
Keyword(s):  
Atomic Bomb ◽  
Kinase Inhibitor ◽  
Biological Effects ◽  
Nuclear Factor Κb ◽  
Internal Exposure ◽  
Whole Body ◽  
Control Group ◽  
Gene Expressions ◽  
Γ Irradiation ◽  
Γ Rays

We have studied the biological effects of the internal exposure to radioactive manganese-56 dioxide (56MnO2), the major radioisotope dust found in soil after atomic bomb explosions. Our previous study of blood chemistry indicated a possible adverse effect of 56MnO2 on the liver. In the present study, we further examined the effects on the liver by determining changes in hepatic gene expressions. Male Wistar rats were exposed to 56MnO2 particles (three groups with the whole-body doses of 41, 90, and 100 mGy), stable MnO2 particles, or external 60Co γ-rays (2 Gy), and were examined together with the non-treated control group on postexposure day 3 and day 61. No histopathological changes were observed in the liver. The mRNA expression of a p53-related gene, the cyclin-dependent kinase inhibitor 1A, increased in 56MnO2 as well as in γ-ray irradiated groups on postexposure day 3 and day 61. The expression of a stress-responsive gene, nuclear factor κB, was also increased by 56MnO2 and γ-rays on postexposure day 3. However, the expression of cytokine genes (interleukin-6 or chemokine ligand 2) or fibrosis-related TGF-β/Smad genes (Tgfb1, Smad3, or Smad4) was not altered by the exposure. Our data demonstrated that the internal exposure to 56MnO2 particles at less than 0.1 Gy significantly affected the short-term gene expressions in the liver in a similar manner with 2 Gy of external γ-irradiation. These changes may be adaptive responses because no changes occurred in cytokine or TGF-β/Smad gene expressions.

Role of ion energy flux on the structural and morphological properties of silicon oxy-nitride composite films deposited by plasma focus device

2018 ◽  
Vol 173 (11-12) ◽  
pp. 929-943
Author(s):  
Ijaz Ahmad Khan ◽  
Syed Anwaar Hussain ◽  
Amjad Farid ◽  
Ali Hussnain ◽  
Zeshan Adeel Umar ◽  
...  
Keyword(s):  
Energy Flux ◽  
Plasma Focus ◽  
Composite Films ◽  
Plasma Focus Device ◽  
Morphological Properties ◽  
Ion Energy

Etude par résonance paramagnétique électronique de la radiolyse en phase solide de composés cycliques perfluorés

1970 ◽  
Vol 48 (3) ◽  
pp. 435-446 ◽  
Author(s):  
Claude Chachaty ◽  
Alain Forchioni ◽  
Masaru Shiotani
Keyword(s):  
Electron Spin Resonance ◽  
Solid State ◽  
Relative Intensity ◽  
Transition Point ◽  
Γ Irradiation ◽  
Ring Inversion ◽  
Spin Resonance ◽  
The Matrix ◽  
Γ Rays ◽  
Transition Points

Perfluorocyclohexane (PFCH) and perfluoromethylcyclohexane (PFMCH) have been irradiated in the solid state by γ rays of 60Co. The electron spin resonance (e.s.r.) spectrum of PFCH irradiated at 77 °K corresponds mainly towhich is tumbling in the matrix above 160 °K and disappears at the transition point (180 °K). When γ irradiation is carried out at 200 °K, C6F11• is also produced, but reacts with PFCH giving a radicalsupposed to be [Formula: see text]The e.s.r. spectrum of PFMCH γ irradiated at 77 °K has not been identified; it might be attributable in part to (•C6F11CF3)−. Above 160–170° K, the e.s.r. spectrum corresponds only toThe equal coupling of the four γ fluorines and also the relative intensity 1:4:1 of the three main groups of lines observed above 210 °K suggest that ring inversion occurs with a high rate.We have also studied the radicals [Formula: see text]produced by γ irradiation in the presence of oxygen. The variation of their spectra with temperature, particularly near the transition points, is very characteristic of the motion involved.

scholarly journals Synthesize of GaN/quartz Nanostructure Using Pulsed Laser Ablation in Liquid for Optoelectronic Devices

2021 ◽  
Author(s):  
Husam Aldin A. Abdul Amir ◽  
Makram A Fakhri ◽  
Ali. A. Alwahib ◽  
Evan T. Salim
Keyword(s):  
Laser Ablation ◽  
Quartz Substrate ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Morphological Properties ◽  
Laser Ablation In Liquid ◽  
Xrd Pattern ◽  
Laser Ablation Method ◽  
A Minor ◽  
Two Peaks

Abstract This study involves synthesizing gallium nitride (GaN) nanoparticles (NPs) under six different ablation energies using the pulsed laser ablation method. The nanoparticle was deposited using drop cast method on a quartz substrate. XRD pattern shows two peaks of h-GaN nanoparticles at 2θ = 34.64 and 37.98, reflected from (002) and (100) planes. The morphological properties indicate the hexagonal crystal nature of GaN that shows in the XRD pattern. Photoluminescence (PL) spectra show the highest laser power, 2000 mj has a minor emission peaked at 3.34 eV. The maximum emission peak 3.83 eV at 1400 mJ. The study depends on the pulsed laser to generate nanoparticles with different characteristics.

MORPHOLOGICAL AND OPTICAL STUDIES OF PZN-4.5PT NANOPARTICLES THIN FILMS ON NANOSTRUCTURED SILICON SUBSTRATE

2021 ◽  
Vol 3 (1) ◽  
pp. CA2105-1-CA2105-4
Author(s):  
C. Y. Fall Ndeye ◽  
◽  
M. Touré ◽  
R. Ndioukane ◽  
D. Kobor ◽  
...  
Keyword(s):  
Thin Films ◽  
Energy Transition ◽  
Global Scale ◽  
Point Of View ◽  
Thin Layers ◽  
Morphological Properties ◽  
Light Power ◽  
Energy Needs ◽  
Major Player ◽  
Uv Visible

The development of renewable energies is today essential to be able to respond in a sustainably way to the growing energy needs on a global scale, as well as to reduce the greenhouse gas emissions responsible for global warming. Among these energies, photovoltaic technology, which converts light power of the sun (renewable source) into electric power, is a major player in the energy transition. However, there is now a need to develop efficient, competitive and less polluting photovoltaic technologies, allowing more energy to be produced at a lower cost. The Pb (Zn<sub>1/3</sub> Nb<sub>2/3</sub>) O<sub>3</sub> (PZN) relaxor and its solid solutions with ferroelectric PbTiO<sub>3</sub> (PT) are of considerable interest both from the applications point of view and from the scientific point of view. In the past, numerous attempts have been made to prepare and study the properties of these materials in the form of thin layers for photovoltaic applications. However, due to the difficulties in preparing pure phase films with a high PZN content, there is very little knowledge of the properties of these materials. The objective of this work is to prepare PZN-4.5PT nanoparticle thin films, to study in detail their morphological and optical properties. The studies were carried out in three main directions: preparation of thin layers (PZN-PT) by deposit of spin coating, and characterize for optical and morphological properties (SEM). UV-visible measurements allowed us to have reflectance of less than 30% after deposit a thin layer PZN-4.5PT doped 1% Mn and undoped for a 70 at 80% absorption in UV-Visible-NIR.

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