Search results for: polymer shells

Authors: María del Carmen Recio-Ruiz, Ramiro Ruiz-Rosas, Juana María Rosas, José Rodríguez-Mirasol, Tomás Cordero

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At the present time, conventional fossil fuels show environmental and sustainability disadvantages with regard to renewables energies. Producing energy and chemicals from biomass is an interesting alternative for substitution of conventional fossil sources with a renewable feedstock while enabling zero net greenhouse gases emissions. Pyrolysis is a well-known process to produce fuels and chemicals from biomass. In this work, conventional and fast pyrolysis of different agro-industrial residues (almond shells, hemp hurds, olive stones, and Kraft lignin) was studied. Both processes were carried out in a fixed bed reactor under nitrogen flow and using different operating conditions to analyze the influence of temperature (400-800 ºC) and heating rate (10 and 20 ºC/minfor conventional pyrolysis and 50 ºC/s for fast pyrolysis)on the yields, products distribution, and composition of the different fractions. The results showed that for both conventional and fast pyrolysis, the solid fraction yield decreased with temperature, while the liquid and gas fractions increased. In the case of the fast pyrolysis, a higher content of liquid fraction than that obtained in conventional pyrolysis could be observed due to cracking reactions occur at a lesser extent. With respect to the composition of de non-condensable fraction, the main gases obtained were CO, CO₂ (mainly at low temperatures), CH₄, and H₂ (mainly at high temperatures).

Keywords: bio-oil, biomass, conventional pyrolysis, fast pyrolysis

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Authors: F. Z. Benabid, F. Zouai, N. Kharchi, D. Benachour

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A HDPE/ZnO nano composites have been successfully performed using the co-mixing. The ZnO was first co-mixed with the stearic acid then added to the polymer in the plastograph. The nano composites prepared with the co-mixed ZnO were compared to those prepared with the neat TiO2. The nano composites were characterized by different techniques as the wide-angle X-ray scattering (WAXS). The micro and nano structure/properties relationships were investigated. The present study allowed establishing good correlations between the different measured properties.

Keywords: exfoliation, ZnO, nano composites, HDPE, co-mixing

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Authors: You-Lin Wu, Yi-Hsing Sung, Shih-Hung Lin, Jing-Jenn Lin

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Performance improvement in optoelectronic devices such as solar cells and photodetectors has been reported when a polymer/ZnO nanorods stack is used. Resistance switching of polymer/ZnO nanocrystals (or nanorods) hybrid has also gained a lot of research interests recently. It has been reported that high- and low-resistance states of a metal/insulator/metal (MIM) structure diode with a polystyrene (PS) and ZnO hybrid as the insulator layer can be switched by applied bias after a high-voltage forming process, while the same device structure merely with a PS layer does not show any forming behavior. In this work, we investigated the current-voltage (I-V) characteristics of an MIM device with a PS/ZnO nanorods stack deposited on fluorine-doped tin oxide (FTO) glass substrate. The ZnO nanorods were grown by a hydrothermal method using a mixture of zinc nitrate, hexamethylenetetramine, and DI water. Following that, a PS layer was deposited by spin coating. Finally, the device with a structure of Ti/ PS/ZnO nanorods/FTO was completed by e-gun evaporated Ti layer on top of the PS layer. Semiconductor parameters analyzer Agilent 4156C was then used to measure the I-V characteristics of the device by applying linear ramp sweep voltage with sweep sequence of 0V → 4V → 0V → 3V → 0V → 2V → 0V → 1V → 0V in both positive and negative directions. It is interesting to find that the I-V characteristics are bias dependent and hysteretic, indicating that the device Ti/PS/ZnO nanorods/FTO structure has ferroelectricity. Our results also show that the maximum hysteresis loop height of the I-V characteristics as well as the voltage at which the maximum hysteresis loop height of each scan occurs increase with increasing maximum sweep voltage. It should be noticed that, although ferroelectricity has been found in ZnO at its melting temperature (1975℃) and in Li- or Co-doped ZnO, neither PS nor ZnO has ferroelectricity at room temperature. Using the same structure but with a PS or ZnO layer only as the insulator does not give and hysteretic I-V characteristics. It is believed that a charge polarization layer is induced near the PS/ZnO nanorods stack interface and thus causes the ferroelectricity in the device with Ti/PS/ZnO nanorods/FTO structure. Our results show that the PS/ZnO stack can find a potential application in a resistive switching memory device with MIM structure.

Keywords: ferroelectricity, hysteresis, polystyrene, resistance switching, ZnO nanorods

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Authors: Vanessa Morgado, Ricardo Bettencourt da Silva, Carla Palma

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The environmental pollution by microplastics is well recognized. Microplastics were already detected in various matrices from distinct environmental compartments worldwide, some from remote areas. Various methodologies and techniques have been used to determine microplastic in such matrices, for instance, sediment samples from the ocean bottom. In order to determine microplastics in a sediment matrix, the sample is typically sieved through a 5 mm mesh, digested to remove the organic matter, and density separated to isolate microplastics from the denser part of the sediment. The physical analysis of microplastic consists of visual analysis under a stereomicroscope to determine particle size, colour, and shape. The chemical analysis is performed by an infrared spectrometer coupled to a microscope (micro-FTIR), allowing to the identification of the chemical composition of microplastic, i.e., the type of polymer. Creating legislation and policies to control and manage (micro)plastic pollution is essential to protect the environment, namely the coastal areas. The regulation is defined from the known relevance and trends of the pollution type. This work discusses the assessment of contamination trends of a 700 km² oceanic area affected by contamination heterogeneity, sampling representativeness, and the uncertainty of the analysis of collected samples. The methodology developed consists of objectively identifying meaningful variations of microplastic contamination by the Monte Carlo simulation of all uncertainty sources. This work allowed us to unequivocally conclude that the contamination level of the studied area did not vary significantly between two consecutive years (2018 and 2019) and that PET microplastics are the major type of polymer. The comparison of contamination levels was performed for a 99% confidence level. The developed know-how is crucial for the objective and binding determination of microplastic contamination in relevant environmental compartments.

Keywords: measurement uncertainty, micro-ATR-FTIR, microplastics, ocean contamination, sampling uncertainty

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Authors: Wei-Wen Hu, Yong-Zhi Zhong

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Depositing conductive polypyrrole (PPy) onto elastic polydimethylsiloxane (PDMS) substrate can obtain a highly stretchable conductive film, which can be used to construct a bioreactor to cyclically stretch and electrically stimulate surface cells. However, how to completely harvest these stimulated muscle tissue to repair damaged muscle is a challenge. To address this concern, N-isopropylacrylamide (NIPAAm), a monomer of temperature-sensitive polymer, was added during the polymerization of pyrrole on PDMS so that the resulting P(Py-co-NIPAAm)/PDMS should own both conductivity and thermo-sensitivity. Therefore, cells after stimulation can be completely harvested as cell sheets by reducing temperature. Mouse skeletal myoblast, C2C12 cells, were applied to examine our hypothesis. In electrical stimulation, C2C12 cells on P(Py-co-NIPAAm)/PDMS demonstrated the best myo-differentiation under the electric field of 1 V/cm. Regarding cyclic stretching, the strain equal to or higher than 9% can highly align C2C12 perpendicular to the stretching direction. The Western blotting experiments demonstrated that the cell sheets harvested by cooling reserved more extracellular matrix (ECM) than cells collected by the traditional trypsin digestion method. Immunostaining of myosin heavy chain protein (MHC) indicated that both mechanical and electrical stimuli effectively increased the number of myotubes and the differentiation ratio, and the myotubes can be aligned by cyclic stretching. Stimulated cell sheets can be harvested by cooling, and the alignment of myotubes was still maintained. These results suggested that the deposition of P(Py-co-NIPAAm) on PDMS can be applied to harvest intact cell sheets after cyclic stretching and electrical stimulation, which increased the feasibility of bioreactor for the application of tissue engineering and regenerative medicine.

Keywords: bioreactor, cell sheet, conductive polymer, cyclic stretching, electrical stimulation, muscle tissue engineering, myogenesis, thermosensitive hydrophobicity

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Authors: M. Arunachalam, M. Pandey

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Nacre, a biological material that forms the inner-layer of sea shells can achieve high toughness and strength by way of staggered arrangement of strong tablets with soft and weak organic interface. Under applied loads the tablets slide over the adjacent tablets, thus generating inelastic deformation and toughness on macroscopic scale. A two dimensional finite element based homogenization methodology is adopted for obtaining the effective material properties of Nacre using a representative volume element (RVE) at finite deformations. In this work, the material behaviour for tablet and interface are assumed to be Isotropic elastic and Isotropic elastic-perfectly plastic with strain softening respectively. Numerical experiments such as uniaxial tension test along X, Y directions and simple shear test are performed on the RVE with uniform displacement and periodic constraints applied at the RVE boundaries to obtain the anisotropic homogenized response and maximum local stresses within each constituents of Nacre. Homogenized material model is then tested for macroscopic structure under three point bending condition and the results obtained are comparable with the results obtained for detailed microstructure based structure, thus homogenization provides a bridge between macroscopic scale and microscopic scale and homogenized material properties obtained from microstructural (RVE) analysis could be used in large scale structural analysis.

Keywords: finite element, homogenization, inelastic deformation, staggered arrangement

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Authors: A. E. Delgado, W. Aperador

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This study evaluated the incidence of concentrated natural fibre, as well as the effects of adding a crosslinking agent on the torque when those components are mixed with low density polyethylene (LDPE). The natural fibre has a particle size of between 0.8-1.2mm and a moisture content of 0.17%. An internal mixer was used to measure the torque required to mix the polymer with the fibre. The effect of the fibre content and crosslinking agent on the torque was also determined. A change was observed in the morphology of the mixes using SEM differential scanning microscopy.

Keywords: WPC, DCP, LDPE, natural fibre, torque

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Authors: Girlly Marchlina Listyono, Abdurrokhim Abdurrokhim, Emi Sukiyah, Pulung Arya Pranantya

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Jakarta Area is composed by deposit which has various lithology characteristics. Based on its lithology types, colors, textures, mineral dan organic content from 22 wells scattered on Jakarta, lithofacies analysis and intra-wells data correlation can be done. From the analysis, it can be interpretated that Jakarta deposit deposited in marine, transition and terrestrial depositional environments. Terrestrial deposit characterized by domination of relatively coarse clastics and content of remaining roots, woods, plants, high content of quartz, lithic fragment, calcareous and oxidated appearace. The thickness of terrestrial deposit is thickening to south. Transitional deposit characterized by fine to medium clastics with dark color, high content of organic matter, various thickness in any ways. Marine deposit characterized by finer clastics, contain remain of shells, fosil, coral, limestone fragments, glauconites, calcareous. Marine deposit relatively thickening to north. Those lateral variety caused by tectonic, subsidence and stratigraphic condition. Deposition of Jakarta deposit from the data research was started on marine depositional environment which surrounded by the event of cycle of regression and transgression then ended with regression which ongoing until form shore line in north Jakarta nowadays.

Keywords: deposit, Indonesia, Jakarta, sediment, stratigraphy

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Authors: Karen L. Rincon-Granados, América R. Vázquez-Olmos, Adriana-Patricia Rodríguez-Hernández, Gina Prado-Prone, Margarita Rivera, Roberto Y. Sato-Berrú

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In this work, a hybrid film based on poly-3-hydroxybutyrate (P3HB) and nickel ferrite (NiFe₂O₄) nanoparticles (NPs) was obtained by a simple and reproducible methodology in order to study its antibacterial and cytotoxic properties. The motivation for this research is the current antimicrobial resistance (RAM). This is a threat to human health and development worldwide. RAM is caused by the emergence of bacterial strains resistant to traditional antibiotics that were used as treatment. Due to this, the need to investigate new alternatives for preventing and treating bacterial infections emerges. In this sense, metal oxide NPs have aroused great interest due to their unique physicochemical properties. However, their use is limited by the nanostructured nature, commonly obtained by chemical and physical synthesis methods, as powders or colloidal dispersions. Therefore, the incorporation of nanostructured materials in polymer matrices to obtain hybrid materials that allow disinfecting and preventing the spread of bacteria on various surfaces. Accordingly, this work presents the synthesis and study of the antibacterial properties of the P3HB@NiFe₂O₄ hybrid film as a potential material to inhibit bacterial growth. The NiFe₂O₄ NPs were previously synthesized by a mechanochemical method. The P3HB and P3HB@NiFe₂O₄ films were obtained by the solvent casting method. The films were characterized by X-ray diffraction (XRD), Raman scattering, and scanning electron microscopy (SEM). The XRD pattern showed that the NiFe₂O₄ NPs were incorporated into the P3HB polymer matrix and retained their nanometric sizes. By energy dispersive X-ray spectroscopy (EDS), it was observed that the NPs are homogeneously distributed in the film. The bactericidal effect of the films obtained was evaluated in vitro using the broth surface method against two opportunistic and nosocomial pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. The bacterial growth results showed that the P3HB@NiFe₂O₄ hybrid film was inhibited by 97% and 96% for S. aureus and P. aeruginosa, respectively. Surprisingly, the P3HB film inhibited both bacterial strains by around 90%. The cytotoxicity of the NiFe₂O₄ NPs, P3HB@NiFe₂O₄ hybrid film, and the P3HB film was evaluated using human skin cells, keratinocytes, and fibroblasts, finding that the NPs are biocompatible. The P3HB film and hybrids are cytotoxic, which demonstrated that although P3HB is known and reported as a biocompatible polymer, under our work conditions, P3HB was cytotoxic. Its bactericidal effect could be related to this activity. Its films are bactericidal and cytotoxic to keratinocytes and fibroblasts, the first barrier of human skin. Despite this, the hybrid film of P3HB@NiFe₂O₄ presents synergy with the bactericidal effect between P3HB and NPs, increasing bacterial inhibition. In addition, NPs decrease the cytotoxicity of P3HB to keratinocytes. The methodology used in this work was successful in producing hybrid films with antibacterial activity. However, future challenges are generated to find relationships between NPs and P3HB that allow taking advantage of their bactericidal properties and do not compromise biocompatibility.

Keywords: poly-3-hydroxybutyrate, nanoparticles, hybrid film, antibacterial

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Authors: Qi Liu, Jiqin Yao, Xiaohu Zhou, Bo Zheng

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The first artificial cell was produced by Thomas Chang in the 1950s when he was trying to make a mimic of red blood cells. Since then, many different types of artificial cells have been constructed from one of the two approaches: a so-called bottom-up approach, which aims to create a cell from scratch, and a top-down approach, in which genes are sequentially knocked out from organisms until only the minimal genome required for sustaining life remains. In this project, bottom-up approach was used to build a new cell-free expression system which mimics artificial cell that capable of protein expression and communicate with each other. The artificial cells constructed from the bottom-up approach are usually lipid vesicles, polymersomes, hydrogels or aqueous droplets containing the nucleic acids and transcription-translation machinery. However, lipid vesicles based artificial cells capable of communication present several issues in the cell communication research: (1) The lipid vesicles normally lose the important functions such as protein expression within a few hours. (2) The lipid membrane allows the permeation of only small molecules and limits the types of molecules that can be sensed and released to the surrounding environment for chemical communication; (3) The lipid vesicles are prone to rupture due to the imbalance of the osmotic pressure. To address these issues, the hydrogel-based artificial cells were constructed in this work. To construct the artificial cell, polyacrylamide hydrogel was functionalized with Acrylate PEG Succinimidyl Carboxymethyl Ester (ACLT-PEG2000-SCM) moiety on the polymer backbone. The proteinaceous factors can then be immobilized on the polymer backbone by the reaction between primary amines of proteins and N-hydroxysuccinimide esters (NHS esters) of ACLT-PEG2000-SCM, the plasmid template and ribosome were encapsulated inside the hydrogel particles. Because the artificial cell could continuously express protein with the supply of nutrients and energy, the artificial cell-artificial cell communication and artificial cell-natural cell communication could be achieved by combining the artificial cell vector with designed plasmids. The plasmids were designed referring to the quorum sensing (QS) system of bacteria, which largely relied on cognate acyl-homoserine lactone (AHL) / transcription pairs. In one communication pair, “sender” is the artificial cell or natural cell that can produce AHL signal molecule by synthesizing the corresponding signal synthase that catalyzed the conversion of S-adenosyl-L-methionine (SAM) into AHL, while the “receiver” is the artificial cell or natural cell that can sense the quorum sensing signaling molecule form “sender” and in turn express the gene of interest. In the experiment, GFP was first immobilized inside the hydrogel particle to prove that the functionalized hydrogel particles could be used for protein binding. After that, the successful communication between artificial cell-artificial cell and artificial cell-natural cell was demonstrated, the successful signal between artificial cell-artificial cell or artificial cell-natural cell could be observed by recording the fluorescence signal increase. The hydrogel-based artificial cell designed in this work can help to study the complex communication system in bacteria, it can also be further developed for therapeutic applications.

Keywords: artificial cell, cell-free system, gene circuit, synthetic biology

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Authors: O. Gsib, U. Peirera, C. Egles, S. A. Bencherif

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In skin regenerative medicine, one of the critical issues is to produce a three-dimensional scaffold with optimized porosity for dermal fibroblast infiltration and neovascularization, which exhibits high mechanical properties and displays sufficient wound healing characteristics. In this study, we report on the synthesis and characterization of macroporous sequential interpenetrating polymer networks (IPNs) combining skin wound healing properties of fibrin with the excellent physical properties of polyethylene glycol (PEG). Fibrin fibers serve as a provisional biologically active network to promote cell adhesion and proliferation while PEG provides the mechanical stability to maintain the entire 3D construct. After having modified both PEG and Serum Albumin (used for promoting enzymatic degradability) by adding methacrylate residues (PEGDM and SAM, respectively), Fibrin/PEGDM-SAM sequential IPNs were synthesized as follows: Macroporous sponges were first produced from PEGDM-SAM hydrogels by a freeze-drying technique and then rehydrated by adding the fibrin precursors. Environmental Scanning Electron Microscopy (ESEM) and Confocal Laser Scanning Microscopy (CLSM) were used to characterize their microstructure. Human dermal fibroblasts were cultivated during one week in the constructs and different cell culture parameters (viability, morphology, proliferation) were evaluated. Subcutaneous implantations of the scaffolds were conducted on five-week old male nude mice to investigate their biocompatibility in vivo. We successfully synthesized interconnected and macroporous Fibrin/PEGDM-SAM sequential IPNs. The viability of primary dermal fibroblasts was well maintained (above 90%) after 2 days of culture. Cells were able to adhere, spread and proliferate in the scaffolds suggesting the suitable porosity and intrinsic biologic properties of the constructs. The fibrin network adopted a spider web shape that covered partially the pores allowing easier cell infiltration into the macroporous structure. To further characterize the in vitro cell behavior, cell proliferation (EdU incorporation, MTS assay) is being studied. Preliminary histological analysis of animal studies indicated the persistence of hydrogels even after one-month post implantation and confirmed the absence of inflammation response, good biocompatibility and biointegration of our scaffolds within the surrounding tissues. These results suggest that our Fibrin/PEGDM-SAM IPNs could be considered as potential candidates for dermis regenerative medicine. Histological analysis will be completed to further assess scaffold remodeling including de novo extracellular matrix protein synthesis and early stage angiogenesis analysis. Compression measurements will be conducted to investigate the mechanical properties.

Keywords: fibrin, hydrogels for dermal reconstruction, polyethylene glycol, semi-interpenetrating polymer network

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Authors: Charmi Chande, Ravindra Phadke

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Microfluidics devices are fabricated by using multiple fabrication methods. Photolithography is one of the common methods wherein SU8 is widely used for making master which in turn is used for making working chip by the process of soft lithography. The high-aspect ratio features of SU-8 makes it suitable to be used as micro moulds for injection moulding, hot embossing, and moulds to form polydimethylsiloxane (PDMS) structures for bioMEMS (Microelectromechanical systems) applications. But due to high cost, difficulty in procuring and need for clean room, restricts the use of this polymer especially in developing countries and small research labs. ‘Bisphenol –A’ based polymers in mixture with curing agent are used in various industries like Paints and coatings, Adhesives, Electrical systems and electronics, Industrial tooling and composites. We present the novel use of ‘Bisphenol – A’ based polymer in fabricating micro channels for Lab On Chip(LOC) devices. The present paper describes the prototype for production of microfluidics chips using range of ‘Bisphenol-A’ based polymers viz. GY 250, ATUL B11, DER 331, DER 330 in mixture with cationic photo initiators. All the steps of chip production were carried out using an inexpensive approach that uses low cost chemicals and equipment. This even excludes the need of clean room. The produced chips using all above mentioned polymers were validated with respect to height and the chip giving least height was selected for further experimentation. The lowest height achieved was 7 micrometers by GY250. The cost of the master fabricated was $ 0.20 and working chip was $. 0.22. The best working chip was used for morphological identification and profiling of microorganisms from environmental samples like soil, marine water and salt water pan sites. The current chip can be adapted for various microbiological screening experiments like biochemical based microbial identification, studying uncultivable microorganisms at single cell/community level.

Keywords: bisphenol–A based epoxy, cationic photoinitiators, microfabrication, photolithography

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Authors: I-Yun Cheng, Min-Yu Chiang, Shwu-Jen Chang, San-Yuan Chen

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Osteoarthritis (OA) is among the most challenging joint diseases, and as far as we know, there is currently no exact and effective cure for it because it has low self-repair ability due to lack of blood vessels and low cell density in articular cartilage. So far, there have been several methods developed to treat cartilage disorder. The most common method is to treat the high molecular weight of hyaluronic acid (HA) injection, but it will degrade after a period of time, so the patients need to inject HA repeatedly. In recent years, self-healing hydrogel has drawn considerable attention because it can recover its initial mechanical properties after damaged and further increase the lifetime of the hydrogel. Here, we aim to develop a self-healable composite hydrogel combined with magnetic microspheres to trigger glutathione(GSH) release for promoting cartilage repair. We use HA-cyclodextrin (CD) as host polymer and poly(acrylic acid)-ferrocene (pAA-Fc) as guest polymer to form the self-healable HA-pAA hydrogel by host and guest interaction where various graft amount of pAA-Fc (pAA:Fc= 1:2, 1:1.5, 1:1, 2:1, 4:1) was conducted to develop different mechanical strength hydrogel. The rheology analysis showed that the 4:1 of pAA-Fc has higher mechanical strength than other formulations. On the other hand, iron oxide nanoparticle, poly(lactic-co-glycolic acid) (PLGA) and polyethyleneimine (PEI) were used to synthesize porous magnetic microspheres via double emulsification water-in-oil-in-water (W/O/W) to increase GSH loading which acted as a reductant to control the hydrogel crosslink density and promote hydrogel self-healing. The results show that the porous magnetic microspheres can be loaded with 70% of GSH and sustained release about 50% of GSH after 24 hours. More importantly, the HA-pAA composite hydrogel can self-heal rapidly within 24 hours when suffering external force destruction by releasing GSH from the magnetic microspheres. Therefore, the developed the HA-pAA composite hydrogel combined with GSH-loaded magnetic microspheres can be in-vivo guided to damaged OA surface for inducing the cartilage repair by controlling the crosslinking of self-healing hydrogel via GSH release.

Keywords: articular cartilage, magnetic microsphere, osteoarthritis, self-healing hydrogel

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Authors: G. N. Simonian, R. F. Basalah, F. T. Abd El Halim, F. F. Abd El Latif, A. M. Adel, A. M. El Shafey.

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Carboxymethyl cellulose (CMC) is an anionic water soluble polymer that has been introduced in paper coating as a strength agent. One of the main objectives of this research is to investigate the influence of CMC concentration in improving the strength properties of paper fiber. In this work, we coated the paper sheets; Xerox paper sheets by different concentration of carboxymethyl cellulose solution (0.1, 0.5, 1, 1.5, 2, 3%) w/v. The mechanical properties; breaking length and tearing resistance (tear factor) were measured for the treated and untreated paper specimens. The retained polymer in the coated paper samples were also calculated. The more the concentration of the coating material; CMC increases, the more the mechanical properties; breaking length and tear factor increases. It can be concluded that CMC enhance the improvement of the mechanical properties of paper sheets result in increasing paper stability. The aim of the present research was also to study the effects on the vessel element structure and vessel picking tendency of the coated paper sheets. In addition to the improved strength properties of the treated sheet, a significant decrease in the vessel picking tendency was expected whereas refining of the original paper sheets (untreated paper sheets) improved mainly the bonding ability of fibers, CMC effectively enhanced the bonding of vessels as well. Moreover, film structures were formed in the fibrillated areas of the coated paper specimens, and they were concluded to reinforce the bonding within the sheet. Also, fragmentation of vessel elements through CMC modification was found to be important and results in a decreasing picking tendency which reflects in a good printability. Moreover, Scanning – Electron Microscope (SEM) images are represented to specifically explain the improved bonding ability of vessels and fibers after CMC modification. Finally, CMC modification enhance paper mechanical properties and print quality.

Keywords: carboxymethyl cellulose (CMC), breaking length, tear factor, vessel picking, printing, concentration

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Authors: Getachew T. Sedebo, Stephan V. Joubert, Michael Y. Shatalov

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Conventional configuration of the vibratory disc gyroscope is based on in-plane non-axisymmetric vibrations of the disc with a prescribed circumferential wave number. Due to the Bryan's effect, the vibrating pattern of the disc becomes sensitive to the axial component of inertial rotation of the disc. Rotation of the vibrating pattern relative to the disc is proportional to the inertial angular rate and is measured by sensors. In the present paper, the authors investigate a possibility of making a 3D sensor on the basis of both in-plane and bending vibrations of the disc resonator. We derive equations of motion for the disc vibratory gyroscope, where both in-plane and bending vibrations are considered. Hamiltonian variational principle is used in setting up equations of motion and the corresponding boundary conditions. The theory of thin shells with the linear elasticity principles is used in formulating the problem and also the disc is assumed to be isotropic and obeys Hooke's Law. The governing equation for a specific mode is converted to an ODE to determine the eigenfunction. The resulting ODE has exact solution as a linear combination of Bessel and Neumann functions. We demonstrate how to obtain an explicit solution and hence the eigenvalues and corresponding eigenfunctions for annular disc with fixed inner boundary and free outer boundary. Finally, the characteristics equations are obtained and the corresponding eigenvalues are calculated. The eigenvalues are used for the calculation of tuning conditions of the 3D disc vibratory gyroscope.

Keywords: Bryan’s effect, bending vibrations, disc gyroscope, eigenfunctions, eigenvalues, tuning conditions

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Authors: D. Abid, A. Guettar, A. Toubane, A. Bouda, K. Daoud

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The aim of this work is to study coating formulations rheology. Fourteen solutions were prepared with Hydroxypropyl methylcellulose (HPMC) percentage which varies from 2 to 20 %, Ethyl cellulose (EC) percentage varying from 1 to 3 % and Titanium dioxide (TiO2) percentage which vary from 1 to 3%, Opadry solution (25%) was used as a reference for this study. Two behaviors appeared obviously ‘pseudo plastic’ and ‘dilatant’ related to the percentage of HPMC, this allowed us to define that HPMC is the polymer which influence the behavior of coating solutions.

Keywords: rheology, opadry, HPMC, B1-B6 tablets

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Authors: Indunil Jayatilake, Warna Karunasena

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Fiber Reinforced Polymer (FRP) composites enjoy an array of applications ranging from aerospace, marine and military to automobile, recreational and civil industry due to their outstanding properties. A structural glass fiber reinforced polymer (GFRP) composite sandwich panel made from E-glass fiber skin and a modified phenolic core has been manufactured in Australia for civil engineering applications. One of the major mechanisms of damage in FRP composites is skin-core debonding. The presence of debonding is of great concern not only because it severely affects the strength but also it modifies the dynamic characteristics of the structure, including natural frequency and vibration modes. This paper deals with the investigation of the dynamic characteristics of a GFRP beam with single and multiple debonding by finite element based numerical simulations and analyses using the STRAND7 finite element (FE) software package. Three-dimensional computer models have been developed and numerical simulations were done to assess the dynamic behavior. The FE model developed has been validated with published experimental, analytical and numerical results for fully bonded as well as debonded beams. A comparative analysis is carried out based on a comprehensive parametric investigation. It is observed that the reduction in natural frequency is more affected by single debonding than the equally sized multiple debonding regions located symmetrically to the single debonding position. Thus it is revealed that a large single debonding area leads to more damage in terms of natural frequency reduction than isolated small debonding zones of equivalent area, appearing in the GFRP beam. Furthermore, the extents of natural frequency shifts seem mode-dependent and do not seem to have a monotonous trend of increasing with the mode numbers.

Keywords: debonding, dynamic response, finite element modelling, novel FRP beams

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Authors: Leon Mishnaevsky Jr., Gaoming Dai

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3D numerical simulations of fatigue damage of multiscale fiber reinforced polymer composites with secondary nanoclay reinforcement are carried out. Macro-micro FE models of the multiscale composites are generated automatically using Python based software. The effect of the nanoclay reinforcement (localized in the fiber/matrix interface (fiber sizing) and distributed throughout the matrix) on the crack path, damage mechanisms and fatigue behavior is investigated in numerical experiments.

Keywords: computational mechanics, fatigue, nanocomposites, composites

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Authors: Mohsin Ejaz, Shiao-Wei Kuo

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The growing production and exploitation of fossil fuels have placed human society in serious environmental issues. As a result, it's critical to design efficient and eco-friendly energy production and storage techniques. Porous organic polymers (POPs) are multi-dimensional porous network materials developed through the formation of covalent bonds between different organic building blocks that possess distinct geometries and topologies. POPs have tunable porosities and high surface area making them a good candidate for an effective electrode material in energy storage applications. Herein, we prepared a fully benzoxazine-based porous organic polymers (TPA–DHTP–BZ POP) through sonogashira coupling of dihydroxyterephthalaldehyde (DHPT) and triphenylamine (TPA) containing benzoxazine (BZ) monomers. Firstly, both BZ monomers (TPA-BZ-Br and DHTP-BZ-Ea) were synthesized by three steps, including Schiff base, reduction, and mannich condensation reaction. Finally, the TPA–DHTP–BZ POP was prepared through the sonogashira coupling reaction of brominated monomer (TPA-BZ-Br) and ethynyl monomer (DHTP-BZ-Ea). Fourier transform infrared (FTIR) and solid-state nuclear magnetic resonance (NMR) spectroscopy confirmed the successful synthesis of monomers as well as POP. The porosity of TPA–DHTP–BZ POP was investigated by the N₂ absorption technique and showed a Brunauer–Emmett–Teller (BET) surface area of 196 m² g−¹, pore size 2.13 nm and pore volume of 0.54 cm³ g−¹, respectively. The TPA–DHTP–BZ POP experienced thermal ring-opening polymerization, resulting in poly (TPA–DHTP–BZ) POP having strong inter and intramolecular hydrogen bonds formed by phenolic groups and Mannich bridges, thereby enhancing CO₂ capture and supercapacitive performance. The poly(TPA–DHTP–BZ) POP demonstrated a remarkable CO₂ capture of 3.28 mmol g−¹ and a specific capacitance of 67 F g−¹ at 0.5 A g−¹. Thus, poly(TPA–DHTP–BZ) POP could potentially be used for energy storage and CO₂ capture applications.

Keywords: porous organic polymer, benzoxazine, sonogashira coupling, CO₂, supercapacitor

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Authors: Leslie Raphael de M. Ferraz, Salvana Priscylla M. Costa, Tarcyla de A. Gomes, Giovanna Christinne R. M. Schver, Cristóvão R. da Silva, Magaly Andreza M. de Lyra, Danilo Augusto F. Fontes, Larissa A. Rolim, Amanda Carla Q. M. Vieira, Miracy M. de Albuquerque, Pedro J. Rolim-Neto

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Efavirenz (EFV) is a drug used as first-line treatment of AIDS. However, it has poor aqueous solubility and wettability, presenting problems in the gastrointestinal tract absorption and bioavailability. One of the most promising strategies to improve the solubility is the use of solid dispersions (SD). Therefore, this study aimed to characterize SD EFZ with the polymers: PVP-K30, PVPVA 64 and SOLUPLUS in order to find an optimal formulation to compose a future pharmaceutical product for AIDS therapy. Initially, Physical Mixtures (PM) and SD with the polymers were obtained containing 10, 20, 50 and 80% of drug (w/w) by the solvent method. The best formulation obtained between the SD was selected by in vitro dissolution test. Finally, the drug-carrier system chosen, in all ratios obtained, were analyzed by the following techniques: Differential Scanning Calorimetry (DSC), polarization microscopy, Scanning Electron Microscopy (SEM) and spectrophotometry of absorption in the region of infrared (IR). From the dissolution profiles of EFV, PM and SD, the values of area Under The Curve (AUC) were calculated. The data showed that the AUC of all PM is greater than the isolated EFV, this result is derived from the hydrophilic properties of the polymers thus favoring a decrease in surface tension between the drug and the dissolution medium. In adittion, this ensures an increasing of wettability of the drug. In parallel, it was found that SD whom had higher AUC values, were those who have the greatest amount of polymer (with only 10% drug). As the amount of drug increases, it was noticed that these results either decrease or are statistically similar. The AUC values of the SD using the three different polymers, followed this decreasing order: SD PVPVA 64-EFV 10% > SD PVP-K30-EFV 10% > SD Soluplus®-EFV 10%. The DSC curves of SD’s did not show the characteristic endothermic event of drug melt process, suggesting that the EFV was converted to its amorphous state. The analysis of polarized light microscopy showed significant birefringence of the PM’s, but this was not observed in films of SD’s, thus suggesting the conversion of the drug from the crystalline to the amorphous state. In electron micrographs of all PM, independently of the percentage of the drug, the crystal structure of EFV was clearly detectable. Moreover, electron micrographs of the SD with the two polymers in different ratios investigated, we observed the presence of particles with irregular size and morphology, also occurring an extensive change in the appearance of the polymer, not being possible to differentiate the two components. IR spectra of PM corresponds to the overlapping of polymer and EFV bands indicating thereby that there is no interaction between them, unlike the spectra of all SD that showed complete disappearance of the band related to the axial deformation of the NH group of EFV. Therefore, this study was able to obtain a suitable formulation to overcome the solubility limitations of the EFV, since SD PVPVA 64-EFZ 10% was chosen as the best system in delay crystallization of the prototype, reaching higher levels of super saturation.

Keywords: characterization, dissolution, Efavirenz, solid dispersions

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Authors: Miroslava Markovic, Snezana Rajkovic, Ljubinko Rakonjac, Aleksandar Lucic

Abstract:

Oak powdery mildew is a serious problem on seedlings in nurseries as well as on naturally and artificially introduced progeny. The experiments were set on oak seedlings in two nurseries located in Central Serbia, where control of oak powdery mildew Microsphaera alphitoides Griff. et Maubl. had been conducted through alternative protection measures by means of various dosages of AQ-10 biofungicide, with and without added polymer (which has so far never been used in this country for control of oak powdery mildew). Simultaneous testing was conducted on the efficiency of a chemical sulphur-based preparation (used in this area for many years as a measure of suppression of powdery mildews, without the possibility of developing resistance of the pathogen to the active matter). To date, the Republic of Serbia has registered no fungicides for suppression of pathogens in the forest ecosystems. In order to introduce proper use of new disease-fighting agents into a country, certain relevant principles, requirements and criteria prescribed by the Forest Stewardship Council (FSC) must be observed, primarily with respect to measures of assessment and mitigation of risks, the list of dangerous and highly dangerous pesticides with the possibility of alternative protection. One of the main goals of the research was adjustment of the protective measures to the FSC policy through selection of eco-toxicologically favourable fungicides, given the fact that only preparations named on the list of permitted active matters are approved for use in certified forests. The results of the research have demonstrated that AQ-10 biofungicide can be used as a part of integrated disease management programmes as an alternative, through application of several treatments during vegetation and combination with other active matters registered for these purposes, so as to curtail the use of standard fungicides for control of powdery mildews on oak seedlings in nurseries. The best results in suppression of oak powdery mildew were attained through use of AQ-10 biofungicide (dose 50 or 70g/ha) with added polymer Nu Film-17 (dose 1.0 or 1.5 l/ha). If the treatment is applied at the appropriate time, even fewer number of treatments and smaller doses will be just as efficient.

Keywords: oak powdery mildew, biofungicides, polymers, Microsphaera alphitoides

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Authors: Kinga Mylkie, Pawel Nowak, Marta Z. Borowska

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The most important proteins in human serum responsible for drug binding are human serum albumin (HSA) and α1-acid glycoprotein (AGP). The AGP molecule is a glycoconjugate containing a single polypeptide chain composed of 183 amino acids (the core of the protein), and five glycan branched chains (sugar part) covalently linked by an N-glycosidic bond with aspartyl residues (Asp(N) -15, -38, -54, -75, - 85) of polypeptide chain. This protein plays an important role in binding alkaline drugs, a large group of drugs used in psychiatry, some acid drugs (e.g., coumarin anticoagulants), and neutral drugs (steroid hormones). The main goal of the research was to obtain magnetic nanoparticles coated with biopolymers in a chemically modified form, which will have highly reactive functional groups able to effectively immobilize the glycoprotein (acid α1-glycoprotein) without losing the ability to bind active substances. The first phase of the project involved the chemical modification of biopolymer starch. Modification of starch was carried out by methods of organic synthesis, leading to the preparation of a polymer enriched on its surface with aldehyde groups, which in the next step was coupled with 3-aminophenylboronic acid. Magnetite nanoparticles coated with starch were prepared by in situ co-precipitation and then oxidized with a 1 M sodium periodate solution to form a dialdehyde starch coating. Afterward, the reaction between the magnetite nanoparticles coated with dialdehyde starch and 3-aminophenylboronic acid was carried out. The obtained materials consist of a magnetite core surrounded by a layer of modified polymer, which contains on its surface dihydroxyboryl groups of boronic acids which are capable of binding glycoproteins. Magnetic nanoparticles obtained as carriers for plasma protein immobilization were fully characterized by ATR-FTIR, TEM, SEM, and DLS. The glycoprotein was immobilized on the obtained nanoparticles. The amount of mobilized protein was determined by the Bradford method.

Keywords: glycoproteins, immobilization, magnetic nanoparticles, polysaccharides

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Authors: M. Kumpugdee-Vollrath, M. Tabatabaeifar, M. Helmis

Abstract:

Shellac is a natural polyester resin secreted by insects. Pectins are natural, non-toxic and water-soluble polysaccharides extracted from the peels of citrus fruits or the leftovers of apples. Both polymers are allowed for the use in the pharmaceutical industry and as a food additive. SSB Aquagold® is the aqueous solution of shellac and can be used for a coating process as an enteric or controlled drug release polymer. In this study, tablets containing 10 mg methylene blue as a model drug were prepared with a rotary press. Those tablets were coated with mixtures of shellac and one of the pectin different types (i.e. CU 201, CU 501, CU 701 and CU 020) mostly in a 2:1 ratio or with pure shellac in a small scale fluidized bed apparatus. A stable, simple and reproducible three-stage coating process was successfully developed. The drug contents of the coated tablets were determined using UV-VIS spectrophotometer. The characterization of the surface and the film thickness were performed with the scanning electron microscopy (SEM) and the light microscopy. Release studies were performed in a dissolution apparatus with a basket. Most of the formulations were enteric coated. The dissolution profiles showed a delayed or sustained release with a lagtime of at least 4 h. Dissolution profiles of coated tablets with pure shellac had a very long lagtime ranging from 13 to 17.5 h and the slopes were quite high. The duration of the lagtime and the slope of the dissolution profiles could be adjusted by adding the proper type of pectin to the shellac formulation and by variation of the coating amount. In order to apply a coating formulation as a colon delivery system, the prepared film should be resistant against gastric fluid for at least 2 h and against intestinal fluid for 4-6 h. The required delay time was gained with most of the shellac-pectin polymer mixtures. The release profiles were fitted with the modified model of the Korsmeyer-Peppas equation and the Hixson-Crowell model. A correlation coefficient (R²) > 0.99 was obtained by Korsmeyer-Peppas equation.

Keywords: shellac, pectin, coating, fluidized bed, release, colon delivery system, kinetic, SEM, methylene blue

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Authors: Saleh O. Allehabi, V. A. Dzubaa, V. V. Flambaum, Jiguang Li, A. V. Afanasjev, S. E. Agbemava

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Recently developed versions of the configuration method for open shells, configuration interaction with perturbation theory (CIPT), and configuration interaction with many-body perturbation theory (CI+MBPT) techniques are used to study the electronic structure of Er, Fm, and No atoms. Excitation energies of odd states connected to the even ground state by electric dipole transitions, the corresponding transition rates, isotope shift, hyperfine structure, ionization potentials, and static scalar polarizabilities are calculated. The way of extracting parameters of nuclear charge distribution beyond nuclear root mean square (RMS) radius, e.g., a parameter of quadrupole deformation β, is demonstrated. In nuclei with spin > 1/2, parameter β is extracted from the quadrupole hyperfine structure. With zero nuclear spin or spin 1/2, it is impossible since quadrupole zero, so a different method was developed. The measurements of at least two atomic transitions are needed to disentangle the contributions of the changes in deformation and nuclear RMS radius into field isotopic shift. This is important for testing nuclear theory and for searching for the hypothetical island of stability. Fm and No are heavy elements approaching the superheavy region, for which the experimental data are very poor, only seven lines for the Fm element and one line for the No element. Since Er and Fm have similar electronic structures, calculations for Er serve as a guide to the accuracy of the calculations. Twenty-eight new levels of Fm atom are reported.

Keywords: atomic spectra, electronic transitions, isotope effect, electron correlation calculations for atoms

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Authors: Lingling Shui, Shuting Xie

Abstract:

As alternatives to electronic devices, optically active structures from responsive nanomaterials offer great opportunity buildup smart functional sensors. Hereby, we report on droplet microfluidics enabled construction and application of photonic microcapsules (PMCs) for colorimetric temperature microsensors, enabling miniaturization for injectable local micro-area sensing and integration for large-area sensing. Monodispersed PMCs are produced by in-situ photopolymerization of hydrogel shells of cholesteric liquid crystal (CLC)-in-water-in-oil double emulsion droplets prepared using microfluidic devices, with controllable physical structures and chemical compositions. Constructed PMCs exhibit thermal responsive structural color according to the selective Bragg reflection of CLC’s periodical helical structures within the microdroplet’s spherical confinement. Constructed PMCs with tunable size and composition have been successfully applied for monitoring the living cell extracellular temperature via co-incubation with cell suspension, and for detecting human body temperature via a flexible device from assembled PMCs. These PMCs could be flexibly applied in either micro-environment or large-area surface, enabling wide applications for precision temperature monitoring biological activities (e.g. cells or organs), optoelectronic devices working conditions (e.g. temperature indicators under extreme conditions), and etc.

Keywords: droplet, microfluidics, assembly, soft materials, microsensor

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Authors: A. Zahra, G. de Cesare, D. Caputo, A. Nascetti

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PDMS (Polydimethylsiloxane) polymer is a suitable material for biological and MEMS (Microelectromechanical systems) designers, because of its biocompatibility, transparency and high resistance under plasma treatment. PDMS round channel is always been of great interest due to its ability to confine the liquid with membrane type micro valves. In this paper we are presenting a very simple way to form round shape microfluidic channel, which is based on reflow of positive photoresist AZ® 40 XT. With this method, it is possible to obtain channel of different height simply by varying the spin coating parameters of photoresist.

Keywords: lab-on-chip, PDMS, reflow, round microfluidic channel

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Authors: Mohanapriya Subramanian, V. Raj

Abstract:

Direct methanol fuel cells (DMFCs) are considered to be one of the most promising candidates for portable and stationary applications in the view of their advantages such as high energy density, easy manipulation, high efficiency and they operate with liquid fuel which could be used without requiring any fuel-processing units. Electrolyte membrane of DMFC plays a key role as a proton conductor as well as a separator between electrodes. Increasing concern over environmental protection, biopolymers gain tremendous interest owing to their eco-friendly bio-degradable nature. Pectin is a natural anionic polysaccharide which plays an essential part in regulating mechanical behavior of plant cell wall and it is extracted from outer cells of most of the plants. The aim of this study is to develop and demonstrate pectin based polymer composite membranes as methanol impermeable polymer electrolyte membranes for DMFCs. Pectin based nanocomposites membranes are prepared by solution-casting technique wherein pectin is blended with chitosan followed by the addition of optimal amount of sulphonic acid modified Titanium dioxide nanoparticle (S-TiO2). Nanocomposite membranes are characterized by Fourier Transform-Infra Red spectroscopy, Scanning electron microscopy, and Energy dispersive spectroscopy analyses. Proton conductivity and methanol permeability are determined into order to evaluate their suitability for DMFC application. Pectin-chitosan blends endow with a flexible polymeric network which is appropriate to disperse rigid S-TiO2 nanoparticles. Resulting nanocomposite membranes possess adequate thermo-mechanical stabilities as well as high charge-density per unit volume. Pectin-chitosan natural polymeric nanocomposite comprising optimal S-TiO2 exhibits good electrochemical selectivity and therefore desirable for DMFC application.

Keywords: biopolymers, fuel cells, nanocomposite, methanol crossover

Procedia PDF Downloads 126

Authors: Yanghui Xu, Qin Ou, Xintu Wang, Feng Hou, Peng Li, Jan Peter van der Hoek, Gang Liu

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The level and removal of microplastics (MPs) in wastewater treatment plants (WWTPs) has been well evaluated by the particle number, while the mass concentration of MPs and especially nanoplastics (NPs) remains unclear. In this study, microfiltration, ultrafiltration and hydrogen peroxide digestion were used to extract MPs and NPs with different size ranges (0.01−1, 1−50, and 50−1000 μm) across the whole treatment schemes in two WWTPs. By identifying specific pyrolysis products, pyrolysis gas chromatography−mass spectrometry were used to quantify their mass concentrations of selected six types of polymers (i.e., polymethyl methacrylate (PMMA), polypropylene (PP), polystyrene (PS), polyethylene (PE), polyethylene terephthalate (PET), and polyamide (PA)). The mass concentrations of total MPs and NPs decreased from 26.23 and 11.28 μg/L in the influent to 1.75 and 0.71 μg/L in the effluent, with removal rates of 93.3 and 93.7% in plants A and B, respectively. Among them, PP, PET and PE were the dominant polymer types in wastewater, while PMMA, PS and PA only accounted for a small part. The mass concentrations of NPs (0.01−1 μm) were much lower than those of MPs (>1 μm), accounting for 12.0−17.9 and 5.6− 19.5% of the total MPs and NPs, respectively. Notably, the removal efficiency differed with the polymer type and size range. The low-density MPs (e.g., PP and PE) had lower removal efficiency than high-density PET in both plants. Since particles with smaller size could pass the tertiary sand filter or membrane filter more easily, the removal efficiency of NPs was lower than that of MPs with larger particle size. Based on annual wastewater effluent discharge, it is estimated that about 0.321 and 0.052 tons of MPs and NPs were released into the river each year. Overall, this study investigated the mass concentration of MPs and NPs with a wide size range of 0.01−1000 μm in wastewater, which provided valuable information regarding the pollution level and distribution characteristics of MPs, especially NPs, in WWTPs. However, there are limitations and uncertainties in the current study, especially regarding the sample collection and MP/NP detection. The used plastic items (e.g., sampling buckets, ultrafiltration membranes, centrifugal tubes, and pipette tips) may introduce potential contamination. Additionally, the proposed method caused loss of MPs, especially NPs, which can lead to underestimation of MPs/NPs. Further studies are recommended to address these challenges about MPs/NPs in wastewater.

Keywords: microplastics, nanoplastics, mass concentration, WWTPs, Py-GC/MS

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Authors: Mohammed Y. Abdellah, Mohamed K. Hassan, A. F. Mohamed, Shadi M. Munshi, A. M. Hashem

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Pips made from glass fiber reinforced polymer has competitive role in petroleum industry. The need of evaluating the mechanical behavior of (GRP) pipes is essential objects. Stress relaxation illustrates how polymers relieve stress under constant strain. Static relaxation test is carried out at room temperature. The material gives poor static relaxation strength, two loading cycles have been observed for the tested specimen.

Keywords: GRP, sandwich composite material, static relaxation, stress relief

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Authors: Agman Gupta, Rajashekar Badam, Noriyoshi Matsumi

Abstract:

Introduction: Recently, silicon has been recognized as one of the potential alternatives as anode active material in Li-ion batteries (LIBs) to replace the conventionally used graphite anodes. Silicon is abundantly present in the nature, it can alloy with lithium metal, and has a higher theoretical capacity (~4200 mAhg-1) that is approximately 10 times higher than graphite. However, because of a large volume expansion (~400%) upon repeated de-/alloying, the pulverization of Si particles causes the exfoliation of electrode laminate leading to the loss of electrical contact and adversely affecting the formation of solid-electrolyte interface (SEI).1 Functional polymers as binders have emerged as a competitive strategy to mitigate these drawbacks and failure mechanism of silicon anodes.1 A variety of aqueous/non-aqueous polymer binders like sodium carboxy-methyl cellulose (CMC-Na), styrene butadiene rubber (SBR), poly(acrylic acid), and other variants like mussel inspired binders have been investigated to overcome these drawbacks.1 However, there are only a few reports that mention the attempt of addressing all the drawbacks associated with silicon anodes effectively using a single novel functional polymer system as a binder. In this regard, here, we report a novel highly robust n-type bisiminoacenaphthenequinone (BIAN)-paraphenylene-based crosslinked polymer as a binder for Si anodes in lithium-ion batteries (Fig. 1). On its application, crosslinked-BIAN binder was evaluated to provide mechanical robustness to the large volume expansion of Si particles, maintain electrical conductivity within the electrode laminate, and facilitate in the formation of a thin SEI by restricting the extent of electrolyte decomposition on the surface of anode. The fabricated anodic half-cells were evaluated electrochemically for their rate capability, cyclability, and discharge capacity. Experimental: The polymerized BIAN (P-BIAN) copolymer was synthesized as per the procedure reported by our group.2 The synthesis of crosslinked P-BIAN: a solution of P-BIAN copolymer (1.497 g, 10 mmol) in N-methylpyrrolidone (NMP) (150 ml) was set-up to stir under reflux in nitrogen atmosphere. To this, 1,6-dibromohexane (5 mmol, 0.77 ml) was added dropwise. The resultant reaction mixture was stirred and refluxed at 150 °C for 24 hours followed by refrigeration for 3 hours at 5 °C. The product was obtained by evaporating the NMP solvent under reduced pressure and drying under vacuum at 120 °C for 12 hours. The obtained product was a black colored sticky compound. It was characterized by 1H-NMR, XPS, and FT-IR techniques. Results and Discussion: The N 1s XPS spectrum of the crosslinked BIAN polymer showed two characteristic peaks corresponding to the sp2 hybridized nitrogen (-C=N-) at 399.6 eV of the diimine backbone in the BP and quaternary nitrogen at 400.7 eV corresponding to the crosslinking of BP via dibromohexane. The DFT evaluation of the crosslinked BIAN binder showed that it has a low lying lowest unoccupied molecular orbital (LUMO) that enables it to get doped in the reducing environment and influence the formation of a thin (SEI). Therefore, due to the mechanically robust crosslinked matrices as well as its influence on the formation of a thin SEI, the crosslinked BIAN binder stabilized the Si anode-based half-cell for over 1000 cycles with a reversible capacity of ~2500 mAhg-1 and ~99% capacity retention as shown in Fig. 2. The dynamic electrochemical impedance spectroscopy (DEIS) characterization of crosslinked BIAN-based anodic half-cell confirmed that the SEI formed was thin in comparison with the conventional binder-based anodes. Acknowledgement: We are thankful to the financial support provided by JST-Mirai Program, Grant Number: JP18077239

Keywords: self-healing binder, n-type binder, thin solid-electrolyte interphase (SEI), high-capacity silicon anodes, low-LUMO

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