Search results for: polymers conductors

Authors: Rachid Dris, Robin Treilles, Max Beaurepaire, Minh Trang Nguyen, Sam Azimi, Vincent Rocher, Johnny Gasperi, Bruno Tassin

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Microplastic sources and fluxes in urban catchments are only poorly studied. Most often, the approaches taken focus on a single source and only carry out a description of the contamination levels and type (shape, size, polymers). In order to gain an improved knowledge of microplastic inputs at urban scales, estimating and comparing various fluxes is necessary. The Laboratoire Eau, Environnement et Systèmes Urbains (LEESU), the Laboratoire Eau Environnement (LEE) and the SIAAP (Service public de l’assainissement francilien) initiated several projects to investigate different urban sources and flows of microplastics. A systemic approach is undertaken at the scale of Paris Megacity, and several compartments are considered, including atmospheric fallout, wastewater treatments plants, runoff and combined sewer overflows. These investigations are carried out within the Limnoplast and OPUR projects. Atmospheric fallout was sampled during consecutive periods ranging from 2 to 3 weeks with a stainless-steel funnel. Both wet and dry periods were considered. Different treatment steps were sampled in 2 wastewater treatment plants (Seine-Amont for activated sludge and Seine-Centre for biofiltration) of the SIAAP, including sludge samples. Microplastics were also investigated in combined sewer overflows as well as in stormwater at the outlet suburban catchment (Sucy-en-Brie, France) during four rain events. Samples are treated using hydroperoxide digestion (H₂O₂ 30 %) in order to reduce organic material. Microplastics are then extracted from the samples with a density separation step using NaI (d=1.6 g.cm⁻³). Samples are filtered on metallic filters with a porosity of 14 µm between steps to separate them from the solutions (H₂O₂ and NaI). The last filtration was carried out on alumina filters. Infrared mapping analysis (using a micro-FTIR with an MCT detector) is performed on each alumina filter. The resulting maps are analyzed using a microplastic analysis software simple, developed by Aalborg University, Denmark and Alfred Wegener Institute, Germany. Blanks were systematically carried out to consider sample contamination. This presentation aims at synthesizing the data found in the various projects. In order to carry out a systemic approach and compare the various inputs, all the data were converted into annual microplastic fluxes (number of microplastics per year), and extrapolated to the Parisian agglomeration. PP, PE and alkyd are the most prevalent polymers found in storm water samples. Rain intensity and microplastic concentrations did not show any clear correlation. Considering the runoff volumes and the impervious surface area of the studied catchment, a flux of 4*107–9*107 MPs.yr⁻¹.ha⁻¹ was estimated. Samples of wastewater treatment plants and atmospheric fallout are currently being analyzed in order to finalize this assessment. The representativeness of such samplings and uncertainties related to the extrapolations will be discussed and gaps in knowledge will be identified. The data provided by such an approach will help to prioritize future research as well as policy efforts.

Keywords: microplastics, atmosphere, wastewater, urban runoff, Paris megacity, urban waters

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Authors: Neda Sinaei, Davood Zare, Mehrdad Azin

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Polyhydroxyalkanoates (PHAs) are biocompatible and biodegradable polymers produced by a wide range of bacterial strains. These biopolymers are significantly studied for drug delivery and tissue engineering applications because of their fascinating physicochemical properties. Polyhydroxybutyrate (PHB) scaffold that has been extracted from a novel bacteria using oil wastewater was selected to study. Some physical parameters affecting scaffold properties such as PHB concentration, solvent evaporation speed, and ultrasonic time were investigated. Scanning electron microscopy was used to evaluate the porosity. Afterward, the biocompatibility of PHB scaffold was assessed. Initial results showed the highly porous PHB scaffold structure with a variety of pore sizes. Subsequent results indicated that more unique pore sizes can be obtained by optimizing physical factors. It would be noticed that the morphology of the pore structure was accordingly affected by ultrasonic time. Hence, In vitro cell viability tests on the PHB scaffold using human foreskin fibroblasts revealed strong cell attachment and proliferation supports. Therefore, it can be concluded that the cost-effective PHB scaffold has the potential using as a biomaterial cell adhesion substrate in therapeutic applications.

Keywords: Polyhydroxybutyrate, biocompatible, scaffold, porous, tissue engineering

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Authors: Chuanxiang Cheng, Tiantian Min, Jin Yue

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Antimicrobial active packaging enables extensive biological effects to improve food safety. However, the efficacy of antimicrobial packaging hinges on factors including the diffusion rate of the active agent toward the food surface, the initial content in the antimicrobial agent, and the targeted food shelf life. Among the possibilities of antimicrobial packaging design, an interesting approach involves the incorporation of volatile antimicrobial agents into the packaging material. In this case, the necessity for direct contact between the active packaging material and the food surface is mitigated, as the antimicrobial agent exerts its action through the packaging headspace atmosphere towards the food surface. However, it still remains difficult to achieve controlled and precise release of bioactive compounds to the specific target location with required quantity in food packaging applications. Remarkably, the development of stimuli-responsive materials for electrospinning has introduced the possibility of achieving controlled release of active agents under specific conditions, thereby yielding enduring biological effects. Relative humidity (RH) for the storage of food categories such as meat and aquatic products typically exceeds 90%. Consequently, high RH can be used as an abiotic trigger for the release of active agents to prevent microbial growth. Hence, a novel RH - responsive polyvinyl alcohol/chitosan (PVA/CS) composite nanofibrous film incorporated with 4-terpineol/β-cyclodextrin inclusion complexes (4-TA@β-CD ICs) was engineered by electrospinning that can be deposited as a functional packaging materials. The characterization results showed the thermal stability of the films was enhanced after the incorporation due to the hydrogen bonds between ICs and polymers. Remarkably, the 4 wt% 4-TA@β-CD ICs/PVA/CS film exhibited enhanced crystallinity, moderate hydrophilic (Water contact angle of 81.53°), light barrier property (Transparency of 1.96%) and water resistance (Water vapor permeability of 3.17 g mm/m2 h kPa). Moreover, this film also showed optimized mechanical performance with a Young’s modulus of 11.33 MPa, a tensile strength of 19.99 MPa and an elongation at break of 4.44 %. Notably, the antioxidant and antibacterial properties of this packaging material were significantly improved. The film demonstrated the half-inhibitory concentrations (IC50) values of 87.74% and 85.11% for scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2′-azinobis (3-ethylbenzothiazoline-6-sulfonic) (ABTS) free radicals, respectively, in addition to an inhibition efficiency of 65% against Shewanella putrefaciens, the characteristic bacteria in aquatic products. Most importantly, the film achieved controlled release of 4-TA under high 98% RH by inducing the plasticization of polymers caused by water molecules, swelling of polymer chains, and destruction of hydrogen bonds within the cyclodextrin inclusion complex. Consequently, low relative humidity is suitable for the preservation of nanofibrous film, while high humidity conditions typical in fresh food packaging environments effectively stimulated the release of active compounds in the film. This film with a long-term antimicrobial effect successfully extended the shelf life of Litopenaeus vannamei shrimp to 7 days at 4 °C. This attractive design could pave the way for the development of new food packaging materials.

Keywords: controlled release, electrospinning, nanofibrous film, relative humidity–responsive, shrimp preservation

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Authors: Mokhtar Nikgoo

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Definition of Concrete and Concreting: Concrete (in French: Béton) in a broad sense is any substance or combination that consists of a sticky substance with the property of cementation. In general, concrete refers to concrete made by Portland cement, which is produced by mixing fine and coarse aggregates, Portland cement and water. After enough time, this mixture turns into a stone-like substance. During the hardening or processing of the concrete, cement is chemically combined with water to form strong crystals that bind the aggregates together, a process called hydration. During this process, significant heat is released called hydration heat. Additionally, concrete shrinks slightly, especially as excess water evaporates, a phenomenon known as drying shrinkage. The process of hardening and the gradual increase in concrete strength that occurs with it does not end suddenly unless it is artificially interrupted. Instead, it decreases more over long periods of time, although, in practical applications, concrete is usually set after 28 days and is considered at full design strength. Concrete may be made from different types of cement as well as pozzolans, furnace slag, additives, additives, polymers, fibers, etc. It may also be used in the way it is made, heating, water vapor, autoclave, vacuum, hydraulic pressures and various condensers.

Keywords: concrete, RCC, batching, cement, Pozzolan, mixing plan

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Authors: Reza Gheisari, Paulo J. Bartolo, Nicholas Goddard

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Polymeric micro-cantilevers (Cs) are rapidly becoming popular for MEMS applications such as chemo- and bio-sensing as well as purely electromechanical applications such as microrelays. Polymer materials present suitable physical and chemical properties combined with low-cost mass production. Hence, micro-cantilevers made of polymers indicate much more biocompatibility and adaptability of rapid prototyping along with mechanical properties. This research studies the effects of three process and one size factors on the filling behaviour in micro cavity, and the role of each in the replication of micro parts using different polymer materials i.e. polypropylene (PP) SABIC 56M10 and acrylonitrile butadiene styrene (ABS) Magnum 8434. In particular, the following factors are considered: barrel temperature, mould temperature, injection speed and the thickness of micro features. The study revealed that the barrel temperature and the injection speed are the key factors affecting the flow length of micro features replicated in PP and ABS. For both materials, an increase of feature sizes improves the melt flow. However, the melt fill of micro features does not increase linearly with the increase of their thickness.

Keywords: flow length, micro cantilevers, micro injection moulding, microfabrication

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Authors: Reyhan Özdoğan, Özgür Ceylan, Mehmet Arif Kaya, Mithat Çelebi

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Food packaging is important for the food industry. Bioplastics have been used as food packaging materials. According to the European Bioplastics organization, bioplastics can be defined as plastics based on renewable resources (bio-based) or as plastics which are biodegradable and/or compostable. Poly(lactic acid) (PLA) has an industrially importance of bioplastic polymers. PLA is a family of biodegradable thermoplastic polyester made from renewable resources. It is produced by conversion of corn, or other carbohydrate sources, into dextrose, followed by fermentation into lactic acid through direct polycondensation of lactic acid monomers or through ring-opening polymerization of lactide. The processing possibilities of this transparent material are very wide, ranging from injection molding and extrusion over cast film extrusion to blow molding and thermoforming. In this study, PLA films were prepared by solution casting method. PLAs which are different molecular weights were plasticized with glycerol and the morphology of films was monitored by optical microscopy. Properties of mechanical and film of PLA were researched with the mechanical testing machine.

Keywords: biodegradable, bioplastics, morphology, solution casting, poly(lactic acid)

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Authors: Amitkumar Barot, Vijaykumar Sinha

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There is growing interest in the development of new materials based on recycled polymers from plastic waste, and also in the field of lubricants much effort has been spent on substitution of petro-based raw materials by natural-based renewable ones. This is due to the facts of depleting fossil fuels and due to strict environmental laws. In relevance to this, new technique for the formulation of grease that combines the chemical recycling of poly (ethylene terephthalate) PET with the use of castor oil (CO) has been developed. Comparison to diols used in chemical recycling of PET, castor oil is renewable, easily available, environmentally friendly, economically cheaper and hence sustainability indeed. The process parameters like CO concentration and temperature were altered, and further, the influences of the process parameters have been studied in order to establish technically and commercially viable process. Further thereby formed depolymerized product find an application as base oil in the formulation of grease. A depolymerized product has been characterized by various chemical and instrumental methods, while formulated greases have been evaluated for its tribological properties. The grease formulated using this new environmentally friendly approach presents applicative properties similar, and in some cases superior, compared to those of a commercial grease obtained from non-renewable resources.

Keywords: castor oil, grease formulation, recycling, sustainability

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Authors: Abdul Basit, Gildas Lhostis, Bernard Durand

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Shape memory polymers (SMPs) are replacing shape memory alloys (SMAs) in many applications as SMPs have certain superior properties than SMAs. However, SMAs possess some properties like recovery under stress that SMPs lack. SMPs cannot give complete recovery even under a small load. SMPs are initially heated close to their transition temperature (glass transition temperature or the melting temperature). Then force is applied to deform the heated SMP to a specific position. Subsequently, SMP is allowed to cool keeping it deformed. After cooling, SMP gets the temporary shape. This temporary shape can be recovered by heating it again at the same temperature that was given it while heating it initially. As a result, it will recover its original position. SMP can perform unconstrained recovery and constrained recovery, however; under the load, it only recovers partially. In this work, the recovery under the load of an asymmetrical shape memory composite called as CBCM-SMPC has been investigated. It is found that it has the ability to recover under different loads. Under different loads, it shows powerful complete recovery in reference to initial position. This property can be utilized in many applications.

Keywords: shape memory, polymer composite, thermo-mechanical testing, recovery under load

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Authors: Meghana Shankara, Priyadarshini Natarajan

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Infrared (IR) spectroscopy has revolutionized the way we look at materials around us. Unraveling the pattern in the molecular spectra of materials to analyze the composition and properties of it has been one of the most interesting challenges in modern science. Applications of the IR spectrometry are numerous in the field’s pharmaceuticals, health, food and nutrition, oils, agriculture, construction, polymers, beverage, fabrics and much more limited only by the curiosity of the people. Near Infrared (NIR) spectrometry is applied robustly in analyzing the solids and liquid substances because of its non-destructive analysis method. In this paper, we have reviewed the application of NIR spectrometry in milk quality analysis and have presented the modes of measurement applied in NIRS measurement setup, Design of Experiment (DoE), classification/quantification algorithms used in the case of milk composition prediction like Fat%, Protein%, Lactose%, Solids Not Fat (SNF%) along with different approaches for adulterant identification. We have also discussed the important NIR ranges for the chosen milk parameters. The performance metrics used in the comparison of the various Chemometric approaches include Root Mean Square Error (RMSE), R^2, slope, offset, sensitivity, specificity and accuracy

Keywords: chemometrics, design of experiment, milk quality analysis, NIRS measurement modes

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Authors: Abdi Djamila, Haffar Hichem

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The poly methylene bleu (PMB) has been successfully electro deposited on fluorine doped tin oxide (FTO) conducting glass as substrate. Its optical, electrical and photoelectrochemical characterizations have been carried out in order to show the performances of such polymer. The deposited film shows a good electric conductivity which is well confirmed by the low gap value determinated optically by UV–vis spectroscopy. Like all polymers the PMB presents an absorption difference in the visible range function of the polarization potential, it is expressed by the strong conjugation at oxidized state but is weakened with leucoform formation at reduced state. The electrochemical analysis of the films permit to show the cyclic voltamperogram with the anodic oxidation and cathodic reduction states of the polymer and to locate the corresponding energy levels HOMO and LUMO of this later. The electrochemical impedance spectroscopy permit to see the conductive character of such film and to calculate important parameters as Rtc and CPE. The study of the photoelectro activity of our polymer shows that under exposure to intermittent light source this later exhibit important photocurrents which enables it to be used in photo organic ells.

Keywords: polymethylene blue, electropolymerization, homo-lumo, photocurrents

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Authors: Abas Mohsenzadeh, Tariq Bashir, Waseen Tahir, Ulf Stigh, Mikael Skrifvars, Kim Bolton

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The area of artificial muscles has received significant attention from many research domains including soft robotics, biomechanics and smart textiles in recent years. Poly(vinylidene fluoride) (PVDF) has been used to form artificial muscles since it contracts upon heating when under load. In this study, PVDF fibers were produced by melt spinning technique at different solid state draw ratios and then actuation mechanism for PVDF tie molecules within the semicrystalline region of PVDF polymer has been investigated using molecular dynamics simulations. Tie molecules are polymer chains that link two (or more) crystalline regions in semicrystalline polymers. The changes in fiber length upon heating have been investigated using a novel simulation technique. The results show that conformational changes of the tie molecules from the longer all-trans conformation at low temperature (β structure) to the shorter conformation (α structure) at higher temperature accrue by increasing the temperature. These results may be applied to understand the actuation observed for PVDF upon heating.

Keywords: poly(vinylidene fluoride), molecular dynamics, simulation, actuators, tie molecules, semicrystalline

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Authors: Blessing A. Aderibigbe

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Combination therapy is a treatment approach that is used to prevent the emergence of drug resistance. This approach is used for the treatment of many chronic and infectious diseases. Potentiating agents are currently explored in combination therapy, resulting in excellent therapeutic outcomes. Breast cancer and malaria are two chronic conditions responsible globally for high death rates. In this research, a class of polymer-drug conjugates containing potentiating agents with either antimalarial or anticancer drugs were prepared by Michael Addition Polymerization reaction and ring-opening polymerization reaction. Conjugation of potentiating agents with bioactive compounds into the polymers resulted in conjugates with good water solubility, highly selective and non-toxic. In vitro cytotoxicity and in vitro antiplasmodial evaluation on the conjugates revealed that the conjugates were more effective when compared to the free drugs. The drug release studies further showed that the release profile of the drugs from the conjugates was sustained. The findings revealed the potential of polymer-drug conjugates to overcome drug toxicity and drug resistance, which is common with the currently used antimalarial and anticancer drugs.

Keywords: anticancer, antimalarials, combination therapy, polymer-drug conjugates

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Authors: Sweta Iyer, Nemeshwaree Behary, Vincent Nierstrasz

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Various organisms involve bioluminescence for their particular biological function. The bio-based molecules responsible for bioluminescence vary from one species to another, research has been done to identify the chemistry and different mechanisms involved in light production in living organisms. The light emitting chemical systems such as firefly and bacterial luminous mostly involves enzyme-catalyzed reactions and is widely used for ATP measurement, bioluminescence imaging, environmental biosensors etc. Our strategy is to design bioluminescent textiles using such bioluminescent systems. Hence, a detailed literature work was carried out to study on how to mimic bioluminescence effect seen in nature. Reaction mechanisms in various bioluminescent living organisms were studied and the components or molecules responsible for luminescence were identified. However, the challenge is to obtain the same effect on textiles by immobilizing enzymes responsible for light creation. Another challenge is also to regenerate substrates involved in the reaction system to create a longer lasting illumination in bioluminescent textiles. Natural film-forming polymers were used to immobilize the reactive components including enzymes on textile materials to design a biomimetic luminescent textile.

Keywords: bioluminescence, biomimetic, immobilize, luminescent textile

Procedia PDF Downloads 235

Authors: Aboli Gore, Aritra Das, Sunil Sonthalia, Tanmay Mahapatra, Sridhar Srikantiah, Hemant Shah

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AMANAT is an initiative, taken in collaboration with the Government of Bihar, aimed at improving the Quality of Maternal and Neonatal care services at Bihar’s public health facilities – those offering either the Basic Emergency Obstetric and Neonatal care (BEmONC) or Comprehensive Emergency Obstetric and Neonatal care (CEmONC) services. The effectiveness of this program is evaluated by conducting cross-sectional assessments at the concerned facilities prior to (baseline) and following completion (endline) of intervention. Direct Observation of Delivery (DOD) methodology is employed for carrying out the baseline and endline assessments – through which key obstetric and neonatal care practices among the Health Care Providers (especially the nurses) are assessed quantitatively by specially trained nursing professionals. Assessment of vitals prior to delivery improved during all three phases of BEmONC and all four phases of CEmONC training with statistically significant improvement noted in: i) pulse measurement in BEmONC phase 2 (9% to 68%), 3 (4% to 57%) & 4 (14% to 59%) and CEmONC phase 2 (7% to 72%) and 3 (0% to 64%); ii) blood pressure measurement in BEmONC phase 2 (27% to 84%), 3 (21% to 76%) & 4 (36% to 71%) and CEmONC phase 2 (23% to 76%) and 3 (2% to 70%); iii) fetal heart rate measurement in BEmONC phase 2 (10% to 72%), 3 (11% to 77%) & 4 (13% to 64%) and CEmONC phase 1 (24% to 38%), 2 (14% to 82%) and 3 (1% to 73%); and iv) abdominal examination in BEmONC phase 2 (14% to 59%), 3 (3% to 59%) & 4 (6% to 56%) and CEmONC phase 1 (0% to 24%), 2 (7% to 62%) & 3 (0% to 62%). Regarding infection control, wearing of apron, mask and cap by the delivery conductors improved significantly in all BEmONC phases. Similarly, the practice of handwashing improved in all BEmONC and CEmONC phases. Even on disaggregation, the handwashing showed significant improvement in all phases but CEmONC phase-4. Not only the positive practices related to handwashing improved but also negative practices such as turning off the tap with bare hands declined significantly in the aforementioned phases. Significant decline was also noted in negative maternal care practices such as application of fundal pressure for hastening the delivery process and administration of oxytocin prior to delivery. One of the notable achievement of AMANAT is an improvement in active management of the third stage of labor (AMTSL). The overall AMTSL (including administration of oxytocin or other uterotonics uterotonic in proper dose, route and time along with controlled cord traction and uterine massage) improved in all phases of BEmONC and CEmONC mentoring. Another key area of improvement, across phases, was in proper cutting/clamping of the umbilical cord. AMANAT mentoring also led to improvement in important immediate newborn care practices such as initiation of skin-to-skin care and timely initiation of breastfeeding. The next phase of the mentoring program seeks to institutionalize mentoring across the state that could potentially perpetuate improvement with minimal external intervention.

Keywords: capacity building, nurse-mentoring, quality of care, pregnancy, newborn care

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Authors: Anthony Chidi Ezika, Gbolahan Joseph Adekoya, Emmanuel Rotimi Sadiku, Yskandar Hamam, Suprakas Sinha Ray

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High-energy-density polymer/ceramic composites require a high breakdown strength and dielectric constant. Interface polarization and electric percolation are responsible for the high dielectric constant. In order to create composite dielectrics, high conductivity ceramic particles are combined with polymers to increase the dielectric constant. In this study, bonding and the non-uniform distribution of charges in the ceramic/ceramic interface zone are investigated using density functional theory (DFT) modeling. This non-uniform distribution of charges is intended to improve the ceramic/ceramic interface's dipole polarization (dielectric response). The interfacial chemical bond formation can also improve the structural stability of the hybrid filler and, consequently, of the composite films. To comprehend the electron-transfer process, the density of state and electron localization function of the PPy with hybrid fillers are also studied. The polymer nanocomposite is anticipated to provide a suitable dielectric response for energy storage applications.

Keywords: energy storage, V₂C/ ZnS hybrid, polypyrrole, MXene, nanocomposite, dielectric

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Authors: Sanjay Kumar, Saikat Dutta, Devendra S. Rawat, Jitendra K. Pandey, Pankaj Kumar

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Exploding demand for various types of fuels and gradually growing impacts of atmospheric carbon dioxide have forced the researchers to search biofuels in general and algae-based biofuels in particular. However, strain identification in terms of fuel productivity and over all economics of fuel generation remains a debatable challenge. Utilization of marine biomass, especially the ones important in the Indian subcontinent, in forming furanic fuels and specialty chemicals would likely to be a better value-addition pathway. Seaweed species e.g. Ulva, Sarconema, and Gracilaria species have been found more productive than land-based biomass sources due to their higher growth rate. Additionally, non-recalcitrant nature of marine biomass unlike lignocellulosics has attracted much attention in recent years towards producing bioethanol. Here we report the production of renewable, biomass-derived platform molecules such as furfural and 5-(chloromethyl) furfural (CMF) from a seaweed species which are abundant marine biomass. These products have high potential for synthetic upgradation into various classes of value-added compounds such as fuels, fuel-additives, and monomers for polymers, solvents, agrochemicals, and pharmaceuticals.

Keywords: seaweeds, Ulva, CMF, furan

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Authors: Ramita Vongrat, Pornsri Sapsrithong, Manit Nithitanakul

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In this work, blends of polyamide 6 (PA6) and polybutylene terephthalate (PBT) were successfully prepared. The effect of epoxidized natural rubber (ENR-25) and n butyl acrylate glycidyl methacrylate ethylene (EBa-GMA) as a compatibilizer on properties of PA6/PBT blends was also investigated by varying amount of ENR-50 and EBa-GMA, i.e., 0, 0.1, 0.5, 5 and 10 phr. All blends were prepared and shaped by using twin-screw extruder at 230 °C and injection molding machine, respectively. All test specimens were characterized by phase morphology, impact strength, tensile, flexural properties, and hardness. The results exhibited that phase morphology of PA6/PBT blend without compatibilizer was incompatible. This could be attributed to poor interfacial adhesion between the two polymers. SEM micrographs showed that the addition of ENR-25 and EBa-GMA improved the compatibility of PA6/PBT blends. With the addition of ENR-50 as a compatibilizer, the uniformity and the maximum reduction of dispersed phase size were observed. Additionally, the results indicate that, as the amount of ENR-25 increased, and EBa-GMA increased, the mechanical properties, including stress at the peak, tensile modulus, and izod impact strength, were also improved.

Keywords: EBa-GMA, epoxidized natural rubber-25, polyamide 6, polybutylene terephthalate

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Authors: A.Cifarelli, L. Boggioni, F. Bertini, L. Magon, M. Pitalieri, S. Losio

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Nowadays, the growing environmental awareness and the dwindling of fossil resources stimulate the polyurethane (PU) industry towards renewable polymers with low carbon footprint to replace the feed stocks from petroleum sources. The main challenge in this field consists in replacing high-performance products from fossil-fuel with novel synthetic polymers derived from 'green monomers'. The bio-polyols from plant oils have attracted significant industrial interest and major attention in scientific research due to their availability and biodegradability. Triglycerides rich in unsaturated fatty acids, such as soybean oil (SBO) and linseed oil (ELO), are particularly interesting because their structures and functionalities are tunable by chemical modification in order to obtain polymeric materials with expected final properties. Unfortunately, their use is still limited for processing or performance problems because a high functionality, as well as OH number of the polyols will result in an increase in cross-linking densities of the resulting PUs. The main aim of this study is to evaluate soy and linseed-based polyols as precursors to prepare prepolymers for the production of polyurethane foams (PUFs) or waterborne-polyurethanes (WPU) used as coatings. An effective reaction route is employed for its simplicity and economic impact. Indeed, bio-polyols were synthesized by a two-step method: epoxidation of the double bonds in vegetable oils and solvent-free ring-opening reaction of the oxirane with organic acids. No organic solvents have been used. Acids with different moieties (aliphatic or aromatics) and different length of hydrocarbon backbones can be used to customize polyols with different functionalities. The ring-opening reaction requires a fine tuning of the experimental conditions (time, temperature, molar ratio of carboxylic acid and epoxy group) to control the acidity value of end-product as well as the amount of residual starting materials. Besides, a Lewis base catalyst is used to favor the ring opening reaction of internal epoxy groups of the epoxidized oil and minimize the formation of cross-linked structures in order to achieve less viscous and more processable polyols with narrower polydispersity indices (molecular weight lower than 2000 g/mol⁻¹). The functionality of optimized polyols is tuned from 2 to 4 per molecule. The obtained polyols are characterized by means of GPC, NMR (¹H, ¹³C) and FT-IR spectroscopy to evaluate molecular masses, molecular mass distributions, microstructures and linkage pathways. Several polyurethane foams have been prepared by prepolymer method blending conventional synthetic polyols with new bio-polyols from soybean and linseed oils without using organic solvents. The compatibility of such bio-polyols with commercial polyols and diisocyanates is demonstrated. The influence of the bio-polyols on the foam morphology (cellular structure, interconnectivity), density, mechanical and thermal properties has been studied. Moreover, bio-based WPUs have been synthesized by well-established processing technology. In this synthesis, a portion of commercial polyols is substituted by the new bio-polyols and the properties of the coatings on leather substrates have been evaluated to determine coating hardness, abrasion resistance, impact resistance, gloss, chemical resistance, flammability, durability, and adhesive strength.

Keywords: bio-polyols, polyurethane foams, solvent free synthesis, waterborne-polyurethanes

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Authors: M. Nagaraja, H. M. Mahesh, K. Rajanna, M. Z. Kurian, J. Manjanna

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In recent years, composites of conjugated polymers with fullerenes (C60) has attracted considerable scientific and technological attention in the field of organic electronics because they possess a novel combination of electrical, optical, ferromagnetic, mechanical and sensor properties. These properties represent major advances in the design of organic electronic devices. With the addition of C60 in the conjugated polymer matrix, the primary photo-excitation of the conjugated polymer undergoes an ultrafast electron transfer, and it has been demonstrated that fullerene molecules may serve as efficient electron acceptors in polymeric solar cells. The present paper includes the systematic studies on the effect of electrical, structural and sensor properties of polyaniline (PANI) matrix by the presence of C60. Polyaniline-fullerene (PANI/C60) composite is prepared by the introduction of fullerene during polymerization of aniline with ammonium persulfate and dodechyl benzene sulfonic acid as oxidant and dopant respectively. FTIR spectroscopy indicated the interaction between PANI and C60. X-ray diffraction proved the formation of a PANI/C60 complex. SEM image shows the highly branched chain structure of the PANI in the presence of C60. The conductivity of the PANI/C60 was found to be more than ten orders of magnitude over the pure PANI.

Keywords: conductivity, fullerene, nanocomposite, polyaniline

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Authors: Chieh-Nan Chen, Ji-Yu Lin, I-Ming Chu

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Polypeptide thermosensitive hydrogel is an excellent candidate as a smart device to deliver drugs and cells due to its remarkable biocompatibility, low gelation concentration, and respond to temperature stimuli, it can be easily injected as a polymer solution into the patient’s body where it undergoes gelation due to an elevation in temperature. Poly (ethylene glycol) monomethyl ether-poly (ethyl-l-glutamate) (mPEG-PELG) contains a hydrophobic side chain –C2H5 which is useful in encapsulating and stabilizing hydrophobic drugs. In this study, we plan to focus on the hydrophobic anti-carcinogenic and anti-inflammatory drug curcumin, which due its insolubility in water, requires a proper carrier for delivery into the body. Our main concept is to use mPEG-PELG to stabilize curcumin, inject the curcumin-loaded hydrogel into the tumor site, and allow the enzymatically-sensitive hydrogel to be degraded by bodily fluids and release the drug. The polymers of interest have been successfully synthesized and characterized by 1H-NMR, FT-IR, SEM, and CMC. Curcumin loading content and drug release were assayed using HPLC. Preliminary results show that these materials have potential as a delivery vehicle for poorly soluble drugs.

Keywords: curcumin, drug release, hydrogel, polypeptide material

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Authors: A. Alvaredo , R. Guzman De Villoria, P. Castell, Juan P. Fernandez-Blazquez

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Since graphene was discovered in 2004, has been considered as superb material, due to its outstanding mechanical, electrical and thermal properties. Graphene has been incorporated as reinforcement in several high performance polymers in order to obtain a good balance of properties and to get new properties as thermal or electric conductivity. As well known, the properties of semicrystalline polymer and its composites depends heavily on degree of crystallinity. In this context, our research group has studied the crystallization behavior from amorphous state of PEEK/GNP composites. The monitoring of cold crystallization processes studied by time-resolved simultaneous wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS). These techniques allowed to get an extremely relevant information about the evolution of the morphology of the PEEK/GNP composites. In addition, the thermal evolution of cold crystallization was followed by differential scanning calorimetry (DSC) as well. The experimental results showed changes in crystallization kinetics and c parameter unit cell when adding graphene. The main aim of this work is to produce PEEK/GNP composites and characterize their morphology, unit cell parameters and crystallization kinetic.

Keywords: PEEK, graphene, synchrotron, cold crystallization

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Authors: A. Ibáñez, A. Martínez, A. Sánchez, M. A. León

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This article is focused on the development of a series of biodegradable and eco-friendly masterbatches based on polylactic acid (PLA) filled with almond shell to study the influence of almond shell in the properties of injected biodegradable parts. These innovative masterbatches have 20 wt % of the almond shell. Different treatments were carried out with sodium hydroxide (NaOH) and maleic anhydride (MA) to obtain better interfacial bonding between fibre and matrix. The masterbatches were produced by varying the fibre treatments (type of treatment, concentration and temperature). The masterbatches have been injected to obtain standardised test samples in order to study mechanical properties. The results show that, the some of the treated fibres present slightly higher flexural modulus and impact strength than untreated fibres. This study is part of a LIFE project (MASTALMOND) aimed to create and test at preindustrial level new coloured masterbatches based on biodegradable polymers and containing in its formulation a high percentage of almond shell, a natural waste material, which firstly will permit to cover technical requirements of two traditional industrial sectors: toy and furniture, although the results achieved could be extended to other industrial sectors.

Keywords: additivation, almond shell, biodegradable, masterbatch, PLA, injection moulding

Procedia PDF Downloads 393

Authors: Benalia Kouini, Aicha Serier

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This work aims to investigate the structure–property relationship in ternary nanocomposites consisting of polypropylene as the matrix, polyamide 66 as the minor phase and treated nanoclay DELLITE 67G as the reinforcement. All PP/PA66/Nanoclay systems with polypropylene grafted maleic anhydride PP-g-MAH as a compatibilizer were prepared via melt compounding and characterized in terms of nanoclay content. Morphological structure was investigated by scanning electron microscopy. The rheological behavior of the nanocomposites was determined by various methods, viz melt flow index (MFI) and parallel plate rheological measurements. The PP/PP-g-MAH/PA66 nanocomposites showed a homogeneous morphology supporting the compatibility improvement between PP, PA66 and nanoclay. SEM results revealed the formation of nanocomposites as the nanoclay was intercalated and exfoliated. In the ternary nanocomposites, the rheological behavior showed that, the complex viscosity is increased with increasing the nanoclay content; however, at low frequencies this increase is governed by the content of nanofiller while at high frequencies it is mainly determined by talc content. A similar trend was also observed for the variations of storage modulus (G′) and loss modulus (G″) with frequency. The results showed that the use of nanoclay considerably affects the melt elasticity.

Keywords: nanocomposites, polypropylene, polyamide66, modified nanoclay, rheology

Procedia PDF Downloads 361

Authors: Doo W. Lee, Soo J. Lee, Bye R. Yoon, Jae Y. Jho, Kyehan Rhee

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Hand exoskeletons have been developed in order to assist daily activities for disabled and elder people. A figure exoskeleton was developed using ionic polymer metal composite (IPMC) actuators, and the performance of it was evaluated in this study. In order to study dynamic performance of a finger dummy performing pinching motion, force generating characteristics of an IPMC actuator and pinching motion of a thumb and index finger dummy actuated by IMPC actuators were analyzed. The blocking force of 1.54 N was achieved under 4 V of DC. A thumb and index finger dummy, which has one degree of freedom at the proximal joint of each figure, was manufactured by a three dimensional rapid prototyping. Each figure was actuated by an IPMC actuator, and the maximum fingertip force was 1.18 N. Pinching motion of a dummy was analyzed by two video cameras in vertical top and horizontal left end view planes. A figure dummy powered by IPMC actuators could perform flexion and extension motion of an index figure and a thumb.

Keywords: finger exoskeleton, ionic polymer metal composite, flexion and extension, motion analysis

Procedia PDF Downloads 214

Authors: Y. Seki, A. Ç. Kılıç, M. Atagür, O. Özdemir, İ. Şen, K. Sever, Ö. Seydibeyoğlu, M. Sarikanat, N. Küçükdoğan

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Cheap and abundant waste materials have been investigated as filler materials in thermoplastic polymers instead of wood- based materials because of deforestation. Vine stem, as an agricultural waste, was used as a filler material for a thermoplastic polymer, high-density polyethylene (HDPE) in this study. Agricultural waste of vine stem was collected from Manisa region, Turkey. Vine stem at different rations was used to reinforce HDPE. The effect of vine stem loading on tensile strength and Young’s modulus of composites were obtained. It was clearly observed that tensile strength and Young’s modulus of HDPE was increased by vine stem loading. Thermal stabilities of composites were obtained by using thermogravimetric analysis. Water absorption behavior of HDPE was improved by loading vine stem into HDPE. The crystallinity index values of neat HDPE and vine stem loaded HDPE composites were investigated byX-ray diffraction analysis. From this study, it was inferred that vine stem, as an agricultural waste, can be used as a filler material for HDPE.

Keywords: waste filler, high density polyethylene, composite, composite materials

Procedia PDF Downloads 494

Authors: Esther Lorrayne M. Pereira, Adriana Souza M. Batista, Fabíola A. S. Ribeiro, Adelina P. Santos, Clascídia A. Furtado, Luiz O. Faria

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The combination of multi–walled carbon nanotubes (MWCNTs) with polymers offers an attractive route to reinforce the macromolecular compounds as well as the introduction of new properties based on morphological modifications or electronic interactions between the two constituents. As they are only a few nanometers in dimension, it offers ultra-large interfacial area per volume between the nano-element and polymer matrix. Nevertheless, the use of MWCNTs as a rough material in different applications has been largely limited by their poor processability, insolubility, and infusibility. Studies concerning the nanofiller reinforced polymer composites are justified in an attempt to overcome these limitations. This work presents one preliminary study of MWCNTs dispersion into the PVDF homopolymer. For preparation, the composite components were diluted in n,n-dimethylacetamide (DMAc) with mechanical agitation assistance. After complete dilution, followed by slow evaporation of the solvent at 60°C, the samples were dried. Films of about 80 μm were obtained. FTIR and UV-Vis spectroscopic techniques were used to characterize the nanocomposites. The appearance of absorption bands in the FTIR spectra of nanofilled samples, when compared to the spectrum of pristine PVDF samples, are discussed and compared with the UV-Vis measurements.

Keywords: composites materials, FTIR, MWNTs, PVDF, UV-vis

Procedia PDF Downloads 421

Authors: Muhammad Zubair, Aman Ullah, Jianping Wu

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During the last decades, petroleum derived synthetic polymers like polyethylene terephthalate, polyvinylchloride, polyethylene, polypropylene and polystyrene has extensively been used in the field of food packaging and mostly are non-degradable. Biopolymers are a good fit for single-use or short-lived products such as food packaging. Spent hens, a poultry by-product which is of little economic value and their disposal are environmentally harmful. Through current study, we have explored the possibility to transform proteins from spent fowl into green food packaging material. Proteins from spent fowl were extracted within 1 hour using pH shift method with recovery of about 74%. Different plasticizers were tried like glycerol, sorbitol, glutaraldehyde, 1,2 ethylene glycol and 1,2 butanediol. Glycerol was the best plasticizer among all these plasticizers. A naturally occurring and non-toxic cross-linking agent, chitosan, was used to form the chitosan/glycerol/protein blend by casting and compression molding techniques. The mechanical properties were characterized using tensile strength analyzer. The nano-reinforcements with homogeneous dispersion of nanoparticles lead to improved physical properties suggesting that these materials have great potential for food packaging applications.

Keywords: differential scanning calorimetry, dynamic mechanical analysis, scanning electron microscopy, spent hen

Procedia PDF Downloads 253

Authors: Ebrahim Zamani Beydokhti, Hashem Shariatmadar

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This paper presents an experimental and analytical investigation on the behavior of retrofitted beam-column joints subjected to reversed cyclic loading. The experimental program comprises 8 external beam–column joint connection subassemblages tested in 2 phases; one was the damaging phase and second was the repairing phase. The beam-column joints were no seismically designed, i.e. the joint, beam and column critical zones had no special transverse stirrups. The joins were tested under cyclic loading in previous research. The experiment had two phases named damage phase and retrofit phase. Then the experimental results compared with analytical results achieved from modeling in OpenSees software. The presence of lateral slab and the axial load amount were analytically investigated. The results showed that increasing the axial load and presence of lateral slab increased the joint capacity. The presence of lateral slab increased the dissipated energy, while the axial load had no significant effect on it.

Keywords: concrete beam-column joints, CFRP sheets, lateral slab, axial load

Procedia PDF Downloads 120

Authors: Cam Minh Tri Tien, Richard Fenrich, Tristan Shelley, Nam Mai-Duy, Allan Malano, Xuesen Zeng

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Since additive manufacturing is a layer-by-layer deposition approach, good bonding quality between adjacent layers is critically important to achieve optimal mechanical performance, including applications in pressure vessels. The need to enhance the strength of printed products, especially in the build direction where layup gaps and voids exist between the printed layers, has garnered significant attention. The proposed research will focus on improving the current Fused Deposition Modelling (FDM) process to produce polymers reinforced with chopped fibers, utilizing a controlled heat zone to enhance the adhesion between printed layers. Energy will be applied to both printed and printing layers to improve the bonding strength between adjacent layers. Through the enhanced FDM process, the mechanical performance of composite parts will experience a substantial improvement, particularly in the build direction, as compared to current FDM methods. A combination of experimental, numerical, and analytical methods will be employed to demonstrate the enhanced performance of heat-controlled 3D printed parts.

Keywords: 3D Printing, pressure vessels, interlayer bonding, controlled heat

Procedia PDF Downloads 27

Authors: V. Balamuralidhara

Abstract:

The aim of the present work was to develop Paclitaxel loaded polyacrylamide grafted guar gum nanoparticles as pH responsive nanoparticle systems for targeting colon. The pH sensitive nanoparticles were prepared by modified ionotropic gelation technique. The prepared nanoparticles showed mean diameters in the range of 264±0.676 nm to 726±0.671nm, and a negative net charge 10.8 mV to 35.4mV. Fourier Transformed Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC) studies suggested that there was no chemical interaction between drug and polymers. The encapsulation efficiency of the drug was found to be 40.92% to 48.14%. The suitability of the polyacrylamide grafted guar gum ERN’s for the release of Paclitaxel was studied by in vitro release at pH 1.2 and 7.4. It was observed that, there was no significant amount of drug release at gastric pH and 97.63% of drug release at pH 7.4 was obtained for optimized formulation F3 at the end of 12 hrs. In vivo drug targeting performance for the prepared optimized formulation (F3) and pure drug Paclitaxel was evaluated by HPLC. It was observed that the polyacrylamide grafted guar gum can be used to prepare nanoparticles for targeting the drug to the colon. The release performance was greatly affected by the materials used in ERN’s preparation, which allows maximum release at colon’s pH. It may be concluded that polyacrylamide grafted guar gum nanoparticles loaded with paclitaxel have desirable release responsive to specific pH. Hence it is a unique approach for colonic delivery of drug having appropriate site specificity and feasibility and controlled release of drug.

Keywords: colon targeting, polyacrylamide grafted guar gum nanoparticles, paclitaxel, nanoparticles

Procedia PDF Downloads 322