The document discusses improving the performance of photopolymer resins used in 3D printing through oxygen desensitization. It examines adding visco enhancers and antioxidants to photopolymer resins to protect the ruthenium catalyst from deactivating in the presence of oxygen. Testing found that increasing the resin viscosity by 30x improved its ambient lifespan by over 100x. Adding the antioxidant 4-methoxyphenol (MEHQ) at 0.1-0.2 wt.% also improved performance by 9x. Raman spectroscopy confirmed MEHQ was the most effective antioxidant at protecting the catalyst compared to others tested. The modifications aim to allow photopolymer resins to polymerize after longer exposures to ambient oxygen levels.
This document summarizes a study on the effect of different solvent systems on poly(lactic acid) (PLA) nanofibres produced through electrospinning. PLA solutions were prepared using various single solvents and mixed solvent systems. Of the single solvents tested, only acetone produced continuous nanofibres, while the others resulted in beads. The addition of acetone to other solvents in a 50/50 mixture improved fibre production. Solutions of acetone/dimethylformamide and acetone/dimethylacetamide produced smooth, bead-free nanofibres with the narrowest diameter distribution. The mixed solvent systems had lower viscosity and surface tension but higher conductivity than single solvents, enabling better fibre formation
The document discusses various applications of nanomaterials in catalysis. It begins by introducing different types of catalysts and how nanocatalysts combine advantages of homogeneous and heterogeneous systems by having a high surface area like homogeneous catalysts while also being easily separable like heterogeneous catalysts. Several examples of nanocatalyst applications are then summarized in areas like water purification, biodiesel production, drug delivery, fuel cells, environmental protection, and solar cells. The document emphasizes how nanocatalysts provide benefits like high activity, selectivity, stability, and being energy efficient.
The document summarizes the synthesis and characterization of a novel glycerol-based non-ionic gemini surfactant. Glycerol was first esterified with cotton seed oil, then reacted with 1,2,7,8-diepoxideoctane to form the gemini surfactant. The surfactant was characterized using FTIR, 1H-NMR, 13C-NMR spectroscopy and SEM. Testing showed the surfactant had good solubilization and wetting properties.
Ultrasound In organic reaction and Supercritical Liquidsal mamun
This document discusses various applications of ultrasound and supercritical fluids in organic chemistry. It begins by defining ultrasound and describing how it is used to accelerate organic reactions by increasing reaction rates and product yields. Specific examples of heterocycle synthesis and other reaction types improved by ultrasound are provided. The document then defines supercritical fluids as substances above their critical point where distinct liquid and gas phases do not exist. Common supercritical fluids of carbon dioxide and water are noted. Applications of supercritical fluids discussed include extraction, dry cleaning, chromatography, chemical reactions, and biodiesel production.
Deep Eutetic Solvents for Biomass Activation by Sauli Vuoti, Jaakko Hiltunen et al., VTT
ACel Programme Seminar June 5, 2015
http://fibic.fi/events/acel-program-seminar-jun-5-cellulose-reactivity-and-recycling-of-ionic-liquids
Innovative Ion Exchange Treatment: Process Engineering and Chemistry Consider...WaterWeUpTo
1. The document evaluates a combined anion/cation ion exchange treatment process for removing natural organic matter and hardness from water. It examines using MIEX resin, which can be regenerated using different counter ions like chloride or bicarbonate.
2. Experiments show that combining anion and cation exchange removes more organic matter than either process alone. Regenerating the resin with bicarbonate rather than chloride also produces less waste.
3. Future work will further explore regenerating MIEX with bicarbonate and its ability to remove various contaminants over multiple regeneration cycles.
This document summarizes a study on the effect of different solvent systems on poly(lactic acid) (PLA) nanofibres produced through electrospinning. PLA solutions were prepared using various single solvents and mixed solvent systems. Of the single solvents tested, only acetone produced continuous nanofibres, while the others resulted in beads. The addition of acetone to other solvents in a 50/50 mixture improved fibre production. Solutions of acetone/dimethylformamide and acetone/dimethylacetamide produced smooth, bead-free nanofibres with the narrowest diameter distribution. The mixed solvent systems had lower viscosity and surface tension but higher conductivity than single solvents, enabling better fibre formation
The document discusses various applications of nanomaterials in catalysis. It begins by introducing different types of catalysts and how nanocatalysts combine advantages of homogeneous and heterogeneous systems by having a high surface area like homogeneous catalysts while also being easily separable like heterogeneous catalysts. Several examples of nanocatalyst applications are then summarized in areas like water purification, biodiesel production, drug delivery, fuel cells, environmental protection, and solar cells. The document emphasizes how nanocatalysts provide benefits like high activity, selectivity, stability, and being energy efficient.
The document summarizes the synthesis and characterization of a novel glycerol-based non-ionic gemini surfactant. Glycerol was first esterified with cotton seed oil, then reacted with 1,2,7,8-diepoxideoctane to form the gemini surfactant. The surfactant was characterized using FTIR, 1H-NMR, 13C-NMR spectroscopy and SEM. Testing showed the surfactant had good solubilization and wetting properties.
Ultrasound In organic reaction and Supercritical Liquidsal mamun
This document discusses various applications of ultrasound and supercritical fluids in organic chemistry. It begins by defining ultrasound and describing how it is used to accelerate organic reactions by increasing reaction rates and product yields. Specific examples of heterocycle synthesis and other reaction types improved by ultrasound are provided. The document then defines supercritical fluids as substances above their critical point where distinct liquid and gas phases do not exist. Common supercritical fluids of carbon dioxide and water are noted. Applications of supercritical fluids discussed include extraction, dry cleaning, chromatography, chemical reactions, and biodiesel production.
Deep Eutetic Solvents for Biomass Activation by Sauli Vuoti, Jaakko Hiltunen et al., VTT
ACel Programme Seminar June 5, 2015
http://fibic.fi/events/acel-program-seminar-jun-5-cellulose-reactivity-and-recycling-of-ionic-liquids
Innovative Ion Exchange Treatment: Process Engineering and Chemistry Consider...WaterWeUpTo
1. The document evaluates a combined anion/cation ion exchange treatment process for removing natural organic matter and hardness from water. It examines using MIEX resin, which can be regenerated using different counter ions like chloride or bicarbonate.
2. Experiments show that combining anion and cation exchange removes more organic matter than either process alone. Regenerating the resin with bicarbonate rather than chloride also produces less waste.
3. Future work will further explore regenerating MIEX with bicarbonate and its ability to remove various contaminants over multiple regeneration cycles.
Polypyrrole/PZT Thermistor: An Effective pre-cursor towards sensor designIJERA Editor
Pristine Polypyrrole was prepared by employing inverse emulsion polymerization technique using
Methanesulfonic acid as a dopant and sodium lauryl sulfate (SLS) as a surfactant. Oxidizing agent used was
Potassium Persulfate. An attempt was made to formulate a Polypyrrole device by blending Polypyrrole with
Lead Zirconate Titanate (PZT) piezoceramic powder which showed characteristics akin to a Thermistor thereby
formulating its use as a pre-cursor to a temperature sensor upon Current vs. Voltage as well as Temperature vs.
Conductivity studies. Characterization studies of Polypyrrole/PZT blends using Fourier Transform Infrared
Spectra, Scanning Electron Microscopy and X-ray diffraction studies yielded satisfactory and confirmatory
results. Extensive conductivity studies were carried out from 298 K - 383 K and Conductivity as high as 3.97
S•cm-1 was obtained at a surfactant and dopant concentration of 9.0 g and 11.0 g respectively. Liquid Phase
Sintering of Ppy/PZT blends with Tin (Sn) metal powder offers exciting opportunity towards formulation of a
temperature sensor, the diffusivity studies of which are still underway.
In this research in order to produce blood sugar biosensor, an appropriate
membrane for glucose oxidase immobilization by using nanofibers created from
polymers of polyacrylic acid and starch are studied. They are biocompatible and
biodegradable respectively and were prepared by electro-spinning method for
nanofiber fabrication. Dimethylformamide and distilled water were used as solvent for
PAA and starch respectively to get a homogeneous solution. Because nanofibers made
of polyacrylic acid-starch face with enzymes, due to its extremely high hydrophilic
‘OH’ groups may lose their cohesion, crosslinking as chemical surface modification
and for better enzyme immobilization, non-thermal plasma surface modification using
atmospheric pressure Dielectric Barrier Discharge (DBD) were used. Crosslinking was
carried out by APTMS and Glutaraldehyde (GA). The effect of electro-spinning process
variables on morphology of nanofibers was examined by Scanning Electron
Microscopy (SEM). Nanofibers structure and chemical composition to demonstrate
the successful linking and immobilization of enzymes in the composite membrane was
obtained by Fourier Transform Infrared spectroscopy (FTIR) and improved thermal
stability of nanofibers in presence of enzyme and surface modifications was
determined by Thermal Gravimetric Analysis (TGA).
Pretreatment of wheat straw using deep eutectic solvents and ultraoundEuropeanPaper
By Andrea Skulcova, Slovak University of Technology. This was presented during the Two Team Project - Winners' first successes session, organised as part of European Paper Week 2015. More at http://www.cepi.org/epw
chitosan nanoparticles synthesis and application in various fields i.e. biocompatible fruit preservatives, water treatment with non toxic substrate, cotton functionalization, etc.
Processing of Lignin and the Removal of Detrimentals with Deep Eutectic SolventsEuropeanPaper
By Laura Kollau, Dannie van Osch & Panos Kourios, PhD Students from TU Eindhoven. This was presented during the Two Team Project - Winners' first successes session, organised as part of European Paper Week 2015. More at http://www.cepi.org/epw
This research article presents a new kinetic spectrophotometric method for determining cefixime concentrations in pure and pharmaceutical formulations using saffron extract as a natural reagent. The method is based on the formation of a yellow product with maximum absorbance at 390nm when a mixture of saffron extract, sodium hydroxide, and potassium permanganate is added to an aqueous cefixime solution. The experimental conditions were optimized. Beer's law was followed for cefixime concentrations between 10-0.6 μg/mL. The method was successfully applied to determine cefixime in pharmaceutical dosage forms.
This document summarizes a study that uses dynamic vapor sorption (DVS) combined with deuterium oxide exchange to directly measure the accessible hydroxyl groups in cellulose samples, which influences cellulose reactivity. Several pulp samples were analyzed using this method. The results showed a correlation between the accessibility of hydroxyl groups and water retention values for industrially dried pulps. Never-dried pulps had relatively low accessibility, possibly because drying during the measurements affected accessibility. Equilibrium moisture content also correlated with water retention values. Further studies are needed to fully understand how drying impacts accessibility measurements.
This document summarizes a study that investigated the potential for photochemical reactions of two thiazide compounds, bendroflumethiazide and hydroflumethiazide, when exposed to sunlight-range illumination. Spectroscopy analysis revealed that both compounds strongly absorb UV light in specific wavelength ranges. When solutions of the compounds were illuminated over time, their absorption spectra changed, indicating photochemical reactions were occurring. However, the reaction kinetics could not be definitively determined due to interference from photoproducts also absorbing at the same wavelengths. Further separation and analysis of photoproducts using HPLC will be needed to fully characterize the photochemical reactions.
Uv radiation assisted photocatalytic transformation of azo dye direct yellow 9eSAT Journals
1. The document summarizes research on using a methylene blue immobilized resin (MBIR) Dowex-11 photocatalyst to transform the azo dye Direct Yellow-9 via UV-assisted photocatalysis.
2. Experiments were conducted to determine the optimum conditions for dye transformation, which achieved 94.60% transformation within 160 minutes. The process followed pseudo-first order kinetics with a rate constant of 1.43*10-2 min-1.
3. The research concludes that MBIR Dowex-11 is a low-cost, highly active photocatalyst that can efficiently catalyze the decolorization of azo dyes like Direct Yellow-9 via generation of reactive oxygen species
This document describes a study that synthesized and characterized an amine-functionalized MCM-41 nano adsorbent (MCM-41/TMSPDETA) for removing lead (Pb(II)) and nickel (Ni(II)) from wastewater. The adsorbent was characterized using various techniques and found to have a high surface area, uniform pore size, and amine functional groups. Batch experiments were conducted to evaluate the effects of pH, contact time, and temperature on adsorption capacity. Optimum conditions for maximum capacity were found to be pH 6, 120 minutes contact time, and 20°C temperature. Kinetic data fit best to a pseudo-second order model, indicating chemisor
This document describes the preparation and characterization of chitosan nanoparticles. Chitosan nanoparticles were prepared using the ionic gelation method by adding sodium tripolyphosphate (TPP) to chitosan solution. Different concentrations of chitosan and TPP were tested to determine optimal conditions for nanoparticle formation. Nanoparticles with average sizes ranging from 168-682 nm were successfully produced. The nanoparticles were characterized using UV-Vis spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering, and scanning electron microscopy. UV-Vis analysis showed an absorption peak at 226 nm. FTIR, DLS, and SEM confirmed the formation of stable, spherical chitosan nanoparticles in the 200 nm size range.
Degradation of Paracetamol by Electro-Fenton and Photoelectro-Fenton Processe...Oswar Mungkasa
prepared by M.C. Lu *, M.L.Veciana**, M.D.G. de Luna*** * Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan 717, Taiwan **Environmental Engineering Graduate Program, University of the Philippines, 1011 Diliman, Quezon City, Philippines *** Department of Chemical Engineering, University of the Philippines, 1011 Diliman, Quezon City, Phi for Urban Environments in Asia, 25-28 May 2011, Manila, Philippines. organized by International Water Association (IWA).
Ultra low dielectric constant (k 1⁄4 1.53) materials with self-cleansing properties were synthesized via incorporation of fluorodecyl-polyhedral oligomeric silsesquioxane (FD-POSS) into recently synthesized perfluorocyclopentenyl (PFCP) aryl ether polymers. Incorporation of fluorine rich, high free volume, and low surface energy POSS into a semifluorinated PFCP polymer matrix at various weight percentages resulted in a dramatic drop in dielectric constant, as well as a significant increase in hydrophobicity and oleophobicity of the system. These ultra-low dielectric self-cleansing materials (qtilt 1⁄4 38) were fabricated into electrospun mats from a solvent blend of fluorinated FD-POSS with PFCP polymers.
ABSTRACT:
Benzimidazole is a fused heterocyclic ring containing two nitrogen at position 1 and 3 in five member ring. This ring have large spectrum of biological activity specifically antimicrobial activity. We synthesis benzimidazole derivatives which have great percentage yield than reported and develop synthetic scheme that less time consuming with high purity of compound as well as no need of any kind of chromatography for purification. all compound was recrystallized with ethanol. We develop economical method of synthesis of benimidazole derivatives also characterization was carried out by IR and H1 NMR (CDCl3), Physical Constant, Solubility, Refractive Index. Benzimidazole derivative biologically evaluated on different microorganism. In the result gram negative and gram positive bacteria was Inhibited.
Visible Light Induced Selective Photocatalytic Oxidation of Benzyl Amine to N...IJERA Editor
Irradiated semiconductor catalysis in the presence of molecular oxygen can be considered as an innovative and sustainable technique for organic transformations. The present work reports the preparation ofGraphene oxide/TiO2composite by improved Hummer’s method followed by hydrothermal technique. The prepared system was characterized by various physico-chemical techniques such as X-Ray diffraction, IR-Spectroscopy, UV-DRS, XPS, SEM and TEM Analysis.On reaction, benzylamine in CH3CN yieldedN-benzylidene-1-phenylmethanamine as the sole product. The reaction was monitored by GC-MS Analysis.
Chitosan capped Silver nanoparticles used as Pressure sensorsIOSR Journals
In the present work, we report the synthesis and characterization of silver nanoparticles, capped with chitosan (biopolymer ). The majority of the particles produced in this way had sizes around 18 nm. Composite films of capped silver nanoparticles and chitosan polymer were studied to understand the charge transport under different pressure. Films of different compositions were prepared to measure current voltage curves across the film thickness. The results reveal that these materials exhibit electrical conductivity as predicted by the “classical theory of percolation”. Pressure dependent electrical conductivity and these composites can be explored to develop low cost pressure sensors.
SiO2@FeSO4 nano composite: A recoverable nano-catalyst for eco-friendly synth...Iranian Chemical Society
This document summarizes a study on the use of a SiO2@FeSO4 nano composite as a recoverable nano-catalyst for the solvent-free synthesis of oximes from various carbonyl compounds. The nano composite was synthesized using a sol-gel method and characterized. It was found to efficiently promote the conversion of aldehydes and ketones to their corresponding oximes within 10-15 minutes at 70-80°C. This protocol provides advantages such as short reaction times, high yields, applicability to various functional groups, and ability to selectively convert one carbonyl group in compounds containing multiple carbonyl groups. The nano composite could be recovered and reused multiple times without loss of activity.
TOTAL POLYPHENOLS AND DPPH FREE RADICALS SCAVENGING ACTIVITY IN SIX LEAFY VEG...Md. Kamaruzzaman
TOTAL POLYPHENOLS AND DPPH FREE RADICALS SCAVENGING ACTIVITY IN SIX LEAFY VEGETABLES OF BANGLADESH
Harun-Ar-Rashid, Sheikh Julfikar Hossain, Sk. Amir Hossain, Md Mahfuzur Rahman, Md. Kamaruzzaman
The document describes an experimental study on improving the productivity of gas metal arc welding (GMAW). It investigates the effect of varying three input parameters - welding current, voltage, and gas flow rate - on the amount of filler metal deposited and welding time. Samples of mild steel were welded using different combinations of the parameters and the weight of deposited metal and welding time were measured. The results showed that higher current leads to higher heat generation and metal deposition rate. Maximizing deposition rate while minimizing welding time can improve the productivity of GMAW.
Polypyrrole/PZT Thermistor: An Effective pre-cursor towards sensor designIJERA Editor
Pristine Polypyrrole was prepared by employing inverse emulsion polymerization technique using
Methanesulfonic acid as a dopant and sodium lauryl sulfate (SLS) as a surfactant. Oxidizing agent used was
Potassium Persulfate. An attempt was made to formulate a Polypyrrole device by blending Polypyrrole with
Lead Zirconate Titanate (PZT) piezoceramic powder which showed characteristics akin to a Thermistor thereby
formulating its use as a pre-cursor to a temperature sensor upon Current vs. Voltage as well as Temperature vs.
Conductivity studies. Characterization studies of Polypyrrole/PZT blends using Fourier Transform Infrared
Spectra, Scanning Electron Microscopy and X-ray diffraction studies yielded satisfactory and confirmatory
results. Extensive conductivity studies were carried out from 298 K - 383 K and Conductivity as high as 3.97
S•cm-1 was obtained at a surfactant and dopant concentration of 9.0 g and 11.0 g respectively. Liquid Phase
Sintering of Ppy/PZT blends with Tin (Sn) metal powder offers exciting opportunity towards formulation of a
temperature sensor, the diffusivity studies of which are still underway.
In this research in order to produce blood sugar biosensor, an appropriate
membrane for glucose oxidase immobilization by using nanofibers created from
polymers of polyacrylic acid and starch are studied. They are biocompatible and
biodegradable respectively and were prepared by electro-spinning method for
nanofiber fabrication. Dimethylformamide and distilled water were used as solvent for
PAA and starch respectively to get a homogeneous solution. Because nanofibers made
of polyacrylic acid-starch face with enzymes, due to its extremely high hydrophilic
‘OH’ groups may lose their cohesion, crosslinking as chemical surface modification
and for better enzyme immobilization, non-thermal plasma surface modification using
atmospheric pressure Dielectric Barrier Discharge (DBD) were used. Crosslinking was
carried out by APTMS and Glutaraldehyde (GA). The effect of electro-spinning process
variables on morphology of nanofibers was examined by Scanning Electron
Microscopy (SEM). Nanofibers structure and chemical composition to demonstrate
the successful linking and immobilization of enzymes in the composite membrane was
obtained by Fourier Transform Infrared spectroscopy (FTIR) and improved thermal
stability of nanofibers in presence of enzyme and surface modifications was
determined by Thermal Gravimetric Analysis (TGA).
Pretreatment of wheat straw using deep eutectic solvents and ultraoundEuropeanPaper
By Andrea Skulcova, Slovak University of Technology. This was presented during the Two Team Project - Winners' first successes session, organised as part of European Paper Week 2015. More at http://www.cepi.org/epw
chitosan nanoparticles synthesis and application in various fields i.e. biocompatible fruit preservatives, water treatment with non toxic substrate, cotton functionalization, etc.
Processing of Lignin and the Removal of Detrimentals with Deep Eutectic SolventsEuropeanPaper
By Laura Kollau, Dannie van Osch & Panos Kourios, PhD Students from TU Eindhoven. This was presented during the Two Team Project - Winners' first successes session, organised as part of European Paper Week 2015. More at http://www.cepi.org/epw
This research article presents a new kinetic spectrophotometric method for determining cefixime concentrations in pure and pharmaceutical formulations using saffron extract as a natural reagent. The method is based on the formation of a yellow product with maximum absorbance at 390nm when a mixture of saffron extract, sodium hydroxide, and potassium permanganate is added to an aqueous cefixime solution. The experimental conditions were optimized. Beer's law was followed for cefixime concentrations between 10-0.6 μg/mL. The method was successfully applied to determine cefixime in pharmaceutical dosage forms.
This document summarizes a study that uses dynamic vapor sorption (DVS) combined with deuterium oxide exchange to directly measure the accessible hydroxyl groups in cellulose samples, which influences cellulose reactivity. Several pulp samples were analyzed using this method. The results showed a correlation between the accessibility of hydroxyl groups and water retention values for industrially dried pulps. Never-dried pulps had relatively low accessibility, possibly because drying during the measurements affected accessibility. Equilibrium moisture content also correlated with water retention values. Further studies are needed to fully understand how drying impacts accessibility measurements.
This document summarizes a study that investigated the potential for photochemical reactions of two thiazide compounds, bendroflumethiazide and hydroflumethiazide, when exposed to sunlight-range illumination. Spectroscopy analysis revealed that both compounds strongly absorb UV light in specific wavelength ranges. When solutions of the compounds were illuminated over time, their absorption spectra changed, indicating photochemical reactions were occurring. However, the reaction kinetics could not be definitively determined due to interference from photoproducts also absorbing at the same wavelengths. Further separation and analysis of photoproducts using HPLC will be needed to fully characterize the photochemical reactions.
Uv radiation assisted photocatalytic transformation of azo dye direct yellow 9eSAT Journals
1. The document summarizes research on using a methylene blue immobilized resin (MBIR) Dowex-11 photocatalyst to transform the azo dye Direct Yellow-9 via UV-assisted photocatalysis.
2. Experiments were conducted to determine the optimum conditions for dye transformation, which achieved 94.60% transformation within 160 minutes. The process followed pseudo-first order kinetics with a rate constant of 1.43*10-2 min-1.
3. The research concludes that MBIR Dowex-11 is a low-cost, highly active photocatalyst that can efficiently catalyze the decolorization of azo dyes like Direct Yellow-9 via generation of reactive oxygen species
This document describes a study that synthesized and characterized an amine-functionalized MCM-41 nano adsorbent (MCM-41/TMSPDETA) for removing lead (Pb(II)) and nickel (Ni(II)) from wastewater. The adsorbent was characterized using various techniques and found to have a high surface area, uniform pore size, and amine functional groups. Batch experiments were conducted to evaluate the effects of pH, contact time, and temperature on adsorption capacity. Optimum conditions for maximum capacity were found to be pH 6, 120 minutes contact time, and 20°C temperature. Kinetic data fit best to a pseudo-second order model, indicating chemisor
This document describes the preparation and characterization of chitosan nanoparticles. Chitosan nanoparticles were prepared using the ionic gelation method by adding sodium tripolyphosphate (TPP) to chitosan solution. Different concentrations of chitosan and TPP were tested to determine optimal conditions for nanoparticle formation. Nanoparticles with average sizes ranging from 168-682 nm were successfully produced. The nanoparticles were characterized using UV-Vis spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering, and scanning electron microscopy. UV-Vis analysis showed an absorption peak at 226 nm. FTIR, DLS, and SEM confirmed the formation of stable, spherical chitosan nanoparticles in the 200 nm size range.
Degradation of Paracetamol by Electro-Fenton and Photoelectro-Fenton Processe...Oswar Mungkasa
prepared by M.C. Lu *, M.L.Veciana**, M.D.G. de Luna*** * Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan 717, Taiwan **Environmental Engineering Graduate Program, University of the Philippines, 1011 Diliman, Quezon City, Philippines *** Department of Chemical Engineering, University of the Philippines, 1011 Diliman, Quezon City, Phi for Urban Environments in Asia, 25-28 May 2011, Manila, Philippines. organized by International Water Association (IWA).
Ultra low dielectric constant (k 1⁄4 1.53) materials with self-cleansing properties were synthesized via incorporation of fluorodecyl-polyhedral oligomeric silsesquioxane (FD-POSS) into recently synthesized perfluorocyclopentenyl (PFCP) aryl ether polymers. Incorporation of fluorine rich, high free volume, and low surface energy POSS into a semifluorinated PFCP polymer matrix at various weight percentages resulted in a dramatic drop in dielectric constant, as well as a significant increase in hydrophobicity and oleophobicity of the system. These ultra-low dielectric self-cleansing materials (qtilt 1⁄4 38) were fabricated into electrospun mats from a solvent blend of fluorinated FD-POSS with PFCP polymers.
ABSTRACT:
Benzimidazole is a fused heterocyclic ring containing two nitrogen at position 1 and 3 in five member ring. This ring have large spectrum of biological activity specifically antimicrobial activity. We synthesis benzimidazole derivatives which have great percentage yield than reported and develop synthetic scheme that less time consuming with high purity of compound as well as no need of any kind of chromatography for purification. all compound was recrystallized with ethanol. We develop economical method of synthesis of benimidazole derivatives also characterization was carried out by IR and H1 NMR (CDCl3), Physical Constant, Solubility, Refractive Index. Benzimidazole derivative biologically evaluated on different microorganism. In the result gram negative and gram positive bacteria was Inhibited.
Visible Light Induced Selective Photocatalytic Oxidation of Benzyl Amine to N...IJERA Editor
Irradiated semiconductor catalysis in the presence of molecular oxygen can be considered as an innovative and sustainable technique for organic transformations. The present work reports the preparation ofGraphene oxide/TiO2composite by improved Hummer’s method followed by hydrothermal technique. The prepared system was characterized by various physico-chemical techniques such as X-Ray diffraction, IR-Spectroscopy, UV-DRS, XPS, SEM and TEM Analysis.On reaction, benzylamine in CH3CN yieldedN-benzylidene-1-phenylmethanamine as the sole product. The reaction was monitored by GC-MS Analysis.
Chitosan capped Silver nanoparticles used as Pressure sensorsIOSR Journals
In the present work, we report the synthesis and characterization of silver nanoparticles, capped with chitosan (biopolymer ). The majority of the particles produced in this way had sizes around 18 nm. Composite films of capped silver nanoparticles and chitosan polymer were studied to understand the charge transport under different pressure. Films of different compositions were prepared to measure current voltage curves across the film thickness. The results reveal that these materials exhibit electrical conductivity as predicted by the “classical theory of percolation”. Pressure dependent electrical conductivity and these composites can be explored to develop low cost pressure sensors.
SiO2@FeSO4 nano composite: A recoverable nano-catalyst for eco-friendly synth...Iranian Chemical Society
This document summarizes a study on the use of a SiO2@FeSO4 nano composite as a recoverable nano-catalyst for the solvent-free synthesis of oximes from various carbonyl compounds. The nano composite was synthesized using a sol-gel method and characterized. It was found to efficiently promote the conversion of aldehydes and ketones to their corresponding oximes within 10-15 minutes at 70-80°C. This protocol provides advantages such as short reaction times, high yields, applicability to various functional groups, and ability to selectively convert one carbonyl group in compounds containing multiple carbonyl groups. The nano composite could be recovered and reused multiple times without loss of activity.
TOTAL POLYPHENOLS AND DPPH FREE RADICALS SCAVENGING ACTIVITY IN SIX LEAFY VEG...Md. Kamaruzzaman
TOTAL POLYPHENOLS AND DPPH FREE RADICALS SCAVENGING ACTIVITY IN SIX LEAFY VEGETABLES OF BANGLADESH
Harun-Ar-Rashid, Sheikh Julfikar Hossain, Sk. Amir Hossain, Md Mahfuzur Rahman, Md. Kamaruzzaman
The document describes an experimental study on improving the productivity of gas metal arc welding (GMAW). It investigates the effect of varying three input parameters - welding current, voltage, and gas flow rate - on the amount of filler metal deposited and welding time. Samples of mild steel were welded using different combinations of the parameters and the weight of deposited metal and welding time were measured. The results showed that higher current leads to higher heat generation and metal deposition rate. Maximizing deposition rate while minimizing welding time can improve the productivity of GMAW.
The Technology Research of Camera Calibration Based On LabVIEWIJRES Journal
The technology of camera calibration is most important part for machine vision detection and
location, the accuracy of calibration directly determines the processing accuracy of machine vision systems. In
this paper, we use LabVIEW and MATLAB to calibrate the internal and external parameters of the camera, at
the same time, we use dot calibration board, the circle edge is detected by Canny operator, then with the method
of circle fitting based on subpixel edge extraction, the information of dots image coordinate is extracted. The
present method reduces the difficulty of camera calibration and shortens the software development cycle, the
most important is that it has a high calibration accuracy, which can meet the actual industrial detection accuracy,
the results of experimental show that the method is feasible.
A study on improvement activities for indian manufacturing industrieseSAT Journals
Abstract This paper presents findings of an extensive survey of Indian manufacturing industries. The survey encompassed three sectors: Four Wheeler Automobile Industries, Two Wheeler Automobile Industries and General Manufacturing Industries. Various Improvement Activities such as Advance Manufacturing Technology, Integrated Information System and Advance Management System have been identified and assessed the degree of investment in Improvement Activities in Indian manufacturing environment. Their sub classifications are also made. Sector wise comparisons of these Improvement Activities are provided. Correlation is also made between the various Improvement Activities. Our results showed that most of the Indian industries are still emphasizing Advanced Management Systems. Four Wheeler Automobile Industries and General Manufacturing Industries are emphasizing on Total Quality Management. However Two Wheeler Automobile Industries are investing more on Activity Based Costing. But, in overall sector it is observed from data analysis that all sectors are emphasizing on Total Quality Management. Key words: Improvement activities, Advance Manufacturing Technology, Integrated Information System, Advance Management System.
EFFECT OF THE PROCESS PARAMETERS ON GEOMETRICAL CHARACTERISTICS OF THE PARTS ...IAEME Publication
This document reviews the direct metal deposition (DMD) process and the effects of various process parameters on the geometrical characteristics of parts produced. It discusses how the laser power, beam diameter, scanning speed, powder flow rate, and other parameters influence characteristics like clad height, width, roughness, and dilution. Several studies that developed models and conducted experiments relating parameters to outcomes are summarized. In general, increasing laser power or powder flow rate tends to increase clad height and deposition rate while increasing scanning speed decreases these. Optimal surface roughness requires intermediate parameter values.
Advanced Materials and Processes Magazine - January 2015 - Additive Manufactu...Machine Tool Systems Inc.
Attached is a research paper about DMLS™ and steels that appeared in the January edition of Advanced Materials and Processes magazine. The paper is authored by engineers at EWI, an EOS partner.
IBC Group provides advanced surface treatment and coating solutions using techniques like laser cladding, thin film coating, nitriding, and heat treating. The company has facilities in Indiana and Canada with about 85 employees. Laser cladding is used to rebuild worn components and increase hardness and wear resistance through applying cladding layers and subsequent treatments. Examples showed laser cladding repaired turbo shafts and agricultural parts with no wear after testing.
Effect of chromium powder mixed dielectric on performance characteristic of a...eSAT Journals
Abstract
In this paper, the effect of chromium powder mixed dielectric fluid on machining characteristics of AISI D2 die steel has been studied. Peak current, pulse on time, pulse off time, concentration of powder are the process parameters. The process performance is measured in terms of material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR). The research outcome will identify the important process parameters that maximize MRR, minimize TWR and SR. The design of experiment has been undertaken using Taguchi method. ANOVA analysis has been used to investigate the percentage contribution of each process parameter for optimizing the performance. The study indicates that all the selected parameters except pulse off time have a significant effect on MRR. Current is found to be the most significant factor for MRR and TWR. With increase in current, TWR increases. Also, surface roughness increases with increase in pulse off time.
Keywords: PMEDM, Material removal rate, Tool wear rate, Surface roughness, Taguchi method
LaserBond™ achieves a welded or metallurgical bond with minimal, precisely controlled heat input provided by an optimized laser beam. Temperature sensitive components and materials, such as hardened shafts, gears etc, can be repaired with minimal risk of distortion or other undesirable heat effects. The metallurgical bond allows LaserBond™ applied layers to be used in high impact, heavily loaded/stressed situations with no risk of spalling or separation of the overlay. The controlled energy minimizes the undesirable thermal decomposition of hard phases such as carbides, resulting in optimum wear resistance. Due to the extremely low dilution with the substrate, high specification materials can be applied in a thin layer with corrosion and wear resistant surfaces as thin as 0.3mm possible. Thick overlays for significant repairs of up to 20mm can also be applied in multiple passes. Heat affected zones are minimized and the stress related cracking inherent in welded or PTA applied hard facing is generally eliminated. Standard LaserBond™ overlay options include Tungsten Carbide, Stainless Steels, Nickel alloys such as Inconel, and Cobalt alloys such as Stellite1. Other materials can be applied on request.
The High Pressure High Velocity Oxy-Fuel process applies coating material at supersonic velocities, resulting in surfaces of the highest possible quality and performance.
HP HVOF coatings are very dense, very well bonded, and free of the oxides and tensile stresses typically found in coatings produced with other thermal spray processes. Consequently, they perform better in most service environments. HP HVOF wear resistant coatings are being adopted globally as an environmentally friendly, and technically superior, alternative to Chrome plating on components such as aircraft landing gear. Surfaces combining resistance to corrosion and wear are also routinely applied by HP HVOF. LaserBond™ approved HP HVOF coatings include Tungsten Carbide, Chrome Carbide, Nickel based alloys (e.g. Inconel 625 and 718), Cobalt alloys such as Stellite1, stainless steels and copper based alloys.
Ajith Ranasinghe | Sales Engineer
LaserBond Ltd
2/57 Anderson Road, Smeaton Grange NSW 2567
| m:+61417618512 | t: +612 4631 4500 | f: +612 4631 4555
ajithr@laserbond.com.au
This document reviews the use of Taguchi methods to optimize gas metal arc welding (GMAW) process parameters for tensile strength. The study used an L09 orthogonal array to experiment with three welding parameters (wire feed rate, voltage, current) at three levels each. Tensile strength and signal-to-noise ratios were calculated for each experiment. Analysis of variance found wire feed rate to be the most influential parameter on tensile strength, followed by current, with voltage having less effect. The optimal welding parameters for maximum tensile strength were determined using the signal-to-noise ratio analysis.
A study on overall quality assurance in just in time manufacturing process in...Sathiskumar M
JIT manufacturing is a philosophy by which an organization seeks continually to improve
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to manufacturing must have several building blocks in place. The building blocks include:
company-wide commitment, proper materials at the right time, supplier relationships, quality,
and personnel. The present work will analyze what have been the results throughout the supply
chain, in terms of inventory management, of those companies who do business with OEMs that
utilize JIT systems. The results of this study should enable managers that have or are considering
implementing or participating in a JIT inventory management system to become more effective.
The JIT system runs smoothly with no peaks or valleys. The typical inventory system, on the
other hand, is fraught with peaks and valleys that represent costs to the organization in the form
of inventory holding costs, back order and stock-out costs, overtime and idle time labor costs,
and waste of materials and space.
This document provides a summary of how lasers are used in various manufacturing applications. It discusses laser welding, cleaning, surface treatments, direct laser fabrication, and selective laser sintering. Laser welding is now commonly used in production and can provide benefits like high speeds, narrow welds with less distortion, and accuracy. Laser cleaning is an emerging process being used for applications like tool restoration and electronics. Surface treatments like hardening, melting, and alloying can improve properties using lasers. Direct laser fabrication and selective laser sintering allow building parts layer-by-layer from powders. Emerging applications also include laser forming of sheet metal and nanostructure generation.
3d Machine Vision Systems Paper Presentationguestac67362
ww
1) 3D machine vision systems have advanced to enable quantitative metrology applications on the shop floor. Technologies like laser scanning, structured light, and stereo vision can provide measurements in the sub-mil range at speeds of a few seconds.
2) Key factors for production use are measurement resolution in mils/sub-mils, speeds under a few seconds, and robustness to varying surface finishes and conditions. Technologies were tested on features like edges, textures, and spheres to evaluate performance.
3) Applications include industrial inspection, autonomous vehicles, transport safety, surveillance, remote sensing, and medical imaging. Continued improvements in computing, cameras, and light sources will further expand use of 3D machine
This document provides instructions for searching for journal articles using the ScienceDirect database. It outlines the steps to access the database through the university library website, perform an advanced search within the Journals tab by entering search terms and limiting the results to journal articles within a specified date range, and download full-text PDFs of matching articles. The last step notes an email contact for additional assistance.
Paper on Forming, Welding & Heat treatment of SS equip & component for NRPSantosh Takale
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This document discusses additive manufacturing (AM) and its potential applications in the maritime and oil & gas industries. It provides an overview of important AM processes such as binder jetting, material jetting, powder bed fusion, sheet lamination, vat photopolymerization, and direct energy deposition. While AM currently only accounts for about 5% of these industries, its use is anticipated to rapidly expand. The document outlines both limiting and encouraging factors for AM adoption. It then presents a Bayesian network approach that can be used to assess risks to manufacturers and end users from AM part variability and lack of standards/regulations. Case studies demonstrate how this approach can evaluate risks from an original equipment manufacturer or end user perspective.
Flexible manufacturing systems (FMS) are automated production systems comprised of multiple computer-controlled machines linked together by an automated material handling and transport system and controlled by a distributed computer system. An FMS allows for flexible production of different part types by easily changing production schedules and introducing new product styles. FMS range from single machine cells to larger systems with multiple workstations. They provide benefits like reduced costs and lead times but also have disadvantages like high initial costs and limited ability to adapt to product changes.
This document discusses industrial robotics and presents techniques for cooperative robot-human systems. It describes the anatomy of robots including joints, configurations, and introduces a hand guiding system that allows both manual and automatic operation. The document also proposes a cooperative handling system using multiple smaller robots instead of one large robot to improve versatility when handling various workpiece sizes. Robot welding applications are also discussed.
3d machine-vision-systems-paper-presentationChidananda M
ww
1) 3D machine vision systems have advanced to enable quantitative metrology applications on the shop floor. Technologies like laser scanning, structured light, and stereo viewing can provide measurements at sub-mil resolution and speeds sufficient for inspection.
2) Key challenges for 3D optical systems include varying surface finishes and textures that can scatter or diffuse light signals. Thorough testing on representative surfaces and features is important to validate measurement capabilities.
3) Comparisons to independent measurement methods help qualify new 3D vision systems, as traditional gauges may not provide the same level of capability or repeatability. Standard artifacts can verify optical measurements.
The Effect of Size of the CuO Nanoleaves on the Sunlight Driven Photocatalyti...IRJET Journal
This document summarizes research on the effect of surfactant concentration on the size and photocatalytic properties of copper oxide nano leaves. Copper oxide nano leaves were synthesized using different concentrations of polyvinyl pyrrolidone (PVP) as a surfactant. Characterization with XRD, FTIR and SEM showed that increasing PVP concentration decreased particle size and altered morphology from narrow leaves to shortened, broadened leaves. Photocatalytic testing demonstrated that the sample with the highest PVP concentration degraded Congo Red dye in sunlight most effectively within 4 hours, indicating smaller size and higher surface area enhanced photocatalytic activity.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document discusses the use of positron annihilation spectroscopy to analyze the free volume nanohole distribution in polymers and its correlation to the physico-chemical properties of polymers. It provides background on positron annihilation spectroscopy and how it can be used to measure free volume in polymers. The document then describes several studies that use this technique to analyze the influence of free volume properties on the swelling of polymer hydrogels, structure-property relationships in modified epoxy resins, and free volume and interfacial interactions in epoxy clay composites.
The document discusses nanocatalysts and their applications in chemical industry. It begins with definitions of catalyst and nanocatalyst. It then discusses different types of nanocatalysts including homogeneous nanocatalysts which are soluble in solvents and heterogeneous nanocatalysts which are insoluble. Methods for preparing both homogeneous and heterogeneous nanocatalysts are described. The document outlines several industrial applications of nanocatalysts such as in biodiesel production, water purification, drug delivery, and fuel cells. It concludes that nanocatalysts have advantages over traditional catalysts like high activity, selectivity, stability, and ease of separation.
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1) Nd-YAG laser pulses were used to irradiate samples of lignin, microcrystalline cellulose, and filter paper. Lignin experienced substantial weight loss and degradation upon irradiation, while cellulose samples were unaffected.
2) Irradiation reduced the molecular weight and narrowed the molecular weight distribution of lignin. Smaller lignin fragments with increased phenolic hydroxyl content were produced.
3) Laser treatment provided a simple way to modify lignin properties without using chemical reagents. This technique could allow production of lignin samples with uniform characteristics.
In this work, membrane based activated carbon have been studied, and because of the large surface area and, consequently, adsorption of pores, has a wide use for purification of liquids or gases in its entirety. The basic idea is the refinement of the technological expertise of obtaining organic resin composite membranes - activated carbon with porosity characteristics typical of type UF membranes. The membranes were prepared with 40% vol. epoxy resin and 60% vol. Commercial activated carbon micro and mesoporous MADECARBO®, crude, evaluating three types of solvents (toluene, ethyl acetate and ethanol). Physical characterizations such as density Archimedes demonstrated an apparent porosity of 47% - 70% for raw coal and 49% - 62% for dry coal. The microstructure of the specimens was evaluated by scanning electron microscopy, indicating good homogeneity of the resin-carbon interaction for both formulations with raw coal, and for dry coal. The flow tests were conducted in a test cell to tubular membranes that simulates parallel flow type filter. As for the flow, the formulation with the lowest result of this property was a coal dry amid ethyl acetate. As for the raw coal, the lowest flow was obtained from the coal of the same nature, but amid absolute ethyl alcohol. From the results, it was concluded that this type of media is strongly influenced by the process for obtaining the formulation and, consequently, the microstructure of the specimens, plays an important role for the type of filtration obtained.
This document summarizes the synthesis and characterization of three titanium-containing metal-organic framework (MOF) photocatalysts: MIL-125, MIL-NH2, and SMIL-NH2. MIL-125 and MIL-NH2 were synthesized via a conventional solvothermal method, while SMIL-NH2 was synthesized using the same method with the addition of a nonionic surfactant. Characterization showed that SMIL-NH2 had a more uniform cylindrical morphology with smaller particle sizes of 50-250 nm and over double the surface area of MIL-NH2. Photocatalytic testing found that under blue LED light, SMIL-NH2 was able to
The document discusses energy saving lighting devices. It introduces LEDs as an efficient lighting source and discusses their advantages over traditional sources like incandescent and fluorescent bulbs. It describes various synthesis methods for producing nanomaterials for lighting applications, including solid-state reaction, sol-gel, combustion, and chemical vapor deposition. Recent research on phosphors doped with rare earth elements to achieve tunable color emissions for LEDs is summarized. Future challenges and opportunities for lighting technology are also outlined.
1) The document discusses fractionating lignin samples through precipitation and re-dissolution processes to extract high molecular weight fractions suitable for producing graphene nano platelets (GnPs). 2) Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used to analyze changes to the lignin samples after fractionation and acid washing to remove sulfur. 3) The results showed solvent fractionation can effectively extract high molecular weight lignin fractions, and acid washing can remove some sulfur bonded to hydrogen in lignin.
This document reports on a study investigating the influence of sodium carboxymethylcellulose (NaCMC) on the aggregation behavior of aqueous solutions of 1-hexadecyl-3-methylimidazolium chloride (C16MeImCl), a cationic surface active ionic liquid (SAIL). Electrical conductivity and surface tension measurements were used to study C16MeImCl aggregation in the presence of NaCMC. Two characteristic concentrations were identified before free C16MeImCl micelles form: the critical aggregation concentration and the polymer saturation concentration. The effects of temperature, NaCMC concentration, and NaCMC charge density on C16MeImCl self-aggregation were analyzed. Thermodynamic parameters of C16MeImCl mic
This document summarizes a study that analyzed the structural characterization of gamma irradiated poly-(diamino naphthalene) doped poly-(vinyl alcohol) films. The researchers irradiated film samples with different doses and dose rates of gamma radiation and then used X-ray diffraction to analyze changes in crystallinity, peak intensity and width, and domain size before and after irradiation. The results showed that gamma irradiation increased crystallinity, caused peaks to become sharper and shift to lower degrees, occur at higher intensities, and increased domain size. This indicates that gamma irradiation induced cross-linking and formation of helical structures in the polymer films.
Interaction of Components in Molecular Optoelectronics for the Next Generati...Scientific Review SR
The interaction of molecular optoelectronic components on the molecular scale were studied where
the solvent shell indicating the influence of the medium was found to be surprisingly small. The transport of
energy as resonant energy transfer covers distances of about 5 nm and was shown not to proceed by a simple to
dipole dipole interaction with typical restrictions, but by a more complex mechanism. Furthermore, a novel -type of
far-reaching interactions of electronically excited structures until macroscopic dimensions were fond and may be
applied for addressing molecular structures by conventional electronics
IRJET- A Study on Dye Sensitized Solar Cell from 2-Naphthalehyde Dye as Sensi...IRJET Journal
The document summarizes a study on dye sensitized solar cells that use 2-naphthaldehyde dye as the sensitizer. Key points:
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2) The efficiency of cells using the synthesized 2-naphthaldehyde dye and its polymer derivative were tested and compared to using 2-naphthol as the starting material. The polymer dye showed the highest efficiency of 0.266%.
3) Characterization of
Final Photocatalysis Lab Report (1) (1)Henry Hsieh
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This document analyzes the absorption properties and I-V characterization of a dye sensitized solar cell using a natural Ruthenium dye extracted from fruits. Anees Ur Rehman et al. fabricated a DSSC using Ruthenium dye extracted from fruits as a sensitizer on a titanium dioxide layer. They measured the cell's short circuit current, open circuit voltage, fill factor, and efficiency, finding values of 11.52 mA/cm2, 0.70V, 0.61, and 4.47% respectively under 110 mW/cm2 illumination. The dye was found to absorb visible light well and support electron transfer at the semiconductor interface, demonstrating the potential of natural dyes as lower-
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This study evaluated the effect of different light curing units and use of chemical catalysts on the degree of conversion of two dual-cured resin luting cements, RelyX ARC and Panavia F. Sixty disk-shaped specimens of each cement were cured with an argon ion laser, LED, or halogen light through a composite disk. The degree of conversion was measured using FTIR spectroscopy. Panavia F without catalyst cured with LED or laser showed significantly lower conversion than other groups. RelyX ARC showed similar high conversion with all light sources and use of catalyst. To achieve satisfactory conversion, Panavia F requires use of chemical catalyst and halogen light.
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2. The copper-catalyzed azide-alkyne cycloaddition, or CuAAC, is a prototypical click reaction that is highly favorable thermodynamically and kinetically. It has found numerous applications in material science, including in adhesives, propellant binders, polymer modification, and surface functionalization of nanoparticles.
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Similar to SULI_Summer_2016_Research Paper_Ainslie_Kenneth (20)
1. 1
Improving Performance of Photopolymer Resins Through
Oxygen Desensitization
Kenneth Ainslie
U.S. Department of Energy Office of Science, Science Undergraduate Laboratory Internship
(SULI)
California Polytechnic State University, San Luis Obispo
Lawrence Berkeley National Laboratory
Berkeley, California
August 5, 2016
Prepared in partial fulfillment of the requirements of the U.S. Department of Energy Office of
Science, Science Undergraduate Laboratory Internship (SULI) under the direction of Raymond
Weitekamp and Aditya Balasubramanian in the Material Science Division at Lawrence Berkeley
National Laboratory
2. 2
INTRODUCTION
Photo-functional resins and photopolymers are crucial components in 3D lithographic
fabrication. Resins are the final building material for 3D printing systems such as direct light
projection (DLP) and stereolithography (SLA).1
Though current resins in commercial use have
low oxophilicity, they lack the chemical and mechanical integrity to be functional components of
a mechanical or thermal system. Commonly used 3D printing resins form highly cross-linked
brittle structures utilizing a free radical mechanism. Once this reaction initiates radical formation,
it is no longer sensitive to oxygen and successfully undergoes chain growth polymerization.2
The
resulting polymeric structures are brittle and only suitable for prototyping rather than direct mass
manufacturing of a product.
Production of higher toughness, 3D printable components requires a different mechanism
of chain growth and cross-linking. One such way of photopolymerization utilizes olefin
metathesis reactions. The polymerization method studied in this work is photolithographic-based
olefin metathesis polymerization (PLOMP).3
This new photo-functional process operates by UV
excitation of ruthenium based Grubb’s catalyst (FIG. 1). The catalyst initiates polymerization of
cyclic olefin monomers (e.g., dicyclopentadiene (DCPD)) to form cyclic olefin polymers
(COPs). COPs are a class of cross-linked, tough, heat resistant, and chemically inert thermoset
polymers typically used in specialty resins.4
However, the metallic center in the catalyst is
readily oxidized in ambient conditions, and once this occurs the catalyst is exhausted and the
polymer can no longer polymerize.5,6
ABSTRACT
Photolithographic-based olefin metathesis polymerization (PLOMP) has shown promise in the
additive manufacturing industry due to its ability to produce polymers with exceptional
mechanical behavior and functional group tolerances [Note: the resulting polymer has the
exceptional mechanical behavior, not the polymerization process]. The major drawback of
polymer resins used in PLOMP is catalyst decomposition due to oxygen in ambient
environments. In this study, the impact of visco enhancers and antioxidants as oxygen-
protective species on the ambient resin performance was analyzed. Raman spectroscopy
analysis indicates that increasing the viscosity by 30x improves the ambient life span of the
material by more than two orders of magnitude. The introduction of an antioxidant improved
performance at low loadings of 0.1 - 0.2 wt. % 4-methoxyphenol (MEHQ) by 9x.
FIG. 1 – PLOMP mechanism. The catalyst performs a photo-activated ring-opening metathesis polymerization (ROMP)
when excited by UV light. The reaction above is what builds the poly(DCPD) chains while cross-linking occurs through the
thermal energy generated during PLOMP.
3. 3
The desired outcome of the project is to desensitize PLOMP resins to oxygen in ambient
atmospheres, thereby enhancing the scope of applications for PLOMP resins in manufacturing.
In this study, the extreme oxygen sensitivity of the resin was addressed using chemical and
physical modifications to the resin system. The resin was modified in two different ways:
increasing viscosity (physical barrier) and implementation of antioxidants (chemical radical
scavengers). Increased viscosity was achieved through the addition of long chain entangled
polymers. The increase in viscosity slows the diffusion of oxygen through DCPD and ultimately
reduces the number of interactions between the catalyst and oxygen. Antioxidants react with
oxygen radicals to make non-reactive product. To test the efficacy of these modifications, a
series of experiments were conducted that measured the amount of time the resin could be
exposed to ambient conditions before the PLOMP resins no longer polymerized.
MATERIALS AND METHODS
Preparation of Resist Samples: Resins with latent catalyst were prepared by first synthesizing the
modified Grubb’s ruthenium catalyst according to Weitekamp3
under inert N2 conditions. 0.25
wt/v. % of the antioxidant 4-methoxyphenol (MEHQ) was added to degassed DCPD monomer
resin and mixed until homogenous.3
The resin was then pumped into a quasi-inert environment
of low purity N2, and latent catalyst in chloroform was pipetted into the resin mixture and mixed
thoroughly to make the resin photosensitive. The resist was shielded from light during the entire
process. 2 ml of resin were pipetted into 4 ml vials while in the quasi-inert atmosphere so that
each vial could be opened at a specific time during tests. The vial opened at time zero served as
the control during the viscosity series and air exposure studies.
Antioxidant Studies: Four different types of antioxidants were purchased from Sigma-Aldrich.
The antioxidants included were 4-methoxyphenol (MEHQ), 4,4′-methylenebis(2,6-di-tert-
butylphenol) (Ethanox ® 702), Tris(2,4-di-tert-butylphenyl) phosphite (Irgafos®
168), and l,3,5-
trimethyl-2,4,6-tris (3,5-di-tert- butyl-4-hydroxybenzyl) benzene (Ethanox®
330). The basis for
selecting these complexes can be found in discussion. Various antioxidant loadings were added
to DCPD for testing (Table I).
Table I – Antioxidant Loadings
Antioxidant Weight/Volume %
MEHQ 0.25 (Control)
702 0.3, 3.0a
330 0.3, 3.0a
168 0.3 ,3.0a
a
from patent: Giardello, Michael A. et al. “Polyolefin compositions having variable density and methods for their
production and use.” U.S. Patent 6,525,125.25 February 2003.
Visco enhancer Studies: Polystyrene-block-polyisoprene-block-polystyrene (PSPIPS) was
chosen as the visco enhancer. PSPIPS loadings ranged from 0 to 10 wt/v. % and were exposed to
air for 0, 2, and 60 minute increments (t=0 was irradiated by UV light within a glove box). The
loading that performed the best was examined under longer air exposure times of up to 4 hours.
4. 4
All visco enhancer solutions included 0.25 wt/v. % MEHQ for comparison to the current
formulation.
Viscosity Measurement: The viscosity of each type of resist was measured using the Brookfield
DV1 Viscometer in order to quantify the increase in viscosity with respect to 100% DCPD
monomer resin. Sample volumes were 6.7 ml following Brookfield guidelines for spindle SC-18
at 10-100 rpm for 1 minute. Each sample was tested thrice (n = 3) and viscosity measurements
were averaged.
UV Exposure: Two fixed plates were aligned as described by Vuorio7
to ensure a constant
distance between the sample and the light source. A 405 nm UV LED was used for irradiation
(FIG. 2). 300 μl of resin was pipetted into a 400 μl well, and 2 wells were exposed (n = 2) to UV
light for each time period. The 300 μl resin volume was used to prevent over-filling of the well,
which would lead to a curved resin surface of varying distance from the light source. To reduce
the possibility of resistive heating by the UV light source, a low power intensity of 22 mW/cm2
was used. This power intensity is the same value used in the DLP printer.8
The LED light source
was calibrated to 22 mW/cm2
± 2.0 mW/cm2
using Thorlabs’ digital optical power meter
console. Four measurements were made within a 1 cm2
area of the well location. A calibration of
the LED was done each day that an exposure test was conducted in order to account for day-to-
day LED power variation.
Prior to UV irradiation, the resin was exposed to air for 0, 2, or 60 minute periods. Resins
that showed greater stability were exposed to air for extended times of 2-4 hours. The vial of
resin opened at time zero remained within a glove box and was irradiated by UV light under the
flow of N2 (15 psi) in a 300 liter glove box. Oxygen levels in the glove boxes ranged from 100-
180 ppm during tests. The irradiance time for each sample was 4 minutes for a total energy input
of 5280 mJ. To prevent further PLOMP reactions, the well plates were placed into a dark box
immediately after exposure and covered with aluminum foil.
FIG. 2 – Three UV LEDs were fixed to the top aluminum plate, while the bottom plate held the PLOMP samples at
a constant distance from the bulbs to ensure repeatable irradiance levels.
Raman Spectroscopy: Raman spectroscopy was used to quantitatively measure the monomer
conversion percent (α) to a cross-linked polymer. The fraction of monomer converted was
calculated as the ratio of the sum of the areas under the peak norbornene and cyclopentene olefin
peaks to the area under the aliphatic cis and trans olefin peaks (FIG. 3). A total of ten α
Well plate
LED
5. 5
measurements were made for each type of resin. Each well was measured once at five different
depths from the surface of the sample. The lowest measurement was 500 μm form the surface.
FIG. 3 – Raman spectra of a characteristic PLOMP sample that has partial monomer conversion (55%). The higher
the intensity of the pDCPD peaks the more conversion there was during PLOMP and post processing.
RESULTS
Influence of Antioxidants
MEHQ proved to be the most effective oxygen scavenger of the 4 antioxidants analyzed
within a quasi-inert N2 atmosphere (FIG. 4). All antioxidant comparison tests were done in a
quasi-inert N2 atmosphere with low levels of oxygen (< 200 ppm) present.
FIG. 4 – MEHQ antioxidant performs the best among the 4 antioxidants studied in protecting the catalyst
from oxygen in solution and in air.
160 ± 21 ppm O2
pDCPD
DCPD
6. 6
0.25 wt/v. % MEHQ improves the performance of the PLOMP resins by ~ 8 times
compared to the control. 3.0 wt./v. % Ethanox®
702 marginally improves resin resistance to
oxygen by 1.3 times. The other antioxidants tested performed worse than the control indicating
they hindered PLOMP through chemical pathways. Since MEHQ performed the best out of the
antioxidants tested, a concentration series was performed to identify optimal MEHQ loading
(FIG. 5). Loadings between 0.05 wt/v. % and 0.4 wt/v. % MEHQ were tested.
FIG. 5 – Monomer conversion percentages from MEHQ concentration series show a maximum around 0.1 wt/v. %
MEHQ.
Raman spectra showed a higher α at lower concentrations of MEHQ. The optimal
concentration of MEHQ is likely to be between 0.1 and 0.2 wt/v. %, with α decreasing at lower
concentrations. This improved the resin conversion, within a low purity N2 atmosphere, by 9
times compared to a control in the quasi-inert testing environment.
Influence of viscosity
An increase in air stability with increase in viscosity is indicated by the lack of change in
α with extended periods of air exposure. α remains constant after 1 hour air exposure with 10
wt/v. % PSPIPS loading (FIG. 6) while the pure DCPD sample exhibits a change from 58% ±
1% to 26% ± 2% monomeric conversion. The 10 wt/v. % PSPIPS resin was tested at up to 4
hours of air exposure with relatively little change in α (25% ± 2% to 16% ± 2%) compared to
standard DCPD resins (54% ± 2% to 12% ± 2%) (FIG. 7). The 10% PSPIPS resin also solidified
at a lower value of α (40%) than observed in the pure DCPD resin. This resulted in a soft
elastomer that was observed to return to its original shape after deformation by hand.
156 ± 32 ppm O2
7. 7
FIG. 6 – Increasing viscosity decreases the maximum possible monomer conversion, likely due to the PSPIPS
slowing down the interaction between the catalyst and DCPD. All samples contain 0.25 wt/v. % MEHQ.
FIG. 7 – 10 wt/v. % PSPIPS resin maintains a relatively steady level of monomer conversion over 4 hours in an
ambient atmosphere.
To reveal the extent of improvement in resin oxygen-desensitization with increased
viscosity, the negative chemical influence of PSPIPS on inhibiting PLOMP reaction was
decoupled from the improvement in viscosity. This was accomplished by normalizing α to the
monomer conversion control (αₒ) (FIG. 8). We used time t80 at α / αₒ = 0.8αₒ as an arbitrary
figure of merit to measure the improvement due to viscosity. The high viscosity resins have t80 >
200 min compared to standard PLOMP resins that had t80 < 2 min. Thus, an increase in viscosity
from 5-150 cP increases the air stability of the resin by two orders of magnitude.
0 2.5 5 7.5 10
PSPIPS wt/v. %
Control in low purity N
2
(145 ± 26 ppm)
1 hour in air
0.25 wt.% MEHQ
10 wt.% PSPIPS,
0.25 wt.% MEHQ
8. 8
FIG. 8 – The MEHQ control samples show a drastic non-linear decrease in monomer conversion over just 1 hour of
exposure to air while the higher viscosity resin decays more linearly with a smaller slope.
DISCUSSION
Our findings indicate that increasing viscosity helps mitigate the degradation of the resin
likely by lowering the diffusivity of oxygen into the resin. Furthermore, this study demonstrates
that the antioxidant MEHQ was the most effective at scavenging oxygen radicals out of the four
antioxidants examined. A trend of slower α decay by increasing visco enhancer concentration
displayed varying degrees of stability at higher viscosities (> 70 cP). Lower loadings of MEHQ
(0.1-0.2 wt/v. %) appear to be optimal for PLOMP processes.
The antioxidants prevent interaction between the catalyst and oxygen through either
hindering a primary or secondary mechanism of oxidation (FIG. 9). Hindered phenols are
primary antioxidants, meaning they are oxygen radical scavengers. Oxygen radicals react with
the phenols, which inhibit oxidation by chain terminating reactions. The three primary
antioxidants in this study were Ethanox®
702, Ethanox®
330, and MEHQ. Both the Ethanox
antioxidants have been used in thermal curing processes to prevent polymer degradation,
especially in DCPD based resins.9
Organophosphorous compounds such as phosphites are
secondary antioxidants. Secondary antioxidants decompose hydroperoxides into non-radical,
non-reactive, and thermally stable products. The secondary antioxidant Irgafos®
168 was chosen
for oxidation reactions that would occur during post-bake steps following initial UV curing.10
0.8αₒ
9. 9
a b
c d
FIG. 9 – Antioxidant complexes (a) 4-Methoxyphenol (MEHQ). (b) 4,4′-Methylenebis(2,6-di-tert-butylphenol)
(Ethanox ® 702). (c)Tris(2,4-di-tert-butylphenyl) phosphite (Irgafos® 168. (d) l,3,5-trimethyl-2,4,6-tris (3,5-di-tert-
butyl-4-hydroxybenzyl) benzene (Ethanox® 330).
Surprisingly, none of the three alternate antioxidants that we chose for this study
outperformed MEHQ. The Ethanox®
702 was patented as an antioxidant for DCPD but still
substantially underperformed compared to MEHQ. The Ethanox®
330 and Irgafos®
168
antioxidants seemed to perform worse than the control sample. A possible explanation for the
poor performance is the alternate antioxidants were patented for use in thermal polymerization
processes where a catalyst would not necessarily be present. This could mean that all three
possibly reacted with the PLOMP catalyst in a negative manner.
Higher viscosity PLOMP resins perform better under ambient conditions over longer
periods of time. Due to its high molecular weight (> 30,000), long chain structure, ability to
dissolve high loadings (up to 20 wt/v. %) in DCPD, and low reactivity with the catalyst, PSPIPS
was chosen as the visco enhancer. From Figure 6 there seems to be a significant change in slope
between 5 wt/v. % and 7.5 wt/v. % PSPIPS (38-75 cP) where the higher loading of PSPIPS
significantly slows down PLOMP leading to a lower α. Looking at Figure 8, the higher viscosity
resin decays much slower suggesting oxygen is diffusing slower. This observation is supported
by one-dimensional diffusion models of oxygen diffusing into DCPD that predicts oxygen
diffusion at extended time scales (in comparison with the time scale of our study) (Eqn. 1).
Combining Stokes-Einstein equation with the generalized form of Fick’s 2nd
Law shows a linear
relationship between diffusion time and viscosity.
𝑡 =
𝑁𝐴6𝜋𝑎
4𝑅𝑇
𝐿2
𝜂
(1)
10. 10
where
𝑁𝐴6𝜋𝑎
4𝑅𝑇
𝜂 = 𝐷−1
D = diffusivity
η = viscosity
a = radius of diffusing molecule
NA = Avogadro’s Number
R = universal gas constant
T = temperature
L = diffusion distance
t = time to diffuse a distance L
A working theory on how the PSPIPS increases viscosity of the resin is by entangling
long chains together which impede the diffusion of oxygen. Entangling could occur through
homogenizing DCPD and PSPIPS together where the individual PSPIPS chains entangle with
each other through mixing (FIG. 10).
FIG. 10 - PSPIPS entangled with itself and isolating DCPD monomer and catalyst from oxygen. Increased amount
of PSPIPS should increase viscosity more by further entangling itself. Photo credit to Wang.11
Variations in α from sample to sample could be due to slight changes in temperature,
which would have a substantial impact on the PLOMP process in both approaches. Another
source of error could be due to variations in the power output of the UV LEDs, which degrade
over time and decrease irradiance.
CONCLUSIONS
A combination of higher viscosities and radical-scavenging antioxidants improves PLOMP
performance in ambient conditions over extended periods of time. Replacing PSPIPS with cross-
linkable moieties will increase the initial monomer conversion of high viscosity resins. These are
general methods that can be used in many photopolymer liquids sensitive to gaseous impurities.
By implementing these methods, the resins may retain their functionality over longer periods of
time in ambient conditions.
11. 11
ACKNOWLEDGMENTS
This work was supported in part by the U.S. Department of Energy, Office of Science, Office of
Workforce Development for Teachers and Scientists (WDTS) under the Science Undergraduate
Laboratory Internship (SULI) program. Thank you to the polySpectra team: Aditya
Balasubramanian, Coleman Rainey, Corinne Allen, and Raymond Weitekamp. Also thank you to
Jean Lee for the use of her time and resources in this study. Thank you to the Molecular Foundry
staff especially Teresa Chen, Tevye Kuykendall, and Tracy Mattox. This work was also
supported by Cyclotron Road and Lawrence Berkeley National Laboratory.
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