scholarly journals Effect of Cationic Photoinitiator on the Polymerization Kinetics of Vinyl Ether Monomers

2020 ◽  
pp. 48-53
Author(s):  
Tran Nhung Hien Phuong ◽  
Pham Thi Kim Hue ◽  
Luu Bach Hiep ◽  
Hoang Thi Kieu Nguyen
Keyword(s):  
Cationic Polymerization ◽  
Uv Light ◽  
Polymerization Rate ◽  
Conversion Degree ◽  
Emission Characteristics ◽  
Vinyl Monomers ◽  
Curing Process ◽  
Free Radical Photopolymerization ◽  
Acrylic Monomers ◽  
Kinetics Of

In this study, the performance of a new triarylsulfonium photoinitiators in the initiation of cationic polymerization of vinyl monomers was investigated by infrared spectroscopy (IR). The photoinitiator exhibit absorption characteristics compatible with the emission characteristics of medium pressure mercury lamps, which are the main sources of UV light in the industry. The experimental results indicate that the photoinitiator is most effective at a concentration of 1%. At the investigated conditions, the maximal conversion degree is 77.8% and the polymerization rate is 0.56 s-1. The curing process is even faster than the corresponding free-radical photopolymerization of acrylic monomers

scholarly journals Concurrent Modelling and Experimental Investigation of Material Properties and Geometries Produced by Projection Microstereolithography

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 506 ◽  
Author(s):  
Khaled G. Mostafa ◽  
Muhammad Arshad ◽  
Aman Ullah ◽  
David S. Nobes ◽  
Ahmed Jawad Qureshi
Keyword(s):  
Material Properties ◽  
Uv Light ◽  
Light Exposure ◽  
Geometry Optimization ◽  
Solid Polymer ◽  
Curing Process ◽  
Geometrical Accuracy ◽  
Free Radical Photopolymerization ◽  
Projection Microstereolithography ◽  
Light Absorbance

Projection microstereolithography additive manufacturing (PµSLA-AM) systems utilize free radical photopolymerization to selectively transform liquid resins into accurate and complex, shaped, solid parts upon UV light exposure. The material properties are coupled with geometrical accuracy, implying that optimizing one response will affect the other. Material properties can be enhanced by the post-curing process, while geometry is controlled during manufacturing. This paper uses designed experiments and analytical curing models concurrently to investigate the effects of process parameters on the green material properties (after manufacturing and before applying post curing), and the geometrical accuracy of the manufactured parts. It also presents a novel accumulated energy model that considers the light absorbance of the liquid resin and solid polymer. An essential definition, named the irradiance affected zone (IAZ), is introduced to estimate the accumulated energy for each layer and to assess the feasibility of the geometries. Innovative methodologies are used to minimize the effect of irradiance irregularities on the responses and to characterize the light absorbance of liquid and cured resin. Analogous to the working curve, an empirical model is proposed to define the critical energies required to start developing the different material properties. The results of this study can be used to develop an appropriate curing scheme, to approximate an initial solution and to define constraints for projection microstereolithography geometry optimization algorithms.

Kinetic Study on Photopolymerization of TPGDA under Containerless Condition

2012 ◽  
Vol 249-250 ◽  
pp. 828-832
Author(s):  
He Peng Zhang ◽  
Qiu Yu Zhang ◽  
Jin Bo Dou ◽  
Shu Xu
Keyword(s):  
Kinetic Study ◽  
Significant Role ◽  
Normal Condition ◽  
Uv Light ◽  
Polymerization Rate ◽  
Acoustic Levitation ◽  
Oxygen Inhibition ◽  
Final Conversion ◽  
Polymerization System ◽  
Kinetics Of

The TPGDA drop was suspended in the atmosphere under acoustic levitation and induced by photoinitiation for polymer preparation at the first attempt. The kinetics of TPGDA photopolymerization induced by the UV light under containerless condition was studied. Compared to the normal condition, the average initial polymerization rate of TPGDA under acoustic levitation is relatively lower, while the final conversion is higher. Relative to oxygen inhibition, container effect plays a more significant role on the conversion in this polymerization system.

Kinetics of Alkyllithium Initiated Polymerizations

1970 ◽  
Vol 43 (1) ◽  
pp. 22-73 ◽  
Author(s):  
H. L. Hsieh ◽  
W. H. Glaze
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Propagation Rate ◽  
Polymerization Rate ◽  
Vinyl Monomers ◽  
Polar Solvents ◽  
Organolithium Compounds ◽  
Rate Of Polymerization ◽  
Kinetics Of

Abstract The kinetics of alkyllithium initiated polymerizations is reviewed for publication in Rubber Reviews for 1970. It contains nine sections: introduction, the structure of organolithium compounds, rate of polymerization, rate of propagation, rate of initiation, molecular weight and molecular weight distribution, polymerization of diene and vinyl monomers in polar solvents, copolymerizations, and polymerizations of polar monomers. A total of 205 references are cited.

The effect of electrondonors on the polymerization kinetics of isoprene

1980 ◽  
Vol 45 (12) ◽  
pp. 3338-3346
Author(s):  
Miroslav Kašpar ◽  
Jiří Trekoval
Keyword(s):  
Induction Period ◽  
Ethyl Ether ◽  
Reaction Order ◽  
Propagation Rate ◽  
Reaction Scheme ◽  
Polymerization Kinetics ◽  
Polymerization Rate ◽  
Constant Concentration ◽  
Initial Concentration ◽  
Kinetics Of

The effect of small additions of 1-octene, butyl ethyl ether and triethylamine on the polymerization kinetics of isoprene (2-methyl-1,3-butadiene) in benzene initiated with butyllithium was investigated by employing the GLC analysis. The addition of 1-octane was reflected only in a shorter induction period of the reaction; the effect on the propagation rate was insignificant. With the increasing amount of butyl ethyl ether, the polymerization rate increases linearly, while the reaction order with respect to the concentration of triethylamine is variable and increases from 0.33 to 0.66 with the increasing concentration of the initiator. For a constant concentration of triethylamine, the reaction order with respect to the initial concentration of the initiator was found to vary considerably, reaching even negative values. A reaction scheme was suggested, taking into account the competition between two different solvates of alkyllithium.

Living cationic polymerization of vinyl monomers by organoaluminum halides

1987 ◽  
Vol 18 (2) ◽  
Author(s):  
Toshinobu Higashimura ◽  
Yasuhisa Kishimoto ◽  
Sadahito Aoshima
Keyword(s):  
Cationic Polymerization ◽  
Vinyl Monomers ◽  
Living Cationic Polymerization

Photocatalysis of Coomassie Brilliant Blue Using Clay Mineral

2016 ◽  
Vol 869 ◽  
pp. 765-767 ◽  
Author(s):  
Layane Rodrigues Almeida ◽  
João Sammy Nery Souza ◽  
Edson Cavalcanti Silva Filho ◽  
Josy Anteveli Osajima
Keyword(s):  
Organic Pollutants ◽  
Uv Light ◽  
Brilliant Blue ◽  
Blue Dye ◽  
Secondary Treatment ◽  
Toxic Compounds ◽  
Coomassie Brilliant Blue ◽  
Kinetics Of ◽  
Coomassie Brilliant ◽  
Photocatalytic Processes

The presence of organic pollutants, which cannot be eliminated by conventional processes of primary and secondary treatment, can be problematic. Photocatalytic processes offer an efficient breakdown of organic pollutants into non-toxic compounds such as CO2 and H2O. This paper proposes the use of the titanium dioxide embedded in palygorskite as a photoactive material in the degradation of cationic dye, Coomassie Brilliant Blue. The system was irradiated using UV light for a maximum time of 120 minutes. The concentration of the dye used was 1.0x10-4 mol L-1 in 0.5 g L-1 of the photoactive material. The kinetics of the system was monitored by UV-Vis spectrophotometry. In 120 minutes of radiation, the process of photocatalysis reduced the initial concentration of the Coomassie Brilliant Blue dye in half.

Kinetics of nonisothermal dehydration of unirradiated and γ-ray irradiated neodymium (III) acetate hydrate

2019 ◽  
Vol 107 (2) ◽  
pp. 165-178
Author(s):  
Noura Mossaed Saleh ◽  
Ghada Adel Mahmoud ◽  
AbdelRahman AbdelMonem Dahy ◽  
Soliman Abdel-Fadeel Soliman ◽  
Refaat Mohamed Mahfouz
Keyword(s):  
Absorbed Dose ◽  
Isoconversional Methods ◽  
Gas Diffusion ◽  
Conversion Degree ◽  
Monoclinic System ◽  
Air Atmosphere ◽  
Dehydration Reactions ◽  
Γ Ray ◽  
Acetate Hydrate ◽  
Kinetics Of

Abstract Kinetics of dehydration of unirradiated and γ-ray irradiated neodymium (III) acetate hydrate with 103 kGy total γ-ray dose absorbed in air atmosphere were studied by isoconversional nonisothermal method. The dehydration proceeds in two steps with the elimination of 0.8 and 0.4 mol of H2O, respectively. This result indicates that the investigated neodymium (III) acetate hydrate contains 1.2 mol of crystalline water in its structure. The dehydration reactions are best described by nucleation (A2 model) and gas diffusion (D4 model) for unirradiated and γ-ray irradiated samples, respectively. Analysis of the kinetic data using linear and nonlinear isoconversional methods showed that the apparent activation energy, Ea (kJ/mol) is dependent on the conversion degree, α, of the dehydration process. The Ea−α plots for both unirradiated and γ-ray irradiated neodymium (III) acetate hydrate showed that the dehydration is a complex process and contains multistep reactions. The results showed that γ-ray irradiation has a significant effect on the kinetics and thermodynamic parameters of the dehydration reaction. Powder X-ray diffraction showed that neodymium (III) acetate hydrate has a monoclinic system (SG P2/m) and no phase transformation was detected by γ-ray irradiation up to 103 kGy absorbed dose. The system maintains the same crystal structure before and after dehydration.

Curing and swelling kinetics of new magnetorheological elastomer based on natural rubber/waste natural rubber gloves composites

2018 ◽  
Vol 51 (7-8) ◽  
pp. 583-602
Author(s):  
Nabil Hayeemasae ◽  
Hanafi Ismail
Keyword(s):  
Natural Rubber ◽  
Material Properties ◽  
Swelling Kinetics ◽  
Curing Process ◽  
Magnetorheological Elastomer ◽  
Rubber Composites ◽  
Rubber Waste ◽  
New Type ◽  
Kinetics Of ◽  
Single Filler

This article proposes a new type of magnetorheological elastomer (MRE) based on natural rubber (NR) and waste natural rubber gloves (wNRg) blends. The material properties of the MRE samples were investigated with specific focus on the curing and swelling kinetics. Two different series were prepared; the first used carbonyl iron (CI) as the single filler in the MRE, whereas the second hybridized CI with carbon black (CB) to prepare an MRE resistant to solvents. The results show that most properties depend strongly on the nature of both fillers. The higher thermal conductivity of the CI caused a substantial decrease in both the scorch and curing times and the activation energy in the curing process. Based on the diffusion study, a higher volume of fillers in the rubber composites resulted in a greater area of blockage and restricted the penetration of the solvent tested throughout the composites, irrespective of whether CI alone or in combination with CB was used in the composites.

Synthesis and Photochromic Properties of 1-(2-methyl-1-phenyl)-2-[2-methyl-5-(4-formylphenyl)-3-thienyl]perfluoroyclopentene

2014 ◽  
Vol 886 ◽  
pp. 183-186
Author(s):  
Xiao Dong Zhang ◽  
Sha Sha Wei ◽  
Shou Zhi Pu
Keyword(s):  
Visible Light ◽  
Uv Light ◽  
Light Irradiation ◽  
Photochromic Properties ◽  
Kinetics Of

An unsymmetrical photochromic diarylethene 1-(2-methyl-1-phenyl)-2-[2-methyl-5-(4-formylphenyl)-3-thienyperfluoroyclopentene (1o) was designed and constructed successfully. Its photochromic properties were examined. The results showed that the compound exhibits good photochromism with UV/Vis light irradiation. The diarylethene 1o changed the color from colorless to blueviolet upon irradiation with 297 nm UV light, in which absorption maxima were observed at 549 and 581nm in hexane and PMMA films, respectively.The photochromic cyclization/cycloreversion kinetics of 1o in hexane were determined by UV-Vis spectra upon alternating irradiation with UV and appropriate wavelength visible light.

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