Cobalt Octoate Research Articles

Sustainable synthesis and characterization of cobalt-based biocatalysts from olive stone waste for enhanced curing of unsaturated polyester resins

The functionalization of native olive wood shell stone for the formation of new active heterogeneous cobalt-based biocatalysts has been conducted. The resulting biocatalysts have been fully characterized using various analytical techniques, including X-ray fluorescence (XRF), elemental analysis, granulometry, X-ray photoelectron spectroscopy (XPS), Fourier-Transform Infrared Spectroscopy (FTIR), thermogravimetry (TGA), moisture content, field-emission scanning electron microscopy (FESEM) and high-angle annular dark-field imaging (HAADF) with energy dispersive X-ray spectroscopy (EDX). The catalytic performance of these new functional heterogeneous materials has been verified by gelation time measurements on a multipurpose unsaturated polyester/styrene/tert-butyl peroxybenzoate system. The results are compared with those obtained using the current workhorse of the industry, which utilizes cobalt-based catalysts, particularly cobalt octoate dissolved in a solvent solution known to have adverse environmental and human health implications.

Thermal and mechanical analysis of the influence of changing the amount of cobalt octoate accelerator in isophthalic polyester resin

The importance of searching for more efficient and cost-effective polymeric materials with potential applications in various industries has led this research to investigate the influence of varying the amount of cobalt octoate in the production of isophthalic polyester resin, examining both the thermal behaviour and mechanical properties of these materials. The primary objective is to understand how the concentration of cobalt octoate mechanically and thermally affects the resin curing process. Experiments were conducted involving the production of isophthalic polyester resins with different concentrations of cobalt octoate (0.5%, 1.0%, and 1.5%). The curing time, temperature, and mechanical strength of the resulting materials were monitored. Statistical analyses were also carried out to assess the relationship between these variables. Based on the analyses conducted, it was observed that increasing the accelerator's quantity did not prove effective in linearly accelerating the curing process. It was also observed that a higher temperature during the curing process could result in superior mechanical strength of this material. Additionally, it was revealed that higher concentrations of octoate resulted in thinner test specimens due to volumetric contraction during the curing process. Furthermore, it was noticed that greater mechanical strength was achieved with the lower concentration of cobalt octoate (0.5%) at a higher temperature, demonstrating that optimising the concentration of cobalt octoate can result in materials with better mechanical performance and lower production costs. Therefore, this research provides valuable insights into how the amount of cobalt octoate influences the thermal and mechanical properties of isophthalic polyester resins, emphasising, above all, the importance of finding a precise balance between the accelerator's concentration, curing temperature, and the final properties of the material.

Production of SBS Reinforced Polyester Composite: Characterization of Physical and Chemical Properties

In this study, dissolved styrene butadiene styrene (SBS) copolymer is homogeneously reinforced into orthophthalic unsaturated polyester (UP) resin. Polyester composite production is carried out with the help of methyl ethyl ketone peroxide (MEKP) and cobalt octoate (Co Oc) catalysts. The density, Shore D hardness, thermal conductivity coefficient, thermal stability, morphological surface structure, and chemical bond structure of the obtained composite have been examined. According to the results, SBS reinforcement decreases the density of the composite and increases the thermal conductivity coefficient. The addition of SBS at different weight ratios (1%, 3%, 5%, 7%, and 10% w/w) reduces both the hardness and thermal stability of the polyester composite. According to the test and analysis results, 5 wt.% SBS reinforced polyester composite production is determined as the optimum ratio. 7 wt.% and above SBS reinforcement negatively affect the physical and chemical properties of the obtained composite. For example, when 10 wt.% SBS reinforced composite is examined by scanning electron microscope (SEM), and irregular pores are observed in the surface morphology. Also, it is understood by Fourier transform infrared spectroscopy (FTIR) that there is a physical interaction between SBS and polyester and that no chemical bond is formed. The thermal decomposition behavior of the composite has been determined according to the decrease in the activation energy. As SBS ratio increases, it is understood that the thermal stability of the product obtained with the decrease in the activation energy of the polyester composite weakens.

Gamma radiation shielding properties for polymer composites reinforced with bismuth tungstate in different proportions

In this study, inorganic compound (Bi2(WO4)3) was added into the composite to improve the radiation shielding properties of polymer composite. A polymer matrix was prepared by combining unsaturated polyester resin with methyl ethyl ketone peroxide and cobalt octoate (6%), and Bi2(WO4)3 was added to this polymer matrix at different ratios as filling material. In order to investigate the gamma radiation attenuation properties of the obtained polymer composites, mass attenuation coefficients, radiation shielding efficiencies, radiation transmission factors, linear attenuation coefficients, half values layer, tenth values layer, mean free path values, effective atomic numbers and effective electron densities parameters were obtained. Experimental studies were carried out with the help of HPGe detector at 22 different energies emitted from 22Na, 54Mn, 57Co, 60Co, 133Ba, 137Cs, 152Eu and 241Am radioactive sources in the photon energy range of 59.5–1408.0 keV. Each obtained experimental result was compared with the theoretical results. It was observed that the sample encoded with BiWO20 is the best radiation shielding material among all studied composites (except 59.5 keV).

Coordination Compound (2,3,5-Triphenyltetrazolium)2[CuBr4] as Catalyst for the Curing Process of Epoxy Vinyl Ester Binders.

This article presents a study on the synthesis and catalytic properties of copper complex (TPhTz)2[CuBr4] (here TPhTz is 2,3,5-triphenyltetrazolium). The obtained complex was characterized by various spectroscopic methods. The catalytic properties of the complex were evaluated in the curing of an epoxy vinyl ester system and their effectiveness was compared with that of cobalt octoate (its synonyms are known as Co(Oct)2, cobalt(II) 2-ethylhexanoate, cobalt isocaprylate, etc.). The catalyst was added at an amount of 2 w.%. The results showed that a 8 w.% solution of the complex provides catalytic properties with an activation energy of 54.7 kJ/mol, which is 25.2 kJ/mol higher than a standard curing system with Co(Oct)2. Thus, the solution of (TPhTz)2[CuBr4] in THF/DMSO accelerates the initiator decay process at room temperature, but for a longer time. The authors suggest that the curing mechanism may be accelerated by the appearance of (TPhTz)2[CuIBr3] and free bromine in the system. A strength test of fiberglass-reinforced plastic revealed that the addition of this complex did not lead to a decrease in flexural strength and hardness. Thus, use of the complex allowed for the production of polymer composite products using vacuum-assisted resin transfer molding where an extended injection time was needed.

Pektin Takviyeli Polyester Kompozit Elde Edilmesi ve Termofiziksel Özelliklerinin İncelenmesi

In this study, pectin powder is mixed homogeneously in unsaturated polyester (UP). For the production of polyester composite, methyl ethyl ketone peroxide (MEKP) and cobalt octoate (Co Oc) are added to the mixture. The obtained composite is poured into standard molds as a gel and allowed to cure for 24 hours. Some physical and chemical properties of the composite are determined and characterization processes are carried out. Density, Shore D hardness, thermal conductivity coefficient, and thermal stability of polyester composite are examined. According to the results obtained, pectin is used as a filler in the polyester composite. There is no change in the chemical structure of the polyester polymer with Fourier transform infrared (FTIR) spectroscopy. The density of polyester composites decreases as the reinforcement of 0 wt.%, 1 wt.%, 3 wt.%, 5 wt.%, and 7 wt.% pectin powder increases. Besides, the reinforcement of pectin powder as filler reduces Shore D hardness of the polyester composite. However, it has been observed that the thermal conductivity coefficient of the polyester composite increases as the filler ratio rises. In thermal decomposition experiments of the composite, the activation energy decreases slightly as the filler ratio increases. According to the optimization results, 3 wt.% pectin powder supplementation does not adversely affect both the surface morphology and thermophysical properties of the polyester composite.

Investigation of gamma radiation shielding characteristics of bismuth reinforced ternary composites in wide photon energy region

The aim of this study is to evaluate gamma ray shielding properties for bismuth doped barite-based ternary polymer composite materials. In the first stage of the study, a polymer matrix was prepared by combining orthophthalic unsaturated polyester resin (OUP), Methyl Ethyl Ketone Peroxide (MEKP) and Cobalt Octoate (6%) (Co-6). Then, barite and bismuth were added in certain proportions as filler material into this polymer matrix and thus ternary composites were produced. Experimental studies for the produced samples were carried out in narrow beam geometry using HPGe detector and 133Ba, 22Na, 137Cs, 60Co radioactive sources which emit photons between 276.4 and 1332.5 keV energy. To determine the gamma ray shielding properties of the produced ternary composites, radiation protection efficiency (RPE), linear attenuation coefficient (μ), mass attenuation coefficient (μ/ρ), half value layer (HVL), tenth value layer (TVL), mean free path (MFP), effective atomic number (Zeff), effective electron density (NE) parameters were obtained. Experimental results were compared with theoretical results obtained with WinXCOM software and GEANT4 Monte Carlo simulation code. Experimental and theoretical results were found to be compatible with each other. According to obtained results, it was found that the sample with the best shielding property among the prepared samples was BaBi50 coded sample.

Cornus Alba Reinforced Polyester-Epoxy Hybrid Composite Production and Characterization

In this study, ornamental cranberry (Cornus Alba) reinforced hybrid composite is synthesized. The plant leaves have been collected, dried, and ground for composite production. After it is reinforced into unsaturated polyester (UP) at different rates by mass, it is mixed to show a homogeneous distribution. Then, 5 wt.% of the total mixture is added to the epoxy resin and polymerization reactions are started with the help of necessary additives and catalysts. The product obtained is poured into standard molds and after waiting one day for curing, necessary tests are carried out. According to the results obtained, biomass supplementation reduces the density of the hybrid composite. Although the addition of epoxy resin increases the hardness of the composite, the ornamental cranberry supplement reduces Shore D hardness. It is observed that the thermal conductivity coefficient decreases as the ratio of polyester resin in the composite increases. However, both epoxy resin and biomass reinforcement slightly raises the thermal conductivity coefficient. Also, high biomass reinforcement both weakens the mechanical strength of the hybrid composite and negatively affects the surface morphology. In this study, it was determined that the composite obtained by using 88.5 wt.% UP, 3 wt.% Epoxy A, 1.5 wt.% Epoxy B, 5 wt.% biomass, 1.5 wt.% methyl ethyl ketone peroxide (MEKP), and 0.5 wt.% cobalt octoate (Co Oc) showed optimum properties.

Production and Characterization of Waste Corncob Reinforced Polyester Composite

In this study, waste corncobs are ground and used in the polyester composite. Homogeneous distribution is provided by mixing it into unsaturated polyester (UP) as a filler under laboratory conditions. Then, methyl ethyl ketone peroxide (MEKP) and cobalt octoate (Co Oc) catalysts are added to the mixture. After mixing the additives and fillers used in certain amounts for a short time, the polyester composites are poured into standard molds and waited for curing. The density, Shore D hardness, and thermal decomposition behavior of the composite obtained after curing have been investigated. As the amount of corncob in the mixture increases, the density of the polyester composite decreases. Besides, the rise in the ratio of this filler in the mixture also increases the porosity of the polyester composite. In the thermal conductivity measurements, it is seen that the thermal conductivity coefficient of the polyester composite increases, albeit slightly, according to the increasing amount of filler. Also, corncob reinforcement reduces both Shore D hardness and activation energy of the polyester composite. According to the results obtained, it was observed that the use of corncob reinforcement above 3 wt.% negatively affected the surface morphology and mechanical properties of the composite. While obtaining an economical and light polyester composite, attention should be paid to the amount of filler so that both thermal and mechanical properties are not weakened.

Effect of Initiator and Accelerator Amounts on Mechanical Properties of Unsaturated Polyester Resin

This research focused on the effect of initiator and accelerator amounts on mechanical properties of unsaturated polyester resin (UPR). Methyl ethyl ketone peroxide (MEKP) and cobalt octoate (CoO) were used as an initiator and an accelerator, respectively. The amount of each chemical was varied from 1, 1.5 to 2 phr. In each batch, UPR, MEKP and CoO were mixed, casted and allowed for curing at room temperature for 24 hours. Mechanical properties of the cured samples were then studied. The results indicated that the effects of MEKP and CoO amounts on flexural properties and impact resistance were greater than those on hardness. It was found that UPR samples prepared by using the same ratio of MEKP and CoO exhibited overall mechanical properties better that those prepared with different MEKP and CoO ratios. When all mechanical properties were considered, the results suggested that the best overall mechanical properties were achieved when MEKP 1.5 phr and CoO 1.5 phr were employed.

Waste Polyurethane Reinforced Polyester Composite, Production, and Characterization

In this research, new composite materials were improved by reinforcing the environment-polluting waste polyurethane (WPU) to unsaturated polyester (UP). Polyester composites were produced with WPU, UP, methyl ethyl ketone peroxide (MEKP), and cobalt octoate (Co. Oc.). The effect of WPU on the changes in density, Shore D hardness, thermal conductivity coefficient, thermal stability, and porosity of the obtained composites were investigated. According to the findings, as WPU ratio increased in the composite, both the thermal conductivity coefficient and the density of the composite decreased. Shore D hardness was been found to decrease as the rate of WPU in polyester composites raised. The use of optimum WPU ratios (7 wt.%) in composite production improved some thermo-physical properties of polyester composite. The high use of WPU negatively affected both the surface morphology and thermal stability of the polyester composite. In addition, the parameters affecting the production of polyester composites were optimized according to response surface methodology (RSM).

Synthesis and characterization of waste polyethylene reinforced modified castor oil‐based polyester biocomposite

AbstractIn this research, modified castor oil (MCO)‐based biocomposite has been synthesized and its structure is strengthened with waste polyethylene (PE) reinforcement. Both the petrochemical raw material used is reduced by 12 wt% and a new environmentally friendly biocomposite is produced using waste PE. Considering some thermophysical properties of the obtained biocomposite, experimental working conditions, and composition ratios have been optimized with response surface methodology (RSM). The chemical bond structure of the biocomposite has been investigated by Fourier transform infrared spectrophotometer, thermal decomposition behavior by thermogravimetric analysis, and surface morphology by scanning electron microscopy. According to the results obtained, the density and hardness of the biocomposite synthesized by the addition of MCO to unsaturated polyester (UP) decreases, and its thermal conductivity and thermal stability increase. The thermal decomposition kinetics of the biocomposite is also modeled with the newly improved hyperbolic function equation. The relationship between conversion rate and the temperature has been determined by the new model with a high correlation coefficient (R2 = 0.9985) and low‐error functions (SST = 0.0096, RMSE = 0.0285, χ2 = 0.0037). Effective and efficient use of MCO, UP, methyl ethyl ketone peroxide, and cobalt octoate in the production process has provided an economical and steady the biocomposite. Evaluation of experimental data with both RSM and artificial neural networks raises the reliability of the model results.

PRODUCTION AND CHARACTERIZATION OF WASTE MASK REINFORCED POLYESTER COMPOSITE

In this research, waste masks (WM) that pollute the environment have been evaluated in the polyester composite. Some physical and chemical properties of the obtained composite have been characterized. In particular, its density, Shore D hardness, thermal conductivity, thermal stability, and porosity have been determined. Waste masks were collected, disinfect, ground, dried and added into unsaturated polyester (UP) at the rates of 0 %, 2 %, 5 %, 7 %, and 10 % by mass as a filler. Mask wastes were reinforced to the unsaturated polyester in certain proportions and were homogenized thoroughly for 10 minutes at a mixing speed of 1000 rpm. Then, the chemical reaction has been carried out with the help of methyl ethyl ketone peroxide (MEKP) and cobalt octoate (Co Oc) catalysts. The chemical bond structure of the produced polyester composites was determined by Fourier transform infrared spectrophotometer (FTIR). According to the results, both density and Shore D hardness of the composites decreased as the WM ratios in the composites increased. It has been evaluated that the mechanical strength of the polyester composite and porosity raises with increasing WM ratio. The increase in WM by mass in the polyester composite raises thermal conductivity and activation energy.

Ultra-fast self-repairing of anti-corrosive coating based on synergistic effect between cobalt octoate and linseed oil

A new microcapsule was prepared by a facile emulsions process for improving the self-repairing speed of anti-corrosive polymer coating. The microcapsule is based on the cobalt octoate/linseed oil and GO nanosheets, which acts as core and shell. The new microcapsule in polyurethane coating provided the ultra-fast self-repairing speed (ca.5.0 min). The result was attributed to synergistic catalytic curing reaction of linseed oil in presence of cobalt octoate and O2. Furthermore, it also improved their anti-corrosion properties due to the good barrier of the GO nanosheets. The work confirms the formation of anti-corrosive polymer coating with ultra-fast self-repairing performance for various applications.

Investigation of Thermophysical Properties of Polyester Composites Produced with Synthesized MSG and Nano-Alumina

In this study, synthesis of a new compound, 4-[(E)-(5-Bromo-2-hydroxy-3-methoxybenzylidene) amino]-N carbamimidoylbenzenesulfonamide (MSG) has been carried out. The structures of MSG are characterized using spectroscopic methods such as Fourier transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance spectroscopy (NMR). In experimental studies, synthesized MSG has been reinforced with 1 wt.% and 2 wt.% unsaturated polyesters. Besides, 1 wt.% and 2 wt.% alumina nanoparticles, 1.5 wt.% methyl ethyl ketone peroxide (MEKP), and 0.5 wt.% cobalt octoate (Co Oc) were used to produce polyester composites. Although alumina nanoparticles increased the density of the produced polyester composite, MSG supplementation decreased it. While nano-alumina raised Shore D hardness of the polyester composite, synthesized MSG went down it. Both nano-alumina and MSG reinforcement have been increased the porosity in the surface morphology of the polyester composite. Also, nano-alumina reinforcement raised the activation energy of the polyester composite and MSG decreased it. In other words, since the alumina filler raises the activation energy, the thermal stability of the polyester composite has gone up.

Cobalt (II) used as a catalyst to drying properties of healing agents for self-healing coatings / Cobalto (II) utilizado como catalisador de propriedades de secagem de agentes de cura para revestimentos auto-regenerativos

Vegetable oils have been largely used as healing agents for self-healing coatings, which in turn, can recover their physical integrity upon damage due to oil film formation resulted of its oxidative polymerization process. Linseed oil (LO) and chia oil (CO) are able to form films because of their air-drying properties and high polyunsaturated fatty acids content. In this work, drying properties of CO and LO with and without cobalt (II) octoate, as a catalyst for the oxidative polymerization, were quantitatively estimated over time by Fourier-Transform Infrared Spectroscopy (FTIR). The CO drying property showed 47% higher than LO and the catalyst has successfully accelerated the oxidative polymerization of both oils in 95%. Microcapsules containing both pure and catalyzed oils were prepared, mixed into epoxy resin, and applied onto AISI 1020 steel samples. Their healing effect was evaluated through a simulated scratch and submitted to electrochemical tests and imaging.

Production of waste polyethylene terephthalate reinforced biocomposite with RSM design and evaluation of thermophysical properties by ANN

In this study, bio-unsaturated polyester (BUP) raw material is synthesized using modified palm oil (MPO). A new BUP composite has been improved by adding waste polyethylene terephthalate (WPET) to the obtained synthesis. The modified palm oil supplementation decreased the density, Shore D hardness, and elastic modulus of the BUP composite while increasing its thermal conductivity, and thermal stability. WPET filler has been used to decrease the thermal conductivity of the BUP composite, rise its elastic modulus and Shore D hardness.When parameters affecting experimental conditions are optimized using Response Surface Methodology (RSM); BUP (86 wt%), WPET (11.7 wt%), methyl ethyl ketone peroxide (MEKP: 1.6 wt%), cobalt octoate (Co. Oc: 0.7 wt%), and curing time (CT: 24 h) are approximately determined. BUP composite’s density is 1324 kg/m3, Shore D hardness 84, elastic modulus 346 MPa, thermal conductivity 0.048 W/m·K, and activation energy 135 kJ/mol. Also, when the thermophysical properties of the produced BUP composite have been evaluated using experimental data, it gives consistent results in both Artificial Neural Networks (ANN) and RSM method.

Effect of The Filler Type and Particle Distribution Changes on Polyester Matrix Composites

In this study, the effect of the usage of additives at different initiator ratios as well as the usage of fillers of different types and different grain distributions on resin consumption and compressive strength of polyester matrix composites were investigated. Orthophthalic unsaturated polyester resin (UP) was used as a matrix. The initiator (methyl ethyl ketone peroxide) at the ratio of 1.0%, 1.5%, and 2.0% and the accelerator (cobalt octoate) at the ratio of 1.0% by weight was used to start the polymerization. Silica, basalt, and quartz sand were used as the filler type. All fillings used in the study were prepared in the grain size distribution of the American Foundry Society (AFS 40-45) and in the grain size distribution determined by reference to the Fuller equation (F 1.0). Resin consumption and pressure resistances of produced composites were determined, and SEM analyses were carried out. As a result of the study, in all filled composites, the minimum resin consumption was achieved at a starting rate of 1.0%. The highest compressive strength was determined as 130.43 MPa in the basalt filled composite and in the AFS40-45 grain distribution.

Fabrication and Mechanical Characterization of Jute-Coir Reinforced Unsaturated Polyester Resin Hybrid Composites with Various Fiber Size using Compression Moulding Technique

Fiber reinforced composites plays major role in improving the strength of various applications in current trends. Based on these trends the combination of natural jute/coir fiber hybrid composite of different size of fiber length was examined in this study. The hybrid fiber composite was fabricated by compression moulding technique by impregnating jute fiber and coir fiber with unsaturated polyester resin, Cobalt octoate and methyl-ethyl-ketone peroxide as accelerator and catalyst. Then the prepared mould placed into the oven to dry for 4 hrs. at 50°C beneath closely to vacuum condition then convert the cured mould to the hot press initially for 1 hr at 105°C under 84 bar pressure until while squeeze out the excess resin, then it was cooled in cold press under constant pressure of 275 bar pressure for 15 min to prevent the warpage of hybrid composites. The micro hardness, tensile, flexural, impact strength of hybrid composite was carried out and the morphology of the composites was evaluated and compared. The test results of the hybrid composite were analyzed by one way ANOVA analysis technique and it shows significant difference among the groups.

Study of Experimental Investigations in the Presence of Ceramic Waste Powder

The paper aims to evaluate the gel time and exotherm temperature properties of the curing of unsaturated polyester resin at various amounts of Methyl ethyl ketone peroxide, cobalt octoate and porcelain powder. The gel time of samples are determined using the simple method, while the exotherm temperature are evaluated using the thermocouple. The variation of these properties is discussed theoretically and experimentally.