Cobalt Naphthenate Research Articles

The Influence of Chemically Pre-treated Chestnut Waste and Pinecone Filler Content on the Properties of Polyester Composites

There is critical concern about meeting future global demand for materials because of the depletion of natural resources. In particular, the balance between future demand and sustainable supply will require a great deal of attention in years to come. The interest in the long term sustainability of material resources has led to advancements in bio-composite or polymer composite materials that are made from natural fibers and resin. Pinecones and chestnut waste are most often used as the biomass/biochar source. Nature proposes, and man disposes; we have to find or create new forms of pinecone and chestnut waste to increase their value and for environmental reasons. That is why the current waste was processed and transformed to filler in an up-graded state. In this study, composites were manufactured using chestnut waste and pinecone powder as filler and polyester as the polymer matrix. In addition, methyl ethyl ketone peroxide as hardener and cobalt naphthenate as accelerator were used to produce polyester composite. Raw materials of the fillers were treated with sodium hydroxide solution. The polyester amount was kept constant while the filler ratio was increased from 3% to 12% by weight. The similarities and differences between composites with different fillers and chemical pre-treatments were assessed by evaluating certain mechanical properties such as flexural strength, elastic modulus and hardness and various physical features such as density, open porosity percentage and water absorption. According to the experimental results, increasing the ratio of both chestnut and pinecone powder led to a decrease in the bending strength and an increase in the elastic modulus. Higher properties were associated with the chestnut waste/polyester composite than the pinecone powder/polyester composite.

Effect of Marble: Pine Cone Waste Ratios on Mechanical Properties of Polyester Matrix Composites

There is ongoing research interest in finding alternative sources of materials for composite manufacturing. Therefore, alternative non-wood based materials may play an important role in the forest product industry. Natural fibers have many advantages compared to synthetic fibers such as low density, lower cost, acceptable specific properties and being renewable and biodegradable. Natural fiber composites show high strength and stiffness, as well as good thermal and insulating properties. In this study, polymer matrix composites were manufactured using pine cone and marble waste and ATH powder as filler and polyester as matrix material with the casting method. Methyl ethyl ketone peroxide as hardener for cross-link network structure and cobalt naphthenate as accelerator were used to produce polyester matrix composites. Marble: ATH filler ratio was kept constant and polyester: filler (pine cone + marble + ATH) ratios were changed. Mechanical properties of composite materials were investigated and the final product tested to determine flexural strength, flexural modulus and hardness as well as some physical features such as bulk density, % total porosity and % open porosity. The experimental results showed that flexural strength and hardness of the composite materials decreased with the increase in pine cone: marble + ATH ratio.

Effects of Curing Temperature and MMA Content on the Working Life of MMA-Modified Vinyl Ester Polymer Concrete

The main purpose of this study is to identify the effects of curing temperature and methyl methacrylate (MMA) content on the working life of vinyl ester polymer concreteusing MMA as a monomer, N,N-dimethyl-p-toluidine (DMP) and methyl ethyl ketone peroxide (MEKPO) as initiators and cobalt naphthenate as a promoter. The results have shown that the working life of vinyl ester polymer concrete was shortened with an increased curing temperature and a decreased MMA content. Also, it was found that the curing temperature had a greater influence on the working life of vinyl ester polymer concrete than MMA content. The working life of vinyl ester polymer concrete was found to be about 70 and 10 min longer than the setting time of vinyl ester polymeric binder at curing temperatures of -10 and 20°C respectively. The MMA content had a much smaller effect on the curing temperature. Lastly, a linear regression equation was drawn by analyzing the correlation between setting time of the binder and working life of polymer concrete, which could be used for the prediction of the working life of vinyl ester polymer concrete based on the setting time of the vinyl ester binder.

Renewable Cardanol-Based Star-Shaped Prepolymer Containing a Phosphazene Core as a Potential Biobased Green Fire-Retardant Coating

A novel star-shaped cardanol oligomer (HCPP) derived from cardanol and hexachlorocyclotriphosphazene was prepared, and its structure was identified using proton nuclear magnetic resonance (1H NMR, 13C NMR, 31P NMR) and Fourier transform infrared spectroscopy (FTIR) techniques. The HCPP underwent a thermal-initiated curing reaction both with and without catalyst. Oxygen was essential to this curing reaction, and the film preparation process was very simple. The curing reaction of HCPP was monitored by differential scanning calorimeter (DSC) and Fourier transform infrared (FTIR) methods. The catalyst (cobalt naphthenate) could remarkably improve the curing reaction speed. The cardanol-based cured films show excellent thermal stabilities. Interestingly, the char yield of the film cured at 800 °C in nitrogen is above 29%, implying that the fire-retardancy of cardanol-based polymers can be notably increased by in traducing a hard phosphazene core into the structure. Meanwhile, all cured films are highly transparent and have Tg values above 50 °C.

Mechanical and thermal properties of modified kaolin clay/unsaturated polyester nanocomposites

ABSTRACTThe improvement in thermal and mechanical properties of Nanocomposites prepared with unsaturated polyester (UP) as polymer matrix and various loadings of amino‐modified nano kaolinite clay as filler has been studied. Mechanical stirring and ultrasonication resulted in better dispersion of the clay. For curing polyester resin, cobalt naphthenate was used as accelerator and MEKP as initiator. Dynamic Mechanical Analysis (DMA) was carried out to find storage and loss modulus. Thermal stability was found through thermogravimetric analysis and the evaluation of structure and morphology of the nanocomposites were done through XRD, SEM, and TEM. Nanocomposite with 3 phr of amino modified clay has shown higher storage modulus and an improved thermal stability of UP/clay nanocomposites has been established. Tensile strength and toughness of the composite have been found to achieve maximum values at 1 phr of clay and the storage modulus has had an improvement of 38% compared to neat UPR. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43245.

Investigating curing kinetics and structural relaxation phenomena of unsaturated polyester resin containing silanized silica

The effect of the incorporation of silica nanoparticles on structural relaxation and curing kinetics of unsaturated polyester resin was investigated. The evaluations were made monitoring the curing behavior of the neat unsaturated polyester resin and the resin containing 3 wt% SiO2 nanoparticles using dynamic differential scanning calorimetry at heating rates of 2, 2.5, 3, and 3.5℃ min−1. Results revealed a salient increase in the redox activation energy of the unsaturated polyester resin containing silica, while the activation energy of thermal decomposition of peroxide did not show any change. On the interface of nanoparticles and matrix resin, the dissociation reaction of cobalt naphthenate reduced the effect of the promoter. Differential scanning calorimetry was also used to estimate the average size of cooperative rearrangement region of the nanocomposite. Results revealed the possible grafting of unsaturated polyester onto the nanoparticle surface. The attractive interaction between the matrix and nanoparticle hindered segmental relaxation of the polymer chains.

The effects of five different types of acid anhydrides and incorporation of montmorillonite nanoclays on thermosetting resins

Five different types of acid anhydrides such as succinic anhydride (SA), maleic anhydride (MA), phthalic anhydride (PA), 3,4,5,6-tetrahydrophthalic anhydride (TPA) and cis-1,2-cyclohexanedicarboxylic anhydride (CDA) were used to prepare various polyalkyd resins from palm oil by following alcoholysis and esterification reaction. Palm oil was subjected to dehydration process using concentrated sulphuric acid prior to alcoholysis to improve the unsaturation in the fatty acid chains. Various physicochemical properties of the resins such as acid value, iodine value, yield, density, specific gravity, molecular weight, non-volatile material content, drying time, colour, solubility, etc., were tested by using standard methods. The resins were cured by using methyl ethyl ketone peroxide (MEKP), styrene and cobalt naphthenate at 120 °C. To enhance the thermal, structural and other resinous properties, 0.5 wt% of montmorillonite nanoclays (MNCs) was dispersed in TPA-based resin. The cured films were tested for X-ray diffraction, surface morphology, tensile properties, pencil hardness, gloss, gel content, swelling ratio, adhesion, thermogravimetric analysis, and chemical resistivity. In addition, hydrophobicity of the cured films was observed by contact angle measurement. A comparison was drawn among the resins as well as the films prepared from different acid anhydrides. Analysis revealed that TPA-based resin/film shows improved characteristics among the others due to high degree of crosslinking. On the other hand, incorporation of MNCs into the polyalkyds led to higher thermal properties, acceptable pencil hardness and reduced wettability, which may suit this film to be applied for high-performance surface coating applications.

Amino acids and their derivatives in catalytic cyclohexane oxidation

Homogeneous catalytic oxidation of cyclohexane can be improved by using additives to industrial catalysts that are based on variable valence metals. Recent studies have been much focused on enzymatic catalysis with protein-based enzymes that consist of amino acids of various structures. We assume that the presence of two functional groups in amino acids enables them to form complexes with catalysts, function as modifiers, and influence the composition of reaction products. The present study reveals how the liquid-phase homogeneous catalytic oxidation is affected by binary catalyst systems that are composed of cobalt naphthenate and amino acids of various origins (glycine or aminosulfonic acid) as well as individual catalyst, which is cobalt salt 2 (heptadecane olamine) of pentadion acid (CSHPA). The research determines and compares qualitative and quantitative impacts of amino acid additives and individual CSHPA on the oxidation process. The study identifies the regular dependence of CSHPA catalyst on the nature of its previous ultrasound processing. It has been found that the origin of an additive and the alteration of its concentration in a catalytic system permit regulating the quantitative composition of reaction products that result from the liquid-phase oxidation of cyclohexane. The researched catalytic systems can be applied in production to improve its technical and economic indices.

BisGMA/jute fibre/fly ash hybrid composites

Purpose – This paper aims to prepare BisGMA (bisphenol-A glycidyldimethacrylate)/jute fibre/fly ash hybrid composites with improved mechanical and corrosive properties. Design/methodology/approach – BisGMA prepolymer was first synthesised using diglycidyl ether of bisphenol-A and methacrylic acid. Then 2-hydroxy ethylacrylate-treated jute fibre and sodium hydroxide-treated fly ash were incorporated in the fabrication of composites using dicumyl peroxide, cobalt naphthenate and N,N-dimethyl aniline as catalyst, accelerator and promoter, respectively. The composition of BisGMA, jute fibre and fly ash was kept constant, whereas treated and untreated jute fibre and fly ash were used alternatively. Findings – Treatment of both jute and fly ash leads to improved mechanical properties of composites. However, treated fabric plays a dominant role compared to treated fly ash as filler. Among all the composites, the one having both treated jute fibre and treated fly ash is the most suitable composite for structural applications. Research limitations/implications – The present investigation has come up with a hybrid composite that can be used for a wide range of applications like low-cost housing and structural projects, structural laminates, etc., as it is both corrosion- and moisture-resistant. It is also the most durable from the mechanical point of view. There is also a scope of using other fillers instead of fly ash to study the changes brought about in the mechanical properties. Originality/value – The above composites have never been fabricated before.

Catalytic cyclohexane oxidation in the presence of alcohols of different nature

One of the ways of improving homogeneous catalytic oxidation of cyclohexane is the use of additives to industrial catalysts based on metals of variable valency. The analysis of literature sources has shown that alcohols that are formed in the process of oxidation and are able to form intermediate complexes with a catalyst have a significant impact. The effect of C2-C5 alcohol additives on the process of homogeneous catalytic oxidation of cyclohexane was studied in the paper. In the paper, the oxidation indices using binary catalytic systems of cobalt naphthenate – alcohol are given. The qualitative and quantitative effect of additives of monohydric and polyhydric alcohols on the process was defined, and their effects were compared. The dependences of the reaction rate on the nature of additives and the ratio between the components were determined. The optimal binary catalytic systems for the liquid-phase homogeneous catalytic oxidation of cyclohexane were selected, the use of which will allow improving the technical and economic production indices.

Tailoring micro-mesoporosity in activated carbon fibers to enhance SO2 catalytic oxidation

Enhanced SO2 adsorption of activated carbon fibers is obtained by tailoring a specific micro-mesoporous structure in the fibers. This architecture is obtained via metal catalytic activation of the fibers with a novel precursor, cobalt naphthenate, which contrary to other precursors, also enhances spinnability and carbon fiber yield. In the SO2 oxidation, it is demonstrated that the combination of micropores and large mesopores is the main factor for an enhanced catalytic activity which is superior to that observed in other similar microporous activated carbon fibers. This provides an alternative way for the development of a new generation of catalytic material.

An investigation on synthesis of alkyd resin with sorbitol

• Three kinds of alkyd resins were synthesized using sorbitol. • The initial and later stage of the reaction followed a second-order rate law. • The average molecular weight were measured and theoretically calculated. • The film properties of the synthesized resins were determined. Sorbitol, as an abundant, cheap and renewable resource, is considered as a potential raw material for the manufacture of alkyd resin. In this study, the kinetics on preparation of alkyd resin using phthalic anhydride, sorbitol and soya bean fatty acid as raw materials is investigated. Three kinds of sorbitol based alkyd resins (SAR) samples having fatty acid content (OL f ) of 42% (SAR1), 52% (SAR2) and 62% (SAR3) were prepared with phthalic anhydride, sorbitol aqueous solution and soya bean fatty acid using fatty acid method. Kinetic studies showed that the initial and latter stages of the reaction follow a second-order rate law. The second-order rate constants were found to be of the order of 10 −5 g/mg KOH/min. Molecular weight and polydispersity index were determined by GPC and end-group analysis. The number average molecular weight of the alkyd resins ranged from 1435 to 1626 and the weight average molecular weight ranged from 3041 to 3648. A large polydispersity index was found in a range from 2.12 to 2.24. The varnish of alkyd resin SAR1 containing 50% 200# solvent gasoline and 1.25% cobalt naphthenate (drying agent) by weight dried faster than the others. The physical and chemical film properties of the sorbitol based alkyd resins were determined and compared with standard alkyd resins. The results showed that the performance of alkyd resin having fatty acid contents (OL f ) of 42% (SAR1) was almost the same as the standard alkyd resins. It could be a choice binder for alkyd resin paint and helpful to reduce production cost.

Cure kinetic study of organoclay‐unsaturated polyester resin nanocomposites by using advanced isoconversional approach

Curing behavior of an unsaturated polyester (UP) resin containing 3 wt % Cloisite 10A (UP/10A) and 3 wt % Cloisite 30B (UP/30B) catalyzed with methyl ethyl ketone peroxide (MEKP) as initiator and promoted by cobalt naphthenate as accelerator was investigated by dynamic differential scanning calorimetry (DSC) at heating rates of 2, 2.5, 3, and 3.5°C min−1. X‐ray diffraction and transmission electron microscopy were utilized to evaluate the morphology of UP/10A and UP/30B nanocomposites. Kinetic parameters of cure reactions were evaluated using the advanced isoconversional method. The addition of nanoclay resulted in a decrease in the activation energy of the redox reaction compared to that of the neat UP resin. The pre‐exponential factor of the redox reaction for UP/10A and UP/30B was less than that of the neat UP. Results showed an increase in the concentration of styrene between Cloisite 10A platelets leading to a decrease in the intralayer styrene content. The high concentration of styrene between nanoclay layers may lead to the formation of polystyrene chains grafted on the alkyds chains. This homo‐polymerization was also observed in the variation of activation energy of UP/10A specimen versus the degree of conversion for 0.42 ≤ α ≤ 0.6 which is very close to the activation energy of free radical homo‐polymerization of styrene. POLYM. COMPOS., 34:1824–1831, 2013. © 2013 Society of Plastics Engineers

Size-controlled synthesis of β-Co(OH)<SUB align="right">2 hexagonal nanoplates and their conversion into CoO octahedrons using cobalt naphthenate under solvothermal conditions

β–Co(OH)2 hexagonal nanoplates with a size range from 300 nm to 3 μm have been synthesised successfully by a template and surfactant–free solvothermal route in a very simple system composed only of water, LiOH and cobalt naphthenate in xylene solution. This method is high–yield, simple and environmentally benign. The as–obtained Co(OH)2 hexagonal nanoplates can be easily converted into CoO octahedrons with the size of 15 μm by increasing reaction temperature.

Study on the Resin Curing Time and the Mechanical Properties of the Composites

In order to study the curing characteristics of common resins including bisphenol-A epoxy vinyl ester resin, phenolic epoxy vinyl ester resin and unsaturated polyester resin, the curing time of three resins was tested using cobalt naphthenate as accelerator and methyl ethyl ketone peroxide as curing agent. The results showed that the resin curing time reduces with the experimental temperature rising; in order to control the curing time at about 25 minutes when the experimental temperature is 23°C, the curing agent adding proportion of bisphenol-A epoxy vinyl ester resin, unsaturated polyester resin and phenolic epoxy vinyl ester resin are respective about 0.7%, 0.5% and 1.8%. The composites made by bisphenol-A epoxy vinyl ester resin have excellent tensile strength and composites made by phenolic epoxy vinyl ester resin have best bending strength.

Palm oil-based unsaturated polyester: Activation energy and swelling properties

In this study, unsaturated polyester (UP) resin based on palm oil was synthesized. Palm oil monoglyceride (POMG) was obtained by alchoholysis process of palm oil at 230°C for 3 h. Then, POMG was treated with maleic anhydride (MA) at different ratio of POMG:MA to produce UP resin. The products were then characterized using Fourier transform infrared (FTIR) spectrometer and proton nuclear magnetic resonance (1H-NMR) spectrometer. FTIR and 1H-NMR spectrum analyses confirmed that the unsaturated group of MA was chemically attached to POMG. The activation energy of POMG/MA reaction was also studied. The results showed that the ratio of reactants and the presence of 2-methylimidazole influenced the activation energy of reaction. The prepared UP resin was mixed with 35% of styrene, 0.3% of cobalt naphthenate, and 1% of methyl ethyl ketone peroxide before it was subjected to curing process. The effect of POMG/MG ratio on swelling properties of the cured UP was studied, and the result indicated that toluene and cured UP resin were compatible. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

A study on the liquid-phase oxidation of toluene in ionic liquids

The effect and mechanism of the hydrophilic ionic liquids (ILs) with cobalt naphthenate as catalyst on the liquid-phase oxidation of toluene were studied systematically. Five ILs with different hydrophilicities were employed as reaction media. The results showed that toluene conversion increased with increasing hydrophilicity of ILs. The toluene conversion and the corresponding selectivity of benzaldehyde reached 19.6% and 19.5%, respectively, in 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim]BF4). The solubilities of toluene, benzaldehyde, benzyl alcohol and benzoic acid in [Emim]BF4 were further measured at temperatures from 299.2K to 343.2K. The correlations between solubility and temperature were developed based on the critical point of phase separation or ideal solution model. The low solubility of toluene in [Emim]BF4 indicated a heterogeneous oxidation mechanism for toluene. The improvement of toluene conversion and product selectivity in [Emim]BF4 was attributed to the interactions between reaction and extraction separation. The sensitivity study demonstrated that the increase in oxygen pressure was beneficial to the reaction. A much lower reaction temperature of 130°C was achieved in [Emim]BF4 instead of a typical 160–170°C for current commercial plants. The high conversion, low reaction temperature and high product selectivity for the liquid-phase oxidation of toluene in [Emim]BF4 makes it a green and efficient hydrocarbon oxidation process.

Studies on the preparation of Parinari polyandra benth seed oil alkyd resins

AbstractParinari polyandra Benth seed oil was utilized in the preparation of four sets of alkyd resin (35%, 50%, 60%, and 75% oil formulations) using a two‐stage alcoholysis‐polyesterification method. The rate of polyesterification was depended on the amount of oil used during synthesis. The properties of the alkyds (drying times, film characteristics, water and acid resistances, and solubility) were evaluated using relevant standards. Inclusion of cobalt naphthenate drier in the alkyds and their exposure to outdoor temperature improved the drying properties. White gloss paints formulated from the alkyds, considering a pigment‐volume concentration of 20.67% in the gloss paint formulation compare well with commercial standard. FTIR and 1H‐NMR analysis confirm the alkyd (glycerol‐phthalate) structure. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

New Promoter System for the Oxidative Curing/Drying of Unsaturated Polyester Resin Based on Ascorbic Acid Metal Complexes of Cobalt and Copper

Unsaturated polyester resin (UPR) can be transformed into valuable and high quality industrial parts like gears, spools, pipes, etc. Curing/drying of UPR required organic peroxide as a source of radical flux. Most commonly used organic peroxide is methyl ethyl ketone peroxide, MEKP. At ambient temperature MEKP provides the flux of radicals very slow, therefore, certain active transition metal salts are added as promoters. These promoters catalyzed the oxidative decomposition of peroxide into radicals hence curing/drying of UPR increases. The efficiency of the promoters depends on the stability of metal salts. In this paper we synthesized ascorbic acid complexes of cobalt and copper with different ratio of metal to ligand and investigate their curing/drying property in comparison with cobalt naphthenate a conventional promoter. The results showed that all complexes are promoters in drying/curing of UPR. The complex with 2:1 ligand to metal ratio is found to be more active in drying/curing of UPR in comparison with 1:1 ligand to metal ratio.

Kinetic modeling of nanoclay‐reinforced unsaturated polyester resin

AbstractCuring behavior of an unsaturated polyester (UP) resin containing 1 wt% organically modified clay (OMC) catalyzed with methyl ethyl ketone peroxide (MEKP) initiator and promoted by cobalt naphthenate accelerator was investigated by dynamic differential scanning calorimetry (DSC) at five different heating rates of 5, 10, 15, 20, and 25°C/min. X‐ray diffraction and transmission electron microscopy were used to evaluate the morphology of UP/OMC composites. Results showed a mixture of intercalated and exfoliated morphology. The dynamic DSC curing curves showed a bimodal exothermic peak; therefore, two independent reactions, namely, redox and thermal copolymerizations were assumed. Kinetic parameters were calculated by using autocatalytic model and using Down hill simplex method and Runge–Kutta algorithm for each reaction. The addition of nanoclay resulted in decrease of the activation energy of the redox reaction compared to that of the neat UP resin. Also, the pre‐exponential factor of the first reaction for UP/OMC was less than that of the neat UP. Two factors including decreasing the activation energy and decreasing the number ofcollisions of reactionary components finally resulted in increasing the reaction rate of the first reaction out of the whole reaction in the system containing nanoclay compared to the neat UP resin. It is interesting that nanoclay has no effect on the thermal decomposition reaction. POLYM. COMPOS., © 2011 Society of Plastics Engineers.