scholarly journals The Effect of Ingredients Mixing Sequence in Rubber Compounding upon Vulcanization Kinetics of Natural Rubber: An Autocatalytic Model Study

2018 ◽  
Vol 18 (4) ◽  
pp. 709
Author(s):  
Abu Hasan ◽  
Rochmadi Rochmadi ◽  
Hary Sulistyo ◽  
Suharto Honggokusumo
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Model ◽  
Reaction Rate Constant ◽  
Model Study ◽  
Vulcanization Kinetics ◽  
Kinetics Of ◽  
Mixing Sequence

This study examined the effect of ingredients mixing sequence to the vulcanization kinetics of natural rubber. The effects of mixing temperature, vulcanization temperature, and the carbon black type upon the kinetics were also studied by using rheography and an autocatalysis reaction model approach. The results showed that this model is good in providing information on vulcanization reaction kinetics of natural rubber. High vulcanization temperature resulted in high reaction rate constant. The more black carbon mixed at the beginning of the rubber mixing process, the higher reaction rate constant would be. The mixing of carbon black and rubber chemicals mixed into the rubber subsequently resulted in the higher reaction rate constant compared with that of simultaneously.

scholarly journals Vulcanization Kinetics of Natural Rubber Based On Free Sulfur Determination

2013 ◽  
Vol 13 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Abu Hasan ◽  
Rochmadi Rochmadi ◽  
Hary Sulistyo ◽  
Suharto Honggokusumo
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Mixing Method ◽  
Vulcanization Kinetics ◽  
Sulfur Determination ◽  
Mixing Sequence ◽  
Free Sulfur

The determination of free sulfur in the rubber vulcanizates provided significant representation of vulcanization reaction. In this research, the effects of vulcanization temperature, the mixing method of carbon black into rubber, the ingredients mixing sequence and the type of carbon black were studied on masticated and milled natural rubber in which the reaction was observed by un-reacted sulfur determination. The results showed that higher vulcanization temperature provided faster vulcanization reaction and greater reaction rate constant. Similarly, the mixing sequence of ingredient and carbon black into rubber influenced the rate of vulcanization reaction. The subsequent ingredients mixing sequence, in this case, resulted in higher vulcanization rate compared to that of the simultaneous one. However, the mixing method of carbon black into rubber brought small effect on the rate of vulcanization reaction. The type of carbon black applied was observed to influence the reaction rate of vulcanization. Smaller particle sizes of carbon black gave larger reaction rate constant. In this case, the type of carbon black N 330 gave faster vulcanization rate than that of N 660.

scholarly journals Analysis of the Kinetics of Swimming Pool Water Reaction in Analytical Device Reproducing Its Circulation on a Small Scale

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4820 ◽  
Author(s):  
Wojciech Kaczmarek ◽  
Jarosław Panasiuk ◽  
Szymon Borys ◽  
Aneta Pobudkowska ◽  
Mikołaj Majsterek
Keyword(s):  
Activation Energy ◽  
Water Quality ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Small Scale ◽  
Pool Water ◽  
Swimming Pool Water ◽  
Kinetics Of ◽  
Analytical Device

The most common cause of diseases in swimming pools is the lack of sanitary control of water quality; water may contain microbiological and chemical contaminants. Among the people most at risk of infection are children, pregnant women, and immunocompromised people. The origin of the problem is a need to develop a system that can predict the formation of chlorine water disinfection by-products, such as trihalomethanes (THMs). THMs are volatile organic compounds from the group of alkyl halides, carcinogenic, mutagenic, teratogenic, and bioaccumulating. Long-term exposure, even to low concentrations of THM in water and air, may result in damage to the liver, kidneys, thyroid gland, or nervous system. This article focuses on analysis of the kinetics of swimming pool water reaction in analytical device reproducing its circulation on a small scale. The designed and constructed analytical device is based on the SIMATIC S7-1200 PLC driver of SIEMENS Company. The HMI KPT panel of SIEMENS Company enables monitoring the process and control individual elements of device. Value of the reaction rate constant of free chlorine decomposition gives us qualitative information about water quality, it is also strictly connected to the kinetics of the reaction. Based on the experiment results, the value of reaction rate constant was determined as a linear change of the natural logarithm of free chlorine concentration over time. The experimental value of activation energy based on the directional coefficient is equal to 76.0 [kJ×mol−1]. These results indicate that changing water temperature does not cause any changes in the reaction rate, while it still affects the value of the reaction rate constant. Using the analytical device, it is possible to constantly monitor the values of reaction rate constant and activation energy, which can be used to develop a new way to assess pool water quality.

Crystallization Kinetics of CaOx in Artificial Urine and in Saline System

2014 ◽  
Vol 881-883 ◽  
pp. 708-711
Author(s):  
Lan Qing Deng ◽  
Jun Fa Xue ◽  
Li Kuan ◽  
Jian Ming Ouyang
Keyword(s):  
Reaction Time ◽  
Calcium Oxalate ◽  
Crystallization Kinetics ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Order ◽  
Reaction Rate Constant ◽  
Artificial Urine ◽  
Kinetics Of

The crystallization kinetics of calcium oxalate (CaOx) was comparatively studied by detecting the change of free Ca2+ ions concentration with the reaction time in artificial urine and in saline system. The dynamics equations of CaOx crystallization was r=kcα, and the average reaction order (α) was 3.3 regardless of the relative suprasaturation degree (RS) of CaOx in the range of RS=10.58~17.53. The average reaction rate constant (κ) was (0.97±0.1)×109 in artificial urine and κ=(3.1±1.8)×109 in saline system, due to the presence of inhibitors to CaOx crystallization in artificial urine.

scholarly journals Kinetics of gibbsite leaching in sodium hydroxide aqueous solution

2002 ◽  
Vol 56 (9) ◽  
pp. 381-385
Author(s):  
Ljubica Pavlovic ◽  
Zagorka Acimovic-Pavlovic ◽  
Ljubisa Andric ◽  
Aurel Prstic
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Sodium Hydroxide ◽  
Kinetic Parameters ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

In order to study the kinetics and mechanism of the reaction, laboratory leaching was carried out with industrially produced gibbsite ?-Al(OH)3 in aqueous solutions containing an excess of sodium hydroxide. The results obtained reaction temperature, duration and base concentration varied. The basic kinetic parameters were determined from: the reaction rate constant k=8.72?107 exp (-74990/RT) and the process activation energy in the range Ea=72.5-96.81 kJ/mol.

scholarly journals Kinetics of heterogeneous methanolysis of sunflower oil with CaO∙ZnO catalyst: Influence of different hydrodynamic conditions

2014 ◽  
Vol 20 (3) ◽  
pp. 425-439 ◽  
Author(s):  
Ivana Lukic ◽  
Zeljka Kesic ◽  
Svetolik Maksimovic ◽  
Miodrag Zdujic ◽  
Jugoslav Krstic ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Rate Constant ◽  
Sunflower Oil ◽  
Reaction Rate ◽  
Catalyst Surface ◽  
Reaction Rate Constant ◽  
Molar Ratio ◽  
Model Parameters ◽  
Pseudo First Order Reaction ◽  
Kinetics Of

The kinetics of heterogeneous methanolysis of sunflower oil was studied at 60?C using mechanochemically synthesized CaO?ZnO as catalyst. Influence of agitation speed, catalyst amount and methanol to oil molar ratio on the rate of reaction was analyzed. The rate of the process depends on the two resistances - mass transfer of triglycerides to the catalyst surface and chemical reaction on the catalyst surface, which are defined as the values of the overall triglyceride volumetric mass transfer coefficient, kmt,TG, and the effective pseudo first-order reaction rate constant, k, respectively. These kinetic parameters actually determine the value of the apparent reaction rate constant, kapp, whose change with time is defined with the change of triglyceride (TG) conversion. The kinetic model was proposed and the model parameters determined.

Kinetics of CO2 Absorption in MEA+DETA Blended Amine Solutions

2013 ◽  
Vol 864-867 ◽  
pp. 194-200
Author(s):  
Juan Wen ◽  
Chun Xiu Huo ◽  
Bin Zhang
Keyword(s):  
Activation Energy ◽  
Dynamic Model ◽  
Rate Constant ◽  
Absorption Rate ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Experimental Results ◽  
Kinetics Of ◽  
Amine Solutions

The kinetics of CO2absorption in unloaded aqueous MEA, MDEA, DETA single amine solutions and MEA+DETA blende amine solutions was studied with the amine concentrations of 3.0 kmol/m3and at temperatures ranging between 298K and 338K. A dynamic model of CO2absorption rate on the basis of the static absorption experimental results was established. The reaction rate constant of CO2absorption in blended amine solutions MEA+DETA is , and its activation energy is 32.89KJ/mol.

scholarly journals The influence of fatty acid composition on the kinetics of the vegetable oil methanolysis reaction

2021 ◽  
Vol 10 (2) ◽  
pp. 24-31
Author(s):  
Milan Kostić ◽  
Olivera Stamenković ◽  
Vlada Veljković
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Rate Constant ◽  
Reaction Rate ◽  
Unsaturated Fatty Acids ◽  
Reaction Rate Constant ◽  
Conversion Degree ◽  
Kinetics Of

The base-catalyzed methanolysis of roadside pennycress, olive, melon, grapeseed, hempseed, sunflower, and plum kernel oils was performed in the presence of KOH (1% to the oil weight) at the temperature of 60° C and the methanol/oil molar ratio of 6:1. The aim of this work was to reveal the influence of the fatty acid composition of the oils on the kinetics of these methanolysis reactions. The irreversible pseudo-first-order reaction was used for modeling the kinetics of the methanolysis reactions, and the reaction rate constant was correlated with the content of unsaturated fatty acids in the oil. The value of the reaction rate constant increases linearly with increasing the unsaturated fatty acids content in the oil. The applicability and reliability of the model were confirmed by high values of the coefficient of determination and low values of the mean relative percentage deviation between the calculated and experimental triacylglycerols conversion degree.

Kinetics of Microwave-Assisted Reduction of Manganese Oxide

2011 ◽  
Vol 239-242 ◽  
pp. 2286-2292 ◽  
Author(s):  
Hai Chuan Wang ◽  
Zhi You Liao ◽  
Yuan Chi Dong ◽  
Shi Jun Wang ◽  
Yun Zhou
Keyword(s):  
Reaction Time ◽  
Manganese Oxide ◽  
Chemical Reaction ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Microwave Oven ◽  
Microwave Assisted ◽  
Kinetics Of

The reduction rates of manganese oxide by carbon and SiC was examined by heating MnO2-carbon and MnO2-SiC mixtures in a 7-kW industrial microwave oven. The results show that the rate of the reduction increased with the amount of carbon in MnO2-carbon mixture and with SiC in MnO2-SiC mixture. The rate of the MnO2 reduction by carbon was proportional to the reaction time, and that by SiC was proportional to 2/3 power of the reaction time. The reduction was found to be controlled by chemical reaction. The reaction rate constant of the reduction of MnO2kC increased with increasing the amount of carbon in the mixtures but kSiC decreased with increasing the amount of SiC in the mixtures.

scholarly journals Reduction Kinetics of Fine Hematite Ore Particles in Suspension

2021 ◽  
Author(s):  
Zhiyuan Chen ◽  
Christiaan Zeilstra ◽  
Jan van der Stel ◽  
Jilt Sietsma ◽  
Yongxiang Yang
Keyword(s):  
Particle Size ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Reduction Kinetics ◽  
Rate Determining Step ◽  
Peak Function ◽  
Hematite Ore ◽  
Heating Up ◽  
Kinetics Of

AbstractSuspension reduction kinetics of hematite ore particles at 1710 K to 1785 K was described by the Johnson-Mehl-Avrami-Kolmogorov model with Avrami exponent of 1.405. The apparent activation energy is 105.5 kJ mol−1 with the rate determining step of nucleation and growth. The reduction degree of the hematite at the endpoint is a linear function of temperature and the logarithmic oxygen potential of the reacting gas. A peak function of reaction rate constant with particle size has been verified in this work, and the maximum value of the reaction rate is located at around 85 µm particle size. The influence of heat transfer on the reaction process has been evaluated. The results suggest that the heating-up process for large particles, 244 µm particles, for instance, cannot be ignored. It can retard the reaction rate compared to small particles. Normally, the reaction rate constant decreases linearly with the increase of ln[p(O2)] of the reacting gas mixture. However, 95 vol pct CO2 in the reacting gas can accelerate the reaction rate of thermal decomposition of hematite due to the emissivity of CO2 gas. It results in a higher reaction rate of 110 µm particles in 95 vol pct CO2-containing gas than that in other less CO2-containing gases.

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