In this paper, it is proposed to consider the improvement of batch rubber mixer by increasing its capacity through the development of a control system. The article presents the results of synthesis of the control system of the temperature regime of the rubber mixing process. On the basis of equations describing the dynamics of the process under study, a mathematical model of the mixture cooling process is drawn up. According to the results of topological synthesis it was expedient to apply a feedback tracking system. Using the frequency method of synthesis, the coefficients of controllers were calculated. A PID-controller was selected and the direct quality indicators of the control system were analyzed. The developed solution can be used to increase the productivity of the rubber mixer due to the possibility of using modes with high heat energy release. This, in turn, is removed by the cooling system, the automatic control system of which is synthesized in this work.

This research paper is devoted to the application of a unit work method for the scale up of rubber mixing process in banbury type internal mixers. Mooney viscosity and carbon black dispersion factor were selected as the parameters for the determination of the state of mixing. Based on a specific compound formulation, the above mentioned parameters were measured in three mixers with different chamber sizes (60, 300 and 1500 mL). It is shown that by this method the operating points of a bigger size mixer can be accurately obtained from the experimental data obtained 011a small size mixer.

Elastomer vulcanizates based on natural rubber (NR), NR reclaim (NRR) and layered silicates were compounded in an internal mixer and cured on a two-roll mill. Cure characteristics and mechanical properties of samples based on 50NR/50NRR reinforced with Cloisite 20A, Cloisite 30B and Nanolin DK1 were compared to those of conventional NR/NRR/kaolin microcomposites. Due to the light/soft nature of organoclays suppressing the friction forces, the minimum torque values decreased in the presence of organoclays, whereas the crosslink density, evidenced by the difference between the maximum and minimum torque values, increased in all samples and scorch times shortened by 37% to a minimum in the presence of Nanolin alkaline/catalytic role in the cure reaction. Fatigue resistance improved by about 10% benefiting the crack tips blunting/energy consuming hysteresis mechanisms motivated by the organoclays among which Nanolin DK1 provides the most efficient dispersion/distribution of nanolayers by faster intragallery crosslinking reactions that pushes the stacks apart. Higher states of dispersion in this sample would also promote strain-induced crystallization under deformation responsible for the improvements seen in the modulus and elongation-at-break. Two-step mixing sequence further improved the compound performance due to the dispersion state progress confirmed by X-ray diffraction and transmission electron microscopy (20% in fatigue resistance and 53% in tensile modulus). In-situ compatibilization through bis(triethoxysilylpropyl)tetrasulfide bi-functional silane coupling agent also promoted modulus and fatigue resistance. However, a prolonged scorch time was observed due to the blinded NR cure-reactive sites as well as steric hindrance of large functional groups in the presence of this coupling agent.

In this research work with the aid of Tagouchi experimental design and drawing of interaction curves with Minitab software, the best rotor speed and dump temperature of mixing for physico-mechanical and rheological properties of the rubber compound with three mixing steps was obtained. Moreover by plotting the mean curves in Excel worksheet, the dependency of properties on rotor speed, dump temperature and mixing energy were analyzed. The Results showed that dispersion was improved with increasing rotor speed and dump temperature at the lower total time. The best dispersion occurred at the highest dump temperature and the rotor speed in the second stage. We attributed better dispersion to lower filler-filler interaction, because of the mixing process performed at higher temperatures when we used higher rotor speeds at higher dump temperatures. Effect of rotor speed and dump temperature on tension properties were negligible. However, the higher dump temperature had negative effect on tear resistance, whereas, the high rotor speed had positive effect. The same results were observed for die swell while the governed mechanism on these properties was studied as well.

The effects of rubber mixing conditions, such as the changes in material loading procedure and rotor speed on die swell behavior were studied with the aid of an experimental small extruder. Also the changes were examined on Mooney viscosity of the compounds, simultaneously. It is shown that these changes in mixing condition considerably affect the Mooney viscosity of the compounds rather than die swell. Two control parameters of Mooney viscosity and die swell, i.e. "rubber breakdown" and "filler dispersion in mixing process" were identified and it may be concluded that the role of the second agent on die swell behavior is not very significant. Finally, by feeding the final compounds in an industrial extruder, it is observed that these processing variables on die swell and extrusion behavior of compound play little effect compared to the formulation variables. The experimental die swell parameter, however could predict the extrusion behavior much better than Mooney viscosity parameter.