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.

A series of ethylene-propylene-2-ethylidenebicyclo [2.2.1] hept.5-ene terpolymers (EPDM) have been prepared using a VOCl3/Al2Et3Cl3 catalyst under various AIN ratios and diene concentrations via solution polymerization and characterized by FTIR, Mooney viscosity (ML1+4, 125°C), and thermal gravimetery analyzing. The polymerization yield was seen to increase with augmentation of the AIN ratio and diene concentration and pass through a maximum of about 200gr polymer/g V. On the other hand, Mooney viscosity decreases with an increase in the two latter parameters. Increasing solvent to monomer ratio increased polymerization yield while it decreased Mooney viscosity. Accordingly, an optimum amount of solvent to monomer ratio (4:1 in mass) was found. One advantage of these polymer systems is that all the measured Tg property remained constant around 232-240 K in the range of incorporated ethylene and diene concentration. It has been observed that when AIN ratio decreases and diene concentration increases, there is an increment in ethylene incorporation (40-60%), and the results have been compared with the characteristics of two commercial EPDMs (Herlen 563, Vistalon 7500).

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.

In this research the effects of formulation and the amount of triallylcyanorate (TAC) as coupling agent on peroxide vulcanization and mechanical properties of the participated amorphous silica filled EPDM elastomer are investigated. The results of curing process and measuring the mechanical properties (hardness, modulus, tensile strength, elongation-at-break, abrasion, resilience and Mooney viscosity) of compounds showed that silica accounts for mechanical properties improvement and TAC increases Mooney scorch time and it reduces optimum curing time, therefore it prevents compound scorching. In addition, results showed that TAC improved rubber-filler interaction and apparent crosslink density, which reflected on mechanical properties under study.

The devocalization process of EPDM compound was carried out using a twinscrew extruder. The effects of barrel temperature, screw speed and diphenyl disulphide as a devulcanization agent (DVA) on the devulcanization were investigated. Percent devulcanization, sol fraction, Mooney viscosity and curing behaviour of devulcanized samples were studied. The devulcanized samples could not cure without addition of the curing agents. After the addition of curing agents into the devulcanizates, the general behaviour of rheometry test for rubber compounds was observed. Percent devocalization was dependent on DVA content and screw speed, especially at low and middle level of barrel temperature. Barrel temperature was the most effective parameter on the amount of sol fraction and Mooney viscosity. The devulcanizates were recured with a semi-efficient curing system. Tensile strength, elongation-atbreak, compression set, hardness and cross-link density of revulcanizates were evaluated. It was found that the mechanical properties were slightly inferior compared to virgin compound.