Rubber recycling technology is a popular issue in many research fields, considering the huge amount of rubber waste in the environment. This paper discusses an application of regenerated ethylene propylene diene monomer (EPDM) to produce vulcanized items such as fiber-reinforced elastomeric isolators (FREIs), which are nowadays considered efficient low-cost seismic protection devices for low rise buildings (e. g., made by masonry) in developing countries. Two types of regenerated EPDM are studies and blended with two different virgin rubbers, Vistalon 3666 and Dutral 4038. The first virgin rubber is used to produce a compound with a hardness of around 30 Shore A, while the latter exhibits 60 Shore A. The present study, which is part of a wider research project aimed at the production of low cost un-bonded seismic isolation devices, focuses exclusively on the determination of both crosslinking degree through rheometer tests and elasticity/mechanical properties of the rubber pads, before and after ageing (hardness, tensile strength, elongation-at-break, stretch-stress behavior before and after ageing). The results show that the compounds with the second reactivated EPDM (type B) exhibit the most satisfactory performance, before and after ageing. This paper discusses also the method of fabrication of FREIs, obtained by the interposition of pads made by the selected recycled rubber and dry glass fiber-reinforced polymer (GFRP) textiles. The hardness tests performed on the sliced FREI specimen indicate that the vulcanization temperature used in the production is roughly suitable to obtain the expected rubber properties.

EPDM Rubber is one of the unsaturated general purpose elastomers having low density and high filler loading ability. Silica is one of the reinforcing fillers used in EPDM rubber compound. In this research work, the effect of three different coupling agents on silica filled EPDM compound were studied. The results showed that coupling agent affected on curing behavior and filler polymer interaction with physical and mechanical properties improvement.

Blends of silicone rubber (SR) and ethylene propylene diene monomer (EPDM) are immiscible due to different polarity and poor interfacial surface tension between their rubber chains. In this study, compatibilizing effect of a nanoclay addition in SR/EPDM blends was investigated. Viscoelasticity and morphology of nanocomposites based on SR and EPDM, containing 10, 20 and 30 wt% of EPDM and 3, 6 and 9 phr of nanoclay (Cloisite 15A), were studied. The curing behavior of the samples showed that the vulcanization rate and cross-link density of the blends increased with increases in SR content. Morphological study was conducted by XRD, SEM and EDX analyses and they indicated that the nanoparticles tended to disperse in the EPDM phase and consequently caused hardness and the elasticity of this phase in nanocomposites increased. Tensile properties of the samples showed a good fitting between that of experiments and the Maxwell model at initial time of testing (1.5 s) for all the blends. Sample parameters including modulus (E), viscosity (h) and relaxation time (t) calculated by the Maxwell model revealed that those samples with higher content of nanoparticles exhibit higher modulus and lower relaxation time. The good match in tensile properties based on Maxwell model and those of the experimental data was attributed to good dispersion of nanoclay in the blends.

Waste EPDM was recycled by using a twin-screw extruder in the thermo-mechanical method; and the effects of processing parameters were investigated. Barrel temperature (220, 280, 340 and 380oC) and screw speed (60, 100 and 140 rpm) were chosen as the variables. Devulcanized characterizations, such as devulcanization percent, solvent swelling, and sole fraction were studied. After curing, the properties of revulcanized compounds (including 30 phr devulcanized EPDM) were compared with the reference compound (100% new EPDM compound). At low temperature and low screw speed, devulcanization was poor while with increasing both of them, devulcanization occurred very significantly indicated as higher solvent swelling. On the other hand, sole fraction increased as a function of processing conditions. Mooney viscosity decreased for high processing parameters; higher sole fraction, lower Mooney viscosity. Normally, compounds having 30 phr devulcanized rubber showed properties poorer than the reference one, but closer to evaluating devulcanization conditions. As the temperature or speed increased, stronger tensile behavior, reduced pressure set, and less creep elongation were achieved, meaning more crosslinks breakdown and successful revulcanization.

Anovel approach for achieving a good dispersion of multi-walled carbon nanotubes (MWCNTs) within the ethylene- propylene diene monomer (EPDM) matrix has been investigated. In this approach, EPDM was modified with vinyltrimethoxysilane (VTMS) through a melt mixing process. In addition, the effect of MWCNTs concentration on the mechanical and rheological properties of the modified EPDM has been studied. The formulated composites exhibited significantly enhanced physical properties even at very low nanotube concentrations. The occurrence of the grafting reaction was confirmed by the Fourier transform infrared spectroscopy (FTIR) peaks at 1070 and 1250 cm-1 according to the Si-O and Si-C vibrations. The state of dispersion of the fillers in the polymer matrix was evaluated through transmission electron microscopy (TEM) and scanning electron microscopy (SEM), in addition surface topology was studied by atomic force microscopy (AFM). The results showed that the VTMS grafted on the EPDM surface improved the dispersion of MWCNTs in the matrix. The rheological characteristics have been studied by rubber process analyzer (RPA). At the low frequencies, the effect of increasing the MWCNT content was significantly high so that the storage modulus (G') and complex viscosity ( h*) increased but the difference in storage modulus and complex viscosity values reduced as the frequency was increased. It was found that at concentration of 1.5 wt% of MWCNT, the nanocomposites exhibited remarkable improvements in the mechanical properties such as modulus and tensile strength.

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.