Synthesis of kaolinite-filled EPDM rubber composites by solution intercalation: structural characterization and studies on mechanical properties

Dual effect of maleic anhydride and gamma radiation on properties of EPDM/microcrystalline newsprint fiber composites

The purpose of this research is to investigate the effect of gamma irradiation, concentration of microcrystalline newsprint fibers (MNF) and maleic anhydride as coupling agent for treating microcrystalline newsprint fibers (MA–MNF) on the mechanical and thermal properties of ethylene propylene diene monomer rubber matrix (EPDM). Maleic anhydride (MA) was used at a different ratios (5, 10, and 15 wt% according to the MNF). The EPDM/MA–MNF composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The results confirm the adhesion between MA–MNF and EPDM rubber matrix in presence of radiation. EPDM/MA–MNF composites have achieved higher mechanical properties than EPDM rubber matrix and EPDM/MNF composites. EPDM composites containing MNF that treated with 15% MA and gamma irradiated at 80 kGy have the highest tensile strength, tensile modulus at 100% strain, crosslink density and thermal stability over all other composites.

Multiscale analysis and experimental validation of the effective elastic modulus of epoxy-dioctahedral phyllosilicate clay composite

In this research, developed finite element codes were used to study the effective elastic modulus and stress-strain distribution profiles of epoxy resin filled with 6 wt. % microparticles of kaolinite. The random distribution of the particles was microstructurally regenerated with Digimat MSC software and random sequential algorithm codes in epoxy matrix. Stochastic representative volume element models of the composites were developed and analyzed under periodic boundary conditions. For validation, the predicted result by finite element analysis was compared with that of Mori-Tanaka's mean field homogenization scheme, selected micromechanical models and experiment. All the results indicated that 6 wt. % of kaolinite microparticles can improve the elastic modulus and load-bearing capacity of epoxy resin with <5 % error between predicted and actual results. The microstructure, phase identification and chemical characterization of the composite were also studied with scanning electron microscopy, x-ray diffraction spectroscopy and energy-dispersive x-ray spectroscopy, respectively. In addition, the particle size and distribution of the kaolinite in the epoxy matrix were experimentally investigated.

Synergistic effect of vermiculite clay and ionizing irradiation on the physical and mechanical properties of polybutadiene rubber/ethylene propylene diene monomer nanocomposite

Blends of rubber-rubber have desired properties intermediated between two rubber matrices. On the other hand, polymer-clay nanocomposites have attracted the attention of many researchers and experimental results are presented in a large number of recent papers and patents because of the outstanding mechanical properties and low gas permeability that are achieved in many cases. Polymer-clay nanocomposites are a new class of mineral-field polymer that contain relatively small amounts (<10%) of nanometer-sized clay particles. In this study, new nanocomposite materials were produced from the blend of polybutadiene rubber (BR) and ethylene propylene diene monomer rubber (EPDM), BR/EPDM (50/50) as matrix and organically modified vermiculite clay (VMT) by quaternary alkylammonium in different contents (3, 6, 9 and 12 phr) as the filler by using rubber mill then, the rubber nanocomposite sheets were irradiated at doses of 25, 50, 75, 100 and 150 kGy using γ-radiation technique as a crosslinking tool. The prepared composites can be characterized by using various analytical techniques including X-ray diffractometer (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) as well as mechanical properties measurements.