The role of nanofillers on (natural rubber)/(ethylene vinyl acetate)/clay nanocomposite in blending and foaming

Abstract

Nanocomposite foams were fabricated from 60/40 wt% ethylene vinyl acetate (EVA)/natural rubber (NR) blends by using azodicarbonamide as a blowing agent. Two different nanofillers (sodium montmorillonite and organoclay) were employed to study their effects on foam properties. The results were also compared with conventional (china clay)‐filled foams. Transmission electron microscopy, X‐ray diffraction, scanning electron microscopy, and three‐dimensional Microfocus X‐ray computed tomography scanning analysis were performed to characterize the EVA/NR blend morphology and foam structures. The results revealed that the nanofiller acted as a blend compatibilizer. Sodium montmorillonite was more effective in compatibilization, generating better phase‐separated EVA/NR blend morphology and improving foam structure. Higher filler loading increased the specific tensile strength of rubber foams. The rubber nanocomposite foam showed superior specific tensile strength to the conventional rubber composite foam. The elastic recovery and compressive strength of the nanocomposite foams decreased with increasing filler content, whereas the opposite trend was observed for the conventional composite foams with china clay. The thermal conductivity measurement indicated that the nanofiller had better beneficial effect on thermal insulation over china clay filler. From the present study, the nanofillers played an important role in obtaining better blend morphology as compatibilizer, rather than the nucleating agent and the nanofiller content of 5 phr (parts by weight per hundred parts of rubber) was recommended for the production of EVA/NR nanocomposite foams. J. VINYL ADDIT. TECHNOL., 21:134–146, 2015. © 2014 Society of Plastics Engineers

Effect of graphene treated with cyclohexyl diamine by diazonium reaction on cure kinetics, mechanical, thermal, and physical properties of natural rubber/graphene nanocomposite foam

“…The elongation at break of NRF/UG3 and NRF/CG3 were similar to that of unfilled NRF. Generally, the elongation at break of NRF composites decreased with increasing filler content due to the rigidity of fillers . However, in our case the addition of graphene particles does not impair the elongation at break of NRF nanocomposites, meaning that it can retain the elastic behavior of NRF product with high tensile strength.…”

“…However, in our case the addition of graphene particles does not impair the elongation at break of NRF nanocomposites, meaning that it can retain the elastic behavior of NRF product with high tensile strength. It can be concluded that NRF/CG3 exhibits high tensile strength while other fillers (such as carbon black [15,16] and organoclay [49,50]) cannot improve tensile strength of NRF composites at the same loading. Moreover, the elongation at break of natural rubber/graphene nanocomposite foam is similar to unfilled NRF product owing to low filler content.…”

“…Some fillers (e.g., calcium carbonate , kenaf powder , and rice husk powder ) can significantly improve tensile strength and compressive stress of NRF only at high filler loading. Nevertheless, some fillers such as carbon black and NRF/organoclay nanocomposites can provide high impact on the properties of NRF. The intrinsic filler factors that effect on the final properties of NRF composites include filler geometry, size and size distribution, content, compatibility, filler‐polymer interaction and the functional group of filler.…”

Vinyl acetate ethylene copolymer and nanosilica reinforced epoxidized natural rubber: Effects of sulfur curing systems on cure characteristics, tensile properties, thermal stability, dynamic mechanical properties and oil resistance

“…It is well established that many desirable properties of rubber products can be achieved through rubber/rubber blend [1][2][3], rubber/polymer blend [4][5][6][7][8] and rubber composites [9][10][11][12][13][14][15][16][17][18][19][20]. It has been reported that latex blending offers compatible or miscible blend without phase separation and flocculation [9,13].…”

Synergistic effects of modified hydrotalcite on improving the fire resistance of ethylene vinyl acetate containing intumescent flame retardants

“…Ethylene vinyl acetate (EVA) copolymer is extensively used as an insulator in the wire, adhesive and cable industry due to its desirable physico-chemical properties and its easy acceptance of additives [1][2][3][4]. The ease of ignition and subsequent combustion with the release of large volumes of toxic smoke prohibits the application of EVAbased materials [5][6][7].…”