Effect of electron beam irradiation on the properties of ethylene‐(vinyl acetate) copolymer/natural rubber/organoclay nanocomposites

Abstract

The effects of electron beam (EB) irradiation on the morphology, crosslink density, and tensile properties of EVA/SMR L (Standard Malaysian Rubber)/organoclay nanocomposites prepared by a melt-blending technique were investigated. All the samples were irradiated by using a 3.0-MeV EB apparatus with doses ranging from 50 to 200 kGy. Organoclay loading was varied from 0 to 10 phr (parts by weight per hundred parts of resin). X-ray diffraction results and transmission electron microscopy images proved that the dispersion of organoclay in the nanocomposites was slightly improved by EB irradiation. The gel fraction yield for the nanocomposites increased with irradiation dose but decreased with organoclay loading. However, at 200 kGy, the gel fraction yield was almost the same at all organoclay loadings. Tensile strength and stress at 100% elongation increased proportionally with the irradiation dose. Elongation at break of the nanocomposites increased up to 100 kGy but then decreased at higher irradiation doses. The intercalation and exfoliation of the organoclay, the barrier effect, and the Hofmann degradation of the modification agent are the three major factors leading to the improvement of the properties of the irradiated nanocomposites. J. VINYL

Preparation and Electron Beam Irradiation of PVC/ENR/CNTs Nanocomposites

“…Thus, the enhancement in the mechanical properties namely, Ts and M100 upon EB irradiation, can be attributed to the uniform dispersion of the CNTs in a rubber matrix, which have led to better stress transfer together with occurrence of irradiation-induced cross-linking in the PVC=ENR blend. Similar observations were reported for ethylene vinyl acetate =natural rubber=organoclay nanocomposites by Munusamy et al [30] . Figure 6 depicts that the SEM micrographs of the fractured surfaces of the irradiated PVC=ENR=CNT nanocomposites prepared via solution and melt blending.…”

Investigation of the interaction of copper(II) oxide and electron beam irradiation crosslinkable polyethylene

“…3(a) and (b), long and thin fibrils can occur on the fractured surface of LDPE composites when added with 1 phr copper(II) oxide. The formation of long and thin fibrils indicates the higher plastic deformation ability of the polymer matrix when subjected to straining stress [32]. When the loading level of copper(II) oxide was increased to 3 phr, the fibrils disappeared from the fractured surface of the matrix as shown in Fig.…”

“…However, the width of the fibrils increased with the increase of electron beam irradiation doses. This is due to the fact that application of electron beam irradiation could highly induce the formation of crosslinked macromolecular chains in the LDPE matrix, which in turn could significantly restrict the tearing of the matrix when subjected to straining stress [32]. Thus, the matrix continuities of 1 phr copper(II) oxide added LDPE composites significantly extended by the formation of long and thick fibrils under straining stress.…”

Effect of organoclay loading on the crosslinking and degradation of irradiated ethylene(vinyl acetate) copolymer/natural rubber nanocomposites

“…The effect of EB irradiation on the morphology, crosslink density, and tensile properties was studied in our previous work. 16 Dispersion of organoclay, crosslink density, tensile strength and stress at 100% elongation improved proportionally with irradiation dosage. Incorporation of a crosslink promoter to the nanocomposites was found to further promote the homogenous dispersion of organoclay as evidenced from transmission electron (TEM) micrographs and x-ray diffraction (XRD) results.…”