Improvement of Structure and Properties of Nanocomposite Foams Based on Ethylene-Vinyl Acetate (EVA)/Natural Rubber (NR)/Nanoclay: Effect of NR Addition

Abstract

Nanocomposite foams made of ethylene-vinyl acetate (EVA), natural rubber (NR) and nanoclay were fabricated by mean of melt mixing in an internal mixer, and later foaming using azodicarbonamide through compression molding. Effect of NR addition (10-40 phr) into the EVA nanocomposite foam was studied. Characterizations by using Oscillating disk rheometer, X-ray diffraction (XRD), scanning electron microscopy (SEM) and mechanical tests were performed. The XRD analysis showed that the clay was mainly intercalated by the rubber. The SEM analysis revealed that the EVA/NR nanocomposite foams had closed-cell structures. Foaming EVA/NR/clay with composition of 100/0/5 (phr/phr/phr) led to low cell density and large cell size. The EVA nanocomposite foam also had low tensile strength, low compressive strength and low elastic recovery. However, the foam cell structure, i.e., greater cell density and smaller cell size, was obtained when combined with NR. Moreover, the strength and elastic recovery of the EVA nanocomposite foam were improved when the NR was added, and the improvement level was increased with increasing NR content.

Enhancing cellular structure, mechanical properties, thermal stability and flame retardation of EVA/NR blend nanocomposite foams by silicon dioxide-based flame retardant

“…non-uniform cell size), poor strength, high compression set, which limits their potential use in rubbery foam applications. 9,10 Owing to high tensile strength and good resistance to permanent deformation, natural rubber (NR) could be successfully formulated with EVA to deliver the foamed materials with uniform cell size and desired mechanical performance. 10-12 The cell uniformity and mechanical properties was further increased when foaming immiscible EVA/NR blend with layered silicate due to compatibilizing effect of layered silicate.…”

“…9,10 Owing to high tensile strength and good resistance to permanent deformation, natural rubber (NR) could be successfully formulated with EVA to deliver the foamed materials with uniform cell size and desired mechanical performance. 10-12 The cell uniformity and mechanical properties was further increased when foaming immiscible EVA/NR blend with layered silicate due to compatibilizing effect of layered silicate. 13 Although, the rubber foams based on the EVA/NR blend modified with layered silicate had interesting properties and a potential to be used in rubbery foam applications, but the obtainable EVA/NR blend nanocomposite foam is a highly flammable material with a fast ignition, and serious burning with melt dripping.…”

Foaming and Physical Properties, Flame Retardancy, and Combustibility of Polyethylene Octene Foams Modified by Natural Rubber and Expandable Graphite

“…In the past, several researchers have highlighted the potential for blending NR in polyolefin‐based foams [4–7]. Kim et al .…”

“…The foaming of EVA/NR/polypropylene (PP) blends with the addition of an appropriate level of NR produces light‐weight foams. The foaming of EVA/NR/polypropylene (PP) blends and EVA/NR/clay nanocomposites with the addition of an appropriate level of NR produces light‐weight foams with excellent heat resistance and improved mechanical properties when compared with EVA/PP blends and EVA/clay nanocomposites [6–7]. However, the influence of NR on the foaming behavior and performance of POE‐blend based foams has never been explored, nor have the mechanisms by which the addition of NR affects the foaming of polyolefin‐blend‐based foams been discussed in previous works.…”

Study on the effect of rubber sole on pressure change of foot movement

“…Table 2 shows the test equipment applied in this study. [12], hard soles made of EVA foam rubber material, soft soles made of high wear-resistant foam rubber material and hard soles made of high wear-resistant foam rubber material [13] respectively, which were similar in sole and upper structure and weight, thereby ensuring the accuracy of the test.…”