Preparation and characterization of hydrophilic and water-swellable elastomeric nanocomposites

Highly polar and hydrophilic polymers; ethylene-vinyl acetate (EVA), epichlorohydrin rubber (GECO), and polyethylene oxide (PEO) reinforced with fillers (carbon black (CB) and/or Silica) were used to prepare water-swellable rubber nanocomposites. The study showed that although the high content of the GECO delayed vulcanization of the corresponding compounds, the sample filled with desired ratio of GECO/PEO/EVA or GPE, cross-linked with peroxide exhibited the highest swelling performance of ⁓150%. The samples exhibited good re-usability performance in the re-swollen test, after drying. At prolonged water swelling, the tensile strength dropped drastically for compounds with high content of the GPE, due to weak filler-matrix interactions. On the other hand, the incorporated GPE also increased the rebound resilience (%) property which is a key requirement in green tire fabrication. For example; peroxide cured sample coded SR3 (GPE-15 phr CB) obtained ⁓30% resilience in non-swollen state and ⁓53.5% after 1440 min of water-swelling, which represents a dramatic development of over ⁓78% in rebound resilience. Thus, a proper balance between the GPE content, curing agent and the reinforcements may guarantee high water-swelling performance and mechanical properties integrity for multifunctional applications such as wound healing, structural works, water collection from oil spillages, and for the development of water-based sensors.