Material propertiesInteresting green elastomeric composites: Silk textile reinforced natural rubber

The reinforcement of natural rubber (NR) with particles and fibres enables their use in even high performance applications, such as in road-racing bicycle tire casings. Here, for the first time, we examine the potential of silk textiles as reinforcements in NR to produce a fully-green, flexible yet strengthened elastomeric composite material. Various material properties were evaluated and compared with similar nylon textile reinforced NR composites. Two types of NR were used: whole and purified natural rubbers. The composite samples were prepared by sandwiching a single layer of textile between layers of NR. NR/silk composites exhibited higher static and dynamic mechanical properties than NR/nylon composites. In addition, silk textiles in whole NR composites performed significantly better than purified NR composites, due to stronger fibre/matrix adhesion and better wettability in the former, as indicated by surface energy measurements and scanning electron microscopy micrographs. Such bio-based natural rubber/silk composites might find interesting applications in soft robotics and as flexible, inflatable tubes.