Thermally assisted self-healing and shape memory behaviour of natural rubber based composites

A series of novel shape memory and self-healing composites of natural rubber (NR) and polycyclooctene (PCO) were designed using a simple physical blending method. These two polymers were selected with the intent of introducing network flexibility and mobility into the prepared blends. The mechanical, curing, thermal, shape memory, and thermally assisted self-healing properties of the NR/PCO composites were investigated in this study. In these composites, the crosslinked network generated in both the NR and PCO portions acted as a fixed phase, while the crystalline regions of the PCO portions acted as a reversible phase in the shape memory behavior. The composites showed self-healing properties at an elevated temperature (90 degrees C), which was attributed to molecular chain interdiffusion processes. Shape memory and thermally assisted self-healing properties were improved by increasing polycyclooctene content. The NR/PCO showed superior mechanical, shape memory, and self-healing properties (Rf= 94.57%, Rr = 98.92% and healing efficiency = 19.03%) when the blending ratio was 50/80. Due to these superior properties, this kind of natural rubber-based composites may have the potential to be used in intelligent and thermal-response shape memory fields.