Preparation and characterization of halloysite nanotube‐silica/silicone rubber composites: Effect of HNTs on mechanical and thermal properties

AbstractA series of halloysite nanotube‐silica (HNTs‐SiO2) nanocomposite fillers were prepared by in‐situ assembly, and a reinforced SiO2/SR composite was obtained by filling them into silicone rubber (SR). The morphology and structural characterization of HNTs‐SiO2 and HNTs‐SiO2/SR and the properties of the HNTs‐SiO2/SR were studied. As a result, the small particle size SiO2 was firmly anchored onto the HNTs surface, and the obtained HNTs‐SiO2 nanofillers were uniformly dispersed in SR. At a 30 phr fixed filler loading, the weakest filler network and the best filler dispersion were obtained when HNTs content in HNTs‐SiO2 was 5%. This resulted in a maximum tensile strength obtained of 6.2 MPa, 1.55 times that of SiO2/SR with the same filler loading, and a maximum elongation at break of 418%, 1.67 times that of the SiO2/SR with the same filler loading, and at the same time the tearing strength and hardness are also improved. Furthermore, the silicone rubber also showed improved thermal stability, with an initial degradation temperature increase of 30°C under a nitrogen atmosphere.Highlights HNTs–SiO2 nanocomposites were successfully prepared by the self‐assembly method and used as fillers in SR as a new type of reinforcing material. The 1D HNTs act as a barrier to prevent SiO2 aggregation and improved fillers dispersion. The elongation at break and tensile strength of 5% HNTs‐SiO2/SR are 67% and 55% higher than those of SiO2/SR, respectively. The silicone rubber also showed improved thermal stability.