Improved mechanical properties of natural rubber composites reinforced by novel SiO2@HCNFs nanofillers at a low filler loading

In order to improve high reinforcement properties of natural rubber (NR), SiO₂@HCNFs as novel double-phase nanofillers at low content have been loaded in NR by using mechanical mixing method. The morphologies and structures of SiO₂@HCNFs and NR composites were characterized, and the performances of NR composites were measured. The results show that compared with pure N330/NR, the modulus at 300% strain, tensile strength, elongation at break of NR composites increase by 10.7, 17.9, and 9.0%, respectively, at only 2.5 phr SiO₂@HCNFs content. Meanwhile, the volume abrasion of NR composites is also dramatically reduced at 2.5 phr SiO₂@HCNFs content, about 53.4% less than that of N330/NR, though the shore hardness increases by only 3.7%. It is also found that NR composites reinforced by SiO₂@HCNFs at 2.5 phr content have much higher hardness and abrasion performance than HCNFs/NR. The DMA results show that high wet skid resistance and low rolling resistance of NR composites were also achieved by loading 6.5 phr SiO₂@HCNFs. The unique structure of SiO₂@HCNFs double-phase nanofillers plays a crucial role in properties of NR composites, in virtue of the significant synergetic reinforcing effect of both HCNFs and silica.