Tensile properties and reinforcement mechanisms of natural rubber/vapor‐grown carbon nanofiber composite

Natural rubber (NR) composites with different contents of 1, 3, 10, and 20 wt% vapor‐grown carbon nanofibers (VGCFs) were synthesized using a solvent casting method. The initial modulus of composites was improved by 26.5 %/wt% as the VGCFs were added, and the NR/3 wt%VGCF composite had the largest tensile strength. The experiment values of initial moduli agreed well with the values predicted by the Halpin‐Tsai theory. The reinforcement mechanisms of the composites were investigated by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and wide‐angle X‐ray diffraction (WAXD). It was found that an efficient stress transfer occurred from NR to VGCFs under the uniaxial stretching. The addition of 10 wt% VGCFs could promote the nucleation process of NR, which resulted in the characteristic of the strain‐induced crystallization (SIC) in NR/10 wt%VGCF composite even for low strain. POLYM. COMPOS., 2010.