Study on volume change and scanning electron microscope observation of carbon black-filled natural rubber upon stretching

The volume of natural rubber vulcanizates varied slightly during stretching. Hydrostatic weighing method was adopted in this study to study the volume change. By measuring the volume change of natural rubber compounds filled with different grades and different loadings of carbon black during extension, the corresponding volume variation-elongation (Delta V/V-epsilon) curves were created, and the differences of Delta V/V-epsilon curves among different carbon black compounds were discussed. The stress differences between different samples were normalized and the Delta V/(V sigma)-epsilon curves were plotted. Scanning electron microscope was utilized to observe the emergence and variation process of cavities in various stretched states. X-ray diffraction was used to explore the change of crystallinity of the rubber after stretching to a certain elongation. Based on the experimental results, the damage at the filler-rubber matrix interface and within the fillers agglomerates would be discussed.

Automated summary

This study investigated the volume change of natural rubber during stretching using hydrostatic weighing method and explored the differences among different carbon black compounds. Scanning electron microscope and X-ray diffraction were used to observe the cavity formation and the change of crystallinity.