Effects of partial replacement of carbon black with nanocrystalline cellulose on properties of natural rubber nanocomposites

Waste cotton materials were used as source materials to prepare waste cotton nanocrystalline cellulose (WCNC) by optimized acid hydrolysis. The final hydrolysis products had an approximately 30 nm diameter, lengths mainly ranging from 400 nm to 800 nm, and a typical cellulose I crystal structure with a high degree of crystallinity. WCNC was further investigated to partially replace carbon black (CB) in natural rubber (NR) composites via coagulation. NR/CB/WCNC and NR/CB composites were prepared. Through comparisons of the morphology, mechanical properties, dynamic compression fatigue performance, thermal stability and soil biodegradation behaviour of the NR/CB/WCNC and NR/CB composites, WCNC was proven to perform efficiently. WCNC could increase tensile and tear strength as well as reduce heat build-up, and it presented slightly lower thermal stability and superior biodegradability. Moreover, a fine WCNC dispersion was achieved in NR/CB/WCNC. The observed reinforcement effects were evaluated based on the results of rubber processing analysis (RPA), thermo-gravimetric and scanning electron microscopic analyses of NR/CB/WCNC compared with the NR/CB composites.