Reinforcement Of Natural Rubber By Nanocrystalline Cellulose

As a kind of environmental-friendly and biodegragable biomacromolecular material, nanocrystalline cellulose(NCC) has extensive sources and low cost and can be easily prepared. Rod-like NCC has perfect crystal structure, relatively high aspect ratio, low density and excellent mechanical properties which make it a new type of green reinforcing filler for rubber.Based on the previous research, NCC was added into natural rubber(NR) as reinforcement filler to partially replace carbon black(CB). NCC was prepared by hydrolysis of microcrystalline cellulose(MCC) with acid. NR/NCC blends were prepared by co-coagulating NR latex with NCC suspension. NR/NCC/CB composites were prepared by adding CB in blending process. The effects of RH and silane coupling agent KH-550 on the composites were also studied.The total dosage of NCC and CB was fixed to 45phr. CB was partially replaced by NCC in NR/NCC/CB composites before and after modified by RH. The effects of the replacement on performance and structure of the two series of composites were studied. The results show that the mechanical properties and resistance to flex cracking are enhanced and dynamic compression heat buildup and rolling resistance are decreased when CB are partially replaced by NCC. Scanning electron microscopy (SEM) indicates that NCC disperses well in both kinds of composites. The composites obtain the best comprehensive performance when loading ratio of NCC to CB is 10phr/35phr. RH can significantly improves some properties of the composites.Loading ratio of NCC to CB was fixed to 10phr/35phr. The effects of RH content on the properties of NR/NCC/CB composites were studied. The apparent crosslinking densities and the abrasion resistance are improved with the increasing of RH content. The composites obtain the highest mechanical performance as RH content is 4phr. Dynamic compression heat buildup and permanent set are reduced by 5.5℃and a percentage of 3 respectively as RH content is 2phr.Silane coupling agent KH-550 was chosen to modify the NR/NCC/CB composites after mechanical tests of NR/NCC composites modified by several kinds of coupling agent respectively. The effects of KH-550 content on the properties of NR/NCC/CB composites were studied when the loading ratio of NCC to CB was fixed to 10phr/35phr. By adding appropriate content of KH-550, the abrasion resistance, resistance to flex cracking and cold resistance of the composites are all improved and the dynamic compression heat buildup, permanent set and rolling are decreased. Compared with unmodified composites, NCC is in better orientation in the composites with 1phr KH-550.