Fabrication of zinc oxide-coated microcrystalline cellulose and its application in truck tire tread compounds

摘要

The severe threat to aquatic environment from zinc oxide (ZnO) in tread debris has become a serious issue for tire manufacturers. Various attempts including the utilization of composite ZnO have therefore been made to reduce ZnO content in tread compounds. In this study, a new composite ZnO was prepared by depositing ZnO nanoparticles on microcrystalline cellulose (MCC) through hydrothermal reactions, called M-ZnO. After characterization by various techniques, cure activation efficiency of M-ZnO in truck tire tread compound was investigated and compared with that of active ZnO (A-ZnO). The results showed that M-ZnO contained approximately 66.7 w/w of ZnO and had comparable specific surface area to A-ZnO. Regardless of the ZnO type, crosslink density increased with increasing ZnO content up to 3 phr leading to the improved mechanical properties of the rubber vulcanizates, that is, hardness, modulus, and abrasion resistance. Tensile and tear strengths, however, were found maximum at 2 phr of both A-ZnO and M-ZnO. Although wet grip index was independent of ZnO content, rolling resistance tended to reduce with increasing ZnO content. The results clearly show the great potential of utilizing M-ZnO to replace conventional A-ZnO in tread compounds when more stringent environmental regulations are imposed.