The Influences of Cure Characteristics and Physical Properties of Recycled Nitrile Glove Filled Epoxidized Natural Rubber Compounds (NBRr/ENR25)

The effects on curing characteristics and physical propertiesof recycled nitrile glove (NBRr) filled epoxidized natural rubbers (ENR25) were examined. Two different size ranges of NBRr particles, i.e., S1 (250μm-500μm) and S2 (2cm-5cm) were used in this study. The NBRr/ENR25 compounds with five different compositions of NBRr (5, 15, 25, 35 and 50 phr) were prepared using a two roll-mill at room temperature. The result of cure characterization show that scorch time, t2 and cure time t90 of the NBRr/ENR25decreased with the increased of NBRr content due to the existence of crosslinked precursors and unreacted curativein the recycled rubber.NBRr/ENR25 compounds with fine size, S1 of NBRr particles exhibit lower minimum torque (ML) compared with the coarse size, S2 which resulted in more efficient processing. The maximum torque (MH) of all NBRr/ENR25 compounds show the increasing trend with increased NBRr content probably due to the good interactions in NBRr/ENR25 compounds. For physical properties, NBRr/ENR25 compounds with fine size, S1 of NBRr particles exhibited the higher hardness and crosslinking density at all compound ratios. The results overall indicated that the NBRr/ENR25 with fine size, S1 of NBRr particles show better cure characteristics and physical properties (crosslink density and hardness test) compared to coarse size, S2 of NBRr particles.

Preparation of Natural Rubber/Sodium Montmorillonite Nanocomposites by Latex Mixing Method with Drying Process

Natural rubber/sodium montmorillonite nanocomposites were prepared by using natural rubber latex without using acid coagulation. Cure characterization indicated that Na-MMT retarded the vulcanization reaction of NR. The mechanical properties of the NR/Na-MMT nanocomposites were improved with addition of Na-MMT which is attributed to the reinforcing effect of Na-MMT with rubber. Furthermore, the storage modulus (E) of the nanocomposites was higher than that of the pure NR vulcanizate. Furthermore, glass transition temperature (Tg) was shifted to higher temperature and lower Tan δ value was observed upon increasing loading levels of Na-MMT. Moreover, the nanocomposite showed higher thermal stability than that of the pure NR vulcanizate.