Coated Nano-Sized CaCO_3 Reinforced Semi-Crystalline EPDM

摘要

Nano-sized calcium carbonate (CaCO_3) was used to reinforce a semi-crystalline ethylene-propylene-diene monomer rubber (EPDM).For comparison,micron-sized CaCO_3 was also studied.It was found that both nano-sized CaCO_3 and micron-sized CaCO_3 improved the mechanical properties of the EPDM vulcanizates,and nano-sized CaCO_3 exhibited better reinforcement effect than micron-sized CaCO_3.The difference in reinforcement effects of nano-sized CaCO_3 and micron-sized CaCO_3 was explained in terms of the filler particle size and the crosslink density of the vulcanizates.The nano-sized CaCO_3 was also modified by titanate,borate,and aluminate-titanate complex coupling agents and used to reinforce EPDM vulcanizates.The results showed that titanate coupling agent coated nano-sized CaCO_3 exhibited the best reinforcement ability.FE-SEM micrographs showed that stearic acid,titanate,and aluminate-titanate complex coupling agents could improve the dispersion of the CaCO_3 in the rubber matrix remarkably,whereas borate coupling agent could not.The effect of modified nano-sized CaCO_3 on the dynamical mechanical properties was also studied.Incorporation of CaCO_3 reduced the glass transition temperature (Tg) of the vulcanizates.In comparison with nano-sized CaCO_3,micron-sized CaCO_3 depressed the Tg more remarkably.