Rubber blends based on ethylene-propylene-diene-monomer (EPDM) rubber and fluoroelastomer (FKM) having various blend ratios were prepared. The phase morphology, cure characteristics, hardness, tensile and dynamic viscoelastic properties of the blends were investigated. The cure rate of the blends increased, while the crosslink-density decreased as the FKM content increased. The hardness, tensile strength and elongation at break, and storage modulus (E') increased with increasing FKM loading. A typical incompatible blend behavior was found by observing two distinct tanδ peaks corresponding to EPDM and FKM. Based on the morphology investigation by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) analyses, a typical 'sea-island' phase morphology was observed for the EPDM/FKM blends. As the FKM loading was increased to 50 phr, the EPDM was found to remain as the continuous phase. At the 80 phr of FKM, a co-continuous phase was observed and the phase inversion was observed at 90 phr of FKM.

에틸렌-프로필렌-디엔-모노머(EPDM) 고무와 불소고무(FKM)를 다양한 조성으로 블렌드를 제조하여 조성에 따른 상 모폴로지와 가교특성, 경도특성, 인장특성 그리고 동적 점탄성 특성을 조사하였다. FKM 함량이 증가할수록 가교속도는 증가한 반면 가교밀도는 감소하였으며, 전반적으로 경도, 인장강도, 파단신장률 및 저장 모듈러스(E')는 증가하였다. 모든 블렌드 컴파운드에서 EPDM과 FKM 고유의 유리전이온도(Tg)를 나타내고 있어, 전형적인 비혼화성 블렌드 거동을 보였다. 전자현미경(SEM)과 원소분석장치(EDS)를 이용하여 상 거동을 관찰한 결과 EPDM/FKM 블렌드는 비혼화성 블렌드의 대표적인 상거동인 연속상-분산상 모폴로지를 나타내었다. FKM 조성이 50 phr 이하에서는 EPDM이 연속상을 나타내었고, FKM이 80 phr 근방에서 공동 연속상 구조를 그리고 FKM이 90 phr에서는 FKM이 연속상을 나타내는 상전이가 나타났다.

Keywords: ethylene-propylene-diene-monomer; fluoroelastomer; blend; phase morphology; energy dispersive X-ray spectroscopy; inversion