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Ethylene–propylene–diene monomer (EPDM) rubber is one of the rapidly developing synthetic rubbers for use as a gasket material in proton exchange membrane (PEM) fuel cell applications. Despite its excellent elastic and sealing properties, EPDM faces challenges such as molding processability and recycling ability. To overcome these challenges, thermoplastic vulcanizate (TPV), which comprises vulcanized EPDM in polypropylene matrix, was investigated as a gasket material for PEM fuel cell applications. TPV showed better long-term stability in terms of tension and compression set behaviors under accelerated aging conditions than EPDM. Additionally, TPV exhibited significantly higher crosslinking density and surface hardness than EPDM, regardless of the test temperature and aging time. TPV and EPDM showed similar leakage rates for the entire range of test inlet pressure values, regardless of the applied temperature. Therefore, we can conclude that TPV exhibits a similar sealing capability with more stable mechanical properties compared with commercialized EPDM gaskets in terms of He leakage performance.

The automotive industry is moving from the internal combustion engine to electric drive motors. Electric motors uses a high voltage system requiring the development of resources and components to shield the system. Therefore, in this study, we analyze electromagnetic interference (EMI) shielding effectiveness (SE) characteristics of an auto crash pad according to the ratio of electrically conductive materials and propylene. In order to combine good mechanical characteristics and electromagnetic shielding of the automotive crash pad, metal-coated glass fiber (MGF) manufacturing methods are introduced and compared with powder-type methods. Through this study, among MGF methods, we suggest that the chopping method is the most effective shielding method.

초록: 두 가지의 종횡비(ρ α = a 1 /a 3 and ρ β = a 1 /a 2 )에 의해 특징지어진 3차원 타원체(a 1 > a 2 > a 3 )를 사용하여 polypropylene 복합체의 판상형 충전제 함량과 방향이 열팽창률에 미치는 영향에 대해 실험적인 연구를 수행하 였다. 측정된 실험적인 값은 Lee와 그의 연구자들이 제안한 이론적인 모델에 의한 계산 값과 비교분석되었다. 판상형 충전제로는 운모와 탈크가 사용되었다. 실험 결과로 운모의 경우 종횡비는 ρ α = 13.5,Abstract: Experimental study was performed regarding the effects of disc-like filler orientation and contents on the coefficient of thermal expansion (CTE) of polypropylene composites using the three dimensional ellipsoids (a 1 > a 2 > a 3 ) analyzed by two aspect ratios(ρ α = a 1 /a 3 and ρ β = a 1 /a 2 ). Measured data were compared with the theoretical approaches proposed by Lee et al. Mica and talc were useed as disk-like fillers in the composites. As experimental results, α 11 /α m decreased down to ca. 0.56 with mica content of 20 wt% and the aspect ratios, ρ α = 13.5, ρ β = 1.8. However, α 33 /α m increased to more than 1. In the case of talc, α 11 /α m decreased to ca. 0.63 with 20 wt% and ρ α = 3.7, ρ β = 1.4. Finally, the longitudinal CTEs (α 11 ) of polypropylene composites decreased as filler contents increased, but normal CTE (α 33 ) increased in the low filler contents like the theory.

초 록: 이 논문은 판상형 충전제의 함량과 배향에 따라 폴리프로필렌 복합체의 영률 변화에 미치는 영향을 연구 하였다. 이론적인 예측은 Lee와 그의 연구자들에 의해 제안된 두 개의 종횡비, ρ α =a 1 /a 3 과 ρ β =a 1 /a 2 를 이용하여 3차원Abstract: This paper studied the effects of the content and the orientation of the disk shape fillers on the modulus of PP composites. The experimental results were compared with the theoretical calculations which included the three dimensional ellipsoids and analyzed by two aspect ratios, ρ α =a 1 /a 3 and ρ β =a 1 /a 2 proposed by Lee and his researchers.Mica and talc were used as disk shape fillers in the composites. The shapes of mica and talc were observed by SEM and aspect ratios were statistically calculated. For the case of mica, the average aspect ratios were ρ α =13.5 and ρ β =1.8, and for the case of talc, they were ρ α =3.8 and ρ β =1.4. Also, the effects of two aspect ratios and the content of filler on the mechanical properties were studied: For 30 wt% of mica, E 11 increased up to about 2.7 times, and for the other case of talc, E 11 increased up to about 2.3 times, respectively.