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폴리에스테르 공중합체의 Fabrication 연구(I) - PET/PETG Blends의 물리적 특성 -
이소화,현은재,황성혁,제갈영순,장상희,김봉식,Lee, So Hwa,Hyeon, Eun Jae,Hwang, Seong Hyeok,Jang, Sang Hui,Kim, Bong Sik 한국섬유공학회 1999 한국섬유공학회지 Vol.36 No.10
Blends of poly(ethylene terephthalate) (PET) and poly(ethylene terephthalate glycol) (PETG) were prepared on a twin-screw extruder. Blend films were prepared by solid state extrusion on a capillary rheometer, Crystallinity, thermal, dynamic mechanical, rheological, and mechanical properties of these blend films were investigated. PET/PETG blend films exhibited single $T_{g}$ and $T_{m}$ because of the compatibility of PET with PETG. The crystallinity and density of these blend films increased with increasing draw ratio. Storage modulus of PET/PETG blend films increased with increasing draw ratio. The viscosity of PET/PETG blends was lower than that of the parent polymers and exhibited a minimum at the PET/PETG composition of 90/10. The tensile strength of PET/PETG blend films increased with increasing draw ratio but decreased with increasing PETG content.
고성능 및 친환경 차량의 복합재 브레이크 안정감 향상을 위한 스퀼 노이즈 강건성 분석에 관한 연구
심재훈,이중희,신웅희,임동원,현은재,전태형,Shim, J.H.,Lee, J.H.,Shin, U.H.,Lim, D.W.,Hyun, E.J.,Jeo, T.H. 한국자동차안전학회 2021 자동차안전학회지 Vol.13 No.3
Composite material is very attractive because it has excellent mechanical property and is possible to lightweight due to the low density. However, composite material is less used compared to other systems in the chassis system because it is very hard to solve NVH problem when composite material is applied to vehicle. Especially, reducing squeal noise of composite brake system is essential to apply it to vehicle successfully. In this paper, we present a new solution to reduce squeal noise of composite brake system. To achieve this goal, we analyze main causes of noise using RCA (Root Cause Analysis), CA (Contradiction Analysis) and sequentially get IFR (Ideal Final Result) to solve the problem. Next, we define the function of composite brake system and derive control factors and noise factors. A variety of tests for factors like chamfer, slot, damping shim, underlayer of brake pad are done. In addition, we analyze level of contribution for control factors theoretically. Finally, we get the effective solution for reducing squeal noise.
친환경 법규 대응을 위한 복합재 브레이크의 Cu Free 마찰재 개발에 관한 연구
심재훈,이중희,신웅희,임동원,현은재 사단법인 한국자동차안전학회 2022 자동차안전학회지 Vol.14 No.2
Composite material is widely used in the automotive industries because it has excellent mechanical properties and is possible to reduce weight due to the low density. However, there is a new obstacle to meet environment regulation like Cu less or Cu free regulation for the friction material. Although it is strongly demanded, there are few research results about that unfortunately. Unless this problem is not solved properly, it is impossible to apply composite brake system to vehicle. In this paper, a new eco-friendly friction material for composite brake system is represented to respond these regulations. To do this, friction characteristics between existing low steel friction material and new eco-friendly friction material are verified to secure performances for brake system such as effect characteristic, fade characteristic and wear characteristic. And composite brake gets the equivalent or better performance compared to a low steel friction material. Finally, this result contributes to the study of major principles for the development of eco-friendly friction material in the future.