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송수완,서민강,박수진,신재섭 한국공업화학회 2002 한국공업화학회 연구논문 초록집 Vol.2002 No.0
In this study, the effects of carbon black (CB) content and particle size on positive temperature coefficient (PTC) behavior of conductive CB/HDPE nanocomposites were investigated in the temperature range of 20~180℃. Also, the silane coupling agent was used to reduce the negative temperature coefficient (NTC) of the composites in the content of 0.1~0.5 wt%. From the experimental results, it was founded that the room temperature volume resistivity was decreased with increasing the carbon black content and specific surface area, which were affected by the particle size of carbon black. The largest PTC intensity of conductive polymer composites showed on the carbon black contents of 30 wt% and particle size of 80-90 nm. It was observed that the resistivity of PTC composites was greatly increased near the crystalline melting temperature, due to the structure change of matrix and the difference of thermal expansion coefficient of carbon black and polymer. It was also found that the silane treatment made a disappearance of NTC phenomenon, due to the improvement of interfacial binding force between polymer and carbon black.
저독성 난연제를 첨가한 에폭시 수지의 경화 동력학 및 유변학적 특성
박수진,송수완,이재락,민병각,신재섭 한국공업화학회 2004 공업화학 Vol.15 No.1
본 실험에서는 2관능성 에폭시 수지(EP)에 저독성 난연제인 tris (chloroisopropyl) phosphate (TCPP) 를 100:0~100:40 phr의 비율로 첨가한 후 이에 따른 경화 동력학과 유변학적 특성을 고찰하였다. 2EP/TCPP 시스템의 경화 활성화 에너지(E_(a))와 진화량(α)은 동적 DSC를 통하여 알아 보았으며, 유변학적 특성은 레오미터를 이용하여 등온 조건하에서 고찰하였다. 또한, 난연성 test인 UL94를 통하여 TCPP 함량에 따른 난연성의 변화를 살펴보았다. 실험 결과, E_(a)는 에폭시 수지 내에 TCPP의 함량이 증가할수록 증가하는 반면, 전화량(α)과 전환속도(d/dt)는 감소하는 경향을 나타내었다. 가교 활성화 에너지(E_(c)) 값은 구한 E_(a) 값과 유사한 경향을 나타내었으며, 이러한 결과는 TCPP의 증가로 인해 2EP 고유의 interpenetrating polymer network (IPN) 구조형성이 방해받기 때문이라 판단된다. 또한, TCPP의 함량이 30 phr 이상인 경우 난연성이 향상되었는데, 이는 TCPP 내의 난연성을 갖는 인과 염소의 영향으로 판단된다. In this work. the cure kinetics and rheological properties of difunctional epoxy (2EP) resins containing a low toxicity flame-retardant based on tris(chloroisopropyl) phosphate (TCPP) are investigated. The 2EP/TCPP content was varied within 100 : 0 ∼100 : 40 phr. The cure system are studied under the isothermal condition using a rheometer, Also, the flame resistance is determined by UL94 vertical test. From experimental results, the Ea of 2EP/TCPP system is higher than that of pure 2EP. While, the conversion (α1 and conversion rate (d/dt) are decreased with increasing of the TCPP content. The cross-linking activation energy (E_(e)) of the system is similar to (E_(a)). This is probably due to the increase of TCPP content. which obstructs the formation of interpenetrating polymer network (IPN) structure of the 2EP. Also, the improvement of flame resistance is achieved by addition of 30 phr TCPP in the 2EP/TCPP system. which can be attributed to the existence of incombustible phosphorous and chlorines in the TCPP.