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Fabrication and Characterization of Electrospun Polyamide 66 FibersCrosslinked by Gamma Irradiation
강효경,신혜경,전준표,김현빈,강필현 한국고분자학회 2011 Macromolecular Research Vol.19 No.4
Polyamide 66 (PA66) was electrospun in the presence and absence of triallyl cyanurate (TAC) and irradiated with gamma rays. The morphology and structure of PA66 and PA66-TAC electrospun fibers were characterized by scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR). SEM showed that the morphology of PA66 was not altered by gamma irradiation. The presence of TAC in the PA66-TAC electrospun fibers was confirmed by ^1H NMR. The physical and mechanical properties of PA66 and PA66-TAC electrospun fibers irradiated with 0~50 kGy radiation were analyzed by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and tensile tests. XRD suggested that the irradiated PA66-TAC electrospun fibers displayed a higher degree of crystallinity than pure PA66 electrospun fibers. The thermal properties of irradiated PA66-TAC electrospun fibers were greater than those of pure PA66 electrospun fibers, and tensile tests showed that the Young’s modulus and stress of PA66-TAC electrospun fibers increased with increasing absorption dose due to TAC-induced crosslinking and the formation of a tighter network. Therefore, the results show that gamma irradiation-induced crosslinking can be used to enhance the mechanical properties of PA66.
AC4C 합금의 기계적 성질에 미치는 주조조건과 열처리의 영향에 관한 연구
강효경,천병욱,최창옥 ( Hyo Gyoung Kang,Byung Wook Cheon,Chang Ock Choi ) 한국주조공학회 1993 한국주조공학회지 Vol.13 No.5
N/A AC4C alloy casts in the metallic mold, zircon sand mold, silica sand mold and shell mold with the pouring temperatures of 680, 710 and 740℃ have been investigated. The tensile strength, elongation and hardness of AC4C alloy castings have been influenced by the kind of molds used. The mechanical properties in zircon sand mold castings were greater than those in other sand mold castings, but were inferior to the properties in metallic mold castings. Eutectic Si particle size and DAS were increased in the order of metallic mold, ziron sand mold, silica sand mold and shell mold. Also, they were increased with the increase of pouring temperatures. DAS, eutectic Si particle size and grain size decreased with the increase of mechanical properties as the cooling rate increased. The eutectic Si particle size and DAS of AC4C alloy castings after T6 treatment were decreased in as-cast. The variation of eutectic Si particle size has been effected on the tensile strength, elongation and fractured surface.