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RISS 인기검색어
- 검색키워드
- 저자 : 장용균 (검색결과 2 건)
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Underfill용 Bisphenol계 에폭시 수지 조성물의 유변학적 거동과 기계적 특성
Rheological behavior and mechanical properties of bisphenol type epoxy composites for underfill were investigated. Viscosity of epoxy composites was measured by rotational viscometer and decreased as increasing aging time at room temperature and decreased as increasing coupling agent contents. Thixotropic index was same behavior with the function of aging time, but was not changed with coupling agent contents. Flow distance was increased with decreasing viscosity and increasing gab size. Spherical silica used is the most efficiently coated with elastomer when process time is thirty minutes and the ratio of elastomer/coupling agent is one to one. In order to show elastomer coating thickness regardless of filler size, the elastomer amount coated in silica surface are represented in terms of coating rate (i.e. coating thickness over silica diameter). The flexural strength and modulus of the composite filled with only silane-treated silica was higher than those of the composites filled with both silane-treated silica and elastomer, and those of the composites filled with elastomer-coated silica. The flexural strength and modulus of the composite slowly decreased with increase in coating rate (t/d).
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(A) study on electrical property of polymeric composite using modification of filler
장용균 Graduate School, Korea University 2011 국내박사
The purpose of this study is to confirm the electrical property of polymeric composite using modification of filler. Modification of filler is classified of functional group grafting and polymer encapsulation. Polyphenylenesulfide (PPS) as matrix, multi-walled carbon nanotube (MWNT) as filler and imidazole as grafting group are used for research of functional group grafting. The pristine MWNTs are oxidized (COOH-MWNT). COOH-MWNT is converted to the acyl chloride functionalized MWNT and then modified successfully with imidazole (Imidazole-MWNT). We have examined the electrical properties of PPS composites filled with COOH-MWNT as well as with Imidazole-MWNT. The better dispersion of Imidazole-MWNT and the low percolation threshold of the functionalized MWNT/PPS are found in all MWNT compositions. Consequently, the electrical properties of MWNT/PPS composites could be improved by the surface modification of MWNT with imidazole. The dispersion of MWNT in Polyphenyleneoxide (PPO) and electrical properties of their composite films are investigated with respect to the encapsulation. The encapsulation of MWNT is carried out by the precipitation process, where the solution composed of MWNT, PPO and toluene is dropped into methanol as a poor solvent for PPO. The encapsulation efficiency is analyzed in terms of the concentration of each component in toluene, dropping speed of the solution into methanol, and so on. The PPO composite films filled with previously PPO-encapsulated MWNT show lower percolation threshold than films filled with COOH-MWNT because of the better dispersion of MWNT in the former. It is seen that the encapsulation of MWNT can enhance the degree of dispersion of MWNT in polymer matrix and thus the physical properties of composite film.
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