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둔감 고에너지 물질 TEX 결정화 연구

초록/요약

Drowning-out crystallization of 4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diaza tetracyclo [5.5.0.05,9.03,11]-dodecane (TEX), known as a less-sensitive high energetic material, was carried out to observe effects of supersaturation and polyvinylpyrollidone (PVP) on nucleation kinetics, crystal size and morphology. Dimethylsulfoxide (DMSO) as a solvent and ethanol as an anti-solvent were used for drowning-out crystallization of TEX. Nucleation kinetics was determined by induction time and nucleation rate measured from FBRM. Under different supersaturations ranging from 1.1-2.9, induction times and nucleation rates followed the trend predicted using the classical nucleation theory (CNT). The heterogeneous nucleation was triggered at low supersaturation below 1.5, whereas homogeneous nucleation became predominant at high supersaturation above 1.5. The shape of the crystals was found to differ with the supersaturation and existence of PVP. Polyhedral TEX was precipitated at supersaturation of 1.1-1.7, hexagonal plate-like crystals were precipitated at 1.9-2.9 and lozenge-shaped crystals were precipitated at 3.5-3.9. On the other hand, PVP acted as a nucleation retarder by increasing induction times and interfacial energy between solution and surface of growing cluster .PVP had a effect on keeping polyhedral morphology of TEX from plate form by increasing supersaturation.

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초록/요약

둔감성 고에너지 물질인 4, 10-Dinitro-2,6,8,12-tetraoxa- 4,10-diazatetracy clo[5.5.0.05,9.03,11]-dodecane(TEX)에 대한 drowning-out 결정화 연구로 과포화도와 첨가제인 polyvinylpyrollidone (PVP)에 따른 TEX 입자의 형상과 평균 입경 변화 및 핵생성 속도론이 논의되었다. Dimethylsulfoxide (DMSO)와 에탄올을 용매와 반용매로 각각 이용한 Drowning-out 결정화 공정에서 induction time과 핵생성 속도를 FBRM으로 측정하여 핵생성 메카니즘을 해석하였다. 과포화도(S) 범위가 1.1~2.9 일 때 측정된 induction time과 핵생성 속도는 고전 핵생성이론(CNT)으로 예측한 결과와 일치하였다. 과포화도가 1.5 이상일 경우 균일 핵생성(homogeneous nucleation)으로 1.5 이하일 경우 불균일 핵생성(heterogeneous nucleation)으로 해석된다. TEX의 결정 형상은 과포화도와 첨가된 PVP에 큰 영향을 받음을 알 수 있었다. 과포화도 1.1-1.7 범위에서는 다면체형, 1.9-2.9 범위에서는 육각판형, 3.5- 3.9 범위에서는 마름모형의 TEX 결정이 제조되었다. 한편 PVP가 첨가되었을 때 핵생성이 억제되어 induction time은 증가하였다. 이는 PVP에 의해 TEX 결정과 용액 사이의 계면에너지가 증가한 때문으로 해석된다.

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