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Water Sorption Kinetics 에 대한 폴리이미드 사슬의 강직도와 두께의 영향
한학수,조영일,서종철,이안나,하순효 한국공업화학회 1998 응용화학 Vol.2 No.2
The water sorption and difussion behavior for the polyimide thin films with various chain rigidities, which include fully rodlike PMDA-PDA, semi-rigid BPOA-PDA, semi-flexible PMDA-ODA, and fully flexible BTDA-ODA, were investigated in detail by water sorption method using a Cahn Micro-balance. The water sorption and diffusion behaviors in thin films were investigated together with backbone structure and morphological structure originated from the difference of thickness. For PMDA-ODA films, the diffusion coefficient of water varied from 9.4x10^-(10)㎠/sec to 32.2x10^-(10)㎠/sec and the water uptake varied from 3.06 to 2.54wt % over 11.97-42.20㎛ thickness, respectively. For BTDA-ODA films, the diffusion coefficient of water varied from 10.8x10^-(10)㎠/sec to 37.5x10^-(10)㎠/sec and the water uptake varied from 2.68 to 2.99wt % over 11.39-41.95㎛ thickness, respectively. For BPDA-PDA the diffusion coefficient of water varied from 1.5x10^-(10)㎠/sec to 3.9x10^-(10)㎠/sec and the water uptake varied from 1.67 to 1.26wt % over 8.24-56.00㎛ thickness, respectively. The film thickness dependence for the diffusion coefficient of water and uptake might result from morphological changes, which may include orientation, crystallinity, and chain packing density, due to the variation of film thickness.
Hydroxyl 기를 갖은 용해성 폴리이미드의 합성 및 제조방법에 따른 특성변화
전경용,김한성,한학수,조영일,하순효 한국공업화학회 1998 응용화학 Vol.2 No.2
Aromatic soluble polyimide was synthesized from 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane and 4,4'-(hexafluoroisopropylidene)-bis-(phthalic anhydride) by one-step high temperature polycondensation and by two-step procedure using chemical imidization of poly(amic acid). Polyimide by chemical imidization was soluble in common organic solvent(acetone, NMP, DMSO, THF), in constrant polyimide synthesized with one-step method was soluble in amide solvent(NMP, DMAc). The difference of solubility was explained by esterification of hydroxyl group with dehydrating agents in chemical imidization.