Article
  • Miscibility in Polybenzimidazole with Synthetic Polyimides Blends
  • Ahn TK, Choe S
  • 방향족 폴리벤즈이미다졸과 합성한 폴리이미드의 블렌드에 대한 상용성
  • 안태광, 최순자
Abstract
Polyamicacids using BTDA (3,3',4,4'-benzophenone tetracarboxylic dianhydride) with 2,4-TDA (2,4'-toluene diamine) and 4,4'-MDA (4,4'-methylene dianiline) were synthesized by condensation polymerization. Blend solutions of poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole](PBI) and the above synthesized polyamicacids were prepared by using a cosolvent, DMAc and cast film or precipitated into powder, then cured at higher temperatures than the estimated Tg's. Miscibility and the specific interactions responsible for miscibility were investigated using DSC and FT-IR. Phase diagram was obtained by DSC and thermal stability of the blends was also stooled using TGA. Both the blend systems, PBI/BTDA+2,4'-TDA(blend Ⅰ ) and PBI/BTDA+4,4'-MDA(blend Ⅱ) are miscible ; evidences for miscibility were optically clear films and single composition dependent Tg's intermediate between those of the homopolymers. LCST type phase behavior was obtained by DSC annealing study and thermal stability was enhanced in these blend systems. From FT-IR studies, carbonyl stretching band of PIs and N-H stretching band of PBI shifted to lower frequencies about 7∼10cm-1 and 50∼55cm-1, respectively. Thus hydrogen bonding between carbonyl arised from 5-membered ring solely and N-H is responsible to bring a miscible system.

BTDA(3,3',4,4',-benzophenone tetracarboxylic anhydride)와 두 종류의 diamine인 2,4-TDA(2,4'-toluene diamine)과 4,4'-MDA(4,4' -methylene dianiline)를 용매 DMAc(di-methyl-acetamide)속에서 반응시켜 폴리아믹산(PAA)을 합성하였으며, 이들 두 종류의 PAA를 고내열성, 무정형 고분자인 poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole : PBI]와 각각 용액 블렌딩하여 PBI/PAA 분말 및 필름으로 제조한 후 각각 블렌드의 Tg보다 높은 온도에서 수분을 빼면서 경화시킨 PBI/PI 시료를 DSC (differential scanning calorimeter) 와 FT-IR (fourier transform-Infrared spectroscopy)를 사용하여 상용성과 상변이 현상 그리고 TGA로 열안정성을 조사하였다. 두 블렌드 시스템, PBI/BTDA+2,4'-TDA(blend I )와 PBI/BTDA+4,4'-MDA(blend Ⅱ)는 광학적으로 투명한 필름과, 전 블렌드조성에서 하나의 유리전이온도를 나타냄으로써 상응성을 가지고 있으며 어닐링 온도를 변화시키면서 측정한 Tg로부터의 상평형 그림은 전형적인 LCST 형의 상분리 현상을 보였다. 또한 FT-IR로 폴리이미드의 C=0와 PBI의 N-H그룹의 band가 낮은 주파수쪽으로 이동하는 현상으로루터 폴리이미드와 폴리벤지미다졸사이의 수소결합이 상용성을 가져다 주는 요인으로 사려된다.

Keywords: polybenzimidazole; aromatic polyimide; polymer blend; miscibility; hydrogen bonding

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  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2023 Impact Factor : 0.4
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This Article

  • 1995; 19(5): 633-643

    Published online Sep 25, 1995