• Title/Summary/Keyword: 6FDA-6FpDA

Search Result 3, Processing Time 0.058 seconds

Transport Properties of Fluorinated Polyimide/PMMA-g-Silica Nanocomposite Membrane (PMMA가 그래프트된 실리카 나노입자를 포함한 불소계 폴리이미드 복합 분리막의 기체 투과 특성)

  • Kwon, Yu-Mi;Im, Hyun-Gu;Kim, Joo-Heon
    • Polymer(Korea)
    • /
    • v.34 no.1
    • /
    • pp.1-7
    • /
    • 2010
  • To enhance the transport properties of gas separation membrane, we prepared 6FDA-6FpDA based polyimide membrane with PMMA-graft-silica nanoparticles. The silica was grafted PMMA which is miscible with 6FDA-based polyimide after surface treatment by 3-methacryloxypropyltrimethoxysilane ($\gamma$-MPS). The untreated silica/6FDA-6FpDA membrane showed greater permeability and less selectivity than PMMA-g-silica/6FDA-6FpDA due to its low dispersion. The transport properties of PMMA-g-silica/6FDA-GFpDA membrane were measured as a function of filler concentration. These membranes were evaluated using pure gases (He, $O_2$, $N_2$, $CO_2$). The increase in permeation was attributed to changes in the free volume distribution until 1 wt%. After 1 wt%, the permeability was decreased by excess silica which decreased effective area in polymer matrix. The selectivity was decreased with increasing permeability on the whole. However, the selectivity of $CO_2$ showed more enhance value.

Electrical Conductivity Behavior of 6FDA-based Fluorinated Polyimide/PMMA-g-MWCNT Nanocomposite Film (6FDA를 포함한 불소계 폴리이미드와 PMMA가 그래프트된 카본나노튜브 나노복합필름의 전기 전도성 연구)

  • Yun, Sung-Jin;Im, Hyun-Gu;Kim, Joo-Heon
    • Polymer(Korea)
    • /
    • v.34 no.2
    • /
    • pp.97-103
    • /
    • 2010
  • PMMA was grafted on MWCNT surface in order to prepare conducting film composed of 6FDAbased polyimide/MWCNT. The electrical conductivity of 6FDA-based polyimide/PMMA-g-MWCNT was investigated as a function of PMMA-g-MWCNT content. Dispersion of MWCNT in 6FDA-based polyimide composite film was better than the pristine MWCNT due to the interaction force between PMMA and 6FDA-based polyimide. Electrical conductivity was interpreted by percolation threshold theory. As a result, 6FDA-6FpDA/PMMA-g-MWCNT which have high critical exponents and low critical concentration showed better dispersion than polyimide composite material that contains DABA(diamino benzoic acid).

Effect of Long Time Physical Aging on Ultra Thin 6FDA-Based Polyimide Films Containing Carboxyl Acid Group (Carboxyl Acid Group을 포함한 6FDA-Based 폴리이미드 박막필름의 장시간 에이징에 따른 특성변화)

  • Im, Hyun-Gu;Kim, Joo-Heon;Lee, Hyuk-Soo;Kim, Tae-Min
    • Polymer(Korea)
    • /
    • v.31 no.4
    • /
    • pp.335-342
    • /
    • 2007
  • The goal of this study is to investigate the effect of molecular structure modifications on the kinetics of physical aging of thin films formed from 6FDA-based polyimides with time. The permeability for 6FDA-based polyimide thin films containing carboxyl acid groups commonly decreased 20-50% after the isothermal aging and the selectivity gained anywhere from 10% to 30% while the rate of permeability loss on the change of polymer structure showed different reciprocal relationship between 6FDA-6FpDA based polyimides and 6FDA-DAM based polyimides. The Lorenz-Lorentz equation was used to relate changes in refractive index to densification and volume relaxation with aging time. The permeability as a function of aging time fits the expected form $P=Ae^{(-B/f)}$. The results matched well with the data for different polymer membranes.