Preparation of Nanoporous Polyimide Films from Poly(urethane‐imide) by Thermal Treatment

Krishnan, P. Santhana Gopala; Cheng, Chia Zheng; Cheng, Yeo Swee; Cheng, Jimmy Wu Chi

doi:10.1002/mame.200300030

Cited by 15 publications

(5 citation statements)

References 24 publications

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“…With the incorporation of PU, the thermograms exhibited two‐step degradation patterns and the pure polyurethane again gave a single step degradation pattern. The first step degradation is due to the degradation of PU backbone and the second step degradation is due to the degradation of PI 26. With increase in PU content, the 5 and 10% weight loss temperatures of the poly(urethane‐imide) thin films decreased as expected.…”

Section: Resultssupporting

confidence: 53%

Synthesis and characterization of new functional poly(urethane‐imide) crosslinked networks

Park

Jang

Yang

et al. 2006

J of Applied Polymer Sci

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ABSTRACT:To synthesize new functional poly(urethaneimide) crosslinked networks, soluble polyimide from 2,2Ј-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 4,4Ј-oxydianiline, and maleic anhydride and polyurethane prepolymer from polycaprolactone diol, tolylene 2,4-diisocyanate and hydroxyl ethyl acrylate were prepared. Poly-(urethane-imide) thin films were finally prepared by the reaction between maleimide end-capped soluble polyimide (PI) and acrylate end-capped polyurethane (PU). The effect of polyurethane content on dielectric constant, residual stress, morphology, thermal property, and mechanical property was studied by FTIR, prism coupler, Thin Film Stress Analyzer (TFSA), XRD, TGA, DMTA, and Nano-indentation. Dielectric constant of poly(urethane-imide) thin films (2.39 -2.45) was lower than that of pure polyimide (2.46). Especially, poly(urethane-imide) thin films with 50% of PU showed lower dielectric constant than other poly(urethaneimide) thin films did. Lower residual stress and slope in cooling curve were achieved in higher PU content. Compared to typical polyurethane, poly(urethane-imide) thin films exhibited better thermal stability due to the presence of the imide groups. The glass transition temperature, modulus, and hardness decreased with increase in the flexible PU content even though elongation and thermal expansion coefficient increased. Finally, poly(urethane-imide) thin films with low residual stress and dielectric constant, which are strongly affected by the morphological structure, chain mobility, and modulus, can be suggested to apply for electronic devices by variation of PU.

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Section: Resultssupporting

confidence: 53%

Synthesis and characterization of new functional poly(urethane‐imide) crosslinked networks

Park

Jang

Yang

et al. 2006

J of Applied Polymer Sci

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“…It possesses outstanding comprehensive performance and extensive range of applications. 1,2 Polyimide foams (PIFs) were prepared by DuPont and Monsanto first in the 1960s. 3,4 Owing to the special cellular structure of the PIFs and especially because of the benzene and imide rings on the backbone, 5,6 PIFs possess excellent performance, such as low density, great insulation, high fire resistance, good thermal stability, lower smoke generation and so on.…”

Section: Introductionmentioning

confidence: 99%

Improved mechanical, thermal and flame resistant properties of flexible isocyanate-based polyimide foams by graphite incorporation

Tian

Yao

et al. 2017

High Performance Polymers

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In order to improve the mechanical, thermal and flame-resistant properties of polyimide foams (PIFs), in the present study, flexible polyimide (PI)/graphite composite foams were prepared with dianhydride and isocyanate as the starting materials and graphite as the filler. The experimental results showed that most cells of PIFs possessed an open cell structure, and the open cell content decreased by graphite incorporation. While with the increase in graphite, the distribution of cellular size became uneven and the size distribution became broad. The compressive strength increased initially and then decreased and reached the maximum value of 26.4 kPa when the graphite content was 1.98 wt%, but all the composite foams exhibited higher strength than the neat PIF. In addition, the limiting oxygen index increased from 31% to 34.8% with the increase in graphite from 0 wt% to 3.25 wt%. The peak heat release rate of composite foams was 2.3% to 24.7% lower than the neat PIF and reached a minimum value of 42.36 kW m−2 with the graphite content of 1.98 wt%. Considering the above analysis, it is feasible to improve mechanical properties, thermal stability and flame-resistant properties of PIFs by graphite addition.

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“…Recently, lot of effort has been paid to improve the mechanical and flame‐retardant properties of polyurethane by chemical modification of its structure containing various soft and hard segments with stable aromatic heterocyclic rings . Polyurethane‐imide (PUI) foams with PI segment as flame‐retardant structure were synthesized and received increasing attentions from scientists as a kind of novel polymer with high performance .…”

Section: Introductionmentioning

confidence: 99%

Enhanced thermal stability and flame resistance of polyurethane‐imide foams by adding silicon carbide

Tian

Yao

et al. 2017

Adv Polym Technol

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Polyurethane-imide (PUI) foams containing both polyimide and polyurethane segments combined the advantage of fine mechanical properties as well as high thermal stability of the two polymers. To further improve the thermal stability and flame resistance of PUI foams, a series of PUI composite foams with different content of SiC (silicon carbide) as fillers were prepared. The cell structure, mechanical properties, flame resistance, and thermal properties of resulting PUI/SiC composite foams were characterized in detail. The experimental results showed that the cell size distribution became uneven, the apparent density was increased, and the compressive strength decreased with the increase in silicon carbide content. Meanwhile, the limiting oxygen index (LOI) showed an increase from 24.7% to 28.1% with increasing of SiC content from 0% to 9.6%. The thermogravimetric analysis showed that the addition of SiC could significantly enhance the thermal stability and flame retardancy of PUI foams. K E Y W O R D Sflame retardant, polyurethane-imide foam, silicon carbide, thermal properties

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Preparation of Nanoporous Polyimide Films from Poly(urethane‐imide) by Thermal Treatment

Cited by 15 publications

References 24 publications

Synthesis and characterization of new functional poly(urethane‐imide) crosslinked networks

Synthesis and characterization of new functional poly(urethane‐imide) crosslinked networks

Improved mechanical, thermal and flame resistant properties of flexible isocyanate-based polyimide foams by graphite incorporation

Enhanced thermal stability and flame resistance of polyurethane‐imide foams by adding silicon carbide

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