Structural Effects on the Transport of Water in Polyimides

Alsten, John G. Van; Coburn, John C.

doi:10.1021/ma00092a011

Cited by 46 publications

(50 citation statements)

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“…Many authors have focused their attention on the diffusion behavior of small molecules in polymers [119,120,121,122,125,126,127,128,129,130,131]. This is discussed in the first part of this subsection.…”

Section: -Determination Of the Diffusion Coefficients By Atr Spectrosmentioning

confidence: 99%

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Spectroscopic characterization of molecular interdiffusion at a poly(vinyl pyrrolidone)/vinyl ester interface

Laot

Marand

Oyama

1999

Polymer

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Mechanical properties of (woven carbon fiber / vinyl ester matrix) composites can be greatly improved if the interphase between the reinforcing high-strength low-weight fiber and the thermoset resin is made more compliant. In order to improve the adhesion of the vinyl ester matrix to the carbon fiber, a thermoplastic coating such as poly(vinyl pyrrolidone) (PVP) can be used as an intermediate between the matrix and the fiber. The extent of mutual diffusion at the (sizing material / polymer matrix) interphase plays a critical role in determining the mechanical properties of the composite.In this research, the molecular interdiffusion across a poly(vinyl pyrrolidone))/vinyl ester monomer (PVP/VE) interface is being investigated by Fourier Transform Infrared Attenuated Total Reflectance (FTIR-ATR) spectroscopy. The ATR method which can be used to characterize the transport phenomena, offers several advantages, such as the ability to monitor the diffusion in situ or to observe chemical reactions. In order to separate the effects of the vinyl ester monomer diffusion and the crosslinking reaction, ATR experiments were carried out at temperatures below the normal curing temperature. Diffusion coefficients were determined by following variations in infrared bands as a function of time, and fitting this data to a Fickian model. The values of the diffusion coefficients calculated were consistent with values found in the literature for diffusion of small molecules in polymers. The dependence of diffusion coefficients on temperature followed the Arrhenius equation. Hydrogen bonding interactions were also characterized. The diffusion model used in this study, however, does not seem to be appropriate for the particular (PVP/VE) system.Because the glass transition temperature of the PVP changed as diffusion proceeded, one would expect that the mutual diffusion coefficient did not stay constant. In fact, it was shown that the T g can drop by 140 o C during the diffusion process. A more suitable model of the (PVP/VE) system should take into account plasticization, hydrogen bonding, and especially a concentration dependent diffusion coefficient. Further analysis is therefore needed.iv ACKNOWLEDGMENTS

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Section: -Determination Of the Diffusion Coefficients By Atr Spectrosmentioning

confidence: 99%

“…Coburn [121] studied the influence of cure conditions and backbone chemistry of polyimides on the diffusion of heavy water. As the chain backbone stiffness increased, and also as the density of the amorphous phase increased, for a given backbone composition, the diffusivity decreased.…”

Section: -Determination Of the Diffusion Coefficients By Atr Spectrosmentioning

confidence: 99%

Spectroscopic characterization of molecular interdiffusion at a poly(vinyl pyrrolidone)/vinyl ester interface

Laot

Marand

Oyama

1999

Polymer

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“…4 The high concentration of polar groups and poor morphological structure of PEl lead to relatively high water sorption. The water sorption causes potential reliability problems in microelectronic devices, [5][6][7][8][9][10] such as displacement, package crack, delamination, loss of adhesion, potential corrosion, and mechanical failures in thin films.…”

Section: Introductionmentioning

confidence: 99%

Water sorption and diffusion behaviors in composite films of poly(ether imide) and bismaleimide

Seo

Lee

Jang

et al. 2005

J of Applied Polymer Sci

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ABSTRACT:The effect of a crosslinkable imide moiety, bismaleimide (BMI), on the water sorption properties of poly(ether imide) (PEl) was gravimetrically measured and interpreted together with the chemical and morphological structures in composite films. The morphological structure of composite films was investigated by using a prism coupler and X-ray diffraction pattern. It indicated that the inplane orientation and intermolecular packing order increased as the content of BMI in composite films increased. The water sorption behaviors showed dependence on the morphological change originating from the addition of BMI to PEI. The composite film with relatively high content of BMI exhibited a relatively high degree of in-plane orientation and a small mean intermolecular distance, which resulted in a decrease in the diffusion rate and water sorption and an increase in the activation energy in composite films.

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“…Al2O3, they undergo chemisorption which causes dissociation of these molecules and creation of surface hydroxyl groups [16]). Diffusion in polyimides depends on their crystallinity and density, as well as on chain stiffness [17]. In FTIR spectra shifts were observed which can be attributed to carbonyl groups as proton acceptors in dipole-dipole interactions with water molecules, which exhibit a strong intrinsic permanent electric dipole moment [18]; these shifts were fully reversible during the water desorption process.…”

Section: Modelling Of Polymer-based Capacitive Humidity Sensorsmentioning

confidence: 99%

Low Humidity Characteristics of Polymer-Based Capacitive Humidity Sensors

Majewski

2017

Metrology and Measurement Systems

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Polymer-based capacitive humidity sensors emerged around 40 years ago; nevertheless, they currently constitute large part of sensors' market within a range of medium (climatic and industrial) humidity 20−80%RH due to their linearity, stability and cost-effectiveness. However, for low humidity values (0−20%RH) that type of sensor exhibits increasingly nonlinear characteristics with decreasing of humidity values. This paper presents the results of some experimental trials of CMOS polymer-based capacitive humidity sensors, as well as of modelling the behaviour of that type of sensor. A logarithmic functional relationship between the relative humidity and the change of sensor output value at low humidity is suggested.

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Structural Effects on the Transport of Water in Polyimides

Cited by 46 publications

References 4 publications

Spectroscopic characterization of molecular interdiffusion at a poly(vinyl pyrrolidone)/vinyl ester interface

Spectroscopic characterization of molecular interdiffusion at a poly(vinyl pyrrolidone)/vinyl ester interface

Water sorption and diffusion behaviors in composite films of poly(ether imide) and bismaleimide

Low Humidity Characteristics of Polymer-Based Capacitive Humidity Sensors

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