Abstract:Diffusion coefficients of Cu2+ in the form of its carboxylate have been measured in isotactic polypropylene as a function of temperature (90–128°C) and extent of preoxidation. Diffusion take place from the metal catalyst/polymer interface into the bulk polymer. The diffusion is dependent on the extent of preoxidation and temperature but not on the type of catalyst (Cu, CuO, CuO0.67). Analysis of polymer sections for Cu2+ ions was carried out with a selective Cu2+ electrode. Diffusion in isotactic polypropylene… Show more
“…Since it has been reported that the higher the temperature, the more easily the carboxylate diffuses in the resin matrix. 66–68 The relatively thick interphase layer might be formed by the diffusion of the carboxylate generated at the interface in some high temperature process during manufacturing. Figure 2.Maps (left) and profiles (right) of height (a) and AFM-IR intensities at 1582 cm −1 (I1582) for carboxylate (b) and 1502 cm −1 (I1502) for epoxyacrylate (c) and the ratio of these intensities (I1582/I1502) (d).…”
There is a great need for the analysis of the chemical composition, structure, functional groups and interactions at polymerâmetal interfaces in terms of adhesion, corrosion, and insulation. Although atomic-force-microscopy-based infrared spectroscopy (AFM-IR) can provides chemical analysis with nanoscale spatial resolution, it generally requires to thin a sample to be placed on a substrate that has low absorption of infrared light and high thermal conductivity, which is often difficult for samples that contain hard materials like metals. This study demonstrates that the combination of AFM-IR with low-angle microtomy (LAM) sample-preparation can analyze buried polymerâmetal interfaces with higher spatial resolution than that with the conventional sample-preparation of a thick vertical cross-section. In the LAM of a polymer layer on a metal substrate, the polymer layer is tapered to be thin in the vicinity of the interface, and thus, sample thinning is not required. An interface between an epoxyacrylate layer and copper wire in a flexible printed circuit cable was measured using this method. A carboxylate interphase layer with a thickness of ~130 nm was clearly visualized at the interface, and its spectrum was obtained without any signal contamination from the neighboring epoxyacrylate, which was difficult to achieve on a thick vertical cross-section. The combination of AFM-IR with LAM is a simple and useful method for high-spatial-resolution chemical analysis of buried polymerâmetal interfaces.
“…Since it has been reported that the higher the temperature, the more easily the carboxylate diffuses in the resin matrix. 66–68 The relatively thick interphase layer might be formed by the diffusion of the carboxylate generated at the interface in some high temperature process during manufacturing. Figure 2.Maps (left) and profiles (right) of height (a) and AFM-IR intensities at 1582 cm −1 (I1582) for carboxylate (b) and 1502 cm −1 (I1502) for epoxyacrylate (c) and the ratio of these intensities (I1582/I1502) (d).…”
There is a great need for the analysis of the chemical composition, structure, functional groups and interactions at polymerâmetal interfaces in terms of adhesion, corrosion, and insulation. Although atomic-force-microscopy-based infrared spectroscopy (AFM-IR) can provides chemical analysis with nanoscale spatial resolution, it generally requires to thin a sample to be placed on a substrate that has low absorption of infrared light and high thermal conductivity, which is often difficult for samples that contain hard materials like metals. This study demonstrates that the combination of AFM-IR with low-angle microtomy (LAM) sample-preparation can analyze buried polymerâmetal interfaces with higher spatial resolution than that with the conventional sample-preparation of a thick vertical cross-section. In the LAM of a polymer layer on a metal substrate, the polymer layer is tapered to be thin in the vicinity of the interface, and thus, sample thinning is not required. An interface between an epoxyacrylate layer and copper wire in a flexible printed circuit cable was measured using this method. A carboxylate interphase layer with a thickness of ~130 nm was clearly visualized at the interface, and its spectrum was obtained without any signal contamination from the neighboring epoxyacrylate, which was difficult to achieve on a thick vertical cross-section. The combination of AFM-IR with LAM is a simple and useful method for high-spatial-resolution chemical analysis of buried polymerâmetal interfaces.
We report in-situ Fourier transform infrared (FTIR) reflection-absorption studies of curing chemistry of polyimide thin films on Crand Cu surfaces, and of the thermal stability of the resulting thin film interfaces when exposed to air at elevated temperatures. The polyimide investigated is based on 4,4'-(hexafluoroisopropylidene)bis(phthalicanhydride)-4,4'-bis(4-aminophenoxy)-biphenyl. The imidization process takes place at temperatures higher than 90°C anda small amount of anhydride is generated during curing. This by-product is converted to imide at temperatures above 250°C. Complete imidization is achieved after curing at 300°C on Cr substrates, while evidence for incomplete curing on Cu is observed under the same conditions. Thermal stability studies with Cr and Cu substrates show that thermal decomposition of thin (∼1000Å) polyimide filmsoccurs on Cu when the film is exposed to air at 200°C, while the polyimide is stable on Cr.
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