Low-modulus die-bonding films made of reaction-induced polymer alloy are useful for stacked multi-chip packages, which are suitable for compact electronic devices. Properties of the films are widely varied by the ratio of epoxy resin and acrylic polymer contents. To optimize the properties of the die-bonding films for thin wafer application, the influence of various parameters on material properties was examined by using the weak conditioned combinatorial linear programming method and nonlinear estimation. By defining solution area as a function of combination index, optimum filler size is acquired.

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Carboxyl-terminated butadiene acrylonitrile (CTBN) liquid rubber / epoxy (diglycidyl ether of bisphenol-A: DGEBA) / diamino diphenyl methane (DDM) network polymer alloys, in which CTBN was the major component (60 wt%), were formulated. In cases where acrylonitrile (AN) was 10 ～18 mol% as copolymerization ratio in CTBN, the polymer alloys showed phase separated morphologies consisting of rubber-rich continuous phases and epoxy-rich dispersed phases with the size of micrometer or sub-micrometer. In the mean time, the polymer alloy where AN was 26 mol% in CTBN showed good compatibility among components. Scanning probe microscopy revealed the existence of heterogeneous nano-phase structures in the polymer alloy. Pulsed NMR indicated that the molecular mobility of CTBN was strongly constrained in the polymer alloy including CTBN with AN 26 mol%, and the interface between the CTBN and the epoxy increased with decreasing the phase size. The nano-phase structure and the thick interface would be the source of the broad glass-transition temperature region of the network polymer alloy, which played an important role to give the excellent impact-energy absorbability in a broad range of temperature.

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SynopsisIn addition to transparency, low thermal expansion and high heat resistance are required for the polymeric materials used in the field of photovoltaic cells and display substrates. We developed the transparent substrate having these properties by dispersing a higher content of colloidal silica into the resin.The plastic substrate having more than 90% of total light transmittances was obtained by immobilizing 33vol.% of silica particles of ca.110 nm diameter into this polymer network. A Bragg lattice spacing obtained from measurement of a synchrotron radiation small-angle X-ray scattering is correlated with the distance between silica particles observed in the scanning electron microscopic images. These results indicate that a synchrotron radiation is powerful tool for evaluation of dispersion of silica nano-particles in the network polymer.(Received November 16, 2009)

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SynopsisThe higher refractive index than 1.8 of materials is required to realize micro-sizing and high accumulation of optical devices. Because the refractive indices of common polymers are not enough high, the design and synthesis of polymersconsisting of heavier elements such as polysilanes and polygermanes have been investigated for this purpose. The properties of polysilanes and polygermanes depend on the σ-conjugation along the Si-Si and Ge-Ge skeleton. An organogermanium polymer which has a germanium nanocluster structure showed the refractive index higher than 1.8.

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SynopsisNanotechnology has been attracting much attention in recent research on insulating materials to realize environmentally-conscious heavy electric apparatuses such as switchgear using solid insulation systems. The apparatuses without gas insulation systems using of sulfur hexafluoride(SF₆), which has been designated as a greenhouse gas, can reduce environmental impact. This paper shows development in the application of epoxy-based nanocomposite with clayspractical solid insulating systems, which would lead to environmental harmony, downsizing, and higher efficiency in heavy electric apparatus.

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