SynopsisIndustrial use of lignophenol obtained from lignin has been desired as new recycle process of wood-sources. As one of the solution, a new epoxy resin from lignophenol was synthesized and used as modifier for commercially available epoxy resin. Epoxidated lignophenol-modified epoxy resins were cured with triethylene glycol diamine at room temperature to investigate their performance in use condition. As a result, it was found that the room temperature setting products had high adhesion strength and high heat resistance.

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SynopsisPhenolic nanocomposites were prepared from high molecular weight novolac and organo-montmorillonite by the use of solid-phase shear continuous kneader. At first, the kneading conditions were studied in order to intercalate the novolac into the layers of organo-montmorillonite. As a result, the novolac could be intercalated into the layers under the kneading conditions as follows; the viscosity of the novolac was above 10⁵ Pa･s at 100ºC, the number of kneading was 2 or 3 times.Secondly, nanocomposites were prepared by compression molding of the kneaded compound and curing agent. Structure and properties of these nanocomposites were studied. According to the investigation of XRD and TEM, it was found that the distance of the layers was increased from 1.84 nm to about 4.3-4.4 nm by the insertion of phenolic resin into the organomontmorillonite layers. When the compound was kneaded 2 or 3 times, the resulting nanocomposite had best tensile strength. But, at 4 times kneading, the aspect ratio of organo-montmorillonite was decreased, and the tensile strength and heat resistance of the nanocomposite were inferior to those of others.

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SynopsisFlip chip assembly has widely been adopted in the electronics industry for realizing smaller and thinner semiconductor packages. In encapsulating flip chip packages, it is important, not only to maintain the interconnect reliability of bumps, but also to control the warpage of the package. In this paper, the effects of several assembly methods on the performance of flip chip package, i.e the warpage of package and interconnect reliability, were investigated. Additionally, three types of underfill material with different mechanical and thermal properties were prepared to understand the factors, which lead to improved protection of the bumps and control of warpage of package. Underfill material with higher Young’smodulus showed a longer interconnect life. From the results of failure analysis after thermal cycling, bump cracking at the corner of chip was observed. It was found from finite element analysis that underfill material with higher Young’s modulus can effectively reduce the strain accumulating inside the bump. Note that the properties of the underfill material affect the relationship between the interconnect reliability and the prestrain caused during encapsulation process, the selection of the optimal underfill material and the appropriate encapsulation process is essential in order to satisfy the high performance requirements of flip chip packaging.

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The alicyclic epoxy resins are broadly divided into a cycloalkene oxide type and an alicyclic polyglycidyl ether type by the oxirane ring structure. As for the cycloalkene oxide type, there are two methods to prepare epoxy resins. One is the direct epoxidation of cycloalkenes, and another is the prepolymerization of cycloalkene oxides having (meth)acrylic or allyl groups. About the glycidyl ether, there are three methods as follows; hydrogenation of aromatic glycidyl ethers, etherification of alicycles with epichlorohydrin, and epoxidation of allyl ethers. Particularly the epoxidation by hydrogen peroxide is very important, since hydrogen peroxide is relatively inexpensive, environmentally friendly and safe. Improvements of alicyclic epoxy resins are focused on the development of fast curing systems and high performance insulation resins. Applications to LED encapsulation materials and printable materials have been examined, so a future development is expected. (Received May 17, 2010)

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SynopsisWe discuss here the construction of tubular nanostructures (abbreviated as “organic nanotubes”) self-assembled from amphiphilic molecules and their utilizations. The organic nanotubes self-assembled from wedge-shaped molecules have different inner and outer surfaces covered with different functional groups. The unique properties of the organic nanotubes afforded us to demonstrate effective and selective encapsulation of guest, such as fluorescent molecules, proteins, and DNA via electrostatic interactions between the tube and the guests. In addition, selective functionalization of inner surfaces of the nanotubes visualized the dynamic behavior of the guest encapsulation, and thereby revealed that the nanotubes are able to stabilize proteins against thermal and chemical denaturation. The nanotubes also release the guest molecules when triggered by external stimuli, such as heating or pH change. These properties are applicable to utilization of the nanotubes for intelligent capsule for unstable biomaterials, drugs, and functional materials.

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[in Japanese]

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