A phenolic derivative 2,5&benz has been synthesized from 2,5-dimethylphenol and benzaldehyde in good yield. 2,5&benz showed high crystallinity. In free radical polymerizations new vinyl monomers (ACv-1 and ALBv-1) obtained from 2,5&benz are used to prepare cross-linked polymeric materials by using photo- or thermal initiator. The resulting materials are expected to improve thermal stability, since they have a lot of aromatic rings in polymer chains. DSC and TGA are used to study on thermal properties of the materials. The cross-linked polymeric materials obtained from ACv-1 showed higher thermal stability than that of poly(methyl acrylate). The phenolic skeleton in ACv-1 unit was found to give high thermal stability.

View full abstract

Cresol formaldehyde novolac resins (Cre/Form) having hard properties cannot be applied minutely the positivetype photoresist material onto dry fi lms. Therefore, a new development was needed, so we carried out the synthesis and application of cresol novolac resins having fl exibility. The polycondensation reactions of cresols (Cre) with adipaldehyde (Adp) were carried to obtain cresol adipaldehyde novolac resins (Cre/Adp). Cre/Adp having both a dissolving rate for alkaline aq. solution below 1000Å/sec and M_w over 3000 were chosen for the test. The 5μm thick cast fi lms of Cre/Adp were applied onto polyimide fi lms in order to evaluate the fl exibility properties of the obtained resins by observation of their bent parts. Though the Cre/Form resin of the bent part was scattered, the Cre/Adp resin was settled with just cracks. The fl exibility of the Cre/Adp resin was also confi rmed from the results of the dynamic storage modulus measurement, too. The lithography performance of the Cre/Adp resin coated 1.5μm in thickness onto the silicon wafers was examined. The residual membrane thickness was high (96%) and the resolution of the resist was up to 2.5μm.

View full abstract

Four types of reworkable dimethacrylates bearing hemiacetal ester groups were applied to UV nanoimprint lithography (UV-NIL) and fi ne line/space patterns were obtained. The shrinkage in height of the UV imprinted pattern was discussed in terms of the kinetic chain length of UV cured networks, hardness, and photoreactivity of the monomers. A reworkable monomer having adamantyl unit was the most promising candidate for application of UV-NIL.

View full abstract

In order to obtain fundamental information of both intra- and inter molecular interactions of lignophenols (LPs), which are phenolic liner type macromolecules derived directly from native lignin through the phase-separation system, analyses on UV-Vis, fl uorescence(FL) and excitation (Ex) spectra of THF solution of LPs were carried out. Although UV-Vis spectra of LP with different phenols or species of wood were similar, there were clear dependences in FL spectra. However strong FL quenches were observed with concentration over 1.0 gL^-1, but these quenching were vanished by lowering of the concentration and chemical modifi cations on -OH such as acetylation. It can be therefore presumed that quench of FL is caused by interactions of LP via rich hydrogen bonds connected to aromatic rings of both lignin and grafted phenols. In addition, excitation spectrum implied that there were several complicated relaxation processes with internal changes of excitation energy and secondary or successive FL with large Stokes shifts.

View full abstract

Polycarbonate (PC) has been increasingly used as plastic glass of rolling stock. PC has some advantages for lightweight and high impact strength as compared to inorganic glass. However, the long-term stability of PC through the service life of rolling stock was not fully examined. The authors analyzed the degradation behavior of PC glass under artifi cial weathering condition. The PC became yellowish through artifi cial weathering; however, the mechanical strengths, for example the fl exural strength and the impact strength, were suffi cient for actual window glass of rolling stock. In addition the degradation of plastic glass was also evaluated by means of color measurement.

View full abstract

Printed circuits on a fl exible fi lm are important components for fl exible electronics. Electroless metal deposition is a simple and cost-effective method to fabricate metallic patterns on a fl exible fi lm. We review the formation of a palladiumnanoparticle/silica-nanoparticle/acrylic-polymer hybrid negative pattern on a flexible film by photolithography and its conversion to a copper pattern by electroless plating. The negative pattern of the hybrid was formed by UV-irradiation of the resist film, which contained acrylate monomer, palladium salt, and a photo-radical initiator. The photochemically generated radicals induced the radical polymerization of the acrylate and also reduced the palladium ion to form palladium nanoparticles. A copper film was deposited on the surface of the hybrid pattern by electroless plating. On the surface of the hybrid, the palladium-nanoparticles work as a catalyst, and the nanometer-scale roughness caused with the silica nanoparticles, increases the adhesion between the polymer and copper.

View full abstract