Recently, Lignophenol has been obtained from Lignin contained in wood-sources, and now, the establishment of the use of them as industrial materials has been required. If the use of Lignophenol has been developed, new recycle process of wood-sources will be constructed. Lignophenol has the properties of phenol resins, so we tried to apply them to industrial materials instead of synthetic phenol resin. First, epoxy resins from Lignophenol were synthesized. The best condition for epoxidation which gave low amount of by-product and low E.E.W. (782g/eq.) was low temperature (55-60°C/100mmHg) and low amount of sodium hydroxide (0.5eq.). Next, the resulted epoxy resins were cured with imidazole catalyst, and their thermal and mechanical properties were studied. As a result, it was found that Lignophenol-based epoxy resins give high performance materials.

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The specimens from an unsaturated polyester resin with a nonuniformly distributed hardener were made using a mechanically stirring vessel which could control mixing conditions. The effect of nonuniformity of hardener distribution and post-cure on mechanical properties was investigated. The flexural strength was evaluated from the viewpoint of reliability engineering based on the strength distribution. The flexural strength of specimens, made by hand mixing with a good stirring effect, showed the normal distribution and a small standard deviation. On the other hand, the specimens made using a mechanically stirring vessel didn't obey the normal distribution and had wide dispersion. Thus they showed the complicated distribution in the strength for each different molding condition. After post curing of all specimens which were made using the mechanically stirring vessel, the strengths and elastic moduli increased and no differences in these properties for any molding conditions were observed. However, the standard deviation in the flexural strength of the post cured specimens was extremely large in comparison with that of the unpostcured specimens. This is due to the increase of residual stress based on shrinkage developed during post curing. Attention should be paid to that the mechanical properties of unsaturated polyester resins could be improved by post curing; on the other hand, however, they also could disperse widely due to the increase of residual stress.

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The specimens from an unsaturated polyester resin with a nonuniformly distributed hardener were made using a mechanically stirring vessel which could control mixing conditions. The effect of nonuniformity of hardener distribution and post-cure on mechanical properties was investigated. The flexural strength was evaluated from the viewpoint of reliability engineering based on the strength distribution. The flexural strength of specimens, made by hand mixing with a good stirring effect, showed the normal distribution and a small standard deviation. On the other hand, the specimens made using a mechanically stirring vessel didn't obey the normal distribution and had wide dispersion. Thus they showed the complicated distribution in the strength for each different molding condition. After post curing of all specimens which were made using the mechanically stirring vessel, the strengths and elastic moduli increased and no differences in these properties for any molding conditions were observed. However, the standard deviation in the flexural strength of the post cured specimens was extremely large in comparison with that of the unpostcured specimens. This is due to the increase of residual stress based on shrinkage developed during post curing. Attention should be paid to that the mechanical properties of unsaturated polyester resins could be improved by post curing; on the other hand, however, they also could disnerse widely due to the increase of residual stress.

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We describe the performance of a size-exclusion chromatographic system equipped with a differential viscometer (SEC-VISCO). The system has been applied to a wide variety of novolac resins for examining their true molecular weight in the range from 200 to 2,300,000. A Universal Calibration Curve (UCC) has been obtained for novolacs narrowly distributed in molecular weight. The curve is coincident with that obtained for standard polystyrenes, demonstrating that the SEC-VISCO measurement accompanied by UCC results in being possible to estimate the absolute molecular weights of novolac resins in the range higher than 200. Additionally, we have found that there is a small difference in the fluid hydrodynamic volume for three isomers of a novolac dimmer. The difference is mainly due to an intramolecular hydrogen bonding effect in the particular dimmer isomer.

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Epoxy laminates composed of a brominated bisphenol A (BPA) epoxy resin and an epoxy o-cresol novolac resin (ECN) were characterized using pyrolysis-gas chromatography- mass spectrometry (PY-GC-MS) and thermally assisted hydrolysis and methylation- (THM-) GC-MS. The brominated BPA epoxy resin could be debrominated by PY-GC-MS, but the debromination by THM-GC-MS did not proceed and the resultant was detected as brominated BPA-methylated derivatives which could easily be analysed. In the case of laminates including the brominated BPA epoxy resin and ECN, it was difficult to analyse phenols derived from the novolac by single-shot method using PY-GC-MS because of BPA decomposition. However, by double-shot method combining PY-GC-MS and THM-GC-MS, epoxy laminates including the novolac could successfully be determined by the detection of several phenols originating in the novolac without being much affected by BPA decomposition.

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Polymer gels have been playing significant roles in the daily life. Recently, several types of hypergels having extraordinarily advanced mechanical properties have been developed. In this review, we explore the structures of these hypergels in terms of small-angle neutron scattering, discuss the cross-kinking mechanisms, and clarify the uniqueness and novelty of the hypergels.

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We succeeded in creating a novel nanocomposite-type hydrogel (abbreviated to NC gel) with a unique organic (polymer) / inorganic (clay) network structure. It was found that NC gels exhibit excellent mechanical, optical and swelling / de-swelling properties, which could solve the most of the problems associated with conventional chemically crosslinked hydrogels (OR gels) by providing, for example, ultra-high extensibility (in excess of 1000 %), widely-controlled moduli, strengths and high fracture energies (more than 3000 times that of OR gels), constant high transparency, large swelling and rapid de-swelling rates. Furthermore, new phenomena, such as the first observation of the generation of a contractile force by changing the temperature, unique sliding frictional behavior on gel surfaces, formation of a layered porous structure by freeze-drying, and total control of the coil-to-globule transition of poly (N-isopropyl acrylamide) chain, were all realized using NC gels. In this review, on the basis of the proposed organic / inorganic network structure model, the origin of the abnormally high mechanical properties and the structural changes of network were discussed.

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