Synthesis and thermal properties of new novolacs from hindered hydroquinone derivatives are described. Sulfuric acid-catalyzed condensation of 3, 5-di-tert-butyl-4-hydroxyanisole (1) or 2, 5-di-tertbutylhydroquinone (2) with paraaldehyde (acetaldehyde) (3) or paraformaldehyde (formaldehyde) (4) in 2-ethoxyethanol afforded the corresponding linear novolac (5) - (8) in high yields. The resulting novolacs were well-soluble in the common organic solvents such as chloroform, tetrahydrofuran, and acetone. The structures of 5-8 were determined by ¹H & ¹³C NMR and IR analyses. From TGA analyses, hydroquinoneacetaldehyde novolac (5 and 7) were less heat-stable than hydroquinone-formaldehyde novolac (6 or 8). These novolacs had easier processability than that of phenol or cresol novolac and will be expected for reactive polymers, cured resins and resist materials.

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Phenoxy phosphazene is widely known as a halogen free flame retardant used for printed circuit board materials. However, it posses the property of reducing thermal resistance of a total resin system as a typical problem originating in a miscible type flame retardant.
We found the way to reduce the solubility of the ring phenoxy phosphazene molecules in the matrix resin by incorporating immiscible functional moieties with them. As a result, an immiscible phase diagram area was confirmed to exist, where the above mentioned functionalized ring phenoxy phosphazene was immiscible in the matrix resin. Moreover, we demonstrated that the technique worked well as a means for overcoming the drawback of the miscible type flame retardant systems.

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Aliphatic polyesters have received much attention because of their biodegradability and biocompatibility. In this study, we describe the ring-opening copolymerization of lactones with oxetanes having hydroxyl group by cationic initiator. The copolymerization of ε-caprolactone (1) with 3-ethyl-3- (hydroxymethyl) oxetane (2b) (equimolar feed ratio) by scandium trifluoromethanesulfonate was carried out in bulk at 60-120 °C for 6 h. In the polymerization at 60 °C, it was found that the resulting polymer was the corresponding copolymer with hydroxyl groups from NMR measurements and was soluble in DMSO and DMF. At 120 °C, the obtained networked copolymer was insoluble in solvents, although respective homopolymerization gave soluble polymers. In addition, it was found that the thermal stability was drastically improved by copolymerization with only addition ca. 6% of 2b to 1. These results might suggest that 2b served as a crosslinkable monomer for ring-opening copolymerization.

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The fundamental study for chemical recycling of vulcanized rubber was carried out with the aim of reproducing functional polymers from used rubber by thermal fragmentation (TF) in the presence of thiophenol (PhSH). The vulcanized rubber samples used were natural rubber (VNR), butadiene rubber (VBR), styrene butadiene rubber (VSBR) and the ones (VNRCB, VBRCB and VSBRCB) containing carbon black (CB). TF of VNR at 140°C for 10 hours in air in the presence of PhSH gave the corresponding low molecular weight VNR in 80% yield. The molecular weights could be effectively controlled by the amount of PhSH added. Also, VBR, VSBR, VNRCB, VBRCB and VSBRCB showed the same behavior in TF. The obtained low molecular weight rubbery substances were soluble in organic solvents such as xylene, chloroform, THE and so on.

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A Liquid crystalline epoxy resin containing a diazomethane type mesogenic group was cured under an electric field. The anisotropy of the cured system was evaluated using polarized optical microscopy, wide angle X-ray diffraction and polarized microscopy FT-IR measurement. As the results, it was clarified that the network chains of cured system existed in an arranged state in a fixed direction. Moreover, dynamic mechanical analyses, thermal expansion measurement and tensile test were carried out to investigate the thermo-mechanical properties of the anisotropic network. The resulting behavior reflected the character of anisotropy network structure.

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This paper reviews our recent studies concerning the synthesis and photochemical reactions of the calixarene-derivatives and cyclodextrin-derivatives containing polymerizable groups, protective groups, and photo-isomerizable groups. It was found that the synthesized materials had high thermal stability, good film-forming property, and high photochemical reactivity. It is expected that the obtained materials are useful for EB-and UV-curing technologies and photo-resist systems. Furthermore, the large refractive-indices changes were observed before and after photo-isomerization of calixarene-derivatives. It is also expected that the obtained calixarene derivatives are widely used for novel optoelectronics materials.

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From the previous issue of this journal, a series of papers summarized on “Plastic Lining-Today's Trends” has started to be published with being focused on their recent topics. To begin with, “FRP water proofing lining technologies and resins” has been reported. In our article entitled “FRP Anti-corrosion Technologies and Resins, ” also have been reported vinylester resins which are being more widely applied by years. Indeed, in this application field, epoxy resins, phenolic resins, furan resins and so forth have been traditionally used. These will be discussed in the later issues focusing on some recent topics.
There are many current topics of vinylester resins even in the field of plastic lining. In this article, therefore, the topics on “Lining in the city water and waste water systems” are mainly discussed. The reason why we intend to have a concern in these systems is as follows : the former system have approved vinylester resins as JWWAK 149. and the latter of sewage systems has the larger size of market.

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