Novel epoxy resin based on biphenol oligomer(BDP-E) was synthesized by the reaction of epichlorohydrin and biphenol oligomer which was obtained by the reaction of 4,4’-biphenol and 4,4’-bischloromethylbiphenyl. In order to evaluate the effect of biphenyl structure on the thermal properties, biphenylaralkyl type epoxy resin (BP-E) and o-cresol novolac type epoxy resin (OCN-E) were used as references. The cured polymer of BDP-E with phenol novolac showed glass transition temperature of 211℃ in DMA measurement which was comparable with 186℃ of the OCN-E polymer. This result might be attributed to increasing crosslinking density and restriction of molecular motion by rigid biphenyl group in the cured polymer. Also the BDP-E polymer showed high char yield of 41wt% at 700℃ in TGA thermogram. This result might be attributed to increasing introduction of the thermalstable biphenyl structure in the cured polymer.

A metal-coordinate cross-linkage is an attractive tool to change the structure and properties in polymer system.A phenolic compound derived from 2,5-dimethylphenol and terephthalaldehydic acid was allowed to react with paraformaldehyde to give the linear polymer, which possessed coordinate sites in regular distance intervals. The polymer formed coordinated network gel with Cu²⁺ and Fe³⁺ ions in DMF. The gel changed to sol immediately by adding HCl. This method could be applied to healing properties and recycling process in thermoset resins.

We synthesized Noria-containing cross-linked materials, Gel (Noria-VES-co-DM [n]), by radical polymerization of a Noria derivative with pendant styryl groups (Noria-VES) and α, ω-alkanedimethacrylamides (DM [n], n = 3, 6, 12) at feed ratios of Noria-MA/DM [n] = 1/24. Acid hydrolysis reaction of Gel (Noria-VES-co-DM [n]) (n = 3 and 6) could remove the Noria moieties to give corresponding cross-linked materials Gel (VES-co-DM [n]) (n = 3 and 6) containing Noria-templated cavities with pendant hydroxy groups. Examination of the inclusion-complex-forming ability using aqueous solutions of metal ions revealed that Gel (VES-co-DM [n]) (n = 3 and 6) had great absorption capacity, indicating that they indeed contain Noria-templated cavities that can accommodate metal ions in aqueous solution.

Following to a previous work, this article reviews properties of cyanate ester as a curing agent of epoxy resin. Main disadvantages of the cured epoxy resin/cyanate ester system are the lack of toughness and the insufficient flame resistance when taking into account the application in the electrical & electronic and the composite materials fields. Research papers, as many as possible, were investigated to find out the development trend to improve cyanate ester properties. The results are summarized in tabular forms, and explained in detail for some typical formulations. Although the improvement of toughness is not always achieved because of the poor balance of cured properties such as sacrificing heat resistance, the flame resistance properties are reported to be considerably improved by the introduction of DOPO (9,10-Dihydro-9-oxa-10- phosphaphenanthrene 10-oxide) structure into cyanate ester. Furthermore, some comments are added on properties of epoxy resin/cyanate ester systems for fiber-reinforced composite materials, including the composite insulation parts equipped in ITER (International Thermonuclear Experimental Reactor) as an actual application example.

Since the dry film formed from positive photoresist is brittle and lacking in flexibility, there is a problem in making it a roll product. In order to solve this problem, cresol novolac resin having flexibility and high precision lithography performance is introduced. When the molecular structure giving flexibility to cresol novolak resin is imaged, i) introduction of aldehyde component with free linkage chain, ii) introduction of aldehyde component with side chain structure, iii) introduction of bulky aldehyde component, etc. can be considered. Specific examples include i) the introduction of dialdehydes with alkyl chains such as glyoxal (alkyl chain length (x) = 0), succinaldehyde (x = 2), glutaraldehyde (x = 3), and/or adipoaldehyde (x = 4), ii) the introduction of butanal, etc., and iii) the introduction of 5-hydroxymethylfurfural (HMF) derived from monosaccharides. Among them, it was found that HMF with rigid heterocyclic component and bulky molecular structure resulted in extremely higher flexibility than the others.