Polymerization promotors of benzoxazine-alicyclic epoxy resin mixtures were investigated aiming to achieve their complete curing at 150 ℃ within 3 hours, and their polymerization bahaviors and thermal properties of the cured materials were examined. As a result, it was found that addition of 0.1mol% Tb(OTf)₃ lowered the polymerization temperature about 20 ℃ and exhibited the maximum promotion effect on the benzoxazine polymerization at 150 ℃ for 3 hours.

Phytic acid (PA) is a naturally occurring cyclic compound bearing six phosphoric acid monoester moieties. In this work, PA was combined with polyamines such as branched polyethyleneimine (BPEI) and chitosan expecting that the acidic moieties of PA and the amino groups of the polyamines would undergo neutralization to give polyion complexes composed of phosphate anions of PA molecules and ammonium cations of the polyamines. Upon mixing an aqueous solution of PA and that of BPEI, the corresponding polyion complex precipitated from the solution quickly. An aqueous solution that contains both PA and BPEI can be prepared by preventing their complexation by adding ammonia. When the solution thus prepared was casted on a Teflon plate and dried, a transparent and flexible film was obtained. On the other hand, the complexation of PA and chitosan was prevented by adding trifluoroacetic acid to enable the preparation of an aqueous solution containing both PA and chitosan. Removal of the volatiles from the solution on a silicone plate led to formation of a cast film of a PAchitosan polyion complex, which was transparent, flexible, and stable under a wide range of pH.

Photo-thermal dual curing system was devised and applied to screen printing technology. New formulation of acrylic anchor resins contains a base polymer, which consists of hydrophilic units and solvent-absorbing units. As crosslinkers, multifunctional acrylates and polyurethane acrylates were employed. Adhesive strength of PET/anchor resin/PET and PET/anchor resin/Cu was evaluated. Adhesive strength was effectively enhanced by photo-thermal dual curing of the base polymer containing crosslinker.

Coarse-grained molecular dynamics (MD) simulation method of phenolic resins using united-atom model was developed in order to enable large-scale MD simulations by using desktop workstation. In the MD simulation, condensation reactions of phenol and formaldehyde were simulated under consideration of the reaction rate constant at ortho and para positions of phenolic units. A cross-linked network structure with a conversion (α) of 0.85 was obtained. The gel point was observed at α of 0.58. In order to reduce influence of local stress originated from the reaction processes, we applied slow reaction rates and geometrical constrains to candidate of reaction sites. Stress－strain analysis at 300 K indicates that Young’s modulus increases with increasing α, and it reaches 4.5 GPa at α of 0.85, which is in good agreement with experimental and theoretical results of previous studies.

In 2008, the authors have reported “Pillar[n]arenes,” which were cyclic phenolic compounds. They are soluble in common organic solvents, thus can be functionalized by various organic protocols. Based on the functionality, they were used not only for host-guest chemistry, but also for engineering. In particular, because pillar[n]arenes are polygonal shapes such as regular pentagon and regular hexagon, it is easy to prepare assemblies with uniformed structures. In this review, first, the authors discuss synthesis and functionalization of pillar[n]arenes. Then, the supramolecular networks constructed by pillar[n]arenes are discussed.