Pseudo-polyrotaxane consisting of polyethylene glycol (PEG) and cyclodextrin (CD) was used as an initiator of the polymerization of lactide for the purpose of introducing multiple cross-linking structures as building blocks of a new network polymer. We aim to prepare a new network polymer utilizing the rotaxane and polylactic acid (PLA) stereocomplex as cross-linking sites in the future. Herein, the hydroxyl groups at both ends of PEG, which is the axial component of pseudo-polyrotaxane, and the hydroxyl groups of CD, which is the ring component, were used as the initiation moieties for the polymerization of lactide. The pseudo-polyrotaxane and the branched polymer were separately collected by fractionation with water and acetone. When PEG (M_n = 1500 and 6000) were used, their solubilities were different. We also attempted to change the number of penetrating PEG axes by using α-CD and γ-CD. The structures of these pseudo-polyrotaxanes and branched polymers were confirmed by ¹H NMR and SEC analysis, and their thermostabilities were investigated by thermogravimetric analysis.

Furan terminated vegetable oil derivatives were obtained by the reaction with 4-(furan-2-ylmethoxy)-4-oxobutanoic acid. Diels－Alder polymerizations of furan terminated vegetable oil derivatives and bismaleimides were carried out at 75 ℃ to give new transparent network polymers. The structures of the network polymers were confirmed from FTIR and ¹³C CPMAS. The network polymer synthesized from castor oil derivatives (FMECO) and bis (3-ethyl-5 methyl4-maleimidophenyl) methane (M1) exhibited high tensile strength (48.3 MPa) and good adhesion to stainless steel plates. It was found that these network polymers showed greater shear adhesive strength than initial one after repeated depolymerization－re-crosslinking process by heating.

In this article, we demonstrate the preparation of epoxy polymer monolith composite films with cellulose fibers for improving the mechanical property, where the monolith is a porous material with a co-continuous skeletal structure. The preparation includes lamination process or simple hanging process for cellulose-fiber nonwoven sheet impregnated with monolith precursor mixtures, followed by polymerization induced phase separation based on spinodal decomposition. The resulting monolith composite films were surface skin-less, exhibiting the pore sizes from 200 nm to 1.5 μm. The tensile Young’s modulus and strength were higher than those of the neat monolith film and the previously-reported cellulose nanofiber-reinforced monolith films. The ionic conductivity of the composite films with lithium-ion electrolyte was comparable to that of commercially-available polyolefin porous membranes. The epoxy polymer monolith composite film is expected to have a great potential as a promising separator for next-generation lithium ion batteries by taking advantage of its high heat resistance and winding channel structure.

An epoxy resin having a biphenylene ether structure (BGPB) was synthesized, and the physical properties of the cured products obtained by curing with phenolic curing agents were investigated. When phenol novolac was used as the curing agent, the glass transition temperature of the BGPB cured product was 159℃, which was 32℃ higher than that of bisphenol A type epoxy resin (DGBPA) and 7℃ higher than that of biphenylaralkyl type epoxy resin (GBPAR). The char yield at 700℃ was 37.8 wt%, which was significantly higher than 28.0 wt% of GBPAR, and the 10% weight loss temperature was 408℃. These results indicate high thermal decomposition stability of the BGPB cured product. In addition, the cured product with 4,4'-oxybisphenol (OBP) gave a crystalline polymer having a melting point at 257.4℃. The thermal conductivity was 0.32 W/m・K, which was about 1.5 times that of the DGBPA polymer.

Photolabile crosslinkers are compounds composed of photolabile units and polymerizing units. As well as conventional crosslinkers, photolabile crosslinkers can be introduced easily and homogeneously into networked polymers. In recent studies, o-nitrobenzylcarbonyl, coumarinmethyl, tertiary ester, and ruthenium complex units are incorporated as the photolabile units and are polymerized with hydrophilic monomers mainly in free-radical, ene－thiol, and click polymerization modes. Resulting hydrogels are used in the fields of medical applications mainly. Oxime-ester based photolabile crosslinkers are also proposed and incorporated in networked polyacrylates and polyurethanes. Their formation and degradation were successfully demonstrated, and photorheometers were useful tools for the evaluation of the formation and degradation behaviors on irradiation.