The interpenetrating polymer networks (IPNs) derived from diglycidylether of bisphenol-A (DGEBA) and poly (ethyleneglycol) diacrylate (PEGDA) were prepared by a simultaneous polymerization technique. Methylhexahydrophthalic anhydride (MeHHPA) as a curing agent for DGEBA, and AIBN, BPO or DTBPO as a free radical initiator for PEGDA were used for curing. The cured products were tested and analyzed by the various measuring techniques including flexural, fracture toughness, and IZOD impact tests. As a result, the products induced by either AIBN or BPO initiation system, had a phase-separated IPN structure. In the case of the DTBPO initiation system, when PEGDA content was low, the resultant products had a sequential-IPN structure; but phase separated IPN was obtained with increasing the PEGDA content. The fracture toughness and IZOD impact strength were improved in comparison with a MeHHPA-cured epoxy resin, and mechanical properties were affected by the microstructure of IPN.

View full abstract

Anionic copolymerization of bicyclic bis (γ-lactone) with triglycidyl isocyanurate was carried out to obtain the corresponding crosslinked polymer quantitatively by controlling the copolymerization conditions.
This crosslinking reaction proceeded could afford the successive double ring-opening isomerization of bicyclic bis (γ-lactone) and the ring-opening of oxiranes alternately to obtain the crosslinked polyesters having ketone groups.
The structure of the alternating copolymer was confirmed by IR spectra and elemental analysis. The glass transition temperature of the crosslinked polymers was possible to be controlled by the addition of styrene oxide. The volume shrinkage during the crosslinking could be suppressed by ring-opening of the bicyclic bis (γ-lactone).

View full abstract

It has been reported that bicyclic orthoester derivatives advance cationic polymerization without volume change. Bicyclic orthoesters having hydroxy groups (BOE), in this paper, also advanced both cationic ring-opening polymerization and crosslinking. The BOE gave THE soluble polyethers [Poly (BOE)] in the cationic ring opening polymerization at 80-130°C. Furthermore, the soluble Poly (BOE) and crosslinked polyethers [Crosslinked Poly (BOE)] were obtained in the polymerization at 150-180°C. This crosslinking reaction of Poly (BOE) may be caused by dehydration of methylol groups formed in the side chain of Poly (BOE). The volume changes on cationic polymerization and crosslinking of BOE showed to bring about low shrinkage.

View full abstract

This article describes the preparation of a functional novolac having electron withdrawing groups (nitro groups) by a polymer reaction of a novolac derivative. o-t-Buthylphenol novolac (a precursor) (2) was prepared by the HCl-catalyzed addition-condensation of o-t-buthylphenol with paraformaldehyde in a good yield. Then 2 was regioselectively into o-nitrophenol novolac (3) in good conversion. The structure of 3 was confirmed by IR, ^lH NMR and GPC analysises, and the property was well-soluble in common organic solvents but insoluble in hexane and water. 3 is expected as an explosive material and a biofunctional polymer.

View full abstract

Developments of new novolak type phenolic resins (PAPS resins) were succeeded, using a new resin production process called phosphoric acid phase separation reaction. The resins obtained had a narrow molecular dispersion ratio with the low content of monomer and dimer. This process could be applied to various base compounds such as phenol, cresols, bisphenols and alkyl phenols, for synthesizing the corresponding PAPS resins which had a narrow molecular dispersion ratio at each region of low, middle and high molecules. In this article, we introduce the mechanism of the phosphoric acid phase separation reaction, and the characteristic of the PAPS resins which were synthesized from the various base compounds.

View full abstract