Morphologies of cured epoxy/brominated-phenoxy blends were observed by scanning transmission electron microscopy (STEM) and energy dispersive X-ray fluorescence spectroscopy (EDX) . When a content of brominated-phenoxy was under 30 wt%, cured epoxy formed continuous phases and brominated-phenoxy formed micro domains. When a content of brominated-phenoxy was 30 wt%, co-continuous phase structures between cured epoxy and brominated-phenoxy were found, and then when a content of brominated-phenoxy was over 40 wt%, it was found that phase inversion occured and then brominated-phenoxy formed continuous phases and cured epoxy formed micro domains . Since every loss tangent (tan δ) curve plotted against temperature showed 2 peaks at 128ºC and 155ºC respectively, Tg's of cured epoxy phases were not decreased. Tensile strength, tensile elongation and lap-shear strength of the cured blends showed the maximum values at a 40 wt% of brominated-phenoxy content. Then the maximum values could be due to coexistence of rigid properties caused by cured epoxy and ductile properties caused by brominated-phenoxy because a rubbery plateau of E' curves was found on the system containing 40 wt% of brominated-phenoxy even though brominated-phenoxy has already formed continuous phases.

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Interaction changes of dental adhesive monomers with dentin during treating time are unknown. This study investigated the in situ interaction changes of dental self-etch adhesive with dentin during the treating time using both time-resolved FTIR-ATR and TEM measurements. Pure 4-acryloxyethyltrimellic acid (4-AET) and its calcium salts (4-AETCa) were synthesized. A 4-AET solution [4-AET/2-HEMA, 40/60 wt%] was placed on hydroxyapatite-exposing dentin, and time-resolved FTIR-ATR measurement was performed for 15 min. A 4-AET-containing, one-step adhesive was placed on cryofractured human dentin and left in the dark for 1/3, 5, 10 and 20 min before lightactivation. Ultrastrucural changes occurred at the resin-dentin interface were then observed using TEM. The FTIR-ATR subtraction spectra indicated that formation of 4-AETCa (1583, 1411 cm-1: assigned to ν C=O of Ca-carboxylate and identified by synthesized 4-AETCa) increased with contact time for 15 min. TEM study revealed the presence of an insoluble interaction layer on the dentin surface that increased in thickness (0-2500 nm thick) during the course of interaction. These findings support a hypothesis that formation of 4-AETCa increases with time of contact between the 4-AET acting as a ligand monomer and dentin apatite.

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