TY - JOUR
T1 - On the microstructure of the epoxy/adherend interphase
AU - Libera, M.
AU - Zukas, W.
AU - Wentworth, S.
AU - Patel, A.
PY - 1995
Y1 - 1995
N2 - It is now recognized that there is a region at the epoxy/adherend interface known as the interphase whose chemistry and structure are different from those of bulk epoxy. There is, however, no adequate understanding of its microstructure. This paper describes differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) studies of the interphase between an aromatic amine cured epoxy and alumina/oxidized-aluminum surfaces. DSC results show dramatic differences in resin-cure behavior in the presence of particulate alumina. TEM results on microtomed cross-sectional specimens of anodized aluminum wire embedded in epoxy show regions of incomplete epoxy infiltration and interfacial stress. RuO4 staining combined with high-angle annular-dark-field STEM imaging indicates that there are structural variations within the bulk epoxy at lengths of approx. 10-30nm. The magnitude of these fluctuations decreases in the near the adherend interface, and there is a simultaneous variation in the average epoxy structure. A plausible interpretation of these observations is that the interphase region suffers a variation in curing-agent concentration of unknown magnitude and there is a higher concentration of homopolymerized epoxy there relative to the bulk.
AB - It is now recognized that there is a region at the epoxy/adherend interface known as the interphase whose chemistry and structure are different from those of bulk epoxy. There is, however, no adequate understanding of its microstructure. This paper describes differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) studies of the interphase between an aromatic amine cured epoxy and alumina/oxidized-aluminum surfaces. DSC results show dramatic differences in resin-cure behavior in the presence of particulate alumina. TEM results on microtomed cross-sectional specimens of anodized aluminum wire embedded in epoxy show regions of incomplete epoxy infiltration and interfacial stress. RuO4 staining combined with high-angle annular-dark-field STEM imaging indicates that there are structural variations within the bulk epoxy at lengths of approx. 10-30nm. The magnitude of these fluctuations decreases in the near the adherend interface, and there is a simultaneous variation in the average epoxy structure. A plausible interpretation of these observations is that the interphase region suffers a variation in curing-agent concentration of unknown magnitude and there is a higher concentration of homopolymerized epoxy there relative to the bulk.
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U2 - 10.1557/proc-385-65
DO - 10.1557/proc-385-65
M3 - Conference article
AN - SCOPUS:0029538822
SN - 0272-9172
VL - 385
SP - 65
EP - 70
JO - Materials Research Society Symposium Proceedings
JF - Materials Research Society Symposium Proceedings
T2 - Proceedings of the 1995 MRS Spring Meeting
Y2 - 17 April 1995 through 20 April 1995
ER -