Structure and Properties of Polymer Interphases
Abstract
The molecular structure of interphases between polymer systems and metal substrates was determined by using x-ray photoelectron spectroscopy (XPS), reflection-absorption infrared spectroscopy (RAIR), and attenuated total- reflection infrared spectroscopy (ATR) to characterize the failure surfaces of double cantilever beam adhesive joints prepared by curing beams of epoxies against metal beams. The structure of the interphases depended strongly on the curing agent, metal substrate, and use of a silane primer on the substrate. When joints were prepared by curing an epoxy with a tertiary amine curing agent at 75 C against a steel substrate primed with a dilute aqueous solution of gamma- aminopropyltriethoxy-silane, there was little reaction between the primer and adhesive and failure occurred near the primer/adhesive interface. The interphase consisted of low molecular weight siloxane oligomers in which the amino groups formed bicarbonates with water and carbon dioxide absorbed from the atmosphere. When similar joints were cured at 150 C, the bicarbonates dissociated, enabling the adhesive and primer to react, and shifting the locus of failure near the primer/adherend interface or into the epoxy. The use of surface-enhanced Raman scattering (sers) for non-destructive characterization of interphases between polymers and metals was demonstrated.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1988
- Accession Number
- ADA200238
Entities
People
- F. James Boerio
Organizations
- University of Cincinnati