Structure and Properties of Polymer Interphases
Abstract
The effect of metal substrates on the molecular structure of gamma- aminopropyltriethoxysilane (gamma-APS) primers during drying at elevated temperatures was determined using infrared spectroscopy. When drying was carried out at 110 C, the amino groups in primer films formed on 2024 aluminum and copper were oxidized to form imine groups but those in films formed on iron, titanium, and 1100 aluminum were not. When drying was carried out at 150 C, the films formed on iron, copper, titanium, and 2024 aluminum were oxidized to form imine structures but films formed on 1100 aluminum were not. These results indicate that copper-containing substrates catalyzed oxidation of the primer but the oxide on 1100 aluminum, which contained no copper, inhibited the free- radical oxidation. The molecular structure of interphases between model adhesive systems and metal substrates was determined by using x-ray photoelectron spectroscopy and infrared spectroscopy to characterize the fracture surfaces of adhesive joints prepared by curing beams of epoxies against metal beams. The structure of the interphase depended strongly on the curing agent, metal substrate, and use of an aminosilane 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 gamma-APS, there was little reaction between the primer and adhesive, and failure occurred near the primer/adhesive interface.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 15, 1989
- Accession Number
- ADA212796
Entities
People
- F. James Boerio
Organizations
- University of Cincinnati