Epoxy Adhesive Formulations
Based on a popular course sponsored by the Society of Plastics Engineers, this comprehensive text presents a variety of methods to ensure optimum epoxy performance and reliability.
TABLE OF CONTENTS Epoxy Adhesive Formulations
Chapter 2: Epoxy Resin Chemistry
2.1 INTRODUCTION
Proper formulation of epoxy adhesives requires knowledge of the chemical reactions that lead to polymerization as well as the chemical and physical properties of both the uncured mixture and the cured material. This chapter reviews the general principles of epoxy resin chemistry including synthesis of the epoxy monomer itself and its possible polymerization reactions.
The general properties of cured and uncured epoxy resins are reviewed in Chap. 3. The chemical of the resin and curing agent will determine these physical properties. They will also determine, to a great extent, the surface chemistry and adhesion properties of the final product.
2.2 EPOXY RESIN CHARACTERISTICS
The term epoxy, epoxy resin, or epoxide (Europe) refers to a broad group of reactive compounds that are characterized by the presence of an oxirane or epoxy ring, shown in Fig. 2.1. This is represented by a three-member ring containing an oxygen atom that is bonded with two carbon atoms already united in some other way.
Figure 2.1: The epoxy or oxirane ring structure.
An epoxy resin can be any molecule containing more than one of these epoxy groups. The number of epoxy groups per molecule is the functionality of the resin. The groups can be situated internally, terminally, or on cyclic structures. Epoxy groups are capable of reacting (1) with suitable curing agents or (2) catalytically (homopolymerized) to form higher-molecular-weight polymers. Once cured, the epoxy polymers have a densely crosslinked, thermosetting structure with high cohesive strength and adhesion properties. However,...
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