SEDL / STP / STP658-EB / STP34859S

Fundamental and Operational Glass Transition Temperatures of Composite Resins and Adhesives

Carter, HG
General Dynamics Corp., Fort Worth, Tex.

Kibler, KG
General Dynamics Corp., Fort Worth, Tex.

Reynolds, JD
General Dynamics Corp., Fort Worth, Tex.

Pages: 14    Published: Jan 1978

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Abstract

Data are presented on the thermomechanical response and electrical conductivity of two commonly used epoxy materials, Narmco 5208 resin and RB 398 adhesive, as a function of increasing temperature. The overall conformity of the results shows that the second-order Ehrenfest-type glass transition temperature, designated as T², governs the onset and evolution of changes in viscoelastic and electrical response as well as thermal expansion. The general features of this behavior are described with a five-element spring-and-dashpot model. The values of T², and two other Williams-Landel-Ferry (WLF)-type parameters for the description of viscoelastic response above T², can thus be derived from a single thermomechanical or electrical conductivity experiment conducted at constant heating rate.