FORMATION AND PROPERTIES OF NETWORK POLYMERIC MATERIALS

A general model for thermosetting materials which relates polymerization to properties is discussed. In particular, a phase diagram relates the four states of matter encountered (i.e., liquid, rubber, ungelled glass and gelled glass) to gelation and vitrification phenomena. The model is extended to rubber‐modified thermosetting systems to show that, by control of the time to gelation, a given chemical formulation can provide different morphologies and hence different material behavior. The principal experimental approach uses a torsional braid analyze (TBA), an automated version of which is described. Use of the technique to measure gelation and vitrification times is discussed. Copyright © 1979 Society of Plastics Engineers, Inc.