Influnce of the chemical structure on the morphology and physical properties of crosslinked macromolecules synthesized by polyaddition reaction

The investigations in epoxy resins and other polymers have shown that by selecting the structure of the segments between the crosslinks it is possible to vary to a great extend the morphology and the physical properties. In a survey, a classification of 7 systems is given, cach of them characterized by specific morphological and physical properties. It is demonstrated that conventional epoxide resins show a distinct maximum of the mechanical damping and elongation at rupture nearly at the same temperature. The toughness‐temperature characteristic however shows a maximum 20°–30°C below the glass transition temperature. One system, the slightly crosslinked epoxy resins e.g. obtained by reacting long chain acid polyesters and diepoxides show a very high toughness in the transition range, compared to the conventional high crosslinked polymers.