Definition of polymerization completeness of epoxy oligomers

Abstract

The article deals with physical and chemical methods that determine the polymerization completeness of epoxy oligomers. New terpenoid products are presented as curing catalysts. The phase transition of epoxy oligomers from soluble to polymerized state is studied. It is known that epoxy oligomers in polymerized state have a small number of cross-links located at a sufficiently large distance from each other, and chain segments between the cross-links have some mobility. The presence of hydroxyl groups in the oligomer macromolecules makes it possible to create composites characterized by high adhesion properties to a variety of materials. The IR spectroscopy method is used to control the quality of polymerized composites. It allows to determine the composition change and polymerization completeness. In the course of research it was found that the IR spectroscopy method can be used to determine the polymerization completeness of epoxy binder by secondary terpenoid products. On the registered spectra there are changes in the area of absorption bands belonging to anhydride and epoxy groups. These bands completely disappear in comparison with similar bands in the spectra of the original binder components. New absorption bands characteristic of ester groups – ν(С=О), νas С–О–С и νs С–О–С – were found in the IR spectrum of the composite. The intensity ratio of aromatics absorption bands in the spectrum of the composite, -CH₃ groups practically remains the same as in the spectrum of the epoxy oligomer, which confirms the nonparticipation of this oligomer part in the polymerization process. The conducted studies made it possible to adapt the method of IR spectroscopy to determine the polymerization reaction completeness of epoxy oligomer by secondary terpenoid products.