A new approach to morphology studies on diacrylate polymer networks using X-ray powder diffraction

X-ray powder diffraction (XRPD) and Fourier transform infrared (FTIR) spectroscopy are used to characterize the morphology of diacrylate polymer networks, obtained by photoinduced homo- and copolymerizations. XRPD reveals the presence of three sized groups of microgel agglomerates. The dimensions of the microgel agglomerates (D) and the degree of conversion (DC) are explained by the monomer chemical structure, the strength of hydrogen bonds, and relate to selected polymer mechanical properties. The D value increases and the DC decreases as the strength of the hydrogen bonds increases. Copolymerization with monomers lacking groups forming strong hydrogen bonds results in more homogeneous networks with improved mechanical properties. An innovative demonstration of the heterogeneity of diacrylate crosslinked materials performed by X-ray powder diffraction is described. These heterogeneities, resulting from microgel formation and their agglomeration, are analyzed from the perspective of the monomer chemical structure and intermolecular interactions, as well as the degree of conversion in polymers. The agglomerate sizes are found to influence the brittleness of polymers.