Synthesis of Tri-Aryl Methane Epoxy Resin Isomers and Their Cure with Aromatic Amines

In this work, two tri-aryl and one bi-aryl epoxy resin, bis[(glycidyloxy)phenyl)]-m-xylene (BGOPmX), bis[(glycidyloxy)phenyl)]-p-xylene (BGOPpX), and bis(glycidyloxy) biphenyl (BGOBP) are synthesized and cured with methylene dianiline and 4,4′-diamino diphenyl sulfone. Structure, property, and processing relationships are investigated and compared against diglycidyl ether of bis-phenol F epoxy resin to better understand the impact of rigid and flexible subunits within the network structure. The rigid BGOBP epoxy network has a higher yield strain, and displays the highest glass transition temperature and a higher coefficient of thermal expansion (CTE) regardless of amine. Conversely, the more flexible tri-aryl epoxy resins, BGOPmX and BGOPpX, have higher moduli and lower CTE. Properties such as yield stress and thermal degradation are relatively unaffected by structure. Results where possible are discussed in terms of the likely equilibrium packing density of the network and short range and segmental motions of the polymer networks determined from sub-ambient dynamic mechanical analysis. Differences between BGOPmX and BGOPpX highlight the effect of minor variations in structure on reactivity, glass transition temperature, and compressive properties. This work clearly illustrates how fine control of chemical structure can tune the mechanical and thermal properties and reaction kinetics of network polymers.