Molecular Mechanism of Deformation in Epoxies – A Neutron Scattering Study
AbstractNeutron scattering was used to investigate the molecular mechanism of large strain deformation in epoxies. Partially deuterated diglycidyl ether of bisphenol A (DGEBA) was cured with either tri- or di-amines of different molecular weights. The change of the average distance between crosslinks along the epoxy and the amine linkages could easily be determined from the shift in the positions of the scattering maxima. It was found that the average distance between crosslinks remained almost unchanged along both the amine and the epoxy linkages as the bulk material underwent a large deformation. The above results are discussed in terms of the functionality of the junctions as well as the molecular weight between crosslinks. Comparisons are also made between the solid state deformation results and those from swollen networks which did show a substantial increase inaverage distance between crosslinks.
