Mechanical Properties of Electron Beam Cured Monomer and Monomer/Liquid Crystal Films

Abstract

This article reports on mechanical properties of electron beam cured tripropylene glycol diacrylate (TPGDA) and propoxylated glycerol triacrylate (GPTA) films. This study has been motivated by the need to have direct access to those properties for analyzing the thermo-mechanical behavior and electro-optical properties of polymer dispersed liquid crystal systems in general, and systems made either of TPGDA or GPTA and low molecular weight liquid crystals in particular. Representative examples of these systems are considered in this work. The effects of the degree of crosslinking on the mechanical strength of the polymer network are analyzed by considering different doses of the electron beam irradiation. As the radiation dose increases, the mechanical strength of the film is enhanced. Addition of a small amount of liquid crystals leads to remarkable plasticizing effects. Young modulus and rubbery state modulus as a function of EB dose for cured TPGDA films. The filled symbols represent the Young modulus and the open symbols represent the rubbery state modulus. Circles are for pure TPGDA and squares are for TPGDA/E7 mixture with 15 wt.-% E7.