Preparation And Properties Research On The Epoxy Resin/Flexible Polyether System

Epoxy resin adhesives are widely used in daily life and the automobile, construction, aerospace and many other fields because of their excellent adhesive properties, electrical properties, process, good mechanical properties of the cured and so on. However, the main components of the epoxy resin contain lots of benzene ring or heterocyclic compounds, the flexibility of molecular chain is poor, and the crosslinking structure can not be deformation after cured and easy to crack, resulting in toughness of epoxy adhesive without toughening is poor, and has high brittleness, which greatly limits its application. Therefore, to improving the flexibility of epoxy resin through a variety of methods has a very important practical significance.In this paper, three kinds of different molecular weight polyethers (MS, epoxy polyether and polyether amine) are used of bisphenol A type epoxy resin by flexible modification. Viscosity, curing time, hardness, tensile properties and dynamic mechanical thermal Analysis and so on of the three different flexible polyether/epoxy resin systems are studied.In MS/E-51 system, MS and E-51 consistent with the best ratio is founded to be 100/50, when the system has the highest tensile strength. The viscosity and the tensile strength of E-51 decreased gradually with amine terminated polyether or epoxy terminated polyether, while the elongation at break increased gradually. Compared with amino polyether, adding epoxy polyether to the system makes the elongation at break increased more significantly, while the tensile strength decreased more, and the hardness is lower.Compared three kinds of the systems, the MS/E-51 is heterogeneous system, which forms interpenetrating network after curing and has poor compatibility, low tensile strength, and has low hardness as elastic materials after curing. The amine terminated polyether/E-51 system and the epoxy terminated polyether/E-51 both are homogeneous systems, which have high tensile strength, but the elongation at break below the MS/E-51 system’s, and has high hardness as thermosetting resin after curing.According to the experiment, when the epoxy terminated polyether/E-51 system’s ratio is E-51/1217/8032-100/30/59.24 at 40℃/8h curing conditions, the breaking elongation reached the maximum value of 70%, which increased about 69% compared with the pure E-51 after curing, the tensile strength is about 19MPa, and the tensile and shear strength of resin bonded aluminum alloy reaches 14.9MPa, which improves the flexibility of epoxy resin in the guarantee of system of higher tensile strength.