Carboxyl‐terminated poly(propylene glycol) adipate‐modified room temperature curing epoxy adhesive for elevated temperature service environment

摘要

AbstractAn investigation was carried out into the effect of modification of an epoxy resin with carboxyl‐terminated poly(propylene glycol) adipate (CTPPGA) liquid rubber, on room temperature and elevated temperature adhesive joint strengths, after curing at room temperature (25°C) with tris‐2,4,6‐(N,N‐dimethyl amino methyl) phenol hardner. CTPPGA prepared by the esterification of poly(propylene glycol) (PPG) and molar excess of adipic acid was incorporated into the epoxy resin by the prereact method. CTPPGA modification showed significant enhancement of adhesive joint strengths over the unmodified epoxy and the joint strengths were found to depend on the molecular weight of CTPPGA and its content in the epoxy resin. The elevated temperature lap shear strength measurement made for the CTPPGA‐modified epoxy adhesive showed that the adhesive formulation has a temperature service capability up to 120°C. The results are discussed in terms of the data obtained from the tensile tests, DSC analysis, and SEM observations of the fractur