Temperature dependence of polymer interaction: Relevance to adhesion

Acid-base interaction parameters, obtained from inverse gas chromatographic data, have been studied as function of temperature for a series of homopolymers. Acid-base functionality varies inversely with temperature, permitting the identification of a critical temperature where acid-base interaction abates, leaving dispersion forces to act at the surface. Polymer assemblies, prepared at temperatures encompassing the critical values, display a discontinuity in lap-shear bond strength. In inherently incompatible pairs, the abatement of unfavorable acid-base forces enhanced bond strength. An adverse effect was noted in assemblies containing polymers with favorable acid-base interaction. Bond strengths of assemblies joined above critical temperatures display a time-dependent reversion to equilibrium values when exposed to lower temperatures.