EFFECT OF THE STRUCTURE OF LATEX-PARTICLES ON ADHESION .3. ANALOGY BETWEEN PEEL ADHESION AND RHEOLOGICAL PROPERTIES OF ACRYLIC COPOLYMERS

This article, the second part of this series, concerns the development of an analogy between the peel behavior of pressure-sensitive adhesives and the dynamic mechanical properties of the corresponding copolymers. The adhesive copolymers used were synthesized by emulsion polymerization processes. Their physical and dynamic mechanical properties were characterized and presented in Part I of this series.(1) In this study, an analogy was built up between the force in a peel test as a function of peel velocity, F-p(upsilon(p)), and the loss modulus of the adhesive as a function of the angular frequency in a dynamic mechanical experiment, G ''(omega). This was done by superimposing the curves of F-p versus upsilon(p) and those of G '' versus omega beta(0)/beta, where beta(0)/beta is a shift factor with beta being a parameter in the Kaelble theory and beta(0) being some reference value of the Kaelble parameter. When the curves of F-p similar to upsilon(p) and those of G '' similar to omega beta(0)/beta were plotted together, they followed the same trend of variation. This analogy between G ''(omega beta(0)/beta) and F-p(upsilon(p)) was further confirmed by the fact that the apparent activation energies of the primary glass transition for G ''(omega) and F-p(upsilon(p)) are virtually the same, suggesting that the analogy between G ''(omega) and F-p(upsilon(p)) is dictated by the glass transition. The existence of the above-mentioned analogy between G ''(omega) and F-p(upsilon(p)) shows that the performance of an adhesive can be evaluated or predicted from the dynamical loss modulus of the corresponding (co)polymer. (C) 1995 John Wiley and Sons, Inc.