Glass transition temperatures of hydrocarbon blends: Adhesives measured by differential scanning calorimetry and dynamic mechanical analysis

Abstract

A comparison of calculated and measured glass transition temperatures of a series of three-component hydrocarbon blends was performed. The blends were prepared as mixtures of an elastomer with different proportions of tackifying resin and oil. Glass transition temperature, Tg, was measured by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) at four measurement frequencies. Most of these blends had pressure-sensitive adhesive (PSA) properties, and were used to prepare a series of PSA tapes. The adhesion of the PSA tapes was shown to be strongly dependent on Tg. Tack of PSA tapes was measured at two different temperatures, and shown to be directly correlated to the blend Tg. Several predictive methods for blend Tg that are based on individual component Tgs were evaluated. The prediction of blend Tg is far more accurate if the individual component Tg values are determined by DMA instead of DSC. In addition, the Gordon-Taylor equation gave a significant improvement on predicted blend Tg when compared to the Fox equation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 826–832, 2000