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

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, T_g, 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 T_g. Tack of PSA tapes was measured at two different temperatures, and shown to be directly correlated to the blend T_g. Several predictive methods for blend T_g that are based on individual component T_gs were evaluated. The prediction of blend T_g is far more accurate if the individual component T_g values are determined by DMA instead of DSC. In addition, the Gordon‐Taylor equation gave a significant improvement on predicted blend T_g when compared to the Fox equation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 826–832, 2000