Determination of mass fractions in polypropylene/polyethylene blends using fast scanning calorimetry

Fast scanning calorimetry (FSC) enables rapid sample cooling from the melt at rates of several thousand Kelvin per second. A perfect amorphous state for polypropylene (PP) can be achieved by fast cooling at rates of 5000 K s(-1). In comparison, polyethylene (PE) crystallizes during cooling, even at cooling rates accessible with FSC. Thus, in this study, a novel method was proposed for determining the PP/PE mixing ratio with a standard deviation of 1.4 mass% that combines FSC and differential scanning calorimetry. The proposed method considers the above thermal behavior of the components of polyolefin blends. In addition, the proposed method is expected to provide a convenient way to analyze the composition of recycled polyolefins from the market or industrial processes without the need for high-temperature solvents that are typically used in nuclear magnetic resonance or for calibration curves in Fourier transform infrared spectrophotometry.