The use of polymers for various applications can require fast cooling rates. Understanding the effect of cooling rate on material properties can guide research to make better materials for these applications. This talk will focus on two industrially relevant systems of interest to Dow. First, there has been recent interest in replacing bisphenol-A based can coatings with other polymers, and Dow has developed a polypropylene based technology. The can coating process requires fast cooling rates which sets limits on the crystallization rates needed to maintain a robust coating. Fast-scanning differential scanning calorimetry (DSC) techniques were able to show how the addition of nucleating agent ensures a coating of sufficient quality for this new coating technology. A second and more general problem is the relative crystallization rates of various types of polyethylene. Predicting the crystallization rate as a function of supercooling has relied on extrapolations of DSC data from a limited temperature range. Fast-scanning DSC techniques allow data over a broader range of supercoolings to be collected and crystallization rate over several orders of magnitude to be determined. The Hoffman-Lauritzen model used to predict crystallization at even deeper supercoolings can be refined with the fast-scanning data with the results being consistent with expectations based on the polyethylene structure.
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