Dynamic bonding/debonding polymers are in the recent focus for applications in field of smart or responsive materials. Such polymers allow controlled change in their properties and can be used for reversible crosslinking, for instance by thermoreversible Diels-Alder reaction. This makes them interesting for intrinsically self-healing materials or drug-delivery systems.Assessing the reversible reactions in real time and in a quantitative manner is a special analytical task because it requires methods working under the reaction conditions. Only if the measurement can be performed onlinereliable data can be obtained. The molecular weight distribution (MWD) of a polymer is a useful characteristic for this scope because it represents the bonding state quantitatively and allows monitoring the extent of bonding/debonding reactions. Setting up a size exclusion chromatography instrument to work in temperature dependent mode gives the opportunity for the online determination of the MWD at different temperatures. Adequate evaluation methods have to be applied for the compensation of temperature effects and for making the results comparable to each other. The method allows monitoring the progress of bonding/debonding reactions and can be used for analyzing not only the extent, but also the kinetics of the reactions, as shown in the figure on the example of a polymer that depolymerizes at 140 �C (chromatograms after various depolymerization times). Verification of the results is achieved by temperature dependent DLS and NMR experiments.

Temperature dependent size exclusion chromatography for the investigation of dynamic bonding/debonding reactions

247th National Meeting (2014)

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