Synthesis and Characterization of Bifunctional ATRP Initiators with Tailored Functionalities: Study of the Thermal Stability

Free radical polymerization is the most diffused process in industry to produce polymers. Nevertheless, the main drawback of this synthetic method is the lack of control over the molecular weight of the resultant polymers, due to unavoidable chain transfer and termination processes. Atom Transfer Radical Polymerization (ATRP) represents one of the most versatile techniques to achieve polymers with low polydispersity and well-defined architecture. We have recently demonstrated that this technique can be implemented on a greener industrial scale and optimized through a homogeneous catalytic system. Moreover, ATRP allows for the introduction of chain functionalities that can be exploited to obtain materials suitable for specific applications. One approach involves the use of functional initiators capable of impart the desired properties to the polymer. For example, some authors explored the use of initiators containing hydrolysis- or heat-sensitive functionalities such that the final polymer exhibits self-healing properties. Since initiators are integrated into the polymer chain, their thermostability is crucial to avoid thermal degradation of the polymer during processing stages. Unfortunately, aliphatic halide esters, the typically employed ATRP initiators, have shown poor thermal stability. In this study, we present the synthesis of a series of new properly functionalised initiators together with a deep study of how their chemical structure influences the thermal stability of the generated polymers.