Fatty acid-based polyesters and amphiphilic block copolymers thereof : compatibilizers for polyethylene-based polymer blends

Polyethylene is one of the most common and versatile plastic materials in our daily life. However, there are several challenges for polyethylene. Polyethylene is non-¿degradable, causing major environmental problems in places where waste collection is impossible, for example in the marine environment. While polyethylene has ideal properties for many applications, it is notoriously difficult to modify in a controlled manner because of its inert chem. structure and the sensitivity of Ziegler-¿Natta catalysts towards functional groups. This creates challenges in areas where adhesion or polymer blending is required. A new class of polymers with the potential to address these challenges are fatty acid-¿based polyesters, which can be produced by polycondensation of w-¿hydroxy fatty acids or by ring-¿opening polymn. of the corresponding macrolactones.1,¿2 As a consequence of the large no. of CH2-¿groups between the ester functionalities, the properties of these polymers resemble those of polyethylene.3 The presence of labile ester bonds implies degradability under conditions found in the environment and in recycling processes. The topic of the current contribution is the marriage of PE-¿like fatty acid-¿based polyesters with polymers that are fundamentally different in nature. Based on the concept that such polyesters are miscible with polyethylenes, synthesis of their linear and branched block copolymers via catalytic ring-¿opening polymn. of macrolactones is relatively easy and ensures control over their mol. wt. and mol. wt. distribution as well as polymer compn., mictrostructure and polarity. We will demonstrate different novel strategies to produce amphiphilic block copolymers by means of catalytic living and immortal ring-¿opening polymn. Blending expts. with polyethylenes and polar polymers were successful and will also be discussed