## 1 Introduction  
Polylactide is one of the polymers under development that, originating from renewable resources, could replace petroleum-based polymers in some applications [1; 2]. Concerning the various sophisticated applications, e.g., in biomedicine, but also in the production of commodity products, the tuning of material properties to meet application requirements is needed. One of the methods of modifying polymer properties is the introduction of other structural units into the polymer macromolecule. This can be achieved in different ways, one of which is copolymerization. Block copolymers are a combination of blocks of two or several homopolymers of different natures that provide new properties in comparison with individual homopolymers, and very often they can self-organize into interesting and sometimes very useful structures. Block copolymers can be synthesized via different approaches. The simplest method is successive polymerization if both blocks can by polymerized by the same mechanism. If, however, two blocks are to be prepared by different mechanisms, such as the copolymer polylactide/poly(vinyl monomer), then ring-opening polymerization has to be combined with known methods of radical polymerization including appropriate block(s) functionalization [3; 4; 5]. Thus, new combinations of known methods are being searched for and applied. We have recently described the preparation of the triblock copolymer PLA/poly(acrylonitrile)/PLA [6] using the \"macronifer\" (MI) concept [7]. The main step of this synthesis is the preparation of a PLA homopolymer containing a thermal \"infer\" group in the middle of the PLA chain [6]. Tetraphenyletahane (TPE) was applied as the infer, which is known as a group that undergoes dissociation into radicals under heating and as being able to initiate radical polymerization [8; 9; 10; 11]. TPE was generated inside the PLA chain from benzophenone fragments [12; 13] via a method we elaborated [6] (commercial benzophenone could not be introduced via the initiation of lactide polymerization due to the insufficient reactivity of tertiary -OH groups, which was proven by us previously [13]). Using a PLA-TPE macroinifer, acrylonitrile (AN) was polymerized at 85 \({}^{\circ}\)C, resulting in the triblock copolymer. As was demonstrated, by varying the molecular weight of the initiating PLA-TPE and the initial AN/PLA-TPE ratio, the composition of the triblock copolymer could be regulated [6]. Following our earlier work, we decided to prepare multiblock copolymers of polylactide and selected poly(vinyl monomers) (PVM) while using the same TPE group as an infer group but with the introduction of multiple TPE groups into a PLA-based polymer. This was achieved by coupling PLA-diol with TPE-containing diol using aliphatic diisocyanate. A similar approach has been used by other groups for the preparation of multiblock copolymers of poly(tetrahydrofuran), poly(propylene oxide), and poly(\(\varepsilon\)-caprolactone) with vinyl monomer blocks [14; 15; 16; 17; 18; 19]. However, the authors used commercial diol containing TPE groups, i.e., tetraphenylethane diol (TPED, benzopinacol), for the coupling reaction. We found that the reaction of such a diol (TPED) with diisocyanate was doubtful due to the insufficient reactivity of the tertiary hydroxyl groups [20]. We also publish the results of experiments aiming to prove this fact, and we suggested replacing the commercial TPED with a derivative synthesized by us. This derivative was synthesized by coupling benzophenone functionalized with primary hydroxyl group [13]. Thus, in the present work, a TPE derivative containing primary hydroxyl groups (TPE-diET, the structure is shown in Figure 1) obtained from 4-hydroxybenzoylone was coupled with a PLA-diol using diisocyanate to obtain a PLA-based macroinifer. This macroinifer (PLA-PU) was used to polymerize radically acrylonitrile and styrene (ST) to produce multiblock copolymers via the insertion of vinyl monomer units in between TPE units in the PLA chain.