**1. Introduction**

Since the 1980s, about 50% of the total production of synthetic polymers used as plastics worldwide has been achieved through free radical polymerization. Peroxy compounds in technical polymerization processes have played the most important role in addition to 60-year redox systems and azo initiators for nearly 100 years. For nearly 30 years, polymer synthesis with free radical polymerization reactions has attracted considerable attention technically, even though their share in total polymer production is still quite small [1].

The most important advantage of conventional free radical polymerization, which is widely used, is that many monomers can be polymerized using this method and that this polymerization can be made under moderate conditions. The most important disadvantage of this polymerization technique is that the polymer architecture and molecular weight are not controlled and also the production of polymers with large molecular weight distribution [2]. The manufacturing of polymers, of which molecular architecture and molecular weight can be controlled in recent years and which have low molecular weight distribution (polydispersity), has been made possible with controlled radical polymerization techniques. Under favor of controlled radical polymerization techniques, polymers with narrow molecular weight distribution can be produced in a

desired molecular weight and desired molecular way in a controlled and repeatable manner. Synthesis of polymers, which have the star, comb, brush, worm, or graft architecture, is provided by molecular structure and size-controlled radical polymerization techniques [3–7].

Until today, the synthesis of block copolymers has usually been made through ionic polymerization. But ionic polymerization requires strict conditions, and the number of monomers is relatively limited. To overcome these disadvantages, simpler and easier techniques have been used recently for block copolymer synthesis [8, 9]. It has been possible to be successful in block copolymer synthesis in recent years with RAFT-ROP [10], ATRP-ROP [11], and redox polymerization-ATRP methods which have many advantages compared to other popular methods and have been implemented by using different techniques together [12]. Due to the practicability of two transformations at the same time or through separate steps, it minimizes homopolymerization which causes side reactions. Combining different polymerization techniques should be an interesting method for block and graft copolymers because the presence of more than one monomer in a polymer chain has been by combining such different techniques [10, 13–15]. The new polymers may have amazing features with their various compositions and architectures. The synthesis of block and graft copolymers was successfully performed by combining controlled radical polymerization techniques and redox polymerization [16]. The synthesis of block copolymers ends with traditional radical polymerization based on the connection of functional groups of the chain and polymers. Though this strategy was effective and successful, it was difficult to test the molecular weight and architecture of the polymer which was obtained. To be able to solve this problem, controlled free radical polymerization techniques were developed quickly [17].

In this present study, the synthesis of block copolymers over separate steps or on the same step was examined with different free radical polymerization techniques and redox polymerization methods. Copolymer synthesis by combining such different techniques has recently attracted considerable attention in polymer synthesis science.
