Orthogonal synthesis of graft copolymers by combination of rop and photoinitiated ATRP

Continuous change and development of ecological and financial conditions increases the demand for polymers. Due to expectations about costs, environment and product properties, it is becoming increasingly important that polymer synthesis methods are biocompatible, environmentally friendly, cost-effective and controlled. With graft copolymerization, polymers can be produced that fulfill requirements of various applications by adjusting chain length, grafting density and side-branch length. Controlled/living radical polymerization (CLRP) methods such as atom-transfer radical polymerization (ATRP) are commonly used to produce graft copolymers. ATRP is an easy to implement method that can work with a wide number of monomers and is compatible with other methods. Metal catalysts and heat treatments used in ATRP are not suitable for health and microelectronic applications. Photoinitiated ATRP (photo-ATRP) is a practical method for metal-free and mild conditions. In photo-ATRP, electron transfer takes place between a photocatalyst and an initiator excited by light to form a radical and polymer grows from the radical. Polymerization can be stopped or continued by turning the light off and on (temporal control). In addition, when the light is directed to a certain area, polymerization takes place only in that area (spatial control). This allows control over the polymerization. Photo-ATRP is used in one-pot synthesis methods since it can be activated with a particular light. One-pot methods are commonly used in synthesis of macromolecular polymers. The methods used in one-pot synthesis should be compatible with each other and should be able to proceed without affecting each other (orthogonal). In orthogonal processes, there is no need for intermediate purification steps. This saves resources and time. Ring opening polymerization (ROP) and photo-ATRP methods are frequently used in one-pot synthesis. ROP mechanism is nucleophilic addition of an alcohol to a cyclic monoester such as ε-caprolactone (ε-CL). Organo-catalysts such as diphenyl phosphate (DPP) are effective catalysts used at room conditions. Within the scope of this thesis, it is aimed to obtain graft polymers by using photo-ATRP technique and ROP technique together. Methyl acrylate (MA), hydroxy ethyl acrylate (HEA) containing hydroxyl group and ε-caprolactone were used as monomers. Perylene was used as photocatalyst in photo-ATRP while diphenyl phosphate (DPP) was used as ROP catalyst. Reactions were carried out sequentially and one-pot. Resulting graft copolymers were characterized by 1H-NMR, GPC and FT-IR.