Synthesis and characterization of the brush type polymethyl methacrylate grafted polyβ-alanine

Synthesis of poly(methyl methacrylate-g-β-alanine) brush type copolymers was carried out by means of free radical polymerization (FRP) of nylon 3 (polyβ-alanine) macro monomer including vinyl group and methyl methacrylate (MMA) vinyl monomer. 2,2′-azobis(2-methylpropionitrile) as initiator and formic acid as a solvent was used at the copolymerization. Synthesis of the brush type copolymer was fulfilled at 70 oC temperature for 50 minutes. For this purpose, polyβ-alanine macro monomer including vinyl group was synthesized by hydrogen transfer polymerization (HTP). Polyβ-alanine was obtained base catalyzed HTP method of acrylamide vinyl monomer. The polymerization that was sensitive to moisture and oxygen was performed in anhydrous o-dichlorobenzene at about 100 oC for 24 hours under inert media. tNaBuO was used as an initiator ([M]/[I]=30). N-phenyl-beta-naphthylamine as free radical polymerization inhibitor was added by 0.1 % to reaction medium to prevent possible free radical polymerization. After the polymerization, acetic acid was added into the reaction medium and the medium was neutralized. Thus, the polymerization was terminated by protonating the active anionic chain-ends. The polymers which were separated by filtration using vacuum pump with Gooch crucible were washed with cold methanol. Traces of inhibitor, base and solvent were removed from the polymers. The polymer samples were kept in a vacuum oven at 49 oC for 7 hours. Then solvent and moisture residues were completely removed. The spectroscopic properties of the products were determined by 1H-NMR and FT-IR techniques, and thermal properties of them were determined by TGA and DSC techniques. The weight molecular weights of synthesized polymers were defined by Dynamic Light Scattering method. The morphological properties of the products were examined by SEM analysis. Keywords: Nylon 3 (polyβ-alanine), methyl methacrylate (MMA), brush type graft copolymer, free radical polymerization (FRP), hydrogen transfer polymerization (HTP)