Amphiphilic diblock copolymers poly(2-hydroxyethylmethacrylate)-b-(N-phenylmaleimide) and poly(2-hydroxyethylmethacrylate)-b-(styrene) using the macroinitiator poly(HEMA)-Cl by ATRP: Preparation, characterization, and thermal properties



In recent years, much attention has been given to the development of specialty polymers from useful materials. In this context, amphiphilic block copolymers were prepared by atom transfer radical polymerization (ATRP) of N-phenylmaleimide (N-PhMI) or styrene using a poly(2-hydroxyethylmethacrylate)-Cl macroinitiator/CuBr/bipyridine initiating system. The macroinitiator P(HEMA)-Cl was directly prepared in toluene by reverse ATRP using BPO/FeCl3 6 H2O/PPh3 as initiating system. The microstructure of the block copolymers were characterized using FTIR, 1H-NMR, 13C-NMR spectroscopic techniques and scanning electron microscopy (SEM). The thermal behavior was studied by differential scanning calorimetry (DSC), and thermogravimetry (TG). The theoretical number average molecular weight (Mn,th) was calculated from the feed capacity. The microphotographs of the film's surfaces show that the film's top surfaces were generally smooth. The TDT of the block copolymer P(HEMA)80-b-P(N-PhMI)20 and P(HEMA)90-b-P(St)10 of about 290°C was also lower than that found for the macroi′nitiator poly(HEMA)-Cl. The block copolymers exhibited only one Tg before thermal decomposition, which could be attributed to the low molar content of the N-PhMI or St blocks respectively. This result also indicates that the phase behavior of the copolymers is predominately determined by the HEMA block. The curves reveal that the polymers show phase transition behavior of amorphous polymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010