1. Synthesis of well-defined amphiphilic poly(d,l-lactide)-b-poly(N-vinylpyrrolidone) block copolymers using ROP and xanthate-mediated RAFT polymerization
- Author
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Niraj Kumar Vishwakarma, Tapas K. Paira, Nira Misra, Kalyan Ramesh, Tarun K. Mandal, Biswajit Ray, Chandra Sekhar Biswas, Vijay Kumar Patel, Avnish Kumar Mishra, and Pralay Maiti
- Subjects
Materials science ,Hydrodynamic radius ,Polymers and Plastics ,Polymerization ,Critical micelle concentration ,Organic Chemistry ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Reversible addition−fragmentation chain-transfer polymerization ,Chain transfer ,Ring-opening polymerization ,Micelle - Abstract
Well-defined amphiphilic poly( d , l -lactide)- b -poly( N -vinylpyrrolidone) (PDLLA- b -PNVP) block copolymers were successfully prepared using ring-opening polymerization (ROP) and xanthate-mediated reversible addition-fragmentation chain transfer (RAFT) polymerization. Synthesized PDLLA- b -PNVP block copolymers were characterized by 1 H NMR spectroscopy and GPC. Spherical micelles of ∼30.2 nm diameter were formed from the aqueous solution of amphiphilic diblock copolymer PDLLA 42 - b -PNVP 63 as revealed by TEM and supported by 1 H NMR and light scattering. The critical micelle concentration value of the block copolymers, determined by fluorescence spectroscopy using pyrene as probe, increased with the increase in the chain length of PNVP block. The average hydrodynamic radius ( R h ) of the micelles remained almost constant above the cmc value over the angles of scattering measurement. Thermal properties of these block copolymers were studied by TGA, DTA and DSC. Crystalline properties of these block copolymers were studied by WXRD.
- Published
- 2012
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