39 research outputs found
Poly(hexyl-substituted lactides) : Novel injectable drug delivery systems.
International audienc
Nitroxide Mediated Polymerization and Addition for Synthesis of Novel PNIPAAm-based Biodegradable Copolymers
Reactions in the System O 2 ‐ NO ‐ SiO2 in a Conventional Furnace: I. Oxygen Exchange Reactions
Reactions in the System O 2 ‐ NO ‐ N 2 O in a Conventional Furnace: II. Chemical Reactions Between O 2 and NO
Poly(d,l-lactic acid) nanoparticle preparation and colloidal characterization
International audienc
Sintesi di nuovi Copolmeri Biodegradabili a base Acrilica per mezzo della Polimerizzazione Radicalica Mediata da Nitrossidi (NMP)
Successful MALDI-MS Analysis of Synthetic Polymers with Labile End-Groups: The Case of Nitroxide-Mediated Polymerization Using the MAMA-SG1 Alkoxyamine
International audienceA sample pretreatment was evaluated to enable the production of intact cationic species of synthetic polymers holding a labile end-group using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. More specifically, polymers obtained by nitroxide-mediated polymerization involving the MAMA-SG1 alkoxyamine were stirred for a few hours in trifluoroacetic acid (TFA) to induce the substitution of a tert-butyl group on the nitrogen of nitroxide end-group by a hydrogen atom. Nuclear magnetic resonance, electrospray ionization tandem mass spectrometry, and theoretical calculations were combined to scrutinize this sample pretreatment from both mechanistic and energetic points of view. The substitution reaction was found to increase the dissociation energy of the fragile C?ON bond to a sufficient extent to prevent this bond to be spontaneously cleaved during MALDI analysis. This TFA treatment is shown to be very efficient regardless of the nature of the polymer, as evidenced by reliable MALDI mass spectrometric data obtained for poly(ethylene oxide), polystyrene and poly(butylacrylate)