202 research outputs found
Comparative studies of poly(dimethyl siloxanes) using automated GPC-MALDI-TOF MS and on-line GPC-ESI-TOF MS
Towards sustainable polymeric nano-carriers and surfactants: facile low temperature enzymatic synthesis of bio-based amphiphilic copolymers in scCO2
We demonstrate that useful bio-based amphiphilic polymers can be produced enzymatically at a mild temperature, in a solvent-free system and using renewably sourced monomers, by exploiting the unique properties of supercritical CO2 (scCO2). We present the use of a novel near-ambient temperature approach to prepare renewable amphiphilic ABA copolymers in scCO2. Bio-based commercially available monomers have been polymerised to prepare chains with targeted molecular weight. The amphiphilic materials were prepared by end-capping the synthesised polymers with methoxy poly(ethylene glycol) (MPEG) chains in a one-pot high pressure reaction utilising Candida Antarctica Lipase B (CaLB) as a catalyst at a temperature as low as 35 °C. The block copolymers are characterised by 1H-NMR, GPC and DSC in order to carefully assess their structural and thermal properties. These polymers form self-assembled aggregates in aqueous environment and these nanostructures are studied through DLS, TEM and UV-Vis. Highly hydrophobic Coumarin-6 was used as a model to prove dispersion in water of lipophilic molecules. Maximum bubble pressure tests demonstrate the reduction in surface tension of these polymers and comparisons are made directly to commercial polymeric non-ionic surfactants
MALDI-TOF MS Characterization of Carboxyl-End-Capped Polystyrenes Synthesized Using Anionic Polymerization
Microstructural study of a nitroxide-mediated poly(ethylene oxide)/polystyrene block copolymer (PEO-b-PS) by electrospray tandem mass spectrometry
Characterization of poly(ethylene glycol) esters using low energy collision-induced dissociation in electrospray ionization mass spectrometry
Effects of composition and transesterification catalysts on the physico-chemical and dynamic properties of PC/PET blends rich in PC
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