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Free Radical Polymerisation (free + radical_polymerisation)
Selected AbstractsMonolithic poly(1,2-bis(p -vinylphenyl)ethane) capillary columns for simultaneous separation of low- and high-molecular-weight compoundsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 15-16 2009Andreas Greiderer Abstract Monolithic poly(1,2-bis(p -vinylphenyl)ethane (BVPE)) capillary columns were prepared by thermally initiated free radical polymerisation of 1,2-bis(p -vinylphenyl)ethane in the presence of inert diluents (porogens) and ,,,,-azoisobutyronitrile (AIBN) as initiator. Polymerisations were accomplished in 200 ,m ID fused silica capillaries at 65°C and for 60 min. Mercury intrusion porosimetry measurements of the polymeric RP support showed a broad bimodal pore-size-distribution of mesopores and small macropores in the range of 5,400 nm and flow-channels in the ,m range. N2 -adsorption (BET) analysis resulted in a tremendous enhancement of surface area (101 m2/g) of BVPE stationary phases compared to typical organic monoliths (,20 m2/g), indicating the presence of a considerable amount of mesopores. Consequently, the adequate proportion of both meso- and (small) macropores allowed the rapid and high-resolution separation of low-molecular-weight compounds as well as biomolecules on the same monolithic support. At the same time, the high fraction of flow-channels provided enhanced column permeability. The chromatographic performance of poly(1,2-bis(p -vinylphenyl)ethane) capillary columns for the separation of biomolecules (proteins, oligonucleotides) and small molecules (alkyl benzenes, phenols, phenons) are demonstrated in this article. Additionally, pressure drop versus flow rate measurements of novel poly(1,2-bis(p -vinylphenyl)ethane) capillary columns confirmed high mechanical robustness, low swelling in organic solvents and high permeability. Due to the simplicity of monolith fabrication, comprehensive studies of the retention and separation behaviour of monolithic BVPE columns resulted in high run-to-run and batch-to-batch reproducibilities. All these attributes prove the excellent applicability of monolithic poly(1,2-bis(p -vinylphenyl)ethane) capillary columns for ,-HPLC towards a huge range of analytes of different chemistries and molecular sizes. [source] Naphthoylenebenzimidazolone sensitisers for photo-oxidisable free radical polymerisation with the aid of pyridinium saltsCOLORATION TECHNOLOGY, Issue 6 2008Jolanta Koli A series of neutral dyes based on the naphthoylenebenzimidazolone skeleton have been synthesised and evaluated as potential light-absorbing chromophores for free radical polymerisation. Kinetic studies of photoinitiated polymerisation of methyl acrylate and trimethylolpropane triacrylate with pyridinium salts have proved that these dyes are efficient electron-donating photoinitiators operating in visible light. [source] Study of free radical polymerisation with dye photoinitiators containing a naphthoylenebenzimidazolone skeletonCOLORATION TECHNOLOGY, Issue 2 2008Rados, aw Podsiad A series of neutral and cationic dyes based on a naphthoylenebenzimidazolone skeleton have been synthesised and evaluated as potential light-absorbing chromophores for free radical polymerisation. The kinetic study of photoinitiated polymerisation of ethyl acrylate performed with the use of N -phenylglycine, ethyl 4- N,N -dimethylaminobenzoate, phenylthioacetic acid and phenoxyacetic acid have proved that the tested dyes are good electron-accepting photoinitiators. The results show that, in the photoinduced electron transfer from donor to excited singlet state of the dye, the radical anion is possibly formed via an associated donor,dye complex. [source] | ||||||||||