Synthesis and characterization of shell-cross-linked polymer networks and large-core star polymers: Effect of the volume of the cross-linking mixture
SourceEuropean Polymer Journal
Google Scholar check
MetadataΕμφάνιση πλήρους εγγραφής
Group transfer polymerization and sequential addition of monomer and cross-linker were employed for the preparation of two new polymer structures, one of a polymer network and the other of a star polymer. The synthesis was completed in two steps, involving the synthesis of linear methyl methacrylate (MMA) arms of degree of polymerization of 20, followed by their cross-linking using a mixture of MMA monomer and ethylene glycol dimethacrylate (EGDMA) cross-linker. In this study, the volume of the cross-linking mixture was varied systematically. Furthermore, two mixture compositions were employed, involving MMA:EGDMA molar ratios of 1:1 and 3:1, leading to two series of polymeric materials. It was found that at a given cross-linking mixture composition, a larger volume of the cross-linking mixture favored the formation of polymer networks, whereas a smaller volume favored the formation of star polymers. The linear precursors, the star polymers and the extractables from the polymer networks were characterized by gel permeation chromatography in tetrahydrofuran (THF). The absolute weight-average molecular weight, the number of arms and the hydrodynamic radii of the star polymers, as determined using static and dynamic light scattering in THF, respectively, and their average radii as determined by atomic force microscopy, increased as the volume of the cross-linking mixture increased. The gravimetrically measured degrees of swelling in THF, the network sol fraction and the percentage of branched polymer in the sol fraction decreased as the volume of the cross-linking mixture increased. © 2008 Elsevier Ltd. All rights reserved.
Showing items related by title, author, creator and subject.
Patrickios, Costas S.; Georgiou, Theoni K. (2003)The recent literature on chemically cross-linked amphiphilic polymer networks is reviewed. The main subjects covered are network synthesis, characterization, modeling and applications. Special mention is made to more modern ...
Degradable polymer networks and star polymers based on mixtures of two cleavable dimethacrylate crosslinkers: Synthesis, characterization, and degradation Themistou, Efrosyni; Patrickios, Costas S. (2009)Mixtures of two cleavable dimethacrylate crosslinkers, the hydrolyzable di(methacryloyloxy-1-ethoxy)methane (DMOEM) and the thermolyzable 1,1-ethylenediol dimethacrylate (EDDMA), were used for the preparation of neat ...
Loizou, Elena; Porcar, L.; Schexnailder, P.; Schmidt, G.; Butler, P. (2010)The structural responses of a polymer-clay nanocomposite hydrogel to an imposed shear field are investigated from the nanometer to the micrometer length scales. The effects of polymer molecular weight and concentration of ...