Macromolecular Chemistry and Physics

Front Cover: Plant oils are valuable renewable resources, especially for the polymer industry. Due to their inherent double bond functionality they offer manifold possibilities to introduce functional groups or to obtain polymers via olefin metathesis. Thus, monomers, platform chemicals and polymers can be obtained from these renewable resources in efficient catalytic one step reactions. Further details can be found in the article by M. A. R. Meier^*on page 1073.

Plant-oil-derived unsaturated fatty acids offer manifold possibilities for the materials use of these renewable resources via olefin metathesis. Both monomers and polymers can, thus, be obtained in a straightforward and sustainable fashion.

Anionic ring-opening polymerization of dimethylgerma[1]ferrocenophane to give polyferrocenyldimethylgermane (PFDMG) homopolymer and block copolymers with polyisoprene (PI) is described. Depending on the volume fractions, these block copolymers undergo microphase separation in thin films to give cylindrical or spherical PFDMG domains in a PI matrix. Moreover, these morphologies are preserved after selective plasma etching of the PI block.

A numerical simulation of the MMA polymerization in the presence of alkanes, representing characteristics moieties of poly[ethylene-co-(1-octene)], and peroxide-derived alkoxyl radicals enabled to systematically predict the experimental results. The numerical simulation has shown that the depropagation reaction is of strong influence when increasing the temperature and decreasing the monomer concentration.

Frontispiece: New polymers containing the bis-silicon-bridged p-terphenyl skeleton and different spacer units in the main chain were synthesized by hydrosilylation reactions. The polymers with saturated spacers show comparable quantum yields to that of chromophoric monomer, while the polymer having an unsaturated linkage exhibits lower fluorescence efficiency. All polymers showed improved thermal stability than that of monomer. Further details can be found in the article by L. Li, C. Xu^*, S. Li^*on page 1097.

A series of new polymers containing the bis-silicon-bridged p-terphenyl skeleton in the main chain is synthesized by hydrosilylation reactions. All polymers show good thermal stability. Those with saturated co-units in the main chain have constant emission maximum wavelengths and comparable fluorescence quantum yields to that of the monomer, while the polymers having an unsaturated linkage between the bis-silicon-bridged p-terphenyl units exhibited longer wavelength emissions with low fluorescence efficiencies.

The effect of incorporation of pristine clay platelets during the suspension polymerization of methyl methacrylate in an aqueous medium is studied. The results show that the addition of a small amount of pristine clay powder in the polymerization system resulted in the formation of spherical beads of poly-(methyl methacrylate)/clay nanocomposite with uniform sizes.

1,3-dipolar cycloaddition of nitrones is qualified to link functional groups onto unsaturated polymers. Since many polymeric materials are subjected to UV-light exposure, it is of great practical interest to apply UV-absorbing reagents and binding them covalently. Two novel UV-absorbing nitrones were synthesized and bound onto an oligo(urethane) and onto fumaric acid diethyl ester.

The secondary imidization process during the synthetic sequence for obtaining MeAm-based pH-sensitive copolymeric microgels leads to a novel thermoresponsive swelling behavior. A temperature volume phase transition at around 40 °C results from the particular combination of MeAm, which does not contribute to the thermal response, with cationic ionizable groups such as ethylamine or pyridine.

The present study focuses on the in situ cationic photopolymerization of chemically modified silica nanoparticles dispersed in various epoxy functional resins. It investigates some important aspects related to surface structural composition of the functionalized silica, the dispersion of the nanofiller into the photocurable monomers and also the role played by the OH groups onto the silica particle surfaces in promoting chain transfer reactions.

This study focuses on the development of new, hydrophilic reactive polymers intended for in vivo reversible coating of gene-delivery vectors. The proposed polymeric systems should protect the vectors during transport to the host and release them after uptake with the target cell (tissue), as shown in the scheme. In this work, the coating of model particles, mimicking real vectors with hydrophilic polymers containing reducible spacers and their subsequent release from particle surface, is studied.

Surface-selective graft functionalization of macroporous membranes has been realized by two steps: (i) immobilization of dithiocarbamate group as iniferter and (ii) heterogeneous photo-graft copolymerization controlled by this iniferter. High grafting efficiency, uniform modification of the pore surface and high controllability over grafted layer thickness and (cross-linked) layer architecture have been demonstrated.

A facile synthesis of low viscosity hyperbranched epoxy resin from A2 and B3 monomers by a pseudo one-step method is presented. The resin can be used as a reactive thinner in thermosetting resin fields, such as environmental resin or no-solvent resin.

Short-range aromatic/aromatic interactions between PSS and MB explain a higher tendency of this polymer to bind the dye both in the presence and in the absence of added NaCl, preventing the formation of large MB self-aggregates. In contrast, a higher local concentration of MB around PAMPS and, more significantly, around PVS due to long-range electrostatic interactions, results in MB self-aggregation that can be quenched in the presence of NaCl.

Back Cover: The graphic presents the scanning electron microscopy images of PMMA/clay nanocomposite beads synthesized by suspension polymerization of MMA in aqueous medium. When the polymerization was carried out in the presence of pristine clay, the beads were found to be more uniform, spherical in shape and size, and with no cluster formation, while the polymerization in the presence of the organoclay resulted in the formation of clusters only. Further details can be found in the article by S. Khatana, A. K. Dhibar, S. Sinha Ray and B. B. Khatua on page 1104.