Macromolecular Materials and Engineering

Cover: The cover image shows a splitting serpentine channel, called the DentIncx, which is the heart of an injection-mouldable microfluidic device. The mixer performance is tested by feeding the mixer, via two syringe pumps, with water and water mixed with a water-soluble fluorescent dye to visualize the flow and to measure cross-channel intensity. Further details can be found in the article by P. E. Neerincx,* R. P. J. Denteneer, and H. E. H. Meijer on page 1081 and the article by P. E. Neerincx,* S. J. M. Hellenbrand, and H. E. H. Meijer on page 1091.

A stream of polyvinyl pyrrolidone (PVP) sol containing copper nitrate was electrospun to form a coil around a rotating PVP fiber bundle axis. The coiled fiber was turned into ribbon when treated in moisture. PVP was burnt off upon calcination in air at 823K, resulting in the formation of a coiled ribbon of copper oxide, which was further reduced in H₂ to a coiled copper ribbon.

Acid-treated montmorillonite suppresses the flammability of polyolefins by a combination of chemical effects (clay-catalyzed reactions) and physical effects (mass and energy diffusion barriers). The overall flammability depends strongly on the extent of clay dispersion. A polyethylene melt-blend and a nanocomposite, both containing 10wt.% clay, exhibit slower combustion and self-extinguishing behavior, respectively, in a vertical burn test.

Downscaling multifunctional laboratory systems decreases the use of device and sample materials, increases the speed of analysis, and decreases the costs of such testing. Based on a two-component co-injection moulding technology to allow flexible/rigid polymer combinations, a disposable microfluidic device is designed based on an ambi-symmetrical 4 (double) layer system design in which all operation units like channels, valves, pumps, static mixers, and storages are integrated.

The mould to fabricate the microfluidic device is designed using an iterative process, aiming at keeping the injection pressure needed low so as to not surpass the machine's maximum clamping force, while still preventing unwanted hesitation. The mould is fabricated, the microfluidic device is successfully moulded and operation units like pumps and mixers are performance-tested.

PSU/MMT nanocomposites are prepared by in situ photoinduced crosslinking polymerization of intercalated methacrylate-functionalized montmorillonite clay and a polysulfone dimethacrylate macromonomer. A random dispersion of silicate layers in the PSU matrix is found. DSC and TGA show higher T_g and improved thermal stability for all nanocomposites.

Magnetic polymeric particles are obtained by in situ incorporation of surface-modified Fe₃O₄nanoparticles via a suspension polymerization process, exhibiting a good superparamagnetic response, which indicates that the modified Fe₃O₄ nanoparticles are appropriately dispersed in the polystyrene matrix.

The development of self-healing materials based on technologically convenient materials is studied. It is shown that the self-healing behavior of EMNa is well maintained in EVA/EMNa blends up to 30% EVA. In ENR/EMNa blends, the self-healing behavior is well maintained up to 50% rubber. A heterogeneous morphology is observed in all blends, even when a good optical clarity is attained.

Generally, shape-memory (SM) polymers do not offer the appropriate material properties to be used in structurally demanding applications. SM epoxies are synthesized whose formulations enable enhanced failure strains while maintaining high strength, elevated SM transformation temperatures, and excellent SM properties. Phase separation is essential in achieving such combination of beneficial properties.

Phosphorylcholine-substituted cyclooctene polymers are prepared as fouling-resistant coatings on ultrafiltration and reverse osmosis membrane materials. These novel PC-polyolefin coatings substantially reduce fouling relative to the native membranes, while preserving excellent rejection properties.

The synthesis, characterization, and long-term in vivo evaluation of crosslinked urethane-doped polyester elastomers are described. It is concluded that the diol component is another route to control the structure/property relationships of the resulting polymer. This work expands upon the current repertoire of biodegradable elastomers for soft-tissue engineering applications.