Macromolecular Materials and Engineering

Cover: The cover presents an optical image of near-monodisperse model-protein (bovine serum albumin, BSA)-coated bubbles generated using a co-axial electrohydro dynamic flow. The drying process of the bubbles results in thin films and porous structures, for which size and distribution can be controlled by the parameters of the technique. Further details can be found in the article by Z. Ekemen, Z. Ahmad,^* M. Edirisinghe, and E. Stride on page 8.

Microbubbles using a model protein (BSA) as the coating material were generated using co-axial electrohydrodynamic flow. The polydispersity index (PI) of these bubbles was controlled by careful modification of the processing parameters and the solution properties. Under optimal conditions, which results in a low PI, protein bubbles can be used to prepare porous and layered structures or be used as standalone agent carriers.

A novel phosphorous compound (DOPI) based on DOPO units linked to the heterocyclic tris-(acryloyloxy)ethyl isocyanurate is proposed for flame retarded DGEBA/DMC, RTM6 and their corresponding carbon fiber (CF) composites. Decomposition pathways, flame retardancy mechanisms and the impact of CF are discussed. The flammability (LOI, UL 94) and the fire behavior (cone calorimeter for different irradiances) are assessed.

Novel waterborne pressure-sensitive adhesives with hard and soft particles were specifically designed to improve their shear resistance without reducing their peel force. Depending on whether the small hard particles are connected or not to the matrix, two different optimal shapes of the stress/strain curve are found giving nearly the same excellent application properties with a different material structure.

The article discusses surface modification of fullerenic carbon black by plasma polymerization. The modified carbon black is incorporated in various rubber systems and their behavior studied using the Payne effect and stress/strain properties. The study shows that plasma-coated carbon black results in a better dispersion in different rubber systems than the uncoated version.

Polyurethane mechanical properties were dramatically enhanced by the addition of 6 wt.-% high-aspect-ratio carbon nanotubes. Oriented nanocomposites showed conductivities of 1 S · cm⁻¹ without any obvious influence due to the direction of nanotube alignment.

The screw speed employed during melt mixing has a significant effect on the level of MWCNT dispersion in the HIPS matrix. The extent of MWCNT dispersion is correlated with both electrical and rheological percolation. The electrical conductivity of HIPS was increased by up to 11 orders of magnitude. Evidence from Raman spectroscopy suggests the MWCNTs are wetted by HIPS.

A novel route to prepare electrically conductive expanded graphite/epoxy/polyol composites using an environmentally friendly UV-curing method is presented. The binder formulation is solventless and less toxic compared to other low-molecular-weight monomers. Electrical percolation occurred at low concentration of filler (less than 1wt.-%). It is possible to vary the electrical percolation of the composites by varying the binder composition.

Liquid crystalline epoxy thermosets were prepared by adding M1 into DGEBA/4,4'-diaminodiphenyl methane blends. The M1/DGEBA blends possessed increased rubbery plateau modulus, higher glass transition temperatures and lower tan δ. The Izod notched impact strength could be enhanced by 55% by addition of 2% M1 compared to unmodified DGEBA blends. Extremely rough and highly deformed fracture surface was obtained in the M1/DGEBA blends.