Tribological properties of epoxy + silica hybrid materials.

Various amounts of nano size silica particles prepared by a sol-gel process were added to epoxy+ amine systems. We have investigated tribological properties including friction and sliding wear resistance of hybrids so obtained, and also relationships between different tribological properties and surface topography. The thermal degradation behavior and thermal stabilities were determined by thermogravimetric analysis (TGA).

Mixing properties of lyophilized protein systems: a spectroscopic and calorimetric study.

The purpose of this study was to investigate the solid-state properties of lyophilized formulations of protein (ribonuclease A) containing sucrose or trehalose across a wide range of compositions, both in the presence or absence of hydroxyethylstarch (HES). Infrared spectroscopy reveals that the protein forms hydrogen bonds to sugars (sucrose or trehalose) as water is removed from the sample. The strength and/or number of hydrogen bonds in dried samples increase as the weight fraction of sugar increases.

Characterization of amorphous solids with weak glass transitions using high ramp rate differential scanning calorimetry.

Measurement of the glass transition temperature (T(g)) of proteins and other high molecular weight polymers in the amorphous state is often difficult, since the transition is extremely weak, that is, the DeltaC(p) at the glass transition temperature is small. For example, little is known about the solid-state properties of hydroxyethyl starch (HES), which is beginning to become more commonly evaluated as a bulking agent in pharmaceutical products. For weak thermal events, such as the change in heat capacity at the T(g) of a pure protein or large synthetic polymer, increased heating rate should produce greater sensitivity in terms of heat flow.