Rheokinetics for reactive polymer processing

Abstract

An important aspect of all reactive polymer processing methods, including reactive injection molding (RIM) and reactive extrusion (REX) is the dramatic increase in viscosity of the material being processed. This paper describes an instrument designed to study rheokinetics of polymerizations relevant to reactive processing. The instrument is capable of measuring simultaneously both viscosity (dynamic or “steady”) and reaction rate during isothermal polymerizations in a closed system. Design aspects of the instrument and some preliminary results are presented.

A fundamental study of polymer melt devolatilization: III More experiments on foam‐enhanced DV

“…In Figs. 10 and 1 1 we see the so-called RPM effect, which has been described previously (1,2,4) and observed in industrial systems as well. Increasing machine speed enhances separation: sufficiently, in fact, to offset the reduction in residence time that accompanies this increase in practice, as in vented extruders for instance (6).…”

“…krn(W0we) = (k,/Kw)SHo (4) Figure 14 confirms that a positive SHo (low P) is necessary for flashing, but it also reveals a second DV mechanism, which is operative at large negative SHO (atmospheric P). viz., separation by entrainment, providing that the vapor space contains air or some other inert (low solubility) gas.…”

“…The rotating drum, illustrated in Fig. 1, together with drive motor was placed in a vacuum glove box where DV experiments were carried out (4). Two blade geometries were investigated: a straight blade, which exposes the pool to a one fixed wall (blade) with adjustable angle (6) relative to the moving wall (drum), and a right-angle blade, which exposes the pool to two fixed walls.…”

“…Separation experiments were conducted in both devices-the drum and the tube. All drum experiments were performed with one fixed wall (straight blade] and all contaminant compositions were measured via gas chromatography, as previously described (2,4). Fractional separation is defined as…”

Reaction Injection Molding

“…Recently, Biesenberger et al 245 have developed an instrument which is capable of measuring simultaneously viscosity and reaction rate during isothermal polymerization in a closed form. The device is basically a rheometer with a Couette type of flow module which also serves as an isothermal calorimeter.…”