Melt rheological properties of polypropylene-maleated polypropylene blends. I. Steady flow by capillary

Abstract

Melt rheological properties of blends of polypropylene (PP) and PP grafted with maleic anhydride (PP-g-MA) are studied using a capillary rheometer. A pseudoplastic flow behavior is observed. The pseudoplasticity of the melt reduces with an increase of PP-g-MA content and/or temperature. The PP-g-MA component in the blend acts as decreasing melt viscosity, especially in the lower shear rate region, while the addition of PP-g-MA to PP does not cause obvious increase of die swell ratio.

Capillary Extrusion Rheology and Thermal Stability of EVA/Organomontmorillonite Nanocomposites

“…This was attributed to the fact that the shearing destroyed the coupling point of the entanglement network and hence resulted in a decreased interaction between chain segments. This was in agreement with the fi ndings of Li et al 26 that a higher shear rate is always accompanied by a rapid decrease in the entanglement density of the macromolecules as well as in the melt viscosity. From Table 2 we could also see that the nanocomposite had a lower fl ow activation energy than the EVA matrix, which is different from the behaviour encountered with conventional microcomposites.…”

“…When the melt left the die, the disentangled and orientated macromolecules would become entangled again, and the stored elastic energy during shear would be released, allowing them to recover their original random states on the disappearance of an outside force fi eld. Furthermore, the higher the shear rate, the stronger the elastic recovery after the die exit, and hence the bigger the extrudate swell 26 .…”

Rheological and extrusion behavior of intercalated high-impact polystyrene/organomontmorillonite nanocomposites

“…Similar phenomena of nonlinear decrease were also observed in the cases of carbon black-filled polybutadiene (or butadiene-styrene copolymer) [29], TiO 2 -filled HDPE composite [30] and glass bead-filled LDPE composite [31]. Li et al [25] supposed it is the combined effect of the melt elasticity of the continuous phase, the extent of deformation of the dispersed phase and the difference in the volume contraction between the two phases due to the increase of density after the strand cools to room temperature that affects the die swell. Considering the special microstructure of montmorillonite, some distinct filler effects from common inorganic fillers occur.…”

“…The data indicate that the temperature sensitivity of shear viscosity is higher in lower shear rate region, and drops at higher shear rates. This phenomenon is agreement to the fact that elevating shear rate always accompanies by a rapid decrease of the entanglement density of macromolecules and the melt viscosity [25]. The temperature dependence of shear viscosity can be stated by Arrhenius-Eyring equation [26] …”

Flow and structure of compatibilized Nylon12/natural rubber blend with functional copolymer

“…The number of entanglement coupling points reduces at higher shear rate, leading to reduction of interaction between chain segments. 34 With the addition of PS/MNR blend, the E a of (Nylon12/NR)/(PS/MNR) blends increases with an increase of compatibilizer content up to 7 phr. This is due to the presence of amide and succinimide linkages causing the limitation of molecular chain motion and configuration.…”