Rheological characterization of filled polyamide 11 and polyamide 12 solutions in polyols

Abstract

A thorough understanding of the rheological properties of real-world, formulated polymer melts and solutions is important to fabricate articles via typical melt processing techniques. Polyamides have been studied extensively in the area of water purification applications. In this work, the viscosity of these homogeneous polyamide 11 and polyamide 12 solutions in specific polyols was measured in the single phase region as a function of shear rate and temperature via capillary rheometry. In addition, the viscosity of the same polyamide solutions containing various levels of dispersed, nanoscale calcium carbonate particles was characterized in order to understand the rheology of the filled systems. Viscosity-reduced shear rate master curves were constructed by applying the principle of time-temperature superposition, and the activation energies were measured for the polyamide-polyol solutions. The observed increase in viscosity caused by the addition of nanofiller could not be explained by simply applying a vertical shift to the master curve, and a density exponent was required to account for the stiffening mechanism. Also, the dependence of the relative viscosity on the filler loading was shown to be consistent with the hypothesis that the filler particles were organized in the form of small fractal aggregates. The filled polyamide 11 systems exhibited higher relative viscosities than the filled polyamide 12 systems, indicating a higher level of particle aggregation and larger mean cluster size for the filled polyamide 11 systems.Additional Supporting Information may be found in the online version of this article.™Trademark of The Dow Chemical Company ("Dow") or an affiliated company of Dow.

Recycling and Degradation of Polyamides

“…Research on filling polyamides includes filling alumina fibers with PA-66 filling multivalent alcohols with PA-11 and PA-12 and layered silicate filling waste PA-12 nanocomposites, etc. [75,76]. However, in terms of the polyamide waste produced every year, this consumption is nothing more than a drop in the bucket, and filling cannot fundamentally solve the pollution problem of polyamides.…”