Dynamic melt flow of nanocomposites based on poly-ε-caprolactam

Rheology of Polymers with Nanofillers

“…Upon cessation of flow in low-viscosity media, the Brownian motion leads to a randomization of the flow-imposed orientation. For PNCs the randomization process may require hours [Utracki and Lyngaae-Jørgensen, 2002;.…”

“…as well as the structure of the flowing body (e.g., skin-core effect, weld lines, flow encapsulation). Evidently, orientation is engendered more efficiently in irrotational flows, but even in shear, an increasing shear rate causes a progressive alignment of clay platelets [Utracki and Lyngaae-Jørgensen, 2002].…”

“…Bartholome et al [2005] confirmed this mechanism indirectly; the solidlike behavior was reduced by grafting the silica particles. Utracki and Lyngaae-Jørgensen [2002] observed several common aspects of exfoliated CPNCs and liquid-crystal polymers (LCPs). Similar six-phase structures are predicted for CPNCs and observed in LCPs: isotropic, nematic, smectic-A, columnar, house of cards, and crystal [Porter and Johnson, 1967;Balazs et al, 1999;Ginzburg et al, 2000].…”

“…Thorough rheological studies have been carried out using a commercial, fully exfoliated CPNC from Ube (1015C2 = PA-6 with 2 wt% MMT-dodecyl ammonium acid) [Utracki and Lyngaae-Jørgensen, 2002;Utracki, 2004]. During the reactive preparation of this CPNC, about one-third of MMT anions were neutralized by ammonium cations, which resulted in a CPNC with direct bonding between clay and the matrix through about 30,000 dodecyl paraffinic links.…”

“…The former resembles highly branched hairy clay platelet with tens of thousands of macromolecules attached to a single clay platelet through the initially reactive intercalant molecules [Okada et al, 1988;Utracki and Lyngaae-Jørgensen, 2002]. The latter systems resemble a composite: polymer reinforced with platelike solids for which the inorganic phase dimensions are enlarged by the intercalation and adsorption of organic molecules.…”