The influence of blending polystyrenes of narrow molecular weight distribution on melt creep flow and creep recovery in elongation

Abstract

Creep and creep recovery experiments in elongation were performed with melts of anionically polymerized polystyrenes (PS) and with their blends at a temperature of 150 °C. For stresses a0 < 10 000 N/m 2 the samples with narrow molecular weight distribution show linear viscoelastic behavior up to the maximum Hencky strain e = 3.5, achievable in a newly developed elongational rheometer for polymer melts. The compliances, D (t), of the blends are linear-viscoelastic only up to a strain limit eL. For strains beyond eL the compliance of each blend depends on the stress a0. For a series of binary blends, prepared from the same components of narrow MWD, the linear-viscoelastic limit eL seems to be independent of the mixing ratio and stress, eL seems to be a function only of the molecular weights of the original components, the blends investigated were made from.

Linear low density polyethylenes and their blends: Part 5 extensional flow of LLDPE blends

“…Turning now to time dependence for the two blends, the dependencies presented in Figs. 5 and 6 are of particular interest. gualitatively, the stress growth behavior for Series-I resembles that of HDPE or LLDPE, whereas that for Series-I1 is similar to that of LDPE with increasingly long chain branching (32).…”

“…The miscibility of the system was not discussed. For miscible, homologous polystyrene (PS) blends, Frank and Meissner (5) reported a systematic variation of the steady state viscosity, qe, with weight fraction of the second component, w2. The plot of log te versus w2 indicated a small positive deviation from the log-additivity rule, or the PDB behavior.…”

Analysis of Polymer Blends by Rheological Techniques

“…For homologous polymer blends [7][8][9], the following dependence has been proposed: where a is a parameter and w, the weight fraction of the species 1. Experimentally, 0.01 _< a < 0.57.…”

“…Furthermore, in the symposia proceedings [17][18][19][20], the subject is of continuing interest. With the exception of the homologous polymer blends [7][8][9]21,22] it is rather difficult to predict the rheological blending rules. The miscibility, morphology and the non-equilibrium state of commercial polymer blends tend to complicate the description.…”

Rheological analysis of the phenolic and furfuryl resins used in the carbon materials processing

“…The knowledge of certain characteristics of the precursor polymer, such as molecular weight distribution, average molecular weight and rheological behavior, orientates the processing conditions in order to control the porous size and its quantity in the carbon matrix and, consequently, the final mechanical, electrical and thermal properties of the CM [8][9][10][11][12][13][14][15] . In this work, rheological characteristics of phenolic and furfuryl resins are determined and used to help the selection of the appropriate raw material and to establish the parameters for processing CRFC and glassy carbon.…”