摘要:

Interfacial tension plays an important role in the manufacture of thermoplastic matrix composites and in the development and stabilization of blend morphologies. The purpose of this work was to develop a rapid method to determine the interfacial tension. The work entailed the microscopic tracking of shape changes of polystyrene fibers imbedded in poly(methyl methacrylate). The measured interfacial tension was found to agree with a value extrapolated from literature data to ±20%. This method reduces the analysis time over traditional techniques, does not require complicated equipment, and provides reasonable precision.

ISSN:0148-6055    

DOI:10.1122/1.550033

出版商:The Society of Rheology    

年代:1989

数据来源: AIP

摘要:

Experimental results are reported for cross‐flow migration of solid spherical nylon balls (0.238 cm diameter and volume fractionφ=0.02) in three different mediums carried out under plane‐Poiseuille flow conditions in a perspex slit channel (length=226 cm,width=27 cm,height=3.97 cm). The three different fluids employed for suspensions are pure corn syrup (a Newtonian medium), 0.2 wt% polyacrylamide in corn syrup (a nonshear‐thinning elastic medium), and an aqueous solution containing 2.5 wt% polyacrylamide (a shear‐thinning elastic medium). Gamma radiation technique is used to monitor the distribution of nylon particles in the transverse direction at four altitudes of 0.35, 0.7, 1.05, and 1.4 cm, respectively from the top of the slit channel. Measured profiles and visual inspection indicated different flow patterns in the three fluid mediums studied. In the Newtonian medium, particle distribution was found to be uniform, whereas in a nonshear‐thinning medium, migration tended toward the center line resulting in formation of a narrow core. In the viscoelastic shear‐thinning medium, the solid particles concentration is observed between two altitudes measured at about 0.35 cm from top and bottom sides of the slit channel and at about 0.6 cm from the central axis of the channel. Analysis for these different flow patterns based on the contribution of the elastic and viscous effects is given in terms of the rheological behavior of the carrier fluids.

ISSN:0148-6055    

DOI:10.1122/1.550034

出版商:The Society of Rheology    

年代:1989

数据来源: AIP

摘要:

Nonlinear viscoelastic properties were measured in the molten state for two series of ABS polymers with rubber particle contents of 5, 10, 15, and 20 wt%. Experimental results for the shear relaxation modulusG(t,γ)obtained at large step strains revealed a striking fact that the strain dependence of the modulus disappears in the region where a long‐time relaxation due to the particles is dominant. In single‐step stress relaxation, theG(t,γ)curves are composed of two contributions, entanglement relaxation of the matrix polymer at shorter time scales and long‐time relaxation due to the particles. In order to separate the above two contributions, double‐step stress relaxation experiments were done in which the first step strain −γ is applied att=−t1and the second step strain γ is added att=0.It is shown thatt1should be comparable with the maximum relaxation time of the matrix polymer for proper evaluation of the particle contribution.

ISSN:0148-6055    

DOI:10.1122/1.550035

出版商:The Society of Rheology    

年代:1989

数据来源: AIP

摘要:

We discuss the connection between the two approaches to the hydrodynamics of dilute polymer solutions: The conventional diffusion equation approach and the recently developed coupled Langevin equations approach. The purpose of this contribution is to show how the rather disjointedly working scientific communities using these two approaches can mutually benefit from the methods, insights, and results of each other.

ISSN:0148-6055    

DOI:10.1122/1.550036

出版商:The Society of Rheology    

年代:1989

数据来源: AIP

摘要:

A direct constrained least‐squares cubic spline method suitable for use with noisy experimental data is explained in detail and applied successfully to examples of shear‐thinning (pseudoplastic), viscoplastic (Bingham), and shear‐thickening (dilatant) fluids. A regularizing linearized curvature smoothness constraint is employed.

ISSN:0148-6055    

DOI:10.1122/1.550037

出版商:The Society of Rheology    

年代:1989

数据来源: AIP

ISSN:0148-6055    

DOI:10.1122/1.550063

出版商:The Society of Rheology    

年代:1989

数据来源: AIP

ISSN:0148-6055    

DOI:10.1122/1.550064

出版商:The Society of Rheology    

年代:1989

数据来源: AIP

ISSN:0148-6055    

DOI:10.1122/1.550065

出版商:The Society of Rheology    

年代:1989

数据来源: AIP