The effects of polymer melt rheology on the replication of surface microstructures in isothermal moulding

Eriksson, Torbjörn; Rasmussen, Henrik Koblitz

doi:10.1016/j.jnnfm.2005.03.007

Cited by 32 publications

(22 citation statements)

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“…Then a subset of the data from the macroscale simulation is used as input to a local simulation on the microscale. (Eriksson and Rasmussen, 2005, Kim and Turng, 2006, Yu et al, 2004 It is assumed that the microfeatures are so small that they exert only minor influence on the flow and the temperature field in the main geometry, and there is only a one way coupling from macroscale to microscale.…”

Section: Previous Simulation Studiesmentioning

confidence: 99%

“…Eriksson and Rasmussen performed viscoelastic, isothermal simulations of the filling of micro ribs (width 22 µm) using a dual domain procedure (Eriksson and Rasmussen, 2005). The whole deformation history in the macroscopic simulation was used as an initial condition and the full stress tensor was employed as a boundary condition in the microscale simulation.…”

Section: Previous Simulation Studiesmentioning

confidence: 99%

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Multiscale Simulation of Injection Molding of Parts with Low Aspect Ratio Microfeatures

Tofteberg

Andreassen

2010

International Polymer Processing

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Section: Previous Simulation Studiesmentioning

confidence: 99%

Section: Previous Simulation Studiesmentioning

confidence: 99%

Multiscale Simulation of Injection Molding of Parts with Low Aspect Ratio Microfeatures

Tofteberg

Andreassen

2010

International Polymer Processing

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“…This version of the MSF model has been applied to describe quantitatively and simultaneously nonlinear shear and elongational flows of LDPE with a minimum number of parameters [Rol onGarrido et al (2009)]. It has been also used in numerical simulations of planar contraction flow [Olley and Wagner (2006)], and in numerical simulations of polymer processes like compression molding [Eriksson and Rasmussen (2005)], inflation of a flat plate ; Rasmussen and Yu (2008)], and gas displacement of polymer melts in a cylinder [Rasmussen and Eriksson (2007)]. …”

Section: Introductionmentioning

confidence: 99%

Increase of long-chain branching by thermo-oxidative treatment of LDPE: Chromatographic, spectroscopic, and rheological evidence

Rolón-Garrido¹,

Zatloukal²,

Wagner³

2013

Journal of Rheology

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SynopsisLow-density polyethylene was thermo-oxidatively degraded at 170 C, i.e., degraded in the presence of air, by a one thermal cycle (1C) treatment during times between 30 and 90 min, and by a two thermal cycles (2C) treatment, i.e., after storage at room temperature, an already previously degraded sample was further degraded during times between 15 and 45 min. Characterization methods include gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy, as well as linear and nonlinear rheology. A reduction of molar mass was detected for all degraded samples by GPC, as well as an increase of the high molar mass fraction of the 1C sample degraded for the longest time. Intrinsic viscosity measurements indicate also a reduction of molar mass with increasing degradation times for both 1C and 2C samples. Thermo-oxidation is confirmed for 1C and 2C samples by analyzing specific indices in FTIR. Linear viscoelasticity seems to be in general only marginally affected by thermo-oxidative exposure, while the enhanced strain-hardening effect observed in uniaxial extension experiments presents a clear evidence for an increased long-chain branching (LCB) content in both 1C and 2C samples. Elongational viscosity data were analyzed by the molecular stress function (MSF) model as well as the Wagner-I model, and for both models, quantitative description of the experimental data for all samples was achieved by fit of only one nonlinear model parameter. Time-deformation separability was confirmed for all samples degraded, 1C as well as 2C, for cumulative degradation times of up to 90 min. The characterization by GPC was confronted with the characterization obtained from nonlinear rheology. It can be stated that elongational rheology is a powerful method to detect structural a) Author to whom correspondence should be addressed; electronic mail: victor.h.rolongarrido@tu-berlin.de

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“…These rates represent the same measurements according to the time-temperature superposition. The strain rate is 3000 times larger than the inverse of largest time constant (of about 10 6 s at 120 C) in the PS melt [Eriksson and Rasmussen (2005); Rasmussen and Eriksson (2007)]. Notice, before the extension of the polystyrene the sample was prestretched to an initial radius of 1.7 mm, to reduce the transmitted force and thereby ensure adhesion between plate and sample.…”

Section: Resultsmentioning

confidence: 99%

Experimental evaluation of the pseudotime principle for nonisothermal polymer flows

Yu¹,

Rasmussen²,

Skov³

2011

Journal of Rheology

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SynopsisWe have applied a series of start-up of uniaxial extensions to very high strain followed by stress relaxation. A potential temperature change was applied during the stress relaxation. We used two thermorheological simple polymers; a linear polystyrene and a branched low density polyethylene. Experiments performed with temperature changes during the stress relaxation were shown to be identical with isothermal ones in the "pseudotime," within the accuracy of the experiments. This verifies that the pseudotime approach seems to be the general basis for nonisothermal microstructural modeling for flow of polymers. The pseudotime is given as nðtÞ ¼ Ð t 0 1=a T ðTðt 0 ÞÞdt 0 , where a T are the well established time-temperature superposition shift factors, calculated from the past temperatures (at time t 0 ) in a particle path V C 2011 The Society of Rheology.

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The effects of polymer melt rheology on the replication of surface microstructures in isothermal moulding

Cited by 32 publications

References 30 publications

Multiscale Simulation of Injection Molding of Parts with Low Aspect Ratio Microfeatures

Multiscale Simulation of Injection Molding of Parts with Low Aspect Ratio Microfeatures

Increase of long-chain branching by thermo-oxidative treatment of LDPE: Chromatographic, spectroscopic, and rheological evidence

Experimental evaluation of the pseudotime principle for nonisothermal polymer flows

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