Die Swell of Complex Polymeric Systems

Wang, Kejian

doi:10.5772/50137

Cited by 26 publications

(40 citation statements)

References 55 publications

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“…The measured average strand diameter across all groups was 324.95 ± 1.95 μm, approximately 24.95 μm larger than the theoretical value. This increase in strand diameter is due to the inks die-swelling and expanding upon extrusion from the nozzles, a behavior which is typical of viscoelastic polymer inks 44,45 . The measured average pore size (395.17 ± 8.41 μm) was approximately 24.83 μm smaller than its respective theoretical value.…”

Section: Morphological Characterization Of the 3d Printed Scaffoldsmentioning

confidence: 99%

Fabrication and characterization of mechanically competent 3D printed polycaprolactone-reduced graphene oxide scaffolds

Seyedsalehi

Daneshmandi

Barajaa

et al. 2020

Sci Rep

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The ability to produce constructs with a high control over the bulk geometry and internal architecture has situated 3D printing as an attractive fabrication technique for scaffolds. Various designs and inks are actively investigated to prepare scaffolds for different tissues. In this work, we prepared 3D printed composite scaffolds comprising polycaprolactone (PCL) and various amounts of reduced graphene oxide (rGO) at 0.5, 1, and 3 wt.%. We employed a two-step fabrication process to ensure an even mixture and distribution of the rGO sheets within the PCL matrix. The inks were prepared by creating composite PCL-rGO films through solvent evaporation casting that were subsequently fed into the 3D printer for extrusion. The resultant scaffolds were seamlessly integrated, and 3D printed with high fidelity and consistency across all groups. This, together with the homogeneous dispersion of the rGO sheets within the polymer matrix, significantly improved the compressive strength and stiffness by 185% and 150%, respectively, at 0.5 wt.% rGO inclusion. The in vitro response of the scaffolds was assessed using human adipose-derived stem cells. All scaffolds were cytocompatible and supported cell growth and viability. These mechanically reinforced and biologically compatible 3D printed PCL-rGO scaffolds are a promising platform for regenerative engineering applications.

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Section: Morphological Characterization Of the 3d Printed Scaffoldsmentioning

confidence: 99%

Fabrication and characterization of mechanically competent 3D printed polycaprolactone-reduced graphene oxide scaffolds

Seyedsalehi

Daneshmandi

Barajaa

et al. 2020

Sci Rep

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“…There have been various interpretations of the extrusion‐swell of viscoelastic fluids from the macroscopic view of polymer rheology . The extent of the swelling depends on the intrinsic characteristics of the polymer as well as the external factors such as the capillary operating conditions (the applied shear rate, stress, and temperature) . Tanner proposed mathematical expressions for the relationship between the swell ratio B and the first normal stress difference or shear stress, on the supposition that polymer melt shear flow obeyed a simple law.…”

Section: Introductionmentioning

confidence: 99%

Rheological behavior of coir‐fiber‐filled polypropylene composites at constant shear stress

Islam

Begum

2014

Polymer Composites

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The rheological behavior of coir-fiber-filled polypropylene (PP) composite has been studied at constant shear stress. The shear stress versus shear rate relationship for the composite follows power law model of viscous flow. Unlike similar studies in the literature, the viscosity is treated as a stress-independent parameter, which increases with the increase of fiber loading; but decreases with the rise of temperature. The SEM reveals that the fibers are loosely bound to the polymer matrix and the outer surface of the composite is rough and irregular, making it susceptible to high friction with the wall of the flow channel. With analogy to nth order chemical reaction, new formula has been derived for the activation energy of viscous flow, which is found to increase with the increase in the fiber content. The die-swell ratio decreases with the increase of fiber loading, but increases with the rise of temperature. The elastics parameters of the composite such as the recoverable shear strain, the first normal stress difference, and the elastic strain induced by the stored energy in the capillary reservoir have been estimated based on the die-swell data. POLYM. COMPOS., 36:51-61,

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“…In addition, as what was done in [7], according to the geometric relation in the region of JBIC (Figure 2c Considering Equations (26) and (30), the balance of W and E leads to, Equation (31)…”

Section: Resultsmentioning

confidence: 72%

“…The former parameter is the ratio between the diameters of the nozzle opening and swelled extrudate, while the latter is the distance where the maximum swell diameter is attained. These two parameters depend on the type of the used polymer, nozzle length/diameter ratio, and shear rate in the nozzle [ 23 , 24 , 25 , 26 ].…”

Section: Modelmentioning

confidence: 99%

“…According to the above discussion and material properties of the filaments used in FFF, Equation (2) [ 1 , 2 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ].

where

and

are surface tension and mass density of the polymer melt, respectively, and L is estimated at the extrusion temperature.…”

Section: Modelmentioning

confidence: 99%

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Bonding widths of Deposited Polymer Strands in Additive Manufacturing

et al. 2021

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In this study, we explore the deformation of a polymer extrudate upon the deposition on a build platform, to determine the bonding widths between stacked strands in fused-filament fabrication. The considered polymer melt has an extremely high viscosity, which dominates in its deformation. Mainly considering the viscous effect, we derive analytical expressions of the flat width, compressed depth, bonding width and cross-sectional profile of the filament in four special cases, which have different combinations of extrusion speed, print speed and nozzle height. We further validate the derived relations, using our experimental results on acrylonitrile butadiene styrene (ABS), as well as existing experimental and numerical results on ABS and polylactic acid (PLA). Compared with existing theoretical and numerical results, our derived analytic relations are simple, which need less calculations. They can be used to quickly predict the geometries of the deposited strands, including the bonding widths.

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Die Swell of Complex Polymeric Systems

Cited by 26 publications

References 55 publications

Fabrication and characterization of mechanically competent 3D printed polycaprolactone-reduced graphene oxide scaffolds

Fabrication and characterization of mechanically competent 3D printed polycaprolactone-reduced graphene oxide scaffolds

Rheological behavior of coir‐fiber‐filled polypropylene composites at constant shear stress

Bonding widths of Deposited Polymer Strands in Additive Manufacturing

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