Wetting of polymer melts on coated and uncoated steel surfaces

Vera, Julie; Contraires, Elise; Brulez, Anne‐Catherine; Larochette, Mathieu; Valette, S.; Benayoun, Stéphane

doi:10.1016/j.apsusc.2017.02.067

Cited by 31 publications

(12 citation statements)

References 30 publications

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“…The stability and defect free window of slot die coating is strongly influenced by the behavior of the dynamic contact angles formed by the meniscus [31], and the stability of the bead is frequently ensured by applying vacuum on the upstream side of the die. Molten thermoplastics, such as the ones used in FDM, usually exhibit large equilibrium contact angles (>90 • ) on non-treated substrates, such as polished metals and glass [32,33].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of the Extrusion and Deposition Process of a Poly(lactic Acid) Strand with Fused Deposition Modeling

et al. 2020

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In the last decade, Fused Deposition Modeling (FDM) has gained popularity for allowing the fabrication of pieces with complex shapes. The final quality of the pieces is strongly linked to the shape, size and surface finish of the strands deposited successively, which themselves depend on the printing parameters and extruded material properties. In this work, we present an experimental characterization of an extruded and deposited single strand of Poly-Lactic Acid (PLA), by means of high-speed visualization of the bead region between the substrate and the nozzle, where the molten polymer is still in liquid phase. A Computational Fluid Dynamics (CFD) model proposed in literature, and, based on isothermal and viscous flow assumptions, is validated with this data in terms of strand height and meniscus shape. The characteristics of the printed layer are also confronted to the measurements of the solidified strands by microscopy, with a good agreement. The focus on high printing speeds allows extending the conclusions of previous studies. Regarding the surface finish, the roughness patterns detected on the printed strands are correlated to the velocity fluctuations of the printing head. The CFD model does not capture those thickness variations, however, due to not accounting for solidification.

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Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of the Extrusion and Deposition Process of a Poly(lactic Acid) Strand with Fused Deposition Modeling

et al. 2020

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“…They observed a decrease in the contact angle of the molten polymers with a rising surface energy of the coating. Vera et al [ 21 ] investigated the contact angle of molten PP, acrylonitrile butadiene styrene (ABS), and PC on steel, different titanium nitride coatings (TiNO x , TiNO y , and TiNO z ), CrN, and DLC. Furthermore, they measured the surface tension of the molten polymers and evaluated work of adhesion on the solid substrates.…”

Section: Introductionmentioning

confidence: 99%

Calculation of the Contact Angle of Polymer Melts on Tool Surfaces from Viscosity Parameters

et al. 2017

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It is of great importance for polymer processing whether and how viscosity influences the wettability of tool surfaces. We demonstrate the existence of a distinct relationship between the contact angle of molten polymers and zero shear viscosity in this paper. The contact angle of molten polypropylene and polymethylmethacrylate on polished steel was studied in a high temperature chamber using the sessile drop method. A high pressure capillary rheometer with a slit die was employed to determine the shear viscosity curves in a low shear rate range. A linear relation between the contact angle and zero shear viscosity was obtained. Furthermore, the contact angle and the zero shear viscosity values of the different polymers were combined to one function. It is revealed that, for the wetting of tool surfaces by molten polymers, a lower viscosity is advantageous. Furthermore, a model based on the temperature shift concept is proposed which allows the calculation of the contact angle of molten polymers on steel for different temperatures directly from shear viscosity data.

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“…In fact, the wetting properties of the different mold surfaces to the melt polymer can provide information about the intensity of the adhesion at the interface. Indeed, the affinity between each coating-polymer couple is controlled by the different chemistry, as observed by Vera et al [36]. Table 6 reports the values of the contact angle, indicating that the coatings resulted in diverse wetting behavior due to the different interface interactions.…”

Section: Wetting Behaviormentioning

confidence: 63%

Thin-wall injection molding of polystyrene parts with coated and uncoated cavities

et al. 2018

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Low-friction mold surface coatings can be used to promote filling of thin-wall parts through reduction of the melt flow resistance by causing wall slip at the polymer-mold interface. This work investigates the effects of different mold coatings (DLC, CrN and CrTiNbN) on the flow resistance of molten polystyrene in thin-wall injection molding. The design of the mold allowed high-speed visualization of the molten polymer flow during the filling phase and measurement of the velocity profile across the cavity thickness. The evaluation of the speed profiles allowed the characterization of the wall-slip phenomenon, indicating the absence of conventional 'fountain-flow' filling mechanism.The results indicate that a DLC deposited on a chrome substrate can significantly reduce the flow resistance of polystyrene, by increasing the slip velocity of polymer melt in contact with the mold surface. Moreover, the contact angle of molten polystyrene over the considered coatings was found to be inversely proportional to the melt flow resistance, indicating the importance of the adhesion at the polymer-mold interface.

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Wetting of polymer melts on coated and uncoated steel surfaces

Cited by 31 publications

References 30 publications

Experimental and Numerical Investigation of the Extrusion and Deposition Process of a Poly(lactic Acid) Strand with Fused Deposition Modeling

Experimental and Numerical Investigation of the Extrusion and Deposition Process of a Poly(lactic Acid) Strand with Fused Deposition Modeling

Calculation of the Contact Angle of Polymer Melts on Tool Surfaces from Viscosity Parameters

Thin-wall injection molding of polystyrene parts with coated and uncoated cavities

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