Simulation of crystallization of isotactic polypropylene with different shear regimes

Spina, Roberto; Spekowius, Marcel; Hopmann, Christian

doi:10.1016/j.tca.2017.10.023

Cited by 26 publications

(11 citation statements)

References 30 publications

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“…The identification of the thermal properties was carried out with a DSC 403 F3 Pegasus (Netzsch-Gerätebau GmbH, Selb, Germany), with a Rhodium Furnace (sensor type S) and a DSC head (sensor types E). The thermal cycle, as well as the heating and cooling rates, were precisely defined, as described in Spina et al [13]. Briefly, there were two consecutive runs with a heating step (from 30 • C to 220 • C), a holding step (10 min) and a cooling step (from 220 to 30 • C).…”

Section: Dsc and Tgamentioning

confidence: 99%

Performance Analysis of Colored PLA Products with a Fused Filament Fabrication Process

Spina

2019

Polymers

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The objective of the present work is to study the influence of color additives used for the polylactic acid (PLA) filament on the final quality of fused filament fabrication (FFF) parts. The main processing parameters of FFF parts were evaluated, identifying the significant correlations between PLA properties and part performance, using a commercial FFF machine. The quality of the products was evaluated in terms of thermo-mechanical properties such as mechanical strength, principal material temperatures, and viscosity. These last properties were characterized using differential scanning calorimetry (DSC) for the thermal measurements and a rotational rheometry (RHEO) for viscosity measurements. Cylindrical specimens were then produced for the compression test. The experimental activity and related testing of products are fully described, pointing out a significant difference in performance between parts made of different colored filaments.

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Section: Dsc and Tgamentioning

confidence: 99%

Performance Analysis of Colored PLA Products with a Fused Filament Fabrication Process

Spina

2019

Polymers

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“…These properties are fundamental due to their influence on certain practical features, such as contact area and characteristics causing surface friction, wearing, light reflection, heat transmission, the ability to distribute and hold a lubricant, load-bearing capacity, and fatigue resistance. Different technical issues appear in processing polymers, making the understanding of the material behavior an important research issue [ 6 ]. Thus, a natural settlement is that they rely on thermoplastic material properties.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Grinding of Unfilled and Glass Fiber Reinforced Polyamide 6,6

Cavalcante

2020

Polymers

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This paper investigates the grinding process on unreinforced (PA66) and reinforced glass-fiber polyamide 6,6 (PA66 GF30) with Al2O3 and SiC abrasive wheels. Both materials were ground by varying rotations, workpiece infeed speed, depth of cuts for sequential roughing/finishing steps. Dry and liquid coolant conditions were also considered during the grinding process to evaluate the effects on part quality. The surface roughness was used to assess the quality of the final products with several parameter combinations, identifying the induced process trends. The results show that at the end of the finishing step, the surface roughness Rz was lower than 4 μm, attaining the lowest value of 1.34 μm for PA66 specimens. The analysis also suggested the choice of the Al2O3 grinding wheel to reach the lowest Rz values for both materials.

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“…Kuzyaev [18] developed a mathematical model for the optimization of mass and heat transfer processes in the working channel of extruders, considering the changes in the geometrical and technological characteristics. Spina et al [19] simulated the crystallization of isotactic polypropylene (PP) with different shear regimes and results indicated that flow had an important influence on the crystallization during polymer melting and solidification of PP. In one of our earlier works, we proposed a novel torsional screw geometry with twisted grooves, namely a torsion element (TOE), by adapting the field synergy principle to induce torsional flow in the working channel of the screw plasticization unit.…”

Section: Introductionmentioning

confidence: 99%

Enhancing Mixing and Thermal Management of Recycled Carbon Composite Systems by Torsion-Induced Phase-to-Phase Thermal and Molecular Mobility

et al. 2020

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A novel torsion screw has been proposed to resolve the inadequate control of mass transfer and the thermal management of two component polymer blends and their carbon fiber composites. The novel torsional screw distinctly introduced radial flow in the torsion screw channel, which is a significant improvement over the flow pattern developed by the conventional screw. The heat transfer and mixing behavior of melt mixtures are enhanced by adapting screws with torsion elements compared with the traditional screw elements. Heat transfer efficacy in the polypropylene–polystyrene bi-phasic extrusion process improved with the increase in torsion element numbers. An increased number of newly designed torsional elements also improved the dispersion of minor phase in bi-phase polypropylene–polystyrene composition and their carbon fiber composites. The unique flow pattern induced by the torsion elements shows a synergistic effect on the melt-phase mass flow and the thermal flow field facilitating phase-to-phase thermal and molecular mobility and enhanced fiber orientation, crystallinity and mechanical properties of composite made from recycled carbon fiber/polypropylene. Microtomographs of recycled carbon fiber demonstrated the extraordinary ability of a torsion screw element to orient carbon fiber in both axial and radial directions.

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Simulation of crystallization of isotactic polypropylene with different shear regimes

Cited by 26 publications

References 30 publications

Performance Analysis of Colored PLA Products with a Fused Filament Fabrication Process

Performance Analysis of Colored PLA Products with a Fused Filament Fabrication Process

Evaluation of Grinding of Unfilled and Glass Fiber Reinforced Polyamide 6,6

Enhancing Mixing and Thermal Management of Recycled Carbon Composite Systems by Torsion-Induced Phase-to-Phase Thermal and Molecular Mobility

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