Modeling and Analysis of Morphology of Injection Molding Polypropylene Parts Induced by In-Mold Annealing

Salomone, Rita; Speranza, Vito; Liparoti, Sara; Titomanlio, G.; Pantani, Roberto

doi:10.3390/polym14235245

Cited by 3 publications

(4 citation statements)

References 24 publications

(30 reference statements)

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“…Morphology and mechanical performances depend on the crystallization experienced by molecules and the preserved orientation. Previous works demonstrated that crystallization occurs within higher temperature ranges when the mold temperature is high [31]; this would determine the increase in the crystalline degree and elastic modulus [34,35]. Crystallization and orientation depend on the temperature and shear rate experienced by the polymer chains.…”

Section: Discussionmentioning

confidence: 99%

“…Polymers 2024, 16, x FOR PEER REVIEW 15 of 18 that crystallization occurs within higher temperature ranges when the mold temperature is high [31]; this would determine the increase in the crystalline degree and elastic modulus [34,35]. Crystallization and orientation depend on the temperature and shear rate experienced by the polymer chains.…”

Section: Discussionmentioning

confidence: 99%

“…The mesh adopted for the simulations is composed of 12,354 triangular elements with a global edge length of 0.52 mm and 6179 nodes [30]. A previous study assessed the validity of the database material and the adopted mesh by comparing the simulations to experimental findings [25,31].…”

Section: Moldflow Simulationsmentioning

confidence: 99%

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Morphology Distribution in Injection Molded Parts

Liparoti,

Salomone,

Speranza

et al. 2024

Polymers

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A more sustainable use of plastic parts makes it necessary to replace current plastic parts with recyclable components, also allowing the modulation of the part properties through the process. Injection molding is one of the most widely used technologies for obtaining rigid plastic parts, so it is crucial to understand how to tailor properties by adopting the correct processing conditions. One way is to perform annealing steps directly inside the mold: in-mold annealing improves the structural integrity and durability of the material, reduces defects, increases the resistance of parts against certain chemicals, reduces wear and tear, increases ductility, and lowers brittleness. In this work, several in-mold annealing steps were conducted, changing the mold temperature and annealing duration selected on the basis of the half crystallization time of the adopted isotactic polypropylene. The typical molded part morphology, composed of oriented layers at the surface, transition zones, and spherulitic core, is strongly affected by in-mold annealing. In particular, the thickness of the oriented layer, which forms in the early phase of the process, decreases, and the spherulites increase in size. Concerning mechanical behavior, the orientation degree mostly determines the elastic modulus value close to the surface, whereas the conditions under which crystallization occurs determine the modulus in the core.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Morphology Distribution in Injection Molded Parts

Liparoti,

Salomone,

Speranza

et al. 2024

Polymers

Self Cite

View full text Add to dashboard Cite

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“…If the air leaks from the insert, the design of the insert and the mould is correct. If the air is trapped in a cavity, it prevents the melt from flowing [ 12 , 13 ].…”

Section: Flow Testmentioning

confidence: 99%

Injection Moulding into 3D-Printed Plastic Inserts Produced Using the Multi Jet Fusion Method

et al. 2023

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Most injection-moulded plastics are injection moulded into moulds made from conventional materials such as steel or aluminium. The production costs of the mould are considerable. 3D printing from plastic can be used for injection moulds to save these costs. This article deals with injection moulding into a 3D-printed plastic mould. The injection insert was produced on a HP Multi Jet Fusion 4200 3D printer. The other part of the mould was made of aluminium. A custom injection mould was designed for the research. One insert was made from plastic, and one from aluminium. Both moulds were injected under the same injection conditions. A comparison of injection moulding into the plastic and aluminium inserts is made in this article. The difference when injection moulding into the plastic insert is explained using the different technological conditions. The part injected into the plastic insert was also different from the part injected into the aluminium insert. The difference is explained in this article. This article also looks at the interface between the injection-moulded part and the plastic insert using an electron microscope. The images taken clarify the differences between injection moulding into a plastic insert and an aluminium insert and the differences of the injection-moulded part from the plastic insert.

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