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Liparoti S, Salomone R, Speranza V, Pantani R. Morphology Distribution in Injection Molded Parts. Polymers (Basel) 2024; 16:337. [PMID: 38337227 DOI: 10.3390/polym16030337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 02/12/2024] Open
Abstract
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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Affiliation(s)
- Sara Liparoti
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy
| | - Rita Salomone
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy
| | - Vito Speranza
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy
| | - Roberto Pantani
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy
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Longo R, Vertuccio L, Speranza V, Pantani R, Raimondo M, Calabrese E, Guadagno L. Nanometric Mechanical Behavior of Electrospun Membranes Loaded with Magnetic Nanoparticles. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1252. [PMID: 37049345 PMCID: PMC10097362 DOI: 10.3390/nano13071252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 03/22/2023] [Accepted: 03/30/2023] [Indexed: 06/19/2023]
Abstract
This work analyzes on nanoscale spatial domains the mechanical features of electrospun membranes of Polycaprolactone (PCL) loaded with Functionalized Magnetite Nanoparticles (FMNs) produced via an electrospinning process. Thermal and structural analyses demonstrate that FMNs affect the PCL crystallinity and its melting temperature. HarmoniX-Atomic Force Microscopy (H-AFM), a modality suitable to map the elastic modulus on nanometric domains of the sample surface, evidences that the FMNs affect the local mechanical properties of the membranes. The mechanical modulus increases when the tip reveals the magnetite nanoparticles. That allows accurate mapping of the FMNs distribution along the nanofibers mat through the analysis of a mechanical parameter. Local mechanical modulus values are also affected by the crystallinity degree of PCL influenced by the filler content. The crystallinity increases for a low filler percentage (<5 wt.%), while, higher magnetite amounts tend to hinder the crystallization of the polymer, which manifests a lower crystallinity. H-AFM analysis confirms this trend, showing that the distribution of local mechanical values is a function of the filler amount and crystallinity of the fibers hosting the filler. The bulk mechanical properties of the membranes, evaluated through tensile tests, are strictly related to the nanometric features of the complex nanocomposite system.
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Affiliation(s)
- Raffaele Longo
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, Italy; (R.L.); (V.S.); (R.P.); (M.R.); (E.C.)
| | - Luigi Vertuccio
- Department of Engineering, University of Campania “Luigi Vanvitelli”, Via Roma 29, 81031 Aversa, Italy;
| | - Vito Speranza
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, Italy; (R.L.); (V.S.); (R.P.); (M.R.); (E.C.)
| | - Roberto Pantani
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, Italy; (R.L.); (V.S.); (R.P.); (M.R.); (E.C.)
| | - Marialuigia Raimondo
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, Italy; (R.L.); (V.S.); (R.P.); (M.R.); (E.C.)
| | - Elisa Calabrese
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, Italy; (R.L.); (V.S.); (R.P.); (M.R.); (E.C.)
| | - Liberata Guadagno
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, Italy; (R.L.); (V.S.); (R.P.); (M.R.); (E.C.)
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Nie C, Peng F, Cao R, Cui K, Sheng J, Chen W, Li L. Recent progress in flow‐induced polymer crystallization. JOURNAL OF POLYMER SCIENCE 2022. [DOI: 10.1002/pol.20220330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Cui Nie
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry University of Science and Technology of China Hefei China
| | - Fan Peng
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry University of Science and Technology of China Hefei China
| | - Renkuan Cao
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry University of Science and Technology of China Hefei China
| | - Kunpeng Cui
- Department of Polymer Science and Engineering, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film University of Science and Technology of China Hefei China
| | - Junfang Sheng
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry University of Science and Technology of China Hefei China
| | - Wei Chen
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry University of Science and Technology of China Hefei China
| | - Liangbin Li
- National Synchrotron Radiation Laboratory, Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, CAS Key Laboratory of Soft Matter Chemistry University of Science and Technology of China Hefei China
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Leyva-Porras C, Balderrama-Aguilar A, Estrada-Ávila Y, Espelosín-Gómez I, Mendoza-Duarte M, Piñón-Balderrama C, Saavedra-Leos MZ, Estrada-Moreno I. Injection Molding of Low-Density Polyethylene (LDPE) as a Model Polymer: Effect of Molding Parameters on the Microstructure and Crystallinity. Polymers (Basel) 2021; 13:3597. [PMID: 34685356 PMCID: PMC8538698 DOI: 10.3390/polym13203597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/07/2021] [Accepted: 10/13/2021] [Indexed: 02/01/2023] Open
Abstract
Due to its relatively simple structure, low-density polyethylene (LDPE) can be considered as a model polymer for the study of its properties. Herein, the effect of processing variables on the microstructure and crystallinity of injection-molded LDPE specimens was quantitatively determined. The polymer was injected at different temperature conditions in the barrel and the mold. The specimens were characterized by scanning electron microscopy and X-ray diffraction. With the data obtained, an analysis of variance (ANOVA) was carried out, and response surface graphs (SRP) were constructed to quantify and to observe the behavior of the processing variables, respectively. Different models were obtained to predict the effect of the experimental factors on the response variables. The results showed that the interaction of the two temperatures has the greatest effect on the size of the spherulite, while the temperature of the mold affects the crystallinity. The SRP showed different behaviors: for the spherulite, the size increases with the mold temperature, while for the crystallinity, higher values were observed at an intermediate mold temperature and a low melt temperature. The results presented herein are valuable for setting empirical relations between the microstructure, crystallinity, and the molding conditions of LDPE.
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Affiliation(s)
- César Leyva-Porras
- Centro de Investigación en Materiales Avanzados S.C. (CIMAV), Complejo Industrial Chihuahua, Miguel de Cervantes No. 120, Chihuahua 31136, Mexico;
| | - Andrea Balderrama-Aguilar
- Tecnológico Nacional de México, Campus Chihuahua (ITCH), Av. Tecnológico No. 2009, Chihuahua 31310, Mexico; (A.B.-A.); (Y.E.-Á.); (I.E.-G.)
| | - Yael Estrada-Ávila
- Tecnológico Nacional de México, Campus Chihuahua (ITCH), Av. Tecnológico No. 2009, Chihuahua 31310, Mexico; (A.B.-A.); (Y.E.-Á.); (I.E.-G.)
| | - Iñaki Espelosín-Gómez
- Tecnológico Nacional de México, Campus Chihuahua (ITCH), Av. Tecnológico No. 2009, Chihuahua 31310, Mexico; (A.B.-A.); (Y.E.-Á.); (I.E.-G.)
| | - Mónica Mendoza-Duarte
- Centro de Investigación en Materiales Avanzados S.C. (CIMAV), Complejo Industrial Chihuahua, Miguel de Cervantes No. 120, Chihuahua 31136, Mexico;
| | - Claudia Piñón-Balderrama
- Departamento de Ingeniería Industrial, Universidad Tecnológica de Chihuahua (UTCH), Montes Americanos No. 9501, Chihuahua 31216, Mexico;
| | - María Zenaida Saavedra-Leos
- Coordinación Académica Región Altiplano, Universidad Autónoma de San Luis Potosí, Carretera Cedral Km. 5+600 Ejido San José de las Trojes, Matehuala 78700, San Luis Potosí, Mexico;
| | - Iván Estrada-Moreno
- Centro de Investigación en Materiales Avanzados S.C. (CIMAV), Complejo Industrial Chihuahua, Miguel de Cervantes No. 120, Chihuahua 31136, Mexico;
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Viscusi G, Liparoti S, Pantani R, Gorrasi G. Natural resources derived biocomposites as potential carriers of green pesticides in agricultural field: Designing and fabrication of a pot‐like device. J Appl Polym Sci 2021. [DOI: 10.1002/app.51240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Gianluca Viscusi
- Department of Industrial Engineering University of Salerno Fisciano Italy
| | - Sara Liparoti
- Department of Industrial Engineering University of Salerno Fisciano Italy
| | - Roberto Pantani
- Department of Industrial Engineering University of Salerno Fisciano Italy
| | - Giuliana Gorrasi
- Department of Industrial Engineering University of Salerno Fisciano Italy
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Liparoti S, Franco P, Pantani R, De Marco I. Polycaprolactone/polyethylene-glycol capsules made by injection molding: A drug release modeling. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 123:112036. [PMID: 33812648 DOI: 10.1016/j.msec.2021.112036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 10/21/2022]
Abstract
Polycaprolactone (PCL)/Polyethylene-glycol (PEG) capsules are prepared by injection molding with the aim of producing Colon-specific Drug Delivery Systems (CDDS). PCL, being a gastroresistant polymer, is suitable for this kind of delivery; however, the release from PCL devices is too slow. For this reason, in this paper, different percentages of PEG (10, 20 and 30 w/w %) have been added to obtain blends able to modulate the release from PCL-based capsules. The drug release rate from PCL/PEG capsules increases with the PEG percentage; using PCL/PEG 70/30 w/w capsules, the drug release is suitable for CDDS. The experimental data have been modelled, accounting for three steps: the penetration of the release medium into the capsule, the drug dissolution in the release medium, and the drug migration from the capsule to the medium. The model accurately describes the data, showing a mass transfer coefficient strongly dependent on the PEG percentage.
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Affiliation(s)
- Sara Liparoti
- Department of Industrial Engineering (DIIn), University of Salerno, via Giovanni Paolo II, 132, Fisciano, SA 84084, Italy
| | - Paola Franco
- Department of Industrial Engineering (DIIn), University of Salerno, via Giovanni Paolo II, 132, Fisciano, SA 84084, Italy
| | - Roberto Pantani
- Department of Industrial Engineering (DIIn), University of Salerno, via Giovanni Paolo II, 132, Fisciano, SA 84084, Italy
| | - Iolanda De Marco
- Department of Industrial Engineering (DIIn), University of Salerno, via Giovanni Paolo II, 132, Fisciano, SA 84084, Italy.
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Liparoti S, Sorrentino A, Speranza V. Morphology-Mechanical Performance Relationship at the Micrometrical Level within Molded Polypropylene Obtained with Non-Symmetric Mold Temperature Conditioning. Polymers (Basel) 2021; 13:462. [PMID: 33572694 PMCID: PMC7867022 DOI: 10.3390/polym13030462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/26/2021] [Accepted: 01/29/2021] [Indexed: 11/28/2022] Open
Abstract
The control of the structural properties of a polymeric material at the micro and nano-metrical scale is strategic to obtaining parts with high performance, durability and free from sudden failures. The characteristic skin-core morphology of injection molded samples is intimately linked to the complex shear flow, pressure and temperature evolutions experienced by the polymer chains during processing. An accurate analysis of this morphology can allow for the assessment of the quality and confidence of the process. Non-symmetric mold temperature conditions are imposed to produce complex morphologies in polypropylene parts. Morphological and micromechanical characterizations of the samples are used to quantify the effects of the processing conditions on the part performance. Asymmetric distribution of temperatures determines asymmetric distribution of both morphology and mechanical properties. The inhomogeneity degree depends on the time that one side of the cavity experiences high temperatures. The spherulites, which cover the thickest of the parts obtained with high temperatures at one cavity side, show smaller values of elastic modulus than the fibrils. When the polymer molecules experience high temperatures for long periods, the solid-diffusion and the partial melting and recrystallization phenomena determine a better structuring of the molecules with a parallel increase of the elastic modulus.
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Affiliation(s)
- Sara Liparoti
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy;
| | - Andrea Sorrentino
- Institute for Polymers, Composites and Biomaterials (IPCB-CNR), Via Previati, 1/C, 23900 Lecco, Italy
| | - Vito Speranza
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy;
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Liparoti S, Sofia D, Romano A, Marra F, Pantani R. Fused Filament Deposition of PLA: The Role of Interlayer Adhesion in the Mechanical Performances. Polymers (Basel) 2021; 13:399. [PMID: 33513767 PMCID: PMC7865617 DOI: 10.3390/polym13030399] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 11/21/2022] Open
Abstract
A set of criteria to enhance mechanical performances of standard specimens (Type V, ANSI D368) made of polylactic acid (PLA) were proposed. Fused PLA deposition was conducted with nozzle temperature ranging from 180 to 230 °C and deposition plate temperature ranging from 70 to 110 °C. Optical microscopy, elastic modulus analysis and density measurement allowed emphasizing the effect of temperature field, also measured during the process, on the morphology and the mechanical characteristics of the specimen. Atomic force microscopy revealed a morphology typical of amorphous samples with globular structures. Poor interlayer adhesion was detected in the part of the specimen located at larger distance from the deposition plate, showing an elastic modulus lower than those measured in the central part (220 MPa vs. 500 MPa). The specimen crystallinity degree was below 3%. The molecular weight between entanglements was adopted as a measure of the interlayer molecular diffusion. A successful diffusion and re-entanglement of the polymer melt at the interface was the key to improving mechanical performance. A mathematical model describing the transient heat transfer during the fused PLA deposition and accounting for solidification and the nonisothermal crystallization kinetics was introduced. Simulated temperature evolutions were consistent with the experimental ones. They were related to the mechanical performances, the morphology, and the molecular weight between entanglements of the parts.
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Affiliation(s)
| | | | | | - Francesco Marra
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fiscian, SA, Italy; (S.L.); (D.S.); (A.R.); (R.P.)
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Liparoti S, Speranza V, De Meo A, De Santis F, Pantani R. Prediction of the maximum flow length of a thin injection molded part. JOURNAL OF POLYMER ENGINEERING 2020. [DOI: 10.1515/polyeng-2019-0292] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractOne of the most significant issues, when thin parts have to be obtained by injection molding (i.e. in micro-injection molding), is the determination of the conditions of pressure, mold temperature, and injection temperature to adopt to completely fill the cavity. Obviously, modern computational methods allow the simulation of the injection molding process for any material and any cavity geometry. However, this simulation requires a complete characterization of the material for what concerns the rheological and thermal parameters, and also a suitable criterion for solidification. These parameters are not always easily reachable. A simple test aimed at obtaining the required parameters is then highly advantageous. The so-called spiral flow test, consisting of measuring the length reached by a polymer in a long cavity under different molding conditions, is a method of this kind. In this work, with reference to an isotactic polypropylene, some spiral flow tests obtained with different mold temperatures and injection pressures are analyzed with a twofold goal: on one side, to obtain from a few simple tests the basic rheological parameters of the material; on the other side, to suggest a method for a quick prediction of the final flow length.
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Affiliation(s)
- Sara Liparoti
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy
| | - Vito Speranza
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy
| | - Annarita De Meo
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy
| | | | - Roberto Pantani
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy
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Microstructure, Tensile Property, and Surface Quality of Glass Fiber-Reinforced Polypropylene Parts Molded by Rapid Heat Cycle Molding. ADVANCES IN POLYMER TECHNOLOGY 2020. [DOI: 10.1155/2020/3161068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The microstructure of a molded product considerably influences its macroscopic properties. In this study, the influence of molding process on microstructure, tensile property, and surface quality was explored on the glass fiber-reinforced polypropylene (GFRPP) parts molded by rapid heat cycle molding (RHCM) and conversion injection molding (CIM). Tensile strength and surface gloss were chosen to measure macroscopic properties of the molded parts. The microstructure including multilayer, fiber orientation, crystallinity, and fiber-matrix bonding strength were analyzed by simulations, scanning electron microscopy, wide-angle X-ray diffraction, and dynamic mechanical analysis. The relationship between the macroscopic properties and microstructure of the RHCM samples was also discussed. The results indicate that as the mold cavity surface temperature increases, the tensile strength increases firstly and decreases thereafter. The tensile strength of RHCM parts reached the maximum at the mold heating temperature of 60°C. It is also observed that the surface gloss of the sample increases as the mold cavity surface temperature rises, and the increase of surface gloss decreases distinctly with the mold heating temperature higher than 90°C.
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Liparoti S, Speranza V, Titomanlio G, Pantani R. Effect of Rapid Mold Heating on the Structure and Performance of Injection-Molded Polypropylene. Polymers (Basel) 2020; 12:polym12020341. [PMID: 32033359 PMCID: PMC7077433 DOI: 10.3390/polym12020341] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/20/2020] [Accepted: 01/23/2020] [Indexed: 12/03/2022] Open
Abstract
The tailoring by the process of the properties developed in the plastic objects is the more effective way to improve the sustainability of the plastic objects. The possibility to tailor to the final use the properties developed within the molded object requires further understanding of the relationship between the properties of the plastic objects and the process conduction. One of the main process parameters that allow adjusting the properties of molded objects is the mold temperature. In this work, a thin electrical heater was located below the cavity surface in order to obtain rapid and localized surface heating/cooling cycles during the injection molding process. An isotactic polypropylene was adopted for the molding tests, during which surface temperature was modulated in terms of values and heating times. The modulation of the cavity temperature was found able to control the distribution of relevant morphological characteristics, thus, properties along the sample thickness. In particular, lamellar thickness, crystallinity distribution, and orientation were analyzed by synchrotron X-ray experiments, and the morphology and elastic modulus were characterized by atomic force microscopy acquisitions carried out with a tool for the simultaneous nanomechanical characterization. The crystalline degree slightly increased with the cavity temperature, and this induced an increase in the elastic modulus when high temperatures were adopted for the cavity surface. The cavity temperature strongly influenced the orientation distribution that, on its turn, determined the highest values of the elastic modulus found in the shear layer. Furthermore, although the sample core, not experiencing a strong flow field, was not characterized by high levels of orientation, it might show high values of the elastic modulus if temperature and time during crystallization were sufficient. In particular, if the macromolecules spent adequate time at temperatures close to the crystallization temperature, they could achieve high levels of structuring and, thus, high values of elastic modulus.
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Affiliation(s)
- Sara Liparoti
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132-84084 Fisciano (SA), Italy; (S.L.); (G.T.); (R.P.)
| | - Vito Speranza
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132-84084 Fisciano (SA), Italy; (S.L.); (G.T.); (R.P.)
- Correspondence:
| | - Giuseppe Titomanlio
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132-84084 Fisciano (SA), Italy; (S.L.); (G.T.); (R.P.)
- Institute of Polymers, Composites and Biomaterials (IPCB), The National Research Council (Cnr), Via Previati 1/C, 23900 Lecco (LC), Italy
| | - Roberto Pantani
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132-84084 Fisciano (SA), Italy; (S.L.); (G.T.); (R.P.)
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Marinello F, La Storia A, Mauriello G, Passeri D. Atomic Force microscopy techniques to investigate activated food packaging materials. Trends Food Sci Technol 2019. [DOI: 10.1016/j.tifs.2018.05.028] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Guadagno L, Naddeo C, Raimondo M, Speranza V, Pantani R, Acquesta A, Carangelo A, Monetta T. UV Irradiated Graphene-Based Nanocomposites: Change in the Mechanical Properties by Local HarmoniX Atomic Force Microscopy Detection. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E962. [PMID: 30909458 PMCID: PMC6470810 DOI: 10.3390/ma12060962] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 03/12/2019] [Accepted: 03/19/2019] [Indexed: 11/17/2022]
Abstract
Epoxy based coatings are susceptible to ultra violet (UV) damage and their durability can be significantly reduced in outdoor environments. This paper highlights a relevant property of graphene-based nanoparticles: Graphene Nanoplatelets (GNPs) incorporated in an epoxy-based free-standing film determine a strong decrease of the mechanical damages caused by UV irradiation. The effects of UV light on the morphology and mechanical properties of the solidified nanocharged epoxy films are investigated by Atomic Force Microscopy (AFM), in the acquisition mode "HarmoniX." Nanometric-resolved maps of the mechanical properties of the multi-phase material evidence that the incorporation of low percentages, between 0.1% and 1.0% by weight, of graphene nanoplatelets (GNPs) in the polymeric film causes a relevant enhancement in the mechanical stability of the irradiated films. The beneficial effect progressively increases with increasing GNP percentage. The paper also highlights the potentiality of AFM microscopy, in the acquisition mode "HarmoniX" for studying multiphase polymeric systems.
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Affiliation(s)
- Liberata Guadagno
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, Salerno, 84084 Fisciano, Italy.
| | - Carlo Naddeo
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, Salerno, 84084 Fisciano, Italy.
| | - Marialuigia Raimondo
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, Salerno, 84084 Fisciano, Italy.
| | - Vito Speranza
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, Salerno, 84084 Fisciano, Italy.
| | - Roberto Pantani
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, Salerno, 84084 Fisciano, Italy.
| | - Annalisa Acquesta
- Department of Chemical Engineering, Materials and Industrial Production, University of Napoli Federico II, Piazzale Tecchio 80, 80125 Napoli, Italy.
| | - Anna Carangelo
- Department of Chemical Engineering, Materials and Industrial Production, University of Napoli Federico II, Piazzale Tecchio 80, 80125 Napoli, Italy.
| | - Tullio Monetta
- Department of Chemical Engineering, Materials and Industrial Production, University of Napoli Federico II, Piazzale Tecchio 80, 80125 Napoli, Italy.
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Speranza V, Liparoti S, Pantani R, Titomanlio G. Hierarchical Structure of iPP During Injection Molding Process with Fast Mold Temperature Evolution. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E424. [PMID: 30704102 PMCID: PMC6384804 DOI: 10.3390/ma12030424] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 01/23/2019] [Accepted: 01/25/2019] [Indexed: 11/24/2022]
Abstract
Mold surface temperature strongly influences the molecular orientation and morphology developed in injection molded samples. In this work, an isotactic polypropylene was injected into a rectangular mold, in which the cavity surface temperature was properly modulated during the process by an electrical heating device. The induced thermo-mechanical histories strongly influenced the morphology developed in the injection molded parts. Polarized optical microscope and atomic force microscope were adopted for morphological investigations. The combination of flow field and cooling rate experienced by the polymer determined the hierarchical structure. Under strong flow fields and high temperatures, a tightly packed structure, called shish-kebab, aligned along the flow direction, was observed. Under weak flow fields, the formation of β-phase, as cylindrites form, was observed. The formation of each morphological structure was analyzed and discussed on the bases of the flow and temperature fields, experienced by the polymer during each stage of the injection molding process.
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Affiliation(s)
- Vito Speranza
- Department of Industrial Engineering, University of Salerno⁻via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy.
| | - Sara Liparoti
- Department of Industrial Engineering, University of Salerno⁻via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy.
| | - Roberto Pantani
- Department of Industrial Engineering, University of Salerno⁻via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy.
| | - Giuseppe Titomanlio
- Department of Industrial Engineering, University of Salerno⁻via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy.
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16
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Liparoti S, Pantani R, Sorrentino A, Speranza V, Titomanlio G. Hydrophobicity Tuning by the Fast Evolution of Mold Temperature during Injection Molding. Polymers (Basel) 2018; 10:E322. [PMID: 30966357 PMCID: PMC6415138 DOI: 10.3390/polym10030322] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 02/26/2018] [Accepted: 03/09/2018] [Indexed: 01/06/2023] Open
Abstract
The surface topography of a molded part strongly affects its functional properties, such as hydrophobicity, cleaning capabilities, adhesion, biological defense and frictional resistance. In this paper, the possibility to tune and increase the hydrophobicity of a molded polymeric part was explored. An isotactic polypropylene was injection molded with fast cavity surface temperature evolutions, obtained adopting a specifically designed heating system layered below the cavity surface. The surface topology was characterized by atomic force microscopy (AFM) and, concerning of hydrophobicity, by measuring the water static contact angle. Results show that the hydrophobicity increases with both the temperature level and the time the cavity surface temperature was kept high. In particular, the contact angle of the molded sample was found to increase from 90°, with conventional molding conditions, up to 113° with 160 °C of cavity surface temperature kept for 18 s. This increase was found to be due to the presence of sub-micro and nano-structures characterized by high values of spatial frequencies which could be more accurately replicated by adopting high heating temperatures and times. The surface topography and the hydrophobicity resulted therefore tunable by selecting appropriate injection molding conditions.
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Affiliation(s)
- Sara Liparoti
- Department of Industrial Engineering, University of Salerno, via G. Paolo II 132, 84084 Fisciano (SA), Italy.
| | - Roberto Pantani
- Department of Industrial Engineering, University of Salerno, via G. Paolo II 132, 84084 Fisciano (SA), Italy.
| | - Andrea Sorrentino
- Institute for Polymers, Composites and Biomaterials (IPCB-CNR), via Previati n. 1/E, 23900 Lecco, Italy.
| | - Vito Speranza
- Department of Industrial Engineering, University of Salerno, via G. Paolo II 132, 84084 Fisciano (SA), Italy.
| | - Giuseppe Titomanlio
- Department of Industrial Engineering, University of Salerno, via G. Paolo II 132, 84084 Fisciano (SA), Italy.
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Buonerba A, Speranza V, Capacchione C, Milione S, Grassi A. Improvement of tensile properties, self-healing and recycle of thermoset styrene/2-vinylfuran copolymers via thermal triggered rearrangement of covalent crosslink. Eur Polym J 2018. [DOI: 10.1016/j.eurpolymj.2017.12.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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18
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Pantani R, Speranza V, Titomanlio G. Effect of flow-induced crystallization on the distribution of spherulite dimensions along cross section of injection molded parts. Eur Polym J 2017. [DOI: 10.1016/j.eurpolymj.2017.10.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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19
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Liparoti S, Speranza V, Sorrentino A, Titomanlio G. Mechanical Properties Distribution within Polypropylene Injection Molded Samples: Effect of Mold Temperature under Uneven Thermal Conditions. Polymers (Basel) 2017; 9:E585. [PMID: 30965891 PMCID: PMC6418651 DOI: 10.3390/polym9110585] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/01/2017] [Accepted: 11/03/2017] [Indexed: 11/17/2022] Open
Abstract
The quality of the polymer parts produced by injection molding is strongly affected by the processing conditions. Uncontrolled deviations from the proper process parameters could significantly affect both internal structure and final material properties. In this work, to mimic an uneven temperature field, a strong asymmetric heating is applied during the production of injection-molded polypropylene samples. The morphology of the samples is characterized by optical and atomic force microscopy (AFM), whereas the distribution of mechanical modulus at different scales is obtained by Indentation and HarmoniX AFM tests. Results clearly show that the temperature differences between the two mold surfaces significantly affect the morphology distributions of the molded parts. This is due to both the uneven temperature field evolutions and to the asymmetric flow field. The final mechanical property distributions are determined by competition between the local molecular stretch and the local structuring achieved during solidification. The cooling rate changes affect internal structures in terms of relaxation/reorganization levels and give rise to an asymmetric distribution of mechanical properties.
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Affiliation(s)
- Sara Liparoti
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy.
| | - Vito Speranza
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy.
| | - Andrea Sorrentino
- Institute for Polymers, Composites and Biomaterials (IPCB-CNR), Via Previati, 1/C, 23900 Lecco, Italy.
| | - Giuseppe Titomanlio
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy.
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Micromechanical Characterization of Complex Polypropylene Morphologies by HarmoniX AFM. INT J POLYM SCI 2017. [DOI: 10.1155/2017/9037127] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This paper examines the capability of the HarmoniX Atomic Force Microscopy (AFM) technique to draw accurate and reliable micromechanical characterization of complex polymer morphologies generally found in conventional thermoplastic polymers. To that purpose, injection molded polypropylene samples, containing representative morphologies, have been characterized by HarmoniX AFM. Mapping and distributions of mechanical properties of the samples surface are determined and analyzed. Effects of sample preparation and test conditions are also analyzed. Finally, the AFM determination of surface elastic moduli has been compared with that obtained by indentation tests, finding good agreement among the results.
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