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Abstract
Abstract
Polymer solidification under processing conditions is a complex phenomenon in which the kinetics of flow, high thermal gradients and high pressures determine the product morphology. The study of polymer structure formed under pressure has been mainly made using conventional techniques such as dilatometry and differential scanning calorimetry under isothermal conditions or non isothermal conditions but at cooling rates several orders of magnitude lower than those experienced in industrial processes. A new equipment has been recently developed and improved to study the crystallization of polypropylene when subjected to pressure and cooled rapidly. An experimental apparatus essentially constituted of a special injection mould has been employed. Polymer samples can be cooled at a known cooling rate and under a known pressure. Micro Hardness (MH), Wide angle x-ray diffraction (WAXD), Polarised Optical Microscopy (POM) and density measurements are then used to characterize the sample morphology. The results of rapid cooling experiments under pressure on an iPP sample display a lower density and a lower density dependence on cooling rate for increasing pressure. Micro hardness confirms the trend.
A deconvolution technique of WAXD patterns is used to evaluate the final phase content of samples and to assess a crystallization kinetics behaviour. Phase distribution results indicate that the decrease of alpha phase with pressure is balanced by an increase of the mesomorphic phase leaving unaffected the amorphous phase content. This peculiar behaviour can be easily related to a negative influence of pressure on the kinetics of the crystallization of alpha phase.
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Affiliation(s)
- V. Brucato
- D.I.C.A., Università di Salerno, Fisciano (SA), Italy
| | | | - S. Piccarolo
- D.I.C.P.M., Università di Palermo, Palermo, Italy
| | - G. Titomanlio
- D.I.C.A., Università di Salerno, Fisciano (SA), Italy
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Colletti C, Piccarolo S, Valenza A. Solidification Behaviour of PA6/iPP Blends at High Cooling Rates. INT POLYM PROC 2013. [DOI: 10.3139/217.1573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
The non isothermal crystallization behaviour of two model blends of immiscible polymers (an isotactic polypropylene and a polyamide-6) was examined by a quenching procedure within a range of cooling rates from 0.1 to above 1000°C/s in order to emulate the solidification conditions arising during polymer processing. The final structure of the blends was analyzed by density and WAXD and the transition from stable to metastable phases in the blends and the pure homopolymers was compared examining their dependence on cooling rate. This shows that crystallization in the blends is always faster since the transitions move to larger cooling rates. Observation of morphological details suggests that this can be due to enhanced nucleation at the interface. The density variation in the case of the polyamide-6 rich blend is larger than expected from an additive volume contribution which may be ascribed to development of microvoids at the interface. In the case of the isotactic polypropylene rich blend the additive volume contribution is consistent with experimental observations.
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Affiliation(s)
- C. Colletti
- D.I.C.P.M., Università di Palermo, Palermo, Italy
| | - S. Piccarolo
- D.I.C.P.M., Università di Palermo, Palermo, Italy
| | - A. Valenza
- D.C.I.I.M., Università di Messina, S. Agata (ME), Italy
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Abstract
Abstract
An experimental study of iPP injection molding is carried out. Pressure distribution during both filling and post filling stages, mass entering the mold during each stage of the process, morphology and crystallinity distribution of the final object are analysed. Interesting features are evidenced and discussed in relation to gate geometry and filling flow rate. Evidence of flow crystallization inside the cavity is also reported.
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Affiliation(s)
- M. Saiu
- Dipartimento di Ingegneria Chimica dei processi e dei Materiali, Palermo, Italy
| | - V. Brucato
- Dipartimento di Ingegneria Chimica dei processi e dei Materiali, Palermo, Italy
| | - S. Piccarolo
- Dipartimento di Ingegneria Chimica dei processi e dei Materiali, Palermo, Italy
| | - G. Titomanlio
- Dipartimento di Ingegneria Chimica dei processi e dei Materiali, Palermo, Italy
- Present address: Prof. Dr. G. Titomanlio, Dipartimento di Ingegneria Chimica ed Alimentare Via Ponte Don Melillo, Universita di Salerno, 84084 Baronissi (Salerno), Italy
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Rueda DR, Gutiérrez MCG, Calleja FJB, Piccarolo S. Order in the amorphous state of poly(ethylene terephthalate) as revealed by microhardness: Creep behavior and physical aging. INT J POLYM MATER PO 2010. [DOI: 10.1080/714975674] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- D. R. Rueda
- a Instituto de Estructura de la Materia , CSIC , Madrid , Spain
| | | | | | - S. Piccarolo
- b Dipartimento di Ingegneria Chimica dei Processi e dei Materiali , Univeristà di Palermo , Viale delle Scienze, Palermo , Italy
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Brucato V, Kiflie Z, La Carrubba V, Piccarolo S. The continuous cooling transformation (CCT) as a flexible tool to investigate polymer crystallization under processing conditions. Adv Polym Technol 2009. [DOI: 10.1002/adv.20151] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Pavia FC, La Carrubba V, Piccarolo S, Brucato V. Polymeric scaffolds prepared via thermally induced phase separation: tuning of structure and morphology. J Biomed Mater Res A 2008; 86:459-66. [PMID: 17975822 DOI: 10.1002/jbm.a.31621] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Scaffolds suitable for tissue engineering applications like dermal reconstruction were prepared by Thermally Induced Phase Separation (TIPS) starting from a ternary solution PLLA/dioxane/water. The experimental protocol consisted of three consecutive steps, a first quench from the homogeneous solution to an appropriate demixing temperature (within the metastable region), a holding stage for a given residence time, and a final quench from the demixing temperature to a low temperature (within the unstable region). A large variety of morphologies, in terms of average pore size and interconnection, were obtained upon modifying the demixing time and temperature, owing to the interplay of nucleation and growth processes during the residence in the metastable state. An interesting combination of micro and macroporosity was observed for long residence times in the metastable state (above 30 min at 35 degrees C). Preliminary degradation tests in a biological mimicking fluid (D-MEM with bovine serum) showed a significant weight loss during the initial stages (ca. 30% in 30 days) related to the degradation of the amorphous part, followed by a negligible weight loss in the next days (few percent from 30 to 60 days).
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Affiliation(s)
- F Carfì Pavia
- Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Università di Palermo, Viale delle Scienze, 90128 Palermo, Italy
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Pavia FC, La Carrubba V, Brucato V, Piccarolo S. Polymeric scaffolds prepared via Thermally Induced Phase Separation (TIPS): tuning of structure and morphology. ACTA ACUST UNITED AC 2007. [DOI: 10.1063/1.2729612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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La Carrubba V, Piccarolo S, Brucato V. Crystallization kinetics of iPP: Influence of operating conditions and molecular parameters. J Appl Polym Sci 2007. [DOI: 10.1002/app.25871] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Affiliation(s)
- S. Piccarolo
- a Dip. Ingegneria Chimica dei Processi e dei , Materiali Viale delle Scienze , 90128, Palermo, Italy
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Affiliation(s)
- K. Søndergaard
- a Dipartimento di Ingegneria Chimica dei Processi e dei Materiali , Università di Palermo Viale delle Scienze , 90128, Palermo, Italy
| | - P. Minà
- a Dipartimento di Ingegneria Chimica dei Processi e dei Materiali , Università di Palermo Viale delle Scienze , 90128, Palermo, Italy
| | - S. Piccarolo
- a Dipartimento di Ingegneria Chimica dei Processi e dei Materiali , Università di Palermo Viale delle Scienze , 90128, Palermo, Italy
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La Carrubba V, Brucato V, Piccarolo S. Isotactic polypropylene solidification under pressure and high cooling rates. A master curve approach. POLYM ENG SCI 2004. [DOI: 10.1002/pen.11375] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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La Carrubba V, Gabriëlse W, van Gurp M, Piccarolo S, Brucato V. Indentation test as a tool for monitoring the solidification process during injection molding. J Appl Polym Sci 2003. [DOI: 10.1002/app.12357] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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La Carrubba V, Briatico-Vangosa F, Brucato V, Piccarolo S. Effect of pressure on the PVT behaviour of iPP as revealed by dilatometric measurements. Polym Bull (Berl) 2002. [DOI: 10.1007/s00289-002-0082-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Brucato V, Piccarolo S, La Carrubba V. An experimental methodology to study polymer crystallization under processing conditions. The influence of high cooling rates. Chem Eng Sci 2002. [DOI: 10.1016/s0009-2509(02)00360-3] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Piccarolo S, Titomanlio G. Thermodynamic behavior of single polymer-binary solvent systems. Qualitative comparison with solubility parameter approach. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/i300009a033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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La Carrubba V, Brucato V, Piccarolo S. Phenomenological approach to compare the crystallization kinetics of isotactic polypropylene and polyamide-6 under pressure. ACTA ACUST UNITED AC 2001. [DOI: 10.1002/polb.10075] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Foresta T, Piccarolo S, Goldbeck-Wood G. Competition between α and γ phases in isotactic polypropylene: effects of ethylene content and nucleating agents at different cooling rates. POLYMER 2001. [DOI: 10.1016/s0032-3861(00)00404-3] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Valenza A, Piccarolo S, Spadaro G. Influence of morphology and chemical structure on the inverse response of polypropylene to gamma radiation under vacuum. POLYMER 1999. [DOI: 10.1016/s0032-3861(98)00294-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Titomanlio G, Piccarolo S, Rallis A. Knit lines structure in injection molding of nylon 6: Relation to first solidified sample cross section. POLYM ENG SCI 1989. [DOI: 10.1002/pen.760290402] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Affiliation(s)
| | - A. Rallis
- Instituto di Ingegneria Chimica, Palermo, Italy
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Kardos JL, Raisoni J, Piccarolo S, Halpin JC. Prediction and measurement of the thermal expansion coefficient of crystalline polymers. POLYM ENG SCI 1979. [DOI: 10.1002/pen.760191407] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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