Effects of Pressure and Cooling Rates on Crystallization Behavior and Morphology of Isotactic Polypropylene
Isotactic Polypropylene (iPP) is a widely used polymer due to its excellent mechanical and thermal properties, as well as its chemical resistance. The crystallization behavior of polypropylene is influenced by several factors, such as temperature, cooling rate, and pressure. The effect of pressure i...
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MDPI AG
2023-06-01
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| Online Access: | https://www.mdpi.com/2073-4352/13/6/922 |
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| author | Vito Speranza Rita Salomone Roberto Pantani |
| author_facet | Vito Speranza Rita Salomone Roberto Pantani |
| author_sort | Vito Speranza |
| collection | DOAJ |
| description | Isotactic Polypropylene (iPP) is a widely used polymer due to its excellent mechanical and thermal properties, as well as its chemical resistance. The crystallization behavior of polypropylene is influenced by several factors, such as temperature, cooling rate, and pressure. The effect of pressure is significant for both scientific and technological points of view, since in important industrial processing techniques the polymer solidifies under high pressures. In this paper, the study of the effect of pressure on the crystallization kinetics of iPP was conducted using a dilatometer in the pressure range from 100 to 600 bar and under two cooling rates: 0.1 and 1 °C/s. The morphology of the samples was characterized using DSC, optical microscopy, and X-ray diffraction. The results showed that pressure had a larger effect on specific volume changes at higher temperatures (in the melt state) than at lower temperatures (in the solid state). The polymer crystallization, which determined the transition between the melt and solid state, occurred at higher temperatures with increasing pressure. The cooling rate affected the crystallization process, with higher cooling rates leading to crystallization at lower temperatures. The size of the spherulites decreased with increasing cooling rates. The crystallinity evolution curves showed a linear relationship between the crystallization temperature and pressure. The study used a Kolmogoroff–Avrami–Evans model to describe the evolution into isotropic structures, and the predictions of the model accurately described the effect of pressure and cooling rates on the final spherulite radii. |
| first_indexed | 2024-03-11T02:35:51Z |
| format | Article |
| id | doaj.art-740ed96c30d345f497cadc0803c24ac2 |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-11T02:35:51Z |
| publishDate | 2023-06-01 |
| publisher | MDPI AG |
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| spelling | doaj.art-740ed96c30d345f497cadc0803c24ac22023-11-18T09:56:38ZengMDPI AGCrystals2073-43522023-06-0113692210.3390/cryst13060922Effects of Pressure and Cooling Rates on Crystallization Behavior and Morphology of Isotactic PolypropyleneVito Speranza0Rita Salomone1Roberto Pantani2Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, SA, ItalyDepartment of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, SA, ItalyDepartment of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, SA, ItalyIsotactic Polypropylene (iPP) is a widely used polymer due to its excellent mechanical and thermal properties, as well as its chemical resistance. The crystallization behavior of polypropylene is influenced by several factors, such as temperature, cooling rate, and pressure. The effect of pressure is significant for both scientific and technological points of view, since in important industrial processing techniques the polymer solidifies under high pressures. In this paper, the study of the effect of pressure on the crystallization kinetics of iPP was conducted using a dilatometer in the pressure range from 100 to 600 bar and under two cooling rates: 0.1 and 1 °C/s. The morphology of the samples was characterized using DSC, optical microscopy, and X-ray diffraction. The results showed that pressure had a larger effect on specific volume changes at higher temperatures (in the melt state) than at lower temperatures (in the solid state). The polymer crystallization, which determined the transition between the melt and solid state, occurred at higher temperatures with increasing pressure. The cooling rate affected the crystallization process, with higher cooling rates leading to crystallization at lower temperatures. The size of the spherulites decreased with increasing cooling rates. The crystallinity evolution curves showed a linear relationship between the crystallization temperature and pressure. The study used a Kolmogoroff–Avrami–Evans model to describe the evolution into isotropic structures, and the predictions of the model accurately described the effect of pressure and cooling rates on the final spherulite radii.https://www.mdpi.com/2073-4352/13/6/922crystallization kineticspolypropylenepressure crystallizationpressure dependence of melting pointsdilatometry |
| spellingShingle | Vito Speranza Rita Salomone Roberto Pantani Effects of Pressure and Cooling Rates on Crystallization Behavior and Morphology of Isotactic Polypropylene Crystals crystallization kinetics polypropylene pressure crystallization pressure dependence of melting points dilatometry |
| title | Effects of Pressure and Cooling Rates on Crystallization Behavior and Morphology of Isotactic Polypropylene |
| title_full | Effects of Pressure and Cooling Rates on Crystallization Behavior and Morphology of Isotactic Polypropylene |
| title_fullStr | Effects of Pressure and Cooling Rates on Crystallization Behavior and Morphology of Isotactic Polypropylene |
| title_full_unstemmed | Effects of Pressure and Cooling Rates on Crystallization Behavior and Morphology of Isotactic Polypropylene |
| title_short | Effects of Pressure and Cooling Rates on Crystallization Behavior and Morphology of Isotactic Polypropylene |
| title_sort | effects of pressure and cooling rates on crystallization behavior and morphology of isotactic polypropylene |
| topic | crystallization kinetics polypropylene pressure crystallization pressure dependence of melting points dilatometry |
| url | https://www.mdpi.com/2073-4352/13/6/922 |
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