Molding Characteristics and Impact Strength of Polypropylene with Different Numbers of Recycling Cycles
We analyzed the changes in the molding properties of polypropylene (PP) resin in the process of recycling after multiple plasticization, injection, and crushing processes. We also explored the changes in the material properties and characteristics with the ASTM-D256 impact test specimen and the numb...
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MDPI AG
2025-05-01
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| Series: | Engineering Proceedings |
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| author | Hui-Mei Zheng Jui-Chan Li Yen-Kai Wang Kai-Fu Liew Hsin-Shu Peng |
| author_facet | Hui-Mei Zheng Jui-Chan Li Yen-Kai Wang Kai-Fu Liew Hsin-Shu Peng |
| author_sort | Hui-Mei Zheng |
| collection | DOAJ |
| description | We analyzed the changes in the molding properties of polypropylene (PP) resin in the process of recycling after multiple plasticization, injection, and crushing processes. We also explored the changes in the material properties and characteristics with the ASTM-D256 impact test specimen and the number of recycling cycles. After the material is injected and crushed, it is recycled to produce the material required for re-injection, and a pressure sensor is installed at the nozzle position to observe the effects of material properties and impact characteristics in recycling. Injecting and pulverizing PP several times results in looser molecular spacing, increasing the fluidity of the material. After several recycling cycles, the fluidity of the material gradually decreased. Its crystallinity fluctuated depending on the crystallinity and crystallization rates. Recycled PP materials in various molding processes were influenced by melt temperature, screw speed, back pressure, and injection speed, which also affected nozzle pressure and strength. As the melt temperature increased, the effect on the nozzle pressure and impact strength became more evident. |
| format | Article |
| id | doaj-art-12fe9cdafdee4e2794616fdcaef263e8 |
| institution | Kabale University |
| issn | 2673-4591 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Engineering Proceedings |
| spelling | doaj-art-12fe9cdafdee4e2794616fdcaef263e82025-08-20T03:26:52ZengMDPI AGEngineering Proceedings2673-45912025-05-019218810.3390/engproc2025092088Molding Characteristics and Impact Strength of Polypropylene with Different Numbers of Recycling CyclesHui-Mei Zheng0Jui-Chan Li1Yen-Kai Wang2Kai-Fu Liew3Hsin-Shu Peng4Department of Mechanical and Computer-Aided Engineering, Feng Chia University, Taichung 40724, TaiwanDepartment of Mechanical and Computer-Aided Engineering, Feng Chia University, Taichung 40724, TaiwanDepartment of Mechanical and Computer-Aided Engineering, Feng Chia University, Taichung 40724, TaiwanDepartment of Ph.D. Program of Mechanical and Aerospace Engineering, Feng Chia University, Taichung 40724, TaiwanDepartment of Mechanical and Computer-Aided Engineering, Feng Chia University, Taichung 40724, TaiwanWe analyzed the changes in the molding properties of polypropylene (PP) resin in the process of recycling after multiple plasticization, injection, and crushing processes. We also explored the changes in the material properties and characteristics with the ASTM-D256 impact test specimen and the number of recycling cycles. After the material is injected and crushed, it is recycled to produce the material required for re-injection, and a pressure sensor is installed at the nozzle position to observe the effects of material properties and impact characteristics in recycling. Injecting and pulverizing PP several times results in looser molecular spacing, increasing the fluidity of the material. After several recycling cycles, the fluidity of the material gradually decreased. Its crystallinity fluctuated depending on the crystallinity and crystallization rates. Recycled PP materials in various molding processes were influenced by melt temperature, screw speed, back pressure, and injection speed, which also affected nozzle pressure and strength. As the melt temperature increased, the effect on the nozzle pressure and impact strength became more evident.https://www.mdpi.com/2673-4591/92/1/88circular economyviscosity indeximpact characteristicsnozzle pressure |
| spellingShingle | Hui-Mei Zheng Jui-Chan Li Yen-Kai Wang Kai-Fu Liew Hsin-Shu Peng Molding Characteristics and Impact Strength of Polypropylene with Different Numbers of Recycling Cycles Engineering Proceedings circular economy viscosity index impact characteristics nozzle pressure |
| title | Molding Characteristics and Impact Strength of Polypropylene with Different Numbers of Recycling Cycles |
| title_full | Molding Characteristics and Impact Strength of Polypropylene with Different Numbers of Recycling Cycles |
| title_fullStr | Molding Characteristics and Impact Strength of Polypropylene with Different Numbers of Recycling Cycles |
| title_full_unstemmed | Molding Characteristics and Impact Strength of Polypropylene with Different Numbers of Recycling Cycles |
| title_short | Molding Characteristics and Impact Strength of Polypropylene with Different Numbers of Recycling Cycles |
| title_sort | molding characteristics and impact strength of polypropylene with different numbers of recycling cycles |
| topic | circular economy viscosity index impact characteristics nozzle pressure |
| url | https://www.mdpi.com/2673-4591/92/1/88 |
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