Creation of Beta Crystal Structure in Random Polypropylene with the Help of Pimelic Acid-Based Nucleator: the Role of Nucleator Addition Method and the Presence of Isotactic Polypropylene in the Composition

Document Type : Original Article

Authors

Department of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran

Abstract

Compared to block copolymer, random polypropylene copolymer has lower toughness and impact resistance. This defect creates limitations in the use of this polymer in some applications such as pipe industry. Creating a beta crystal structure in random polypropylene with the help of nucleating agent is a well-known method to solve this problem. In this research, two types of nucleating agent were used to create a crystal structure, namely pre-synthesized pimelic acid nucleating agent and in-situ synthesis of pimelic acid during processing (0.2% by weight). Also, 4 wt.% isotactic polypropylene was added to increase the efficiency of nucleation. The goal was to compare the effectiveness of isotactic polypropylene with two types of nucleating agents.The samples needed for the tests were produced by compression molding method. Crystal structure evaluation was done by differential scanning calorimetry and X-ray diffraction methods. A transmission optical microscope  was employed to examine the microstructure of the samples. Tensile and impact tests were performed to examine the mechanical behavior of the samples. According to the differential scanning calorimetry and X-ray diffraction tests, it was observed that the sample made by adding 4 wt. % isotactic polypropylene has the highest amount of beta phase (67 and 72% in each test, respectively). Microscopic images also clearly showed the collapse of the structure due to the increase in beta phase. Also, according to the purpose of the research, the aforementioned sample revealed a 100% increase in toughness compared to the pure sample.

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  1. Moore EP. Polypropylene Handbook: Polymerization, Characterization, Properties, Processing, Applications. Hanser-Gardner Publishing; 1996. http://dx.doi.org/10. 1007/978-3-642-40872-4_2016
  2. Karger-Kocsis J, editor. Polypropylene: Structure, Blends and Composites. Volume 2: Copolymers and Blends. 1st ed. Dordrecht: Springer; 1994. https://doi.org/10.1007/978-94-011-0521-7
  3. Wang S, Zhang J. Effect of nucleating agent on the crystallization behavior, crystal form and solar reflectance of polypropylene. Sol Energy Mater Sol Cells 2013; 117: 577-584. https://doi.org/10.1016/ j.solmat.2013.07.033
  4. Papageorgiou DG, Bikiaris DN, Chrissafis K. Effect of crystalline structure of polypropylene random copolymers on mechanical properties and thermal degradation kinetics. Thermochim Acta. 2012; 543: 288–94. https://doi.org/10.1016/j.tca.2012.06.007
  5. Horváth F, Bihari L, Menyhárd A. Effect of N,N’-Dicyclohexyl Terephthalic Dihydrazide on the Crystallization and Properties of Isotactic Polypropylene. Period Polytech Chem Eng. 2022; 66(2): 182–191. https://doi.org/10.3311/PPch.19074
  6. Wang Y, Cheng L, Cui X, Guo W. Crystallization behavior and properties of glass fiber reinforced polypropylene composites. Polymers (Basel). 2019; 11(7): 1198. https://doi.org/10.3390/polym11071198
  7. Xu T, Yu J, Jin Z. Effects of crystalline morphology on the impact behavior of polypropylene. Mater Des. 2001; 22(1): 27-31. https://doi.org/10.1016/S0261-3069(00)00033-9
  8. Varga J. Spherulitic crystallization in polypropylene. J Macromol Sci - Phys. 2002; 41B(4–6):1121–71. https://doi.org/10.1081/MB-120013089
  9. Villarreal-Martínez D, Eduardo Gutiérrez-Páramo H, Laura Martínez-Hernández A, Velasco-Santos C, Almendarez-Camarillo A. Induction of the β-phase in isotactic polypropylene with pimelic acid modified graphene nanoplatelets. FlatChem. 2023; 38: 100472. https://doi.org/10.1016/j.flatc.2023.100472
  10. Wang J, Gahleitner M, Gloger D, Bernreitner K. β-Nucleation of isotactic polypropylene: Chain structure effects on the effectiveness of two different nucleating agents. Express Polym Lett. 2020; 14(5): 491-502. https://doi.org/10.3144/expresspolymlett. 2020.39
  11. Wang SW, Yang W, Bao RY, Wang B, Xie BH, Yang MB. The enhanced nucleating ability of carbon nanotube-supported β-nucleating agent in isotactic polypropylene. Colloid Polym Sci. 2010; 288(6): 681–8. https://doi.org/10.1007%2Fs00396-010-2194-x
  12. Qin W, Xin Z, Pan C, Sun S, Jiang X, Zhao S. In situ formation of zinc phthalate as a highly dispersed Β-nucleating agent for mechanically strengthened isotactic polypropylene. Chem Eng J. 2019; 358: 1243–52. https://doi.org/10.1016/j.cej.2018.10.108.
  13. Gao J, Jiang Q, Yao Z, Ju H. Effect of β-nucleating agents on the crystallization behavior and force-electric properties of the polypropylene blends. J Vinyl Addit Technol. 2024; 30(1): 217–29. https:// doi.org/10.1002/vnl.22043
  14. Jiang N, Wang K, Leng J, He B. Effect of isotactic polypropylene on crystal structure and morphology of β-modified random copolymerized polypropylene. Polym Bull. 2018; 75(9): 4085–101. https://doi.org/ 10.1007/s00289-017-2244-3
  15. Luo F, Zhu Y, Wang K, Deng H, Chen F, Zhang Q, et al. Enhancement of β-nucleated crystallization in polypropylene random copolymer via adding isotactic polypropylene. Polymer (Guildf). 2012; 53(21): 4861–70. https://doi.org/10.1016/j.polymer. 2012.08.037
  16. Lou F. Enhancement of beta nucleated crystallization in polypropylene random copolymer via adding isotactic polypropylene. Polym. 2012; 53(19): 4268-74. https://doi.org/10.1016/j.polymer.2012.08.037
  17. Li D, Xin Y, Song Y, Dong T, Ben H, Yu R, et al. Crystalline modification of isotactic polypropylene with a rare earth nucleating agent based on ultrasonic vibration. Polymers (Basel). 2019; 11(11): 1–13. https://doi.org/10.3390/polym11111777.
  18. Gajzlerova L, Navratilova J, Zenzingerova S, Jaska D, Benicek L, Kudlacek M, et al. On isotactic polypropylene annealing: Difference in final properties of neat and β-nucleated polypropylene. Express Polym Lett. 2022; 16(5): 453-464. https:// doi.org/10.3144/expresspolymlett.2022.34
  19. International Organization for Standardization. ISO 527-1, ISO 527-2: Tensile test on plastics. [cited 2024 Sep 5]. Available from: https://www.zwickroell.com/industries/plastics/thermoplastics-and-thermosetting-molding-materials/tensile-test-iso-527-1-2/
  20. International Organization for Standardization. Plastics — Determination of Charpy impact properties. ISO; 2020.

 

 

 

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