Isotactic poly (1-butene) (iPB) is an interesting semi-crystalline thermoplastic material characterized by notable physical and mechanical attributes encompassing superior creep and stress resistance, elevated toughness, stiffness, and thermal endurance. These distinctive features position iPB as a viable candidate for specific applications; however, its widespread utilization is hindered by certain inherent limitations. Indeed, iPB manifests an intricate polymorphic behavior, and the gradual and spontaneous transition of the kinetically favored form II to the thermodynamically favored form I during aging introduces alterations to the material's properties. Despite its potential, the attainment of iPB with an exceedingly high molecular mass remains elusive, particularly when employing homogeneous catalysts renowned for their efficacy in propene polymerization. In this study we analyze the mechanistic aspects governing 1-butene polymerization by using DFT calculations modelling the regioselectivity of 1-butene insertions and the termination reactions occurring after primary (1,2) and secondary (2,1) insertions. Finally, the isomerization pathways leading to the formation of 4,1 units in iPB samples synthesized by homogenous catalysts is also discussed. All these aspects, furnish a mechanistic picture of the main drawbacks of an "old" but still interesting material.
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http://dx.doi.org/10.3389/fchem.2024.1377740 | DOI Listing |
Sci Adv
September 2024
Frontiers Science Center for Transformative Molecules, Zhangjiang Institute for Advanced Study, and Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Radical polymerization is a powerful technique for producing a variety of polymeric materials. However, the chain transfer reaction impedes the formation of polymers from many common α-olefins such as propene and 1-butene using this method. Consequently, poly(α-olefins) are predominantly produced via coordination polymerization.
View Article and Find Full Text PDFMacromol Rapid Commun
July 2024
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, P. R. China.
The II-I phase transition of isotactic poly(1-butene) (iPBu) leads to improved mechanical performance. However, this will take several weeks and increase storage and processing costs. In this work, shear forces are introduced into the supercooled iPBu melt, and the effects of isothermal crystallization temperature (T) and shear temperature (T) on crystallization and phase transition are explored.
View Article and Find Full Text PDFFront Chem
March 2024
Scuola Superiore Meridionale, Napoli, Italy.
Isotactic poly (1-butene) (iPB) is an interesting semi-crystalline thermoplastic material characterized by notable physical and mechanical attributes encompassing superior creep and stress resistance, elevated toughness, stiffness, and thermal endurance. These distinctive features position iPB as a viable candidate for specific applications; however, its widespread utilization is hindered by certain inherent limitations. Indeed, iPB manifests an intricate polymorphic behavior, and the gradual and spontaneous transition of the kinetically favored form II to the thermodynamically favored form I during aging introduces alterations to the material's properties.
View Article and Find Full Text PDFJ Mol Graph Model
January 2024
School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran, Iran.
A vigorous and progressed Monte Carlo strategy was developed to precisely simulate the ethylene and 1-butene copolymerization within the presence of hydrogen by dual-site metallocene catalyst. The results showed up that the ethylene and 1-butene consumption rates at the second catalyst site were approximately 5 times higher than at the first site, and hydrogen transfer rates at the first catalyst site were over 3 times more rapid than at the second site. It was found that the most elevated molar percentage of 1-butene inside the copolymers synthesized from the second site was around 12% and within the copolymers gotten from the first site was around 2%.
View Article and Find Full Text PDFPolymers (Basel)
February 2023
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
Poly(1-butene) (PB-1) resin has excellent mechanical properties, outstanding creep resistance, environmental stress crack resistance and other excellent properties. However, PB-1 resin experiences a crystal transformation for a period, which seriously affects the production efficiency and directly restricts its large-scale commercial production and application. The factors affecting the crystal transformation of PB-1 are mainly divided into external and internal factors.
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