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Polymers
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Effects of Inhibitors on Polymerization, Properties, and Final Application of...
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Effects of Inhibitors on Polymerization, Properties, and Final Application of Polymers

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Chemistry".

Deadline for manuscript submissions: 31 October 2024 | Viewed by 2249

Special Issue Editors

Dr. Joaquín Hernández-Fernández

E-Mail Website
Guest Editor
Departamento de Química, Universidad de Cartagena, Cartagena 130001, Colombia
Interests: chemical inhibitors; polypropylene; biopolymers; polyolefins; analytical chemistry; industrial processes; Ziegler Natta catalyst; chemometric; catalysis; removal and recovery of contaminants
Prof. Dr. Juan López Martínez

E-Mail Website
Guest Editor
Department of Mechanical and Materials Engineering, Polytechnic University of València, 03801 Alcoy, Spain
Interests: chemical inhibitors; biopolymers; polyolefins; analytic chemistry; industrial processes; sustainability; eco-design; elimination of contaminants

Special Issue Information

Dear Colleagues,

The synthesis of conventional and unconventional polymeric materials plays a fundamental role in a nation's economic and scientific development. The efficiency and effectiveness of the synthesis at the industrial scale, pilot plant, or laboratory scale and the final properties of these biopolymers are drastically affected by the presence of traces or ultra traces of chemical impurities that may be present in raw materials, in the environment, in equipment materials, or in others. These inhibitors tend to react with the catalysts, supports, and co-catalysts; they displace monomers, react and degrade synthesized polymers, and affect the yields of the final applications of polymers. These affectations generate million-dollar losses to production processes, limit scientific progress, affect the environment, and can cause damage to health. This Special Issue aims to:

  • Present analytical methodologies that allow the identification and quantification of the most significant number of chemical inhibitors in raw materials, the environment, or materials from industrial processes.
  • Present theoretical–experimental demonstrations allowing an understanding of the reaction processes and mechanisms these inhibitors induce in the polymerization stages.
  • Demonstrate industrial processes and academic research aimed at removing these inhibitors from raw materials and chemical processes.

Investigate the physicochemical changes that these inhibitors generate in polymers and biopolymers.

Dr. Joaquín Hernández-Fernández
Prof. Dr. Juan López Martínez
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Polymers is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • chemical inhibitors
  • polypropylene
  • biopolymers
  • polyolefins
  • analytical chemistry
  • industrial processes

Published Papers (2 papers)

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Research

22 pages, 6142 KiB  
Article
Evaluation of the Reactivity of Methanol and Hydrogen Sulfide Residues with the Ziegler–Natta Catalyst during Polypropylene Synthesis and Its Effects on Polymer Properties
by Joaquín Hernández-Fernández, Rafael González-Cuello and Rodrigo Ortega-Toro
Polymers 2023, 15(20), 4061; https://doi.org/10.3390/polym15204061 - 12 Oct 2023
Viewed by 866
Abstract
The study focused on the evaluation of the influence of inhibitory compounds such as hydrogen sulfide (H2S) and methanol (CH3OH) on the catalytic productivity and properties of the polymers in the polymerization process with the Ziegler–Natta catalyst. The investigation [...] Read more.
The study focused on the evaluation of the influence of inhibitory compounds such as hydrogen sulfide (H2S) and methanol (CH3OH) on the catalytic productivity and properties of the polymers in the polymerization process with the Ziegler–Natta catalyst. The investigation involved experimental measurements, computational calculations using DFT, and analysis of various parameters, such as molecular weight, melt flow index, xylene solubility, and reactivity descriptors. The results revealed a clear correlation between the concentration of H2S and methanol and the parameters evaluated. Increasing the H2S concentrations, on average by 0.5 and 1.0 ppm, resulted in a drastic decrease in the polymer’s molecular weight. A directly proportional relationship was observed between the flow rate and the H2S concentration. In the case of methanol, the change occurred from 60 ppm, causing a sharp decrease in the molecular weight of the polymer, which translates into an increase in the fluidity index and a decrease in solubility in xylene. The presence of these inhibitors also affected the catalytic activity, causing a reduction in the productivity of the Ziegler–Natta catalyst. Computational calculations provided a deeper understanding of the molecular behavior and reactivity of the studied compounds. The computational calculations yielded significantly lower results compared to other studies, with values of −69.0 and −43.9 kcal/mol for the Ti-CH3OH and H2S interactions, respectively. These results indicate remarkable stability in the studied interactions and suggest that both adsorptions are highly favorable. Full article
(This article belongs to the Special Issue Effects of Inhibitors on Polymerization, Properties, and Final Application of Polymers)
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25 pages, 5826 KiB  
Article
Parts per Million of Propanol and Arsine as Responsible for the Poisoning of the Propylene Polymerization Reaction
by Joaquín Hernández-Fernández, Rafael González-Cuello and Rodrigo Ortega-Toro
Polymers 2023, 15(17), 3619; https://doi.org/10.3390/polym15173619 - 01 Sep 2023
Cited by 3 | Viewed by 1060
Abstract
Polypropylene synthesis is a critical process in the plastics industry, where control of catalytic activity is essential to ensure the quality and performance of the final product. In this study, the effect of two inhibitors, propanol and arsine, on the properties of synthesized [...] Read more.
Polypropylene synthesis is a critical process in the plastics industry, where control of catalytic activity is essential to ensure the quality and performance of the final product. In this study, the effect of two inhibitors, propanol and arsine, on the properties of synthesized polypropylene was investigated. Experiments were conducted using a conventional catalyst to polymerize propylene, and different concentrations of propanol and arsine were incorporated into the process. The results revealed that the addition of propanol led to a significant decrease in the Melt Flow Index (MFI) of the resulting polypropylene. The reduction in the MFI was most notable at a concentration of 62.33 ppm propanol, suggesting that propanol acts as an effective inhibitor by slowing down the polymerization rate and thus reducing the fluidity of the molten polypropylene. On the other hand, introducing arsine as an inhibitor increased the MFI of polypropylene. The maximum increase in the MFI was observed at a concentration of 0.035 ppm arsine. This suggests that small amounts of arsine affect the MFI and Mw of the produced PP. Regarding the catalyst productivity, it was found that as the concentration of propanol in the sample increased (approximately seven ppm), there was a decrease in productivity from 45 TM/kg to 44 TM/kg. Starting from 10 ppm, productivity continued to decline, reaching its lowest point at 52 ppm, with only 35 MT/kg. In the case of arsine, changes in catalyst productivity were observed at lower concentrations than with propanol. Starting from about 0.006 ppm, productivity decreased, reaching 39 MT/kg at a concentration of 0.024 ppm and further decreasing to 36 TM/kg with 0.0036 ppm. Computational analysis supported the experimental findings, indicating that arsine adsorbs more stably to the catalyst with an energy of −60.8 Kcal/mol, compared to propanol (−46.17 Kcal/mol) and isobutyl (−33.13 Kcal/mol). Analyses of HOMO and LUMO orbitals, as well as reactivity descriptors, such as electronegativity, chemical potential, and nucleophilicity, shed light on the potential interactions and chemical reactions involving inhibitors. Generated maps of molecular electrostatic potential (MEP) illustrated the charge distribution within the studied molecules, further contributing to the understanding of their reactivity. The computational results supported the experimental findings and provided additional information on the molecular interactions between the inhibitors and the catalyst, shedding light on the possible modes of inhibition. Solubles in xylene values indicate that both propanol and arsine affect the polymer’s morphology, which may have significant implications for its properties and final applications. Full article
(This article belongs to the Special Issue Effects of Inhibitors on Polymerization, Properties, and Final Application of Polymers)
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