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Polymerization and Kinetic Studies

A topical collection in Polymers (ISSN 2073-4360). This collection belongs to the section "Polymer Chemistry".

Viewed by 19674

Editors

Prof. Dr. Shin-Ichi Yusa

E-Mail Website
Collection Editor
Department of Materials Science and Chemistry, University of Hyogo, Shosha, Himeji 2167, Hyogo, Japan
Interests: controlled/living radical polymerization; RAFT; TERP; water-soluble polymer; self-organization; polymer micelle; bioconjugate polymer
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Binyuan Liu

E-Mail Website
Collection Editor
Hebei Key Laboratory of Functional Polymers, Department of Polymer Materials and Engineering, Hebei University of Technology, 8 Guangrong Street, Tianjin 300130, China
Interests: ecological environment (carbon dioxide, biomass, etc.) polymer synthesis and utilization; olefin coordination polymerization and new catalysts; new method for structure-controlled polymerization
Special Issues, Collections and Topics in MDPI journals

Topical Collection Information

Dear Colleagues,

In polymer chemistry, the study of polymerization kinetics is fundamental to the production of polymers. Polymerization is an important process of combining molecules to form polymer chains or even complex topological chains, in which bifunction or multifunction monomers react to form dimers, trimers, longer oligomers, and eventually long chain polymers. Most recently, the concept of precision polymer synthesis has emerged, which seeks to control all aspects of polymer structure and needs basic and advanced knowledge about the kinetics and reaction mechanism of their formation, i.e., mechanism of polymerization in different media, effect of reaction conditions, effect of modifying additives, etc.

This Topic Collection of Polymers on “Polymerization and Kinetic Studies” will be especially focused on the application of kinetic studies to precision polymerization and the use of insights derived from polymerization kinetics to the synthesis of new polymers and copolymers.

Prof. Dr. Shin-Ichi Yusa
Prof. Dr. Binyuan Liu
Collection Editors

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Keywords

  • precision polymerization
  • reversible deactivation radical polymerization
  • living/controlled polymerization
  • step polymerization
  • copolymerization
  • branching

Published Papers (9 papers)

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2024

Jump to: 2023, 2022

26 pages, 13730 KiB  
Article
In Situ Monitoring of the Curing of Highly Filled Epoxy Molding Compounds: The Influence of Reaction Type and Silica Content on Cure Kinetic Models
by Julian Vogelwaid, Felix Hampel, Martin Bayer, Michael Walz, Larysa Kutuzova, Günter Lorenz, Andreas Kandelbauer and Timo Jacob
Polymers 2024, 16(8), 1056; https://doi.org/10.3390/polym16081056 - 11 Apr 2024
Cited by 3 | Viewed by 1384
Abstract
Monitoring of molding processes is one of the most challenging future tasks in polymer processing. In this work, the in situ monitoring of the curing behavior of highly filled EMCs (silica filler content ranging from 73 to 83 wt%) and the effect of [...] Read more.
Monitoring of molding processes is one of the most challenging future tasks in polymer processing. In this work, the in situ monitoring of the curing behavior of highly filled EMCs (silica filler content ranging from 73 to 83 wt%) and the effect of filler load on curing kinetics are investigated. Kinetic modelling using the Friedman approach was applied using real-time process data obtained from in situ DEA measurements, and these online kinetic models were compared with curing analysis data obtained from offline DSC measurements. For an autocatalytic fast-reacting material to be processed above the glass transition temperature Tg and for an autocatalytic slow-reacting material to be processed below Tg, time–temperature–transformation (TTT) diagrams were generated to investigate the reaction behavior regarding Tg progression. Incorporating a material containing a lower silica filler content of 10 wt% enabled analysis of the effects of filler content on sensor sensitivity and curing kinetics. Lower silica particle content (and a larger fraction of organic resin, respectively) favored reaction kinetics, resulting in a faster reaction towards Tg1. Kinetic analysis using DEA and DSC facilitated the development of highly accurate prediction models using the Friedman model-free approach. Lower silica particle content resulted in enhanced sensitivity of the analytical method, leading, in turn, to more precise prediction models for the degree of cure. Full article
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2023

Jump to: 2024, 2022

13 pages, 6043 KiB  
Article
Synthesis of Ultrahigh Molecular Weight Poly(methyl Methacrylate) via the Polymerization of MMA Initiated by the Combination of Palladium Carboxylates with Thiols
by Panpan Zhang, Qiongqiong Xu, Wenyu Mao, Jiaxing Lv, Haodong Tang and Huadong Tang
Polymers 2023, 15(11), 2501; https://doi.org/10.3390/polym15112501 - 29 May 2023
Cited by 2 | Viewed by 2170
Abstract
A novel synthesis of ultrahigh molecular weight poly(methyl methacrylate) (PMMA) using organosulfur compounds combined with a catalytical amount of transition metal carboxylates as an initiator has been developed. The combination of 1-octanethiol with palladium trifluoroacetate (Pd(CF3COO)2) was found to [...] Read more.
A novel synthesis of ultrahigh molecular weight poly(methyl methacrylate) (PMMA) using organosulfur compounds combined with a catalytical amount of transition metal carboxylates as an initiator has been developed. The combination of 1-octanethiol with palladium trifluoroacetate (Pd(CF3COO)2) was found to be a very efficient initiator for the polymerization of methyl methacrylate (MMA). An ultrahigh molecular weight PMMA with a number-average molecular weight of 1.68 × 106 Da and a weight-average molecular weight of 5.38 × 106 Da has been synthesized at the optimal formulation of [MMA]:[Pd(CF3COO)2]:[1-octanethiol] = 94,300:8:23 at 70 °C. A kinetic study showed that the reaction orders with respect to Pd(CF3COO)2, 1-octanethiol, and MMA are 0.64, 1.26, and 1.46, respectively. A variety of techniques such as proton nuclear magnetic resonance spectroscopy (1H NMR), electrospray ionization mass spectroscopy (ESI-MS), size exclusion chromatography (SEC), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and electron paramagnetic resonance spectroscopy (EPR) were employed to characterize the produced PMMA and palladium nanoparticles (Pd NPs). The results revealed that Pd(CF3COO)2 was firstly reduced by the excess of 1-octanethiol to form Pd NPs at the early stage of the polymerization, followed by the adsorption of 1-octanethiol on the surface of nanoparticles and subsequent generation of corresponding thiyl radicals to initiate the polymerization of MMA. Full article
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16 pages, 2331 KiB  
Article
Phosphazene Functionalized Silsesquioxane-Based Porous Polymer as Thermally Stable and Reusable Catalyst for Bulk Ring-Opening Polymerization of ε-Caprolactone
by Yuliya A. Piskun, Evgenii A. Ksendzov, Anastasiya V. Resko, Mikhail A. Soldatov, Peter Timashev, Hongzhi Liu, Irina V. Vasilenko and Sergei V. Kostjuk
Polymers 2023, 15(5), 1291; https://doi.org/10.3390/polym15051291 - 3 Mar 2023
Cited by 2 | Viewed by 2327
Abstract
The bulk ring-opening polymerization (ROP) of ε-caprolactone using phosphazene-containing porous polymeric material (HPCP) has been studied at high reaction temperatures (130–150 °C). HPCP in conjunction with benzyl alcohol as an initiator induced the living ROP of ε-caprolactone, affording polyesters with a controlled molecular [...] Read more.
The bulk ring-opening polymerization (ROP) of ε-caprolactone using phosphazene-containing porous polymeric material (HPCP) has been studied at high reaction temperatures (130–150 °C). HPCP in conjunction with benzyl alcohol as an initiator induced the living ROP of ε-caprolactone, affording polyesters with a controlled molecular weight up to 6000 g mol−1 and moderate polydispersity (Ð~1.5) under optimized conditions ([BnOH]/[CL] = 50; HPCP: 0.63 mM; 150 °C). Poly(ε-caprolactone)s with higher molecular weight (up to Mn = 14,000 g mol−1, Ð~1.9) were obtained at a lower temperature, at 130 °C. Due to its high thermal and chemical stability, HPCP can be reused for at least three consecutive cycles without a significant decrease in the catalyst efficiency. The tentative mechanism of the HPCP-catalyzed ROP of ε-caprolactone, the key stage of which consists of the activation of the initiator through the basic sites of the catalyst, was proposed. Full article
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17 pages, 2901 KiB  
Article
DFT and ONIOM Simulation of 1,3-Butadiene Polymerization Catalyzed by Neodymium-Based Ziegler–Natta System
by Alexey N. Masliy, Ildar G. Akhmetov, Andrey M. Kuznetsov and Ilsiya M. Davletbaeva
Polymers 2023, 15(5), 1166; https://doi.org/10.3390/polym15051166 - 25 Feb 2023
Cited by 5 | Viewed by 2140
Abstract
Using modern methods of quantum chemistry, a theoretical substantiation of the high cis-stereospecificity of 1,3-butadiene polymerization catalyzed by the neodymium-based Ziegler–Natta system was carried out. For DFT and ONIOM simulation, the most cis-stereospecific active site of the catalytic system was used. [...] Read more.
Using modern methods of quantum chemistry, a theoretical substantiation of the high cis-stereospecificity of 1,3-butadiene polymerization catalyzed by the neodymium-based Ziegler–Natta system was carried out. For DFT and ONIOM simulation, the most cis-stereospecific active site of the catalytic system was used. By analyzing the total energy, as well as the enthalpy and Gibbs free energy of the simulated catalytically active centers, it was found that the coordination of 1,3-butadiene in the trans-form was more favorable than in the cis-form by 11 kJ/mol. However, as a result of π-allylic insertion mechanism modeling, it was found that the activation energy of cis-1,3-butadiene insertion into the π-allylic neodymium–carbon bond of the terminal group on the reactive growing chain was 10–15 kJ/mol lower than the activation energy of trans-1,3-butadiene insertion. The activation energies did not change when both trans-1,4-butadiene and cis-1,4-butadiene were used for modeling. That is, 1,4-cis-regulation was due not to the primary coordination of 1,3-butadiene in its cis-configuration, but to its lower energy of attachment to the active site. The obtained results allowed us to clarify the mechanism of the high cis-stereospecificity of 1,3-butadiene polymerization by the neodymium-based Ziegler–Natta system. Full article
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2022

Jump to: 2024, 2023

9 pages, 772 KiB  
Article
Polymerization of Hexene-1 and Propylene over Supported Titanium–Magnesium Catalyst: Comparative Data on the Polymerization Kinetics and Molecular Weight Characteristics of Polymers
by Mikhail Matsko, Ludmila Echevskaya and Vladimir Zakharov
Polymers 2023, 15(1), 87; https://doi.org/10.3390/polym15010087 - 26 Dec 2022
Cited by 1 | Viewed by 2013
Abstract
Data are presented on the great differences of the kinetics of hexene-1 and propylene polymerization over the same supported titanium–magnesium catalyst, as well as molecular weight and molecular weight distribution of the polymers produced. It is found that the composition of cocatalysts (AlEt [...] Read more.
Data are presented on the great differences of the kinetics of hexene-1 and propylene polymerization over the same supported titanium–magnesium catalyst, as well as molecular weight and molecular weight distribution of the polymers produced. It is found that the composition of cocatalysts (AlEt3 or Al(i-Bu)3 greatly affects the kinetics of hexene-1 polymerization and molecular weight distribution of polyhexene, contrary to data obtained at propylene polymerization. The presence of hydrogen at hexene-1 polymerization leads to a much higher increase of activity in comparison with propylene polymerization. Possible reasons for these differences are discussed on the basis of experimental results. Full article
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16 pages, 2501 KiB  
Article
Temperature Dependence of the Kinetic Parameters of the Titanium–Magnesium Catalyzed Propylene Polymerization
by Veronika Bronskaya, Galiya Manuyko, Guzel Aminova, Olga Kharitonova, Denis Balzamov and Alsu Lubnina
Polymers 2022, 14(23), 5183; https://doi.org/10.3390/polym14235183 - 28 Nov 2022
Cited by 1 | Viewed by 1528
Abstract
This paper provides a study of the liquid-phase polypropylene polymerization on a heterogeneous titanium–magnesium Ziegler–Natta-type catalyst. A kinetic model was developed that included the activation of potential active centers, chain growth, transferring the chains to hydrogen and monomer, and the deactivation of active [...] Read more.
This paper provides a study of the liquid-phase polypropylene polymerization on a heterogeneous titanium–magnesium Ziegler–Natta-type catalyst. A kinetic model was developed that included the activation of potential active centers, chain growth, transferring the chains to hydrogen and monomer, and the deactivation of active centers. The model was created to predict the polymerization rate, polymer yield, and average molecular weights of polymer chains where the polymerization temperature changes from 40 to 90 °C. In developing polycentric kinetic models, there is a difficulty associated with evaluating the kinetic constants of the rates of elementary reactions/stages in polymerization. Each heterogeneous titanium–magnesium catalyst (TMC), including a co-catalyst, as well as an internal and an external electron donor, has its own set of kinetic parameters. Therefore, its kinetic parameters must be defined for each new catalyst. The presented algorithm for identifying the kinetic constants of rates starts with a kinetic model that considers one type of active centers. At the second stage, a deconvolutional analysis is used for the molecular weight distribution (MWD) of the gel permeation chromatography (GPC) data of the polypropylene samples and the most probable distribution of Flory chain lengths is found for each type of active centers. At the third stage, the single-center model is transformed into a polycentric kinetic model. For the catalyst system, five types of active centers were identified, together with a mass fraction and a number-average molecular weight for each active center type of the catalyst, which is consistent with the published results for similar Ti-based Ziegler–Natta catalysts. Full article
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14 pages, 4254 KiB  
Article
Slurry Homopolymerization of Ethylene Using Thermostable α-Diimine Nickel Catalysts Covalently Linked to Silica Supports via Substituents on Acenaphthequinone-Backbone
by Kening Zong, Yanhui Hou, Xiaobei Zhao, Yali Sun, Binyuan Liu and Min Yang
Polymers 2022, 14(17), 3684; https://doi.org/10.3390/polym14173684 - 5 Sep 2022
Cited by 2 | Viewed by 1917
Abstract
Four supported α-diimine nickel(II) catalysts covalently linked to silica via hydroxyl functionality on α-diimine acenaphthequinone-backbone were prepared and used in slurry polymerizations of ethylene to produce branched polyethylenes. The catalytic activities of these still reached 106 g/molNi·h at 70 °C. The life [...] Read more.
Four supported α-diimine nickel(II) catalysts covalently linked to silica via hydroxyl functionality on α-diimine acenaphthequinone-backbone were prepared and used in slurry polymerizations of ethylene to produce branched polyethylenes. The catalytic activities of these still reached 106 g/molNi·h at 70 °C. The life of the supported catalyst is prolonged, as can be seen from the kinetic profile. The molecular weight of the polyethylene obtained by the 955 silica gel supported catalyst was higher than that obtained by the 2408D silica gel supported catalyst. The melting points of polyethylene obtained by the supported catalysts S-C1-a/b are all above 110 °C. Compared with the homogeneous catalyst, the branching numbers of the polyethylenes obtained by the supported catalysts S-C1-a/b is significantly lower. The polyethylenes obtained by supported catalyst S-C1-a/b at 30–50 °C are free-flowing particles, which is obviously better than the rubber-like cluster polymer obtained from homogeneous catalyst. Full article
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18 pages, 4593 KiB  
Article
Progress toward Polymerization Reaction Monitoring with Different Dienes: How Small Amounts of Dienes Affect ansa-Zirconocenes/Borate/Triisobutylaluminium Catalyst Systems
by Amjad Ali, Jamile Mohammadi Moradian, Ahmad Naveed, Tariq Aziz, Nadeem Muhammad, Chanez Maouche, Yintian Guo, Waleed Yaseen, Maria Yassen, Fazal Haq, Mobashar Hassan, Zheqing Fan and Li Guo
Polymers 2022, 14(16), 3239; https://doi.org/10.3390/polym14163239 - 9 Aug 2022
Cited by 6 | Viewed by 1912
Abstract
The objectives of this work were to address the fundamental characteristics of ansa-zirconocene catalyzed E/diene copolymerization and E/diene/1-hexene and E/diene/propylene terpolymerizations, and the quantitative relationship between diene structure and polymer chain propagation rate constant in term of quantifiable catalytic active sites. One of [...] Read more.
The objectives of this work were to address the fundamental characteristics of ansa-zirconocene catalyzed E/diene copolymerization and E/diene/1-hexene and E/diene/propylene terpolymerizations, and the quantitative relationship between diene structure and polymer chain propagation rate constant in term of quantifiable catalytic active sites. One of the most important but unknown factors in olefins ansa-zirconocene complexes is the distribution of the catalyst between sites actively participating in polymer chain formation and dormant sites. A set of ethylene/dienes copolymerizations, and ethylene/dienes/1-hexene and ethylene/dienes/1-hexene terpolymerizations catalyzed with ansa-zirconocenes/borate/triisobutylaluminium (rac-Et(Ind)2ZrCl2/[Ph3C][B(C6F5)4]/triisobutylaluminium (TIBA) were performed in toluene at 50 °C To determine the active center [C*]/[Zr] ratio variation in the copolymerization of E with different dienes and their terpolymerization with 1-hexene and propylene, each polymer propagation chain ends were quenched with 2-thiophenecarbonyl, which selectively quenches the metal–polymer bonds through acyl chloride. The ethylene, propylene, 1-hexene, and diene composition-based propagation rate constants (kpE, kpP, kp1-H, and kpdiene), thermal (melting and crystalline) properties, composition (mol% of ethylene, propylene, 1-hexene, and diene), molecular weight, and polydispersity were also studied in this work. Systematic comparisons of the proportion of catalytically [Zr]/[C*] active sites and polymerization rate constant (kp) for ansa-zirconocenes catalyzed E/diene, E/diene/1-hexene, and E/diene/propylene polymerization have not been reported before. We evaluated the addition of 1-hexene and propylene as termonomers in the copolymerization with E/diene. To make a comparison for each diene under identical conditions, we started the polymerization by introducing an 80/20 mole ratio of E/P and 0.12 mol/L of 1-hexene in the system. The catalyst behavior against different dienes, 1-hexene, and propylene is very interesting, including changes in thermal properties, cyclization of 1-hexene, and decreased incorporation of isoprene and butadiene, changes in the diffusion barriers in the system, and its effect on kp. Full article
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15 pages, 2018 KiB  
Article
Synthesis of a Curing Agent Derived from Limonene and the Study of Its Performance to Polymerize a Biobased Epoxy Resin Using the Epoxy/Thiol-Ene Photopolymerization Technique
by Ricardo Acosta Ortiz, Rebeca Sadai Sánchez Huerta, Antonio Serguei Ledezma Pérez and Aida E. García Valdez
Polymers 2022, 14(11), 2192; https://doi.org/10.3390/polym14112192 - 28 May 2022
Cited by 6 | Viewed by 2994
Abstract
This study describes the synthesis of a curing agent derived from limonene as well as its application to prepare biobased thermoset polymers via the epoxy/thiol-ene photopolymerization (ETE) method. A biobased commercial epoxy resin was used to synthesize a crosslinked polymeric matrix of polyether-polythioether [...] Read more.
This study describes the synthesis of a curing agent derived from limonene as well as its application to prepare biobased thermoset polymers via the epoxy/thiol-ene photopolymerization (ETE) method. A biobased commercial epoxy resin was used to synthesize a crosslinked polymeric matrix of polyether-polythioether type. The preparation of the curing agent required two steps. First, a diamine intermediate was prepared by means of a thiol-ene coupling reaction between limonene and cysteamine hydrochloride. Second, the primary amino groups of the intermediate compound were alkylated using allyl bromide. The obtained ditertiary amine-functionalized limonene compound was purified and characterized by FTIR and NMR spectroscopies along with GC-MS. The curing agent was formulated with a tetrafunctional thiol in stoichiometric ratio, and a photoinitiator at 1 mol % concentration, as the components of a thiol-ene system (TES). Two formulations were prepared in which molar concentrations of 30 and 40 mol % of the TES were added to the epoxy resin. The kinetics of the ETE photopolymerizations were determined by means of Real-Time FTIR spectroscopy, which demonstrated high reactivity by observing photopolymerization rates in the range of 1.50–2.25 s−1 for the epoxy, double bonds and thiol groups. The obtained polymers were analyzed by thermal and thermo-mechanical techniques finding glass transition temperatures (Tg) of 60 °C and 52 °C for the polymers derived from the formulations with 30 mol % and 40 mol % of TES, respectively. Potential applications for these materials can be foreseen in the area of coatings. Full article
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