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Special Issue "Polymer: A Themed Issue in Honor of Professor Julian Chojnowski on the Occasion of His 85th Birthday"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Macromolecular Chemistry".

Deadline for manuscript submissions: 30 June 2021.

Special Issue Editors

Dr. Sławomir Rubinsztajn
E-Mail Website
Guest Editor
Centre of Molecular and Macromolecular Studies of Polish Academy of Sciences, Lodz, Poland
Interests: organosilicon chemistry; polymer chemistry; catalysis; kinetics and reaction mechanisms
Prof. Dr. Marek Cypryk
E-Mail Website
Guest Editor
Centre of Molecular and Macromolecular Studies of Polish Academy of Sciences, Lodz, Poland
Interests: organosilicon polymer chemistry; reaction mechanisms in organometallic chemistry, computational chemistry, and molecular modeling
Prof. Dr. Wlodzimierz Stanczyk
E-Mail Website
Guest Editor
Centre of Molecular and Macromolecular Studies of Polish Academy of Sciences, Lodz, Poland
Interests: organosilicon chemistry; liquid crystal polymers; silsesquioxanes; nanotechnology in biomedicine

Special Issue Information

Dear Colleagues,

Professor Dr. hab. Julian Chojnowski is an outstanding chemist who has significantly contributed to the development of many fields of organosilicon chemistry and organosilicon polymer chemistry. His fundamental research in the field of kinetic and thermodynamic aspects of polymerization processes and substitution at the silicon atom has led to understanding the mechanisms of ring-opening polymerization reactions of cyclic siloxanes, as well as the discovery of the importance of inter- and intramolecular catalysis in siloxane polymerization and polycondensation processes. His expertise in the field of siloxane polymer chemistry has resulted in cooperation with the leading silicone material manufacturers such as Dow Corning and General Electric Company. His collaboration with GE resulted in the discovery of several new reactions of hydride-functional silanes and siloxanes involving activation of Si–H bond by electron-deficient boranes. Recently, he expanded his research interest into silicon-based materials. He developed the synthesis of a new class of polymers, poly(oxymultisilylene)s, and new processes leading to the synthesis of highly cross-linked polyorganosiloxane beads, which can be subsequently converted into ceramic materials.

Professor Chojnowski was born on 17 June 1935 in Warsaw, Poland. He obtained his MSc degree in chemistry from Technical University of Lodz in 1957. He carried out his graduate studies at Technical University of Lodz under the supervision of Professor Stanisław Chrzczonowicz, where he obtained his PhD in 1963. In 1966, he spent two years as a postdoctoral fellow at the University of Wisconsin–Milwaukee, USA in the research group of Professor W.W. Brandt. Upon returning to Poland, he finished his habilitation in 1971. Shortly afterwards, he moved to the newly created Centre of Molecular and Macromolecular Studies of Polish Academy of Sciences, where he became the head of the Laboratory of Heteroorganic Polymers. In 1983, he obtained the academic title of Professor of Chemistry. He retired in 2005, but he continues research at the Centre of Molecular and Macromolecular Studies as a professor emeritus. Professor J. Chojnowski is the promoter of 15 doctoral dissertations. He published about 180 original papers, 16 review papers and chapters in books, as well as several Polish and US patents. He was also a co-editor of two books. In 2005, Professor Chojnowski was awarded the Jan Zawidzki medal for outstanding achievements in the field of physical chemistry by the Polish Chemical Society. He serves as a member of the Advisory Board of Journal of Inorganic and Organometallic Polymers and Materials, Silicon (Springer), and Main Group Chemistry.

Molecules is pleased to announce a Special Issue honoring Professor Julian Chojnowski on the occasion of his 85th birthday for his outstanding achievements in silicon chemistry. This Special Issue is dedicated to all aspects of organosilicon chemistry, including silicon-based polymer chemistry, mechanistic aspects of organosilicon chemistry, and catalysis and synthesis of silicon-based materials and ceramics.

We are pleased to invite you to submit a manuscript to this Special Issue; regular articles, communications, and reviews are all welcome.

Dr. Sławomir Rubinsztajn
Prof. Marek Cypryk
Prof. Wlodzimierz Stanczyk
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 papers will be 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. Molecules 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 2000 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

  • Chemistry of silicon-based polymers and materials
  • Organosilicon chemistry
  • Kinetics and mechanisms of chemical reactions
  • Catalysis
  • Chemistry of silicon-based polymers and materials
  • Organosilicon-polymer-derived ceramic materials

Published Papers (9 papers)

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Research

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Open AccessArticle
An Approach to the Use of Glycol Alkoxysilane–Polysaccharide Hybrids in the Conservation of Historical Building Stones
Molecules 2021, 26(4), 938; https://doi.org/10.3390/molecules26040938 - 10 Feb 2021
Viewed by 556
Abstract
Stone consolidants have been widely used to protect historical monuments. Consolidants and hydrophobic formulations based on the use of tetraethoxysilane (TEOS) and alkylalkoxysilanes as precursors have been widely applied, despite their lack of solubility in water and requirement to be applied in organic [...] Read more.
Stone consolidants have been widely used to protect historical monuments. Consolidants and hydrophobic formulations based on the use of tetraethoxysilane (TEOS) and alkylalkoxysilanes as precursors have been widely applied, despite their lack of solubility in water and requirement to be applied in organic media. In the search for a “greener” alternative based on silicon that has potential use in this field, the use of tetrakis(2-hydroxyethyl)silane (THEOS) and tris(2-hydroxyethyl)methyl silane (MeTHEOS) as precursors, due their high water solubility and stability, is proposed in this paper. It is already known that THEOS and MeTHEOS possess remarkable compatibility with different natural polysaccharides. The investigated approach uses the water-soluble silanes THEOS–chitosan and MeTHEOS–chitosan as a basis for obtaining hybrid consolidants and hydrophobic formulations for the conservation of siliceous and calcareous stones. In the case of calcareous systems, their incompatibility with alkoxysilanes is known and is expected to be solved by the developed hybrid consolidant. Their application in the conservation of building stones from historical and archeological sites from Guanajuato, México was studied. The evaluation of the consolidant and hydrophobic formulation treatment was mainly conducted by determining the mechanical properties and contact angle measurements with satisfactory results in terms of the performance and compatibility with the studied stones. Full article
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Open AccessArticle
New Antiadhesive Hydrophobic Polysiloxanes
Molecules 2021, 26(4), 814; https://doi.org/10.3390/molecules26040814 - 04 Feb 2021
Viewed by 503
Abstract
Intrinsic hydrophobicity is the reason for efficient bacterial settlement and biofilm growth on silicone materials. Those unwelcomed phenomena may play an important role in pathogen transmission. We have proposed an approach towards the development of new anti-biofilm strategies that resulted in novel antimicrobial [...] Read more.
Intrinsic hydrophobicity is the reason for efficient bacterial settlement and biofilm growth on silicone materials. Those unwelcomed phenomena may play an important role in pathogen transmission. We have proposed an approach towards the development of new anti-biofilm strategies that resulted in novel antimicrobial hydrophobic silicones. Those functionalized polysiloxanes grafted with side 2-(carboxymethylthioethyl)-, 2-(n-propylamidomethylthioethyl)- and 2-(mercaptoethylamidomethylthioethyl)- groups showed a wide range of antimicrobial properties towards selected strains of bacteria (reference strains Staphylococcus aureus, Escherichia coli and water-borne isolates Agrobacterium tumefaciens, Aeromonas hydrophila), fungi (Aureobasidium pullulans) and algae (Chlorella vulgaris), which makes them valuable antibacterial and antibiofilm agents. Tested microorganisms showed various levels of biofilm formation, but particularly effective antibiofilm activity was demonstrated for bacterial isolate A. hydrophila with high adhesion abilities. In the case of modified surfaces, the relative coefficient of adhesion for this strain was 18 times lower in comparison to the control glass sample. Full article
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Open AccessArticle
Synthesis of Silsesquioxanes with Substituted Triazole Ring Functionalities and Their Coordination Ability
Molecules 2021, 26(2), 439; https://doi.org/10.3390/molecules26020439 - 15 Jan 2021
Viewed by 513
Abstract
A synthesis of a series of mono-T8 and difunctionalized double-decker silsesquioxanes bearing substituted triazole ring(s) has been reported within this work. The catalytic protocol for their formation is based on the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) process. Diverse alkynes were in the scope [...] Read more.
A synthesis of a series of mono-T8 and difunctionalized double-decker silsesquioxanes bearing substituted triazole ring(s) has been reported within this work. The catalytic protocol for their formation is based on the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) process. Diverse alkynes were in the scope of our interest—i.e., aryl, hetaryl, alkyl, silyl, or germyl—and the latter was shown to be the first example of terminal germane alkyne which is reactive in the applied process’ conditions. From the pallet of 15 compounds, three of them with pyridine-triazole and thiophenyl-triazole moiety attached to T8 or DDSQ core were verified in terms of their coordinating properties towards selected transition metals, i.e., Pd(II), Pt(II), and Rh(I). The studies resulted in the formation of four SQs based coordination compounds that were obtained in high yields up to 93% and their thorough spectroscopic characterization is presented. To our knowledge, this is the first example of the DDSQ-based molecular complex possessing bidentate pyridine-triazole ligand binding two Pd(II) ions. Full article
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Open AccessFeature PaperArticle
Controlled Synthesis of Polyphosphazenes with Chain-Capping Agents
Molecules 2021, 26(2), 322; https://doi.org/10.3390/molecules26020322 - 10 Jan 2021
Viewed by 500
Abstract
N-alkyl phosphoranimines were synthesized via the Staudinger reaction of four different alkyl azides with tris(2,2,2-trifluoroethyl) phosphite. N-adamantyl, N-benzyl, N-t-butyl, and N-trityl phosphoranimines were thoroughly characterized and evaluated as chain-capping compounds in the anionic polymerization of P [...] Read more.
N-alkyl phosphoranimines were synthesized via the Staudinger reaction of four different alkyl azides with tris(2,2,2-trifluoroethyl) phosphite. N-adamantyl, N-benzyl, N-t-butyl, and N-trityl phosphoranimines were thoroughly characterized and evaluated as chain-capping compounds in the anionic polymerization of P-tris(2,2,2-trifluoroethoxy)-N-trimethylsilyl phosphoranimine monomer. All four compounds reacted with the active chain ends in a bulk polymerization, and the alkyl end groups were identified by 1H-NMR spectroscopy. These compounds effectively controlled the molecular weight of the resulting polyphosphazenes. The chain transfer constants for the monomer and N-benzyl phosphoranimine were determined using Mayo equation. Full article
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Open AccessCommunication
When Attempting Chain Extension, Even Without Solvent, It Is Not Possible to Avoid Chojnowski Metathesis Giving D3
Molecules 2021, 26(1), 231; https://doi.org/10.3390/molecules26010231 - 05 Jan 2021
Cited by 1 | Viewed by 453
Abstract
A simple, mild and efficient method to prepare HSi- or HOSi-telechelic, high-molecular-weight polydimethylsiloxane polymers (to 41,600 g·mol−1) using the one-shot hydrolysis of MHMH is reported; titration of the water allowed for higher molecular weights (to 153,900 g·mol−1 [...] Read more.
A simple, mild and efficient method to prepare HSi- or HOSi-telechelic, high-molecular-weight polydimethylsiloxane polymers (to 41,600 g·mol−1) using the one-shot hydrolysis of MHMH is reported; titration of the water allowed for higher molecular weights (to 153,900 g·mol−1). The “living” character of the chain extension processes was demonstrated by adding a small portion of MHMH and B(C6F5)3 (BCF) to a first formed polymer, which led to a ~2-fold, second growth in molecular weight. The heterogeneous reaction reached completion in less than 30 min, much less in some cases, regardless of whether it was performed neat or 50 wt% in dry toluene; homogeneous reactions in toluene were much slower. The process does not involve traditional redistribution, as judged by the low quantities (<3%) of D4 produced. However, it is not possible to avoid Chojnowski metathesis from MHDDMH giving D3, which occurs competitively with chain extension. Full article
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Open AccessArticle
Reliable Condensation Curing Silicone Elastomers with Tailorable Properties
Molecules 2021, 26(1), 82; https://doi.org/10.3390/molecules26010082 - 27 Dec 2020
Viewed by 896
Abstract
The long-term stability of condensation curing silicone elastomers can be affected by many factors such as curing environment, cross-linker type and concentration, and catalyst concentration. Mechanically unstable silicone elastomers may lead to undesirable application failure or reduced lifetime. This study investigates the stability [...] Read more.
The long-term stability of condensation curing silicone elastomers can be affected by many factors such as curing environment, cross-linker type and concentration, and catalyst concentration. Mechanically unstable silicone elastomers may lead to undesirable application failure or reduced lifetime. This study investigates the stability of different condensation curing silicone elastomer compositions. Elastomers are prepared via the reaction of telechelic silanol-terminated polydimethylsiloxane (HO-PDMS-OH) with trimethoxysilane-terminated polysiloxane ((MeO)3Si-PDMS-Si(OMe)3) and ethoxy-terminated octakis(dimethylsiloxy)-T8-silsesquioxane ((QMOEt)8), respectively. Two post-curing reactions are found to significantly affect both the stability of mechanical properties over time and final properties of the resulting elastomers: Namely, the condensation of dangling and/or unreacted polymer chains, and the reaction between cross-linker molecules. Findings from the stability study are then used to prepare reliable silicone elastomer coatings. Coating properties are tailored by varying the cross-linker molecular weight, type, and concentration. Finally, it is shown that, by proper choice of all three parameters, a coating with excellent scratch resistance and electrical breakdown strength can be produced even without an addition of fillers. Full article
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Open AccessFeature PaperArticle
Novel Polyhedral Silsesquioxanes [POSS(OH)32] as Anthracycline Nanocarriers—Potential Anticancer Prodrugs
Molecules 2021, 26(1), 47; https://doi.org/10.3390/molecules26010047 - 24 Dec 2020
Viewed by 461
Abstract
Anthracyclines belong to the anticancer drugs that are widely used in chemotherapy. However, due to their systemic toxicity they also exert dangerous side effects associated mainly with cardiovascular risks. The pathway that is currently often developed is their chemical and physical modification via [...] Read more.
Anthracyclines belong to the anticancer drugs that are widely used in chemotherapy. However, due to their systemic toxicity they also exert dangerous side effects associated mainly with cardiovascular risks. The pathway that is currently often developed is their chemical and physical modification via formation of conjugated or complexed prodrug systems with a variety of nanocarriers that can selectively release the active species in cancer cells. In this study, six new nanoconjugates were synthesized with the use of polyhedral oligosilsesquioxanes [POSS(OH)32] as nanocarriers of the anticancer drugs anthracyclines—doxorubicin (DOX) and daunorubicin (DAU). These prodrug conjugates are also equipped with poly(ethylene glycol) (PEG) moieties of different structure and molecular weight. Water-soluble POSS, succinic anhydride modified (SAMDOX and SAMDAU) with carboxylic function, and PEGs (PEG1, PEG2 and PEGB3) were used for the synthesis. New nanoconjugates were formed via ester bonds and their structure was confirmed by NMR spectroscopy (1H-NMR, 13C-NMR, 1H-13C HSQC, DOSY and 1H-1H COSY), FTIR and DLS. Drug release rate was evaluated using UV-Vis spectroscopy at pH of 5.5. Release profiles of anthracyclines from conjugates 49 point to a range of 10 to 75% (after 42 h). Additionally, model NMR tests as well as diffusion ordered spectroscopy (DOSY) confirmed formation of the relevant prodrugs. The POSS-anthracycline conjugates exhibited prolonged active drug release time that can lead to the possibility of lowering administered doses and thus giving them high potential in chemotherapy. Drug release from conjugate 7 after 42 h was approx. 10%, 33% for conjugate 4, 47% for conjugate 5, 6, 8 and 75% for conjugate 9. Full article
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Open AccessArticle
Limonene Derivative of Spherosilicate as a Polylactide Modifier for Applications in 3D Printing Technology
Molecules 2020, 25(24), 5882; https://doi.org/10.3390/molecules25245882 - 12 Dec 2020
Viewed by 555
Abstract
The first report of using limonene derivative of a spherosilicate as a modifier of polylactide used for 3D printing and injection moulding is presented. The paper presents the use of limonene-functionalized spherosilicate derivative as a functional additive. The study compared the material characteristics [...] Read more.
The first report of using limonene derivative of a spherosilicate as a modifier of polylactide used for 3D printing and injection moulding is presented. The paper presents the use of limonene-functionalized spherosilicate derivative as a functional additive. The study compared the material characteristics of polylactide modified with SS-Limonene (0.25–5.0% w/w) processed with traditional injection moulding and 3D printing (FFF, FDM). A significant improvement in the processing properties concerning rheology, inter-layer adhesion, and mechanical properties was achieved, which translated into the quality of the print and reduction of waste production. Moreover, the paper describes the elementary stages of thermal transformations of the obtained hybrid systems. Full article
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Review

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Open AccessReview
Applications of Hybrid Polymers Generated from Living Anionic Ring Opening Polymerization
Molecules 2021, 26(9), 2755; https://doi.org/10.3390/molecules26092755 - 07 May 2021
Viewed by 227
Abstract
Increasingly precise control of polymer architectures generated by “Living” Anionic Ring-Opening Polymerization (Living AROP) is leading to a broad range of commercial advanced material applications, particularly in the area of siloxane macromers. While academic reports on such materials remain sparse, a significant portion [...] Read more.
Increasingly precise control of polymer architectures generated by “Living” Anionic Ring-Opening Polymerization (Living AROP) is leading to a broad range of commercial advanced material applications, particularly in the area of siloxane macromers. While academic reports on such materials remain sparse, a significant portion of the global population interacts with them on a daily basis—in applications including medical devices, microelectronics, food packaging, synthetic leather, release coatings, and pigment dispersions. The primary driver of this increased utilization of siloxane macromers is their ability to incorporate the properties of silicones into organic structures in a balanced manner. Compared to organic polymers, the differentiating properties of silicones—low Tg, hydrophobicity, low surface energy, and high free molal space—logically lend themselves to applications in which low modulus, release, permeability to oxygen and moisture, and tactile interaction are desired. However, their mechanical, structural and processing properties have until recently precluded practical applications. This review presents applications of “Living” AROP derived polymers from the perspective of historical technology development. Applications in which products are produced on a commercial scale—defined as not only offered for sale, but sold on a recurrent basis—are emphasized. Hybrid polymers with intriguing nanoscale morphology and potential applications in photoresist, microcontact printing, biomimetic soft materials, and liquid crystals are also discussed. Previously unreported work by the authors is provided in the context of this review. Full article
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: The Critical Role of Peroxy Compounds in The Ru-Catalyzed Hydrosilylation of Allyl Chloride by Trimethoxysilane
Authors: Kenrick M. Lewis; Andrea Trotto; Guiseppe D’Agostino; Jitendra Rathore
Affiliation: 1 Momentive Performance Materials, Inc., 769 Old Sawmill River Rd, Tarrytown, NY 10591; 2 Momentive Performance Materials SRL, Termoli, CB 86039, Italy; 3 3M Innovative Properties Co., St. Paul, MN 55144
Abstract: 3-Chloropropyltrimethoxysilane is a key intermediate for the manufacture of amino-, thio- and many other organofunctionalized silanes. It is manufactured via the Ru-catalyzed hydrosilylation of allyl chloride by trimethoxysilane. Over time, it was observed that allyl chloride obtained from various suppliers showed inconsistent rate and completeness of hydrosilylation. The problem was eventually traced to the need for peroxy compounds as promoters in the hydrosilylation. Already, it is known that hydrosilylations can be assisted or inhibited by peroxy compounds. In this case, allyl hydroperoxide and diallyl peroxide can be formed during the synthesis of allyl chloride. However, the concentrations retained in allyl chloride just prior to the hydrosilylation might be inadequate to promote the reaction due to thermal decomposition of the peroxy compounds during transport and storage. This paper will report the studies which led to the recognition of the critical role of peroxy compounds in the hydrosilylation process. The comparative performance of hydroperoxides, peroxides, peroxyesters in promoting the hydrosilylation will also be illustrated.

Title: Cationic emulsion polymerization of octamethylcyclotetrasiloxane (D4) in mixtures with alkoxysilanes : A study by FTIR
Authors: Janusz Kozakiewicz; Michał Kędzierski; Izabela Ofat-Kawalec; Joanna Trzaskowska; Jarosław Przybylski
Affiliation: Łukasiewicz Research Network, Industrial Chemistry Institute, Department of Polymer Technology and Processing, 02-724 Warsaw, Poland

Title: Phase Transfer of Aqueous Gold Nanoparticles to Organic Solvents
Authors: Elijah Cook; Qiaxian Johnson; Gurjeet Longia; Bhanu P.S. Chauhan*
Affiliation: Engineered Nanomaterials Laboratory, Department of Chemistry, William Paterson University of New Jersey, Wayne, NJ 07470, USA

Title: T and Q-rich Linear Silicones from the Piers-Rubinsztajn Reaction
Authors: Michael Yin Wong; Ian Vishnu; Michael A. Brook
Affiliation: McMaster University, Hamilton, Canada

 

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