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12 pages, 2875 KiB

Open AccessArticle

Copolymerization of Phenylselenide-Substituted Maleimide with Styrene and Its Oxidative Elimination Behavior

by Qian Liu, Xinghua Lv, Na Li, Xiangqiang Pan, Jian Zhu and Xiulin Zhu

Polymers 2018, 10(3), 321; https://doi.org/10.3390/polym10030321 - 15 Mar 2018

Cited by 6 | Viewed by 4907

Selenium-containing monomer monophenyl maleimide selenide (MSM) was synthesized and copolymerized with styrene (St) using reversible addition-fragmentation chain transfer (RAFT) polymerization. Copolymers with controlled molecular weight and narrow molecular weight distribution were obtained. The structure of the copolymer was characterized by nuclear magnetic resonance, [...] Read more.

Selenium-containing monomer monophenyl maleimide selenide (MSM) was synthesized and copolymerized with styrene (St) using reversible addition-fragmentation chain transfer (RAFT) polymerization. Copolymers with controlled molecular weight and narrow molecular weight distribution were obtained. The structure of the copolymer was characterized by nuclear magnetic resonance, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrum, Fourier transform infrared spectroscopy (FT-IR) and Ultraviolet–visible spectroscopy (UV-vis) spectroscopy. The copolymer can be oxidized by H₂O₂ to form carbon-carbon double bonds within the main chain due to the unique sensitivity of selenide groups in the presence of oxidants. Such structure changing resulted in an interesting concentration-related photoluminescence emission enhancement. Full article

(This article belongs to the Special Issue Tailored Polymer Synthesis by Advanced Polymerization Techniques)

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16 pages, 2421 KiB

Open AccessArticle

Synthesis of Waterborne Polyurethane by the Telechelic α,ω-Di(hydroxy)poly(n-butyl acrylate)

by Xin Chen, Chi Zhang, Weidong Li, Lei Chen and Wusheng Wang

Polymers 2018, 10(2), 219; https://doi.org/10.3390/polym10020219 - 23 Feb 2018

Cited by 7 | Viewed by 5098

Abstract

A key for the preparation of polyacrylate-based polyurethane is the synthesis of hydroxyl-terminated polyacrylate. To our knowledge, exactly one hydroxyl group of every polyacrylate chain has not been reported. The hydroxyl-terminated poly(butyl acrylate) (PBA) has been successfully synthesized by degenerative iodine transfer polymerization [...] Read more.

A key for the preparation of polyacrylate-based polyurethane is the synthesis of hydroxyl-terminated polyacrylate. To our knowledge, exactly one hydroxyl group of every polyacrylate chain has not been reported. The hydroxyl-terminated poly(butyl acrylate) (PBA) has been successfully synthesized by degenerative iodine transfer polymerization (DITP) of the n-butyl acrylate (n-BA) using 4,4′-azobis(4-cyano-1-pentanol) (ACPO) and diiodoxylene (DIX) as initiator and chain transfer agent, respectively, and subsequently substituted reaction of the iodine-terminated PBA with β-mercaptoethanol in alkaline condition. The latter reaction was highly efficient, and the terminal iodine at the end of polymer chains were almost quantitatively transformed to a hydroxyl group. 2,2′-Azobis(isobutyronitrile) (AIBN) and ACPO were used as initiators in the DITPs of n-BA. The results demonstrated that they had a significant influence on the terminal groups of the formed polymer chains. The structure, molecular weight, and molecular weight distribution of the hydroxyl-terminated PBA have been studied by ¹H, ¹³C NMR, and GPC results. The components of hydroxyl-terminated PBA were determined by MALDI-TOF MS spectra, and their formation is discussed. The broad molecular weight distribution of the PBA and the difference in the polymerization behaviors from typical living radical polymerization are explained based on the results of ¹H NMR and MALDI-TOF MS spectra. The hydroxyl-terminated PBA has been successfully used in the preparation of PBA-based polyurethane dispersions (PUDs). The aqueous PUDs were stable, and based on the DSC results it can be said that the miscibility of hard segments with PBA chains was improved. Full article

(This article belongs to the Special Issue Tailored Polymer Synthesis by Advanced Polymerization Techniques)

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15 pages, 1708 KiB

Open AccessArticle

Advantageous Microwave-Assisted Suzuki Polycondensation for the Synthesis of Aniline-Fluorene Alternate Copolymers as Molecular Model with Solvent Sensing Properties

by Rebeca Vázquez-Guilló, Alberto Falco, M. José Martínez-Tomé, C. Reyes Mateo, María Antonia Herrero, Ester Vázquez and Ricardo Mallavia

Polymers 2018, 10(2), 215; https://doi.org/10.3390/polym10020215 - 22 Feb 2018

Cited by 14 | Viewed by 5744

Abstract

Polymerization via Suzuki coupling under microwave (µW) irradiation has been studied for the synthesis of poly{1,4-(2/3-aminobenzene)-alt-2,7-(9,9-dihexylfluorene)} (PAF), chosen as molecular model. Briefly, µW-assisted procedures accelerated by two orders of magnitude the time required when using classical polymerization processes, and [...] Read more.

Polymerization via Suzuki coupling under microwave (µW) irradiation has been studied for the synthesis of poly{1,4-(2/3-aminobenzene)-alt-2,7-(9,9-dihexylfluorene)} (PAF), chosen as molecular model. Briefly, µW-assisted procedures accelerated by two orders of magnitude the time required when using classical polymerization processes, and the production yield was increased (>95%). In contrast, although the sizes of the polymers that were obtained by non-conventional heating reactions were reproducible and adequate for most applications, with this methodology the molecular weight of final polymers were not increased with respect to conventional heating. Asymmetric orientation of the amine group within the monomer and the assignments of each dyad or regioregularity, whose values ranged from 38% to 95% with this molecule, were analysed using common NMR spectroscopic data. Additionally, the synthesis of a new cationic polyelectrolyte, poly{1,4-(2/3-aminobenzene)-co-alt-2,7-[9,9´-bis(6’’-N,N,N-trimethylammonium-hexyl)fluorene]} dibromide (PAFAm), from poly{1,4-(2/3-aminobenzene)-co-alt-2,7-[9,9´-bis(6’’-bromohexyl)fluorene]} (PAFBr) by using previously optimized conditions for µW-assisted heating procedures was reported. Finally, the characterization of the final products from these batches showed unkown interesting solvatochromic properties of the PAF molecule. The study of the solvatochromism phenomena, which was investigated as a function of the polarity of the solvents, showed a well-defined Lippert correlation, indicating that the emission shift observed in PAF might be due to its interaction with surrounding environment. Proven high sensitivity to changes of its environment makes PAF a promising candidate of sensing applications. Full article

(This article belongs to the Special Issue Tailored Polymer Synthesis by Advanced Polymerization Techniques)

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12 pages, 4391 KiB

Open AccessArticle

Microencapsulated Comb-Like Polymeric Solid-Solid Phase Change Materials via In-Situ Polymerization

by Wei Li, Xiaoye Geng, Rui Huang, Jianping Wang, Ning Wang and Xingxiang Zhang

Polymers 2018, 10(2), 172; https://doi.org/10.3390/polym10020172 - 11 Feb 2018

Cited by 15 | Viewed by 5241

Abstract

To enhance the thermal stability and permeability resistance, a comb-like polymer with crystallizable side chains was fabricated as solid-solid phase change materials (PCMs) inside the cores of microcapsules and nanocapsules prepared via in-situ polymerization. In this study, the effects on the surface morphology [...] Read more.

To enhance the thermal stability and permeability resistance, a comb-like polymer with crystallizable side chains was fabricated as solid-solid phase change materials (PCMs) inside the cores of microcapsules and nanocapsules prepared via in-situ polymerization. In this study, the effects on the surface morphology and microstructure of micro/nanocapsules caused by microencapsulating different types of core materials (i.e., n-hexadecane, ethyl hexadecanoate, hexadecyl acrylate and poly(hexadecyl acrylate)) were systematically studied via field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). The confined crystallization behavior of comb-like polymer PCMs cores was investigated via differential scanning calorimeter (DSC). Comparing with low molecular organic PCMs cores, the thermal stability of PCMs microencapsulated comb-like polymer enhanced significantly, and the permeability resistance improved obviously as well. Based on these resultant analysis, the microencapsulated comb-like polymeric PCMs with excellent thermal stability and permeability resistance showed promising foreground in the field of organic solution spun, melt processing and organic coating. Full article

(This article belongs to the Special Issue Tailored Polymer Synthesis by Advanced Polymerization Techniques)

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1422 KiB

Open AccessFeature PaperArticle

The Effect of Hydrogen Bonding on Radical Semi-Batch Copolymerization of Butyl Acrylate and 2-Hydroxyethyl Acrylate

by Jan E. S. Schier, David Cohen-Sacal, Owen R. Larsen and Robin A. Hutchinson

Polymers 2017, 9(8), 368; https://doi.org/10.3390/polym9080368 - 17 Aug 2017

Cited by 10 | Viewed by 7063

Abstract

The radical copolymerization of butyl acrylate (BA) and 2-hydroxyethyl acrylate (HEA) was investigated under batch and semi-batch operations, with a focus on the influence of hydrogen-bonding on acrylate backbiting. The effect of hydrogen bonding on HEA to BA relative incorporation rates during copolymerization, [...] Read more.

The radical copolymerization of butyl acrylate (BA) and 2-hydroxyethyl acrylate (HEA) was investigated under batch and semi-batch operations, with a focus on the influence of hydrogen-bonding on acrylate backbiting. The effect of hydrogen bonding on HEA to BA relative incorporation rates during copolymerization, previously seen in low-conversion kinetic studies, was also observed under high-conversion semi-batch conditions. However, overall reaction rates (as indicated by free monomer concentrations), polymer molar masses, and branching levels did not vary as copolymer HEA content was increased from 0 to 40 wt % in the semi-batch system. In contrast, introduction of a H-bonding solvent, n-pentanol, led to an observable decrease in branching levels, and branching levels were also reduced in batch (co)polymerizations with HEA. These differences can be attributed to the low levels of unreacted HEA in the starved-feed semi-batch system. Full article

(This article belongs to the Special Issue Tailored Polymer Synthesis by Advanced Polymerization Techniques)

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4571 KiB

Open AccessFeature PaperArticle

“Living” Polymerization of Ethylene and 1-Hexene Using Novel Binuclear Pd–Diimine Catalysts

by Jianding Ye and Zhibin Ye

Polymers 2017, 9(7), 282; https://doi.org/10.3390/polym9070282 - 15 Jul 2017

Cited by 3 | Viewed by 7103

Abstract

We report the synthesis of two novel binuclear Pd–diimine catalysts and their unique behaviors in initiating “living” polymerization of ethylene and 1-hexene. These two binuclear catalysts, [(N^N)Pd(CH₂)₃C(O)O(CH₂)_mO(O)C(CH₂)₃Pd(N^N)](SbF₆)₂ ( [...] Read more.

We report the synthesis of two novel binuclear Pd–diimine catalysts and their unique behaviors in initiating “living” polymerization of ethylene and 1-hexene. These two binuclear catalysts, [(N^N)Pd(CH₂)₃C(O)O(CH₂)_mO(O)C(CH₂)₃Pd(N^N)](SbF₆)₂ (3a: m = 4, 3b: m = 6) (N^N≡ArN=C(Me)–(Me)C=NAr, Ar≡2,6–(iPr)₂C₆H₃), were synthesized by simply reacting [(N^N)Pd(CH₃)(N≡CMe)]SbF₆ (1) with diacrylates, 1,4-butanediol diacrylate and 1,6-hexanediol diacrylate, respectively. Their unique binuclear structure with two identical Pd–diimine acrylate chelates covalently linked together through an ester linkage was confirmed by NMR and single crystal XRD measurements. Ethylene “living” polymerizations were carried out at 5 °C and under ethylene pressure of 400 and 100 psi, respectively, with the binuclear catalysts, along with a mononuclear chelate catalyst, [(N^N)Pd(CH₂)₃C(O)OMe]SbF₆ (2), for comparison. All the polyethylenes produced with both binuclear catalysts show bimodal molecular weight distribution with the number-average molecular weight of the higher molecular weight portion being approximately twice that of the lower molecular weight portion. The results demonstrate the presence of monofunctional chain growing species resembling catalyst 2, in addition to the expected bifunctional species leading to bifunctional “living” polymerization, in the polymerization systems. Both types of chain growing species exhibit “living” characteristics under the studied conditions, leading to the simultaneous linear increase of molecular weight in both portions. However, when applied for the “living” polymerization of 1-hexene, the binuclear catalyst 3a leads to polymers with only monomodal molecular weight distribution, indicating the sole presence of monofunctional chain growing species. These two binuclear catalysts are the first Pd–diimine catalysts capable of initiating bifunctional ethylene “living” polymerization. Full article

(This article belongs to the Special Issue Tailored Polymer Synthesis by Advanced Polymerization Techniques)

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1459 KiB

Open AccessArticle

Synthesis of Aluminum Complexes Bearing 8-Anilide-5,6,7-trihydroquinoline Ligands: Highly Active Catalyst Precursors for Ring-Opening Polymerization of Cyclic Esters

by Shaofeng Liu, Jie Zhang, Weiwei Zuo, Wenjuan Zhang, Wen-Hua Sun, Hongqi Ye and Zhibo Li

Polymers 2017, 9(3), 83; https://doi.org/10.3390/polym9030083 - 01 Mar 2017

Cited by 18 | Viewed by 5748

Abstract

The stoichiometric reactions of 8-(2,6-R¹-4-R²-anilide)-5,6,7-trihydroquinoline (LH) with AlR₃ (R = Me or Et) afforded the aluminum complexes LAlR₂ (Al1–Al5,Al1: R¹ = ⁱPr, R² = H, R [...] Read more.

The stoichiometric reactions of 8-(2,6-R¹-4-R²-anilide)-5,6,7-trihydroquinoline (LH) with AlR₃ (R = Me or Et) afforded the aluminum complexes LAlR₂ (Al1–Al5,Al1: R¹ = ⁱPr, R² = H, R = Me; Al2: R¹ = Me, R² = H, R = Me; Al3: R¹ = H, R² = H, R = Me; Al4: R¹ = Me, R² = Me, R = Me; Al5: R¹ = Me, R² = Me, R = Et) in high yields. All aluminum complexes were characterized by NMR spectroscopy and elemental analysis. The molecular structures of complexes Al4 and Al5 were determined by single-crystal X-ray diffractions and revealed a distorted tetrahedral geometry at aluminum. In the presence of BnOH, complexes Al1–Al5 efficiently initiated the ring-opening homopolymerization of ε-caprolactone (ε-CL) and rac-lactide (rac-LA), respectively, in a living/controlled manner. Full article

(This article belongs to the Special Issue Tailored Polymer Synthesis by Advanced Polymerization Techniques)

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Review

Jump to: Research

556 KiB

Open AccessReview

Polyolefins, a Success Story

by Dominique W. Sauter, Mostafa Taoufik and Christophe Boisson

Polymers 2017, 9(6), 185; https://doi.org/10.3390/polym9060185 - 24 May 2017

Cited by 155 | Viewed by 17748

Abstract

This paper reports the principal discoveries which have played a major role in the polyolefin field and have positioned polyolefins as the most produced plastics. The early development of polyolefins covering the production of LDPE (Low density polyethylene) at ICI (Imperial Chemical Industries) [...] Read more.

This paper reports the principal discoveries which have played a major role in the polyolefin field and have positioned polyolefins as the most produced plastics. The early development of polyolefins covering the production of LDPE (Low density polyethylene) at ICI (Imperial Chemical Industries) and the discovery of Phillips or Ziegler-Natta catalysts are highlighted in the first section. In the second part, the impact of the implementation of molecular catalysts on the research in polyolefins is discussed together with the most recent advances leading to high-performance tailor-made resins. Full article

(This article belongs to the Special Issue Tailored Polymer Synthesis by Advanced Polymerization Techniques)

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