The use of stable carbene‐CO2 adducts for the polymerization of trimethylene carbonate

The synthesis of poly(trimethylene carbonate) via carbene catalyzed ring‐opening polymerization (ROP) was investigated. The N‐heterocyclic carbenes were protected as CO₂‐adducts to improve their handling (e.g., carbene generation without base). The influence of catalyst structure, different solvents and microwave radiation on conversion, molecular weight and end groups was investigated to gain an insight into the reaction mechanism. Different NHC structures were investigated for their catalytic activity toward the ROP of trimethylene carbonate. The analytic studies were performed by using NMR spectroscopy, SEC and ESI‐IMS mass spectrometry. It was found that the reaction can be performed in acetonitrile, toluene, THF and CH₂Cl₂. Synthesis in CH₂Cl₂ allows the best control over the resulting polymer with regards to polydispersity and molecular weight. Microwave radiation accelerates the reaction at 80 °C. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 820–829     

Synthesis and chiroptical properties of helical polyallenylferrocenes

The allylnickel‐catalyzed living coordination polymerization of allenylferrocene was compounded, two allenylferrocene derivatives (L‐1 and D‐1) bearing chiral amide pendants were designed and synthesized. The living coordination polymerization of L‐1 and D‐1 were afforded by the allynickel(II) complexes, which gave the polymer with controlled molecular weights and narrow molecular weight distribution in high yields. Three polyallenylferrocenes exhibited electrochemical properties. The helical structure was stable in the aprotic solvents observed through the circular dichroism spectra. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2663–2669     

Reactive polymer zwitterions: Sulfonium sulfonates

Sulfonium sulfonate, or sulfothetin, zwitterionic monomers were synthesized by ring‐opening of 1,3‐propanesultone with dialkyl sulfides containing styrenic or methacrylic moieties. Reversible addition‐fragmentation chain‐transfer polymerization of these monomers was achieved in water or trifluoroethanol, and the resulting polymers exhibited higher upper critical solution temperatures than the analogous sulfobetaine polymers. Unlike typical polymer zwitterions, these polymeric sulfothetins possess an inherent reactivity that proved tunable based on their chemical structures. This reactivity makes them amenable to post‐polymerization modification by nucleophilic dealkylation to rapidly access novel substituted polymers and gels. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 83–92     

Reactive ligand influence on initiation in phenylene catalyst‐transfer polymerization

Synthesizing conjugated polymers via catalyst‐transfer polymerization (CTP) has led to unprecedented control over polymer sequence and molecular weight. Yet many challenges remain, including broadening the monomer scope and narrowing the molecular weight dispersities. Broad polymer dispersities can arise from nonliving pathways as well as slow initiation. Previously, slow initiation was observed in Ni‐mediated CTP of phenylene monomers. Although precatalysts with faster initiation rates have been reported, the rates still do not exceed propagation. Herein a second‐ and third‐generation of reactive ligands are described, along with a simple method for measuring initiation rates. A precatalyst with an initiation rate that exceeds propagation is now reported, however, the resulting polymer samples still exhibit broad dispersities, suggesting that slow initiation is not the most significant contributing factor in Ni‐mediated phenylene polymerizations. In addition, initiation rates measured under authentic polymerization conditions revealed that both exogenous triphenylphosphine and an ortho‐trifluoroethoxy substituent on the reactive ligand have a strong influence. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1530–1535     

Organocatalyzed ring‐opening polymerization of cyclic butylene terephthalate oligomers

In this study, various organic compounds, with different activation modes, have been tested as catalysts for the ring‐opening polymerization (ROP) of cyclic butylene terephthalate oligomers (CBT) in bulk at 210 °C, using tert‐butylbenzyl alcohol (tBnOH) as initiator. Among them, 1,3,5‐triazabicyclo[4.4.0]dec‐5‐ene (TBD) appeared to be the most efficient, achieving high monomer conversions in short reaction times (within minutes). Analysis by size‐exclusion chromatography (SEC) of the poly(butylene terephthalate) (PBT) synthesized using this catalyst also showed that the polymerization follows the expected theoretical M _n trend for molecular weights up to 50 kg·mol^?1. Chain‐end fidelity relatively to the alcohol initiator has been confirmed by MALDI‐TOF mass spectroscopy, which showed that all polymer chains possess the tert‐butylbenzyl moiety as chain‐end. Finally, to demonstrate the potential of this system for the synthesis of PBT‐based block copolymers, a monomethyl ether poly(ethylene glycol) (PEG) of 5000 g·mol^?1 has been employed as initiator for the ROP of CBT. A PEO‐b‐PBT block copolymer of 15,000 g·mol^?1 could thus been obtained, as confirmed by the shift of the SEC traces towards higher molecular weights and the same diffusion coefficient determined for ¹H NMR signals of the PEO block and the PBT block. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1611–1619     

BIAN‐Fe(η6‐C6H6): Synthesis,characterization, and l‐lactide polymerization

The α‐diimine‐ligated Fe‐complex, BIAN‐Fe(C₆H₆) , was synthesized and evaluated for the polymerization of l ‐lactide. Characterization of BIAN‐Fe(C₆H₆) reveals that it is redox non‐innocent and suggests that it is an Fe(I) species bearing a radical‐anionic ligand. We will demonstrate that BIAN‐Fe(C₆H₆) is active for the ring‐opening polymerization of l ‐lactide, and that polymer is produced with, or without, the use of an added external initiator. Interestingly, very high molecular weight polymers are produced in the absence of external initiator whereas polymer molecular weights that agree with theoretical calculations are produced in the presence of external initiator. To the best of our knowledge, BIAN‐Fe(C₆H₆) is the first Fe‐based α‐diimine catalyst reported to be active for the polymerization of l ‐lactide. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2824–2830     

Hyperbranched narrow‐bandgap DPP homopolymers synthesized via direct arylation polycondensation

Narrow bandgap and hyperbranched polymers (h‐PTDPP) are synthesized by directly arylation polymerization (DAP) of 2‐bromo‐thiophene‐flanked diketopyrrolopyrrole (Br‐TDPP) as the monomer. Their optical properties as well as chemical structures are studied. The detailed optimization of DAP conditions from catalyst, temperature, solvent, ligand to additive not only leads to high molecular weight h‐PTDPP, but also provides some insight to minimize structural defects in DAP when brominated TDPP is involved as a monomer. The increase in the degree of branching results in lower charge‐carrier mobilities in organic field‐effect transistors involving h‐PTDPP‐3 as the semiconducting channel. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1040–1047     

Radical polymerization in the presence of peroxide and reducing agent monomer for branched polymers

In this article, we report the radical polymerization in the presence of peroxide and commercially available or designed reducing agent monomer (RAM) for the preparation of branched poly(methyl methacrylate)s (PMMAs). The reaction behavior of the RAM was studied by NMR. Triple‐detection SEC (TD‐SEC) analysis was used to confirm the branching structure of the prepared PMMAs and to investigate the influence of peroxide concentration and RAM concentration on molecular weight and branched structure. The obtained branched PMMAs exhibited high molecular weights and relatively narrow polydispersities at high conversion of MMA. Interestingly, a significant increase in molecular weight and degree of branching of the obtained polymers are observed in higher BPO concentration, these results are quite different from that reported in the literature. The unique radical polymerization mechanism in the RAM/BPO redox‐initiated radical polymerization system resulted in branched PMMAs with high molecular weights at relatively high RAM and BPO concentrations. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 833–840     

Radical addition‐coupling polymerization with various nitroso compounds

Four nitroso esters were prepared by oxidation of 4,4‐dimethyl dihydro‐1,3‐oxazine or 4,4‐dimethyl‐2‐oxazoline with two equiv of m‐chloroperoxybenzoic acid. All of them can be applied in radical addition‐coupling polymerization to produce periodic polymer together with introduction of ester group at side chain. Compared with 2‐methyl‐2‐nitrosopropane, 2‐nitroso‐2‐methyl‐4‐acetoxypentane and 2‐methyl‐2‐nitrosopropyl hexanoate present good stability at high temperature up to 70 °C and can result polymer with high molecular weight. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 810–815     

Synthesis of well‐defined hairy polymer microspheres by precipitation polymerization and surface‐initiated atom transfer radical polymerization

A variety of polymer microspheres were successfully synthesized by the surface‐initiated atom transfer radical polymerization (SI‐ATRP) of monomers by using monodisperse polymer microsphere having benzyl halide moiety as a multifunctional polymeric initiator. First, a series of monodisperse polymer microsphere having benzyl chloride with variable monomer ratio (P(St‐DVB‐VBC)) were synthesized by the precipitation polymerization of styrene (St), divinylbenzene (DVB), and 4‐vinylbenzyl chloride (VBC). Next, hairy polymer microspheres were synthesized by the surface‐initiated ATRP of various monomers with P(St‐DVB‐VBC) microsphere as a multifunctional polymeric initiator. The hair length determined by the SEC analysis of free polymer was increased with the increase of M/I. These hairy polymer microspheres were characterized by SEM, FT‐IR, and Cl content measurements. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1296–1304     

Study of the composition and morphology of new modifications of titanium‐magnesium catalysts with improved properties in ethylene polymerization

Data on new modifications of supported titanium‐magnesium catalysts (TMCs) with improved performance in ethylene polymerization are reported. These catalysts possess a high and stable activity, an enhanced ability to regulate molecular weight of the polymer by hydrogen, a controllable particle size at a narrow particle size distribution, and the ability to produce the polymer with an increased bulk density. Various physicochemical methods were used to obtain data on the chemical composition of novel supports and catalysts, their phase composition and crystal structure as well as the pore structure. The results obtained were used to discuss possible correlations between composition and structure of TMCs and their catalytic properties. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2545–2558     

Two‐dimensional polymer synthesis through the topochemical polymerization of alkylenediammonium muconate as a multifunctional monomer

Here we demonstrate a unique two‐dimensional polymer synthesis through topochemical polymerization via polymer crystal engineering, which is useful for controlling and designing the polymerization reactivity as well as the polymer chain and crystal structures. We have succeeded in the synthesis of a sheet polymer through the polymerization of alkylenediammonium (Z,Z)‐muconate as a multifunctional 1,3‐diene monomer in the crystalline state under the irradiation of UV and γ‐rays or upon heating in the dark. The photopolymerization reactivity of several muconates and the structural control of the obtained polymer are described. The stereochemical structure of the polymer and the polymerization mechanism are discussed on the basis of the results of IR and NMR spectroscopy, thermogravimetric measurements, and solid‐state hydrolysis for the transformation into poly(muconic acid). © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3922–3929, 2004     

Reversible addition‐fragmentation chain transfer polymerization of diisopropyl fumarate using various dithiobenzoates as chain transfer agents

Dialkyl fumarates as 1,2‐disubstituted ethylenes exhibit unique features of radical polymerization kinetics due to their significant steric hindrance in propagation and termination processes and provide polymers with a rigid chain structure different from conventional vinyl polymers. In this study, we carried out reversible addition‐fragmentation chain transfer polymerization of diisopropyl fumarate (DiPF) in bulk at 80 °C using various dithiobenzoates with different leaving R groups as chain transfer agents to reveal their performance for control of molecular weight, molecular weight distribution, and chain end functionality of the resulting poly(DiPF) (PDiPF). 2‐(Ethoxycarbonyl)‐2‐propyl dithiobenzoate ( DB1 ) and 2,4,4‐trimethyl‐2‐pentyl dithiobenzoate ( DB2 ) underwent fragmentation and reinitiation at a moderate rate and consequently led to the formation of PDiPF with well‐controlled chain structures. It was confirmed that molecular weight of PDiPF produced by controlled polymerization with DB1 and DB2 agreed with theoretical one and molecular weight distribution was narrow. Dithiobenzoate and R fragments were introduced into the polymer chain ends with high functionality as 95% by the use of DB1 . In contrast, polymerizations using 1‐(ethoxycarbonyl)benzyl dithiobenzoate ( DB3 ), 1‐phenylethyl dithiobenzoate ( DB4 ), and 2‐phenyl‐2‐propyl dithiobenzoate ( DB5 ) resulted in poor control of molecular weight, molecular weight distribution, and chain end structures of PDiPF. Fragmentation and reinitiation rates of the used benzoates as chain transfer agents significantly varied depending on the R structures in an opposite fashion; that is, introduction of bulky and conjugating substituents accelerated fragmentation, but it retarded initiation of DiPF polymerization. It was revealed that balance of fragmentation and reinitiation was important for controlled polymerization of DiPF. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3266–3275     

Schiff base as a novel kind of catalyst for reversible complexation‐mediated radical polymerization of methyl methacrylate

Two kinds of Schiff base, N,N′‐dibenzylidene‐1,2‐diaminoethane (NDBE) and N,N′‐disalicylidene‐1,2‐diaminoethane, have been found as efficient organic catalyst for reversible complexation‐mediated radical polymerization (RCMP) of methyl methacrylate (MMA) for the first time. The polymerization results show obvious features of “living”/controlled radical polymerization. Well‐defined and low‐polydispersity polymers (M_w/M_n = 1.20–1.40) are obtained in RCMP of MMA catalyzed by Schiff base at mild temperature (65–80°C). Moreover, Schiff base also exhibits a particularly high reactivity for RCMP of MMA with in situ formed alkyl iodide initiator. The polymer molecular weight and its polydispersity (M_w/M_n is around 1.20) are well controlled even with high monomer conversion. Notably, when the dosage of azo initiator is same as the dosage of iodine, the polymerization could also be realized in the presence of NDBE. The living feature of synthesized polymer is confirmed through the chain extension experiment. In short, Schiff base is a kind of high‐efficient catalyst for RCMP and reverse RCMP of MMA, which can be one of the most powerful and robust techniques for polymer synthesis. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1653–1663     

Direct arylation polymerization toward ultra‐low bandgap poly(thienoisoindigo‐alt‐diketopyrrolepyrrole) conjugated polymers: The effect of β‐protection on the polymerization and properties of the polymers

Direct arylation polymerization between derivatives of dibromodiketopyrrolopyrrole (DPP) and thienoisoindigo (TIIG) resulted in two π‐conjugated copolymers with average molecular weights up to 24.0 kDa and bandgaps as low as 0.8 eV. The structural analysis of the obtained two polymers revealed well‐defined alternating conjugation backbones without obvious structural defects. The introduction of hexyl‐group in the β‐position of thiophene rings in the DPP units not only reduces the bandgap of conjugated polymer compared to a similar polymer containing bare‐thiophene flanked DPP but also affects polymer morphology in thin films. P‐type charge‐transport characteristics were observed for two polymers in organic field‐effect transistors with comparable hole mobilities. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3205–3213     

Cationic ring‐opening polymerization of trimethylene carbonate to α,ω‐dihydroxy telechelic and star‐shaped polycarbonates catalyzed by reusable o‐benzenedisulfonimide

Cationic ring‐opening polymerization of trimethylene carbonate using o‐benzenedisulfonimide as a reusable catalyst under mild conditions was described. The polymerization proceeded homogeneously without decarboxylation and poly(trimethylene carbonates) (PTMCs) were synthesized with well‐controlled molecular weights and narrow polydispersities (M_w/M_n = 1.12–1.18). The spectra of ¹H‐NMR, SEC, and MALDI–ToF MS clearly demonstrated the incorporation of the initiator residue into the polymer chains and the controlled/living nature of the polymerizations. Furthermore, the catalyst can be easily recovered, and its efficiency was fully retained. In addition, 1,3‐propanediol, 1,1,1‐trimethylolpropane, and pentaerythritol were successfully used as initiators to produce telechelic and star‐shaped polycarbonates which were determined by intrinsic viscosity experiments. The number of arms estimated by the shrinking factors ( ) were 2.0, 2.6, and 3.5, respectively, indicating the successful syntheses of the two‐, three‐, and four‐armed PTMCs. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 729–736     

Optimization of an α‐(Amino acid)‐N‐carboxyanhydride polymerization using the high vacuum technique: Examining the effects of monomer concentration,polymerization kinetics,polymer molecular weight,and monomer purity

l ‐Ornithine‐based poly(peptides) have been widely utilized in the field of drug delivery, however few studies have been conducted examining the details of polymerization. In this article, the effects of monomer concentration, polymerization kinetics, polymer molecular weight and monomer purity were investigated using l ‐carboxybenzyl (Cbz)‐ornithine as a model monomer. The mechanism of polymerization herein follows the normal amine mechanism to produce poly(peptides) having controlled molecular weights, known chain ends and a narrow polydispersity index (PDI). A preferred monomer concentration range was determined, which required minimal polymerization times and allowed for predictable and reproducible molecular weights with narrow PDIs. The impact of monomer purity on the polymerization was established and monomer purification conditions are reported, which produce high‐purity monomer after a single recrystallization. Additionally, the optimized polymerization conditions and monomer purification protocol were combined with a sequential monomer addition technique to produce high molecular weight poly(ornithine) with a narrow PDI and known chain ends. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1385–1391     

Polybenzobisimidazole‐derived two‐dimensional supramolecular polymer

We report a novel crystalline supramolecular polybenzobisimidazole (SP‐PBBI) capable of providing a two‐dimensional polymer (2DSP‐PBBI) by liquid‐phase exfoliation. A regular arrangement of rigid rod‐like polybenzobisimidazole (PBBI) chains is achieved by interchain hydrogen bonding. Titration of 2DSP‐PBBI with cobalt chloride (CoCl₂) using UV‐Vis spectroscopy demonstrates the presence of bidentate NO ligands on the PBBI backbone and NO–Co(II) complexation. Imaging analysis using atomic force microscopy (AFM) reveals the planar surface morphology of exfoliated 2DSP‐PBBI sheets with lateral dimensions of <1 μm and thickness of <30 nm. The size of the polymer crystal growth is tuned by employing condensation/precipitation polymerization under nonisothermal conditions. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1095–1101     

Chemo‐ and stereoselective polymerization of 3‐methylenehepta‐1,6‐Diene and Its thiol‐ene modification

Here we report on the coordination polymerization of a vinyl‐functionalized butadiene monomer, 3‐methylenehepta‐1,6‐diene (MHD) with exclusive conjugated diene chemoselectivity, high 1,2‐regioselectivity and moderate isotacticity (1,2‐selectivity > 99%, mm triad = 93%). Random copolymers of MHD and other conjugated diene (isoprene or myrcene) are also synthesized. The pendent vinyl groups of MHD homo or copolymers could be quantitatively converted into various functional groups via thiol‐ene click reaction. The resulting functionalized polybutadiene‐based material display versatile thermal and surface properties. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1031–1039     

Living radical polymerization of diisopropyl fumarate to obtain block copolymers containing rigid poly(substituted methylene) and flexible polyacrylate segments

Living radical polymerizations of diisopropyl fumarate (DiPF) are carried out to synthesize poly(diisopropyl fumarate) (PDiPF) as a rigid poly(substituted methylene) and its block copolymers combined with a flexible polyacrylate segment. Reversible addition‐fragmentation chain transfer (RAFT) polymerization is suitable to obtain a high‐molecular‐weight PDiPF with well‐controlled molecular weight, molecular weight distribution, and chain‐end structures, while organotellurium‐mediated living radical polymerization (TERP) and reversible chain transfer catalyzed polymerization (RTCP) give PDiPF with controlled chain structures under limited polymerization conditions. In contrast, controlled polymerization for the production of high‐molecular‐weight and well‐defined PDiPF is not achieved by atom transfer radical polymerization (ATRP) and nitroxide‐mediated radical polymerization (NMP). The block copolymers consisting of rigid poly(substituted methylene) and flexible polyacrylate segments are synthesized by the RAFT polymerization. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2136–2147