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Journal Cover Journal of Polymer Science Part A: Polymer Chemistry
  [SJR: 1.037]   [H-I: 123]   [140 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0360-6376 - ISSN (Online) 1099-0518
   Published by John Wiley and Sons Homepage  [1592 journals]
  • A water-soluble, AIE-active polyelectrolyte for conventional and
           fluorescence lifetime imaging of mouse neuroblastoma neuro-2A cells
    • Authors: Yinan Wang; Hongming Yao, Jian Zhou, Yuning Hong, Bin Chen, Bolong Zhang, Trevor A. Smith, Wallace W. H. Wong, Zujin Zhao
      Abstract: A new conjugated polyelectrolyte containing tetraphenylethene units in the backbone is synthesized and characterized. This polyelectrolyte is water-soluble and exhibits aggregation-induced emission (AIE) behavior. It is biocompatible and can be directly used in conventional and fluorescence lifetime imaging of mouse neuroblastoma neuro-2A cells, providing useful information of cellular morphology and intracellular aggregation or motion. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018A new conjugated polyelectrolyte containing tetraphenylethene units in the backbone is synthesized and characterized. This polyelectrolyte is water-soluble and exhibits aggregation-induced emission (AIE) behavior. It is biocompatible and can be directly used in conventional and fluorescence lifetime imaging of mouse neuroblastoma neuro-2A cells, providing useful information of cellular morphology and intracellular aggregation or motion.
      PubDate: 2018-01-12T23:05:49.617122-05:
      DOI: 10.1002/pola.28943
       
  • Arm-first synthesis of star polymers with polywedge arms using
           ring-opening metathesis polymerization and bifunctional crosslinkers
    • Authors: Robert Learsch; Garret M. Miyake
      Abstract: This work presents a two-step, one-pot process to make star polymers with polywedge arms. In a one-pot reaction, after the polywedge arms are synthesized, crosslinker species are added to the reaction, rapidly forming star polymers. Crosslinker species with different degrees of conformational freedom were designed and synthesized and their capacity to generate star polymers was evaluated. Mass conversions up to 92% and stars with up to 17 arms were synthesized with the most rigid crosslinker. The effects of arm molecular weight and molar ratio of crosslinker to arm on mass conversion and arms per star were explored further. Finally, the size-molecular weight scaling relationship for polywedges with linear and star architectures was compared, corroborating theoretical results regarding star polymers with arms much larger than their core. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018.Crosslinkers with varying rigidity are synthesized and their ability to form star polymers from rigid, linear, high molecular weight polymer arms is investigated. The conformation of linear homopolymers and star polymers is analyzed and theoretical predictions are confirmed.
      PubDate: 2018-01-08T04:40:49.700364-05:
      DOI: 10.1002/pola.28946
       
  • Bis-substituted thiophene-containing oxime sulfonates photoacid generators
           for cationic polymerization under UV–visible LED irradiation
    • Authors: Xin Sun; Ming Jin, Xingyu Wu, Haiyan Pan, Decheng Wan, Hongting Pu
      Abstract: Three novel types of thiophene-containing oxime sulfonates with a big π-conjugated system were reported as non-ionic photoacid generators. The irradiation of the newly synthesized photoacid generators using near UV–visible light-emitting diodes (LEDs) (365–475 nm) results in the cleavage of two weak NO bonds in single molecules, which lead to the generation of different sulfonic acids in good quantum and chemical yields. The mechanism for the NO bond cleavage for acid generation was supported by the UV–visible spectra and real-time 1H NMR spectra. They are developed as high-performance photoinitiators without any additives for the cationic polymerization of epoxide and vinyl ether upon exposure to near-UV and visible LEDs (365–475 nm) at low concentration. In the field of photopolymerization, especially visible light polymerization, it has great potential for application. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018.Three novel photoacid generators (PAGs) which containing thiophene ring and bis-substituted oxime esters were prepared. The big π-conjugated system prolongs the absorption of PAGs to over 480 nm. PAGs show excellent photoacid generation performance (Φchem = 1.28). These PAGs can efficiently initiate cationic photopolymerization under irradiation of 365–475 nm LEDs. With the characteristics of wide absorption spectra, simple synthesis and so on, these PAGs can find a lot of interest in the application of photocuring and microelectronics.
      PubDate: 2018-01-08T04:40:43.689609-05:
      DOI: 10.1002/pola.28951
       
  • Ring-expansion polymerization of meso-lactide catalyzed by dibutyltin
           derivatives
    • Authors: Hans Rytger Kricheldorf; Steffen M. Weidner
      Abstract: Meso-Lactide was polymerized in bulk at 60, 80, and 100 °C by means of three different types of catalysts: dibutyltin sulfides (2,2-dibutyl-2-stanna-1,3-dithiolane and 2,2′-dibutyl-2-stanna-1,3-dithiane), dibutyltin derivatives of substituted catechols (BuCa, CyCa, and BzCa), and dibutyltin derivatives of 2,2′dihydroxybiphenyl (SnBi) and 2,2′-dihydroxy-1,1′-binaphthyl (SnNa). Only the latter two catalysts were active at 60 °C. The architecture of the resulting polylactides depends very much on the structure of the catalyst and on the temperature. At the lowest temperature (60 °C), SnBi and SnNa mainly yielded even-numbered linear chains, but SnNa also yielded even-numbered cycles at 100 °C and short reaction times. In contrast, BuCa, CyCa, and BzCa mainly yielded odd-numbered cycles, although the same catalysts yielded even-numbered linear chains when benzylalcohol was added. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018.Meso-lactide allows ring-opening and ring-expansion polymerizations at relatively low temperatures (e.g., 60 °C), and thus, enables a deeper insight into the polymerization mechanisms. Dependent on catalyst and reaction conditions, polylactides with three different architectures were obtained: even-numbered linear chains, odd-numbered cycles, and equimolar mixtures of even- and odd-numbered cycles.
      PubDate: 2018-01-08T04:40:36.949792-05:
      DOI: 10.1002/pola.28948
       
  • Intrinsically microporous polyimides containing spirobisindane and
           phenazine units: Synthesis, characterization and gas permeation properties
           
    • Authors: Bharat Shrimant; Yuvraj Dangat, Ulhas K. Kharul, Prakash P. Wadgaonkar
      Abstract: A new diamine containing spirobisindane and phenazine units, namely, 3,3,3′,3′-tetramethyl-2,2′,3,3′-tetrahydro-1,1′-spirobi[cyclopenta[b]phenazine]-7,7′-diamine (TTSBIDA) was synthesized starting from commercially available 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobisindane (TTSBI). TTSBI was oxidized to 3,3,3′,3′-tetramethyl-2,2′,3,3′-tetrahydro-1,1′-spirobi[indene]-5,5′,6,6′-tetraone (TTSBIQ) which was subsequently condensed with 4-nitro-1,2-phenylenediamine to obtain 3,3,3′,3′-tetramethyl-7,7′-dinitro-2,2′,3,3′-tetrahydro-1,1′-spirobi[cyclopenta[b]phenazine] (TTSBIDN). TTSBIDN was converted into TTSBIDA by reduction of the nitro groups using hydrazine hydrate in the presence of Pd/C as the catalyst. A series of new polyimides of intrinsic microporosity (PIM-PIs) were synthesized by polycondensation of TTSBIDA with commercially available aromatic dianhydrides. PIM-PIs exhibited amorphous nature, high thermal stability (T10 > 480 °C) and intrinsic microporosity (BET surface area = 59–289 m2/g). The gas permeation characteristics of films of selected PIM-PIs were evaluated and they exhibited appreciable gas permeability as well as high selectivity. The CO2 and O2 permeability of PIM-PIs were in the range 185.4–39.2 and 30.6–6.2 Barrer, respectively. Notably, polyimide derived from TTSBIDA and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (PIM-PI-6FDA) exhibited high CO2 and O2 permeability of 185.4 and 30.6 Barrer with CO2/CH4 and O2/N2 selectivity of 43.1 and 5.1, respectively. The data of PIM-PI-6FDA for CO2/CH4 and O2/N2 gas pairs were located near Robeson upper bound. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018.A new series of intrinsically microporous polyimides (PIM-PIs) containing spirobisindane and phenazine units were synthesized by polycondensation of 3,3,3′,3′-tetramethyl-2,2′,3,3′-tetrahydro-1,1′-spirobi[cyclopenta[b]phenazine]-7,7′-diamine (TTSBIDA) with aromatic dianhydrides. The gas permeability studies of PIM-PIs demonstrated appreciable permeability and high selectivity.
      PubDate: 2018-01-04T05:11:35.794887-05:
      DOI: 10.1002/pola.28950
       
  • Synthesis and characterization of alkaline-soluble triazine-based
           
    • Authors: Mao-Chun Fu; Yoshitaka Murakami, Mitsuru Ueda, Shinji Ando, Tomoya Higashihara
      Abstract: High-refractive-index (high-n) polymers (HRIPs) with a high optical transparency are highly needed in advanced optoelectronic devices. In this work, we report the synthesis and characterization of a series of high-n, transparent, totally colorless, and high-sulfur-containing poly(phenylene sulfide)s (PPSs) bearing a triazine unit. Two new triazine monomers T1 and T2 with hydroxyl and tert-butyl acetate side chains, respectively, were designed and synthesized to develop PPSs with high-n and high alkaline solubility. These PPSs were prepared by the single-phase polycondensation from T1/T2 and commercial aromatic dithiols such as 4,4′-thiobisbenzenethiol (TBT) and benzene-1,3-dithiol (BDT), achieving very high-n up to 1.7530 at 633 nm, a high optical transparency (T% > 90% @400 nm) and low birefringence (Δn = 0.0014–0.0080), and exhibiting high potential on the application of high-n photoresists. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018.For the future application of high-n photoresists, a series of poly(phenylene sulfide)s (PPSs) was synthesized from triazine derivatives and aromatic dithiols by single-phase polymerization successfully, exhibiting high-n values (1.6448–1.7530), high transparency (T% > 90% @400 nm), low birefringence values (Δn = 0.0014–0.0080), and good alkaline solubility.
      PubDate: 2018-01-04T05:11:06.057522-05:
      DOI: 10.1002/pola.28945
       
  • Influence of sodium dodecyl sulfate on the kinetics and control of
           RAFT/MADIX polymerization of acrylamide
    • Authors: Cécile Barthet; James Wilson, Arnaud Cadix, Mathias Destarac, Christophe Chassenieux, Simon Harrisson
      Abstract: Aqueous radical polymerizations of acrylamide were conducted in the presence of varying concentrations of sodium dodecyl sulfate (SDS) and two xanthate reversible addition-fragmentation chain transfer (RAFT) agents: the small, hydrophobic Rhodixan A1 and the oligomeric, amphiphilic PAm7-XA1. The presence of SDS led to significant retardation of the polymerization, while the apparent activity of both RAFT/MADIX agents decreased as the SDS concentration increased. PAm7-XA1 was affected to a lesser degree than Rhodixan A1, probably due to its lesser tendency to become sequestered in SDS micelles. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018.Partitioning of xanthate reversible addition-fragmentation chain transfer agent between sodium dodecyl sulfate (SDS) micelles and water leads to apparent loss of activity in aqueous polymerizations of acrylamide in the presence of SDS.
      PubDate: 2018-01-04T05:10:51.732462-05:
      DOI: 10.1002/pola.28949
       
  • Cover Image, Volume 56, Issue 4
    • Abstract: An innovative method has been developed to make nanofiller with a surface anchored polymeric chain. The grafting from RAFT polymerization strategy has been utilized to graft poly (N-vinyl imidazole) (PNVI) chains on the silica nanoparticles surface. Control over the polymer chain length and the grafting density on the particles surface enabled the preparation of size-tunable nanoparticles. Proton exchange membrane fabricated from the nanocomposite of polybenzimidazole with these nanofillers displayed significant improvement in various physical properties. The image from Tushar Jana and colleagues on page 365 shows nanoparticles of ∼60 nm size in which ∼750 repeat unit of PNVI chain is anchored. (
      DOI : 10.1002/pola.28917)
      PubDate: 2018-01-03T22:33:40.215864-05:
       
  • Issue Information - Cover Description
    • Pages: 351 - 357
      PubDate: 2018-01-03T22:33:38.329694-05:
      DOI: 10.1002/pola.28795
       
  • Acetalization of poly(vinyl alcohol) by a fatty aldehyde in water medium:
           Model study, kinetics, and structure analysis
    • Authors: Pierre Piluso; Fernande Da-Cruz Boisson, Véronique Bounor-Legaré, Eliane Espuche
      Abstract: Acid catalyzed poly(vinyl alcohol) (PVA) acetalization was investigated in aqueous medium at 80 °C for a PVA concentration of 8 wt %. The reactant, 10-undecenal, was composed of a long alkyl chain with a vinyl end group, and the functionalization reaction was studied in heterogeneous media for low reactant concentrations (from 0.33 to 2.0 mol % compared with PVA hydroxyl groups concentration). First, the reaction was scrutinized with pentane-2,4-diol, as a model compound of PVA. Besides the expected reaction, the oxidation of the aldehyde into 10-undecenoic acid in the presence of water was evidenced. This carboxylic acid appeared unreactive toward esterification of pentane-2,4-diol and PVA in water. Characterization of acetal stereochemical structure formed on the PVA backbone was performed by NMR spectroscopy in accordance to the model approach. A protocol based on 1H NMR analysis was developed to quantify grafted aldehyde, residual aldehyde, and created carboxylic acid through direct sampling of the reaction medium. Conversions and reaction rate constants were calculated for pH ranging from 1 to 3. Finally, the acetalization yield was found to be enhanced at low pH and, in such conditions, the oxidation reaction contribution was limited. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017Poly(vinyl alcohol) (PVA) acid catalyzed acetalization by 10-undecenal was successfully carried out in water medium for grafting degrees below 2 mol %. Kinetics were first studied using pentane-2,4-diol as a model compound of PVA, then using a quantitative NMR titration method developed specifically. Acetalization reaction was completed in 30 min at a pH value of 1 in our conditions. Oxidation of 10-undecenal occurred as a side reaction in water medium and decreased at lower pH values.
      PubDate: 2017-12-28T08:24:17.871031-05:
      DOI: 10.1002/pola.28942
       
  • Bonding and in-channel microfluidic functionalization using the huisgen
           cyclization
    • Authors: Talena Rambarran; Ferdinand Gonzaga, Ayodele Fatona, Michael Coulson, Sokunthearath Saem, Jose Moran-Mirabal, Michael A. Brook
      Abstract: The bonding of layers of silicone elastomers during the manufacturing of microfluidic devices is often accomplished using plasma oxidation. The process can be costly, may require a clean room and materials that ensure the flatness of the bonding layers and, as a consequence of hydrophobic recovery, can lead to high variability in the degree of adhesion. As importantly, the process precludes incorporation of chemical functionalities that work as anchors to immobilize biomolecules within the microfluidic channel. We hypothesized that it would be possible to fabricate microfluidic channels using the Huisgen 1,3-dipolar cycloaddition of azides to alkynes to crosslink silicones and form PDMS elastomers and, in a subsequent step, bond one PDMS layer to another simply by heating, with the added advantage of producing microfluidic channels with embedded chemical functionalities. After thermal bonding, the microfluidic devices underwent cohesive failure (rupture of the elastomer layer) at ∼145 kPa during pressure tests, but did not exhibit adhesive failure (delamination), showing that the azide–alkyne reaction provides a strong bond between elastomer layers. Furthermore, the internal microfluidic channel surfaces retained alkyne and azide functionality during the process, as shown by the grafting of one or more fluorescent dyes, through Huisgen cyclization. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017The metal-free Huisgen cyclization between azides and alkynes permits both assembly and (bio)functionalization of microfluidic devices. The Huisgen cyclization reaction can be used to cure silicone rubbers simply by heating. Azide- and alkyne-rich elastomers, respectively, formed strong adhesive bonds simply by catalyst-free thermal welding. The assembly of microfluidic devices using this approach avoids many of the problems associated with silicones and, additionally, provides azide, and alkyne functionality on the inside surfaces of the microchannel that may be used to tether (bio)molecules.
      PubDate: 2017-12-28T08:19:22.054203-05:
      DOI: 10.1002/pola.28930
       
  • Synthesis and characterization of highly conjugated side-group-substituted
           benzo[1,2-b:4,5-b′]dithiophene-based copolymer for use in organic solar
           cells
    • Authors: Jiyoung Kim; Jong Baek Park, Woo-Hyung Lee, Jiwon Moon, Joonghan Kim, Do-Hoon Hwang, In-Nam Kang
      Abstract: A new donor–acceptor (D–A) conjugated copolymer based on benzo[1,2-b:4,5-b′]dithiophene (BDT) and thieno[3,4-c]pyrrole-4,6-dione (TPD) was synthesized via a Stille cross-coupling reaction. A highly conjugated thiophene-based side group, tris(thienylenevinylene) (TTV), was incorporated into each BDT unit to generate the two-dimensional D–A copolymer (PBDT-TTV). An alkoxy-substituted BDT-based TPD copolymer (PBDT-OR) was synthesized using the same polymerization method for comparison. PBDT-TTV thin films produced two distinct absorption peaks. The shorter wavelength absorption (458 nm) was attributed to the BDT units containing the TTV group, and the longer wavelength band (567–616 nm) was attributed to intramolecular charge transfer between the BDT donor and the TPD acceptor. The highest occupied molecular orbital energy levels of PBDT-OR and PBDT-TTV were calculated to be −5.53 and −5.61 eV, respectively. PBDT-TTV thin films harvested a broad solar spectrum covering the range 300–700 nm. A comparison with the PBDT-OR films revealed stronger interchain π–π interactions in the PBDT-TTV films and, thus, a higher hole mobility. A polymer solar cell device prepared using PBDT-TTV as the active layer was found to exhibit a higher power conversion efficiency than a device prepared using PBDT-OR under AM 1.5 G (100 mW/cm2) conditions. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017Synthesis and characterization of two-dimensional BDT-based donor–acceptor polymer (PBDT-TTV) was described. Alkoxy-substituted BDT-based polymer was synthesized to compare the optoelectronic and photovoltaic properties. The PBDT-TTV film can harvest a broad solar spectrum covering the range 300–700 nm and thus improves solar cell performances.
      PubDate: 2017-12-28T08:16:01.299814-05:
      DOI: 10.1002/pola.28941
       
  • Synthesis and properties of ultralow dielectric porous polyimide films
           containing adamantane
    • Authors: Pengxia Lv; Zhixin Dong, Xuemin Dai, Hanfu Wang, Xuepeng Qiu
      Abstract: A series of novel ultralow dielectric porous polyimide (PI) films containing adamantane groups was prepared via the thermolysis of polyethylene glycol (PEG) oligomers mixed into PI matrix. Scanning electron microscopy results indicated that the porous PI films showed closed pores with an average diameter of 120 ± 10 nm. Good thermal properties with 5% weight loss temperature of 499 °C in air atmosphere and glass transition temperature in excess of 310 °C were shown for porous PI films. Notably, the ultralow dielectric constant of porous PI films with 1.85 at 1 MHz was obtained and revealed via broadband dielectric spectroscopy. The effects of the chemical structure of the PI matrix and PEG content on the decomposition behavior of PEG and the performance of porous films were investigated. Wide-angle X-ray diffraction results indicated that the PI matrix with large d-spacing generated weaker interactions between the PEG and PI backbone than those of PI matrix with small d-spacing. As a result, the PEG for the PI matrix with large d-spacing was completely decomposed. As indicated by the broadband dielectric spectroscopy results, lower dielectric porous PI films were prepared when the PEG contents in the PI matrix increased from 0 to 20 wt %. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017Novel ultralow dielectric porous polyimide (PI) films containing adamantane were successfully prepared via the thermolysis of thermal labile component (PEG) mixed into PI matrix. Moreover, the effects of the chemical structure of the PI matrix and PEG content on the decomposition behavior of PEG and the performance of porous films were investigated.
      PubDate: 2017-12-26T23:28:31.973994-05:
      DOI: 10.1002/pola.28928
       
  • Synthesis and characterization of poly(ethylene
           oxide)/polylactide/polylysine tri-arm star copolymers for gene delivery
    • Authors: Tianyuan Wu; Yu Cai, Xia Zhao, Chai K. Ngai, Benjamin Chu, Benjamin Hsiao, Michael Hadjiargyrou, Robert B. Grubbs
      Abstract: Amphiphilic cationic poly(ethylene oxide)-S(polylysine)-poly(d,l-lactide) (mPEO-S(CKn)-PLA) tri-arm star copolymers were synthesized by a combination of ring opening polymerization (ROP) and a thiol–disulfide exchange. The mPEO-S(CKn)-PLA copolymers were found to be non-cytotoxic and could effectively condense GFP plasmid DNA into nanometer-sized complexes, as characterized by dynamic light scattering (DLS), suitable for endocytotic cellular uptake. In vitro DNA transfection studies showed that the amphiphilic structure is capable of DNA transfection and GFP expression. Addition of chloroquine into the medium further enhanced the DNA transfection efficiency. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017Star copolymers with hydrophilic, hydrophobic, and cationic arms can be synthesized by a combination of ring-opening polymerization and coupling steps. The star copolymers have low toxicity to cells and model studies with GFP and HeLa cells show they can be used to deliver DNA to cell nuclei.
      PubDate: 2017-12-26T23:26:44.240425-05:
      DOI: 10.1002/pola.28938
       
  • Stimuli-responsive amphiphilic PDMAEMA-b-PLMA copolymers and their
           cationic and zwitterionic analogs
    • Authors: Varvara Chrysostomou; Stergios Pispas
      Abstract: In this work, the synthesis and characterization of novel amphiphilic diblock copolymers of poly(2-dimethylamino ethyl methacrylate)-b-poly(lauryl methacrylate), PDMAEMA-b-PLMA, using the reversible addition-fragmentation chain transfer (RAFT) polymerization technique, are reported. The diblocks were successfully derivatized to cationic and zwitterionic block polyelectrolytes by quaternization and sulfobetainization of the PDMAEMA block, respectively. Furthermore, their molecular and physicochemical characterization was performed by using characterization techniques such as NMR and FTIR, size exclusion chromatography, light scattering techniques, and transmission electron microscopy. The structure of the diblock micelles, their behavior, and properties in aqueous solution were investigated under the effect of pH, temperature, and ionic strength, as PDMAEMA and its derivatives are stimuli-responsive polymers and exhibit responses to variations of at least one of these physicochemical parameters. These new families of stimuli-responsive block copolymers respond to changes of their environment giving interesting nanostructures, behavioral motifs, and properties, rendering them useful as nanocarriers for drug delivery and gene therapy. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017.Novel amphiphilic block copolymers of PDMAEMA-b-PLMA were synthesized using RAFT polymerization technique and were derivatized by quaternization and sulfobetainization of the PDMAEMA block into polyelectrolyte copolymers. The self-assembly behavior and properties of the copolymers in aqueous media are investigated under the effects of pH, temperature, and ionic strength.
      PubDate: 2017-12-22T21:37:27.615489-05:
      DOI: 10.1002/pola.28931
       
  • Crosslinked anion exchange membranes with connected cations
    • Authors: Wenxu Zhang; Ye Liu, Xiaohui Liu, James L. Horan, Ying Jin, Xiaoming Ren, S. Piril Ertem, Soenke Seifert, Matthew W. Liberatore, Andrew M. Herring, Edward Bryan Coughlin
      Abstract: The selective transport of ions has crucial importance in biological systems as well as modern-day energy devices, such as batteries and fuel cells, and water purification membranes. Control over ion movement can be exerted by ligation, ion channel dimensions, solvation, and electrostatic interactions. Polyelectrolyte hydrogels can provide aligned pathways for counter ion transport but lack mechanical integrity, while polyelectrolyte membranes typically suffer from the absence of an ion transport channel network. To develop polymer membranes for improved ion transport, we present the design of a novel material that combines the advantages of aligned pathways found in polyelectrolyte hydrogel and mechanical robustness in conventional membranes. The ionic species were organized via controlled copolymerization of a quaternizable monomer. Additionally, dimensional stability was then incorporated through a cast/crosslinking method to lock in the network of connected cationic groups. This strategy resulted in dramatically enhanced ion transport, as characterized by ionic conductivities (>80 mS/cm for Cl–, and ∼200 mS/cm for OH–). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 00, 000–000Ion transport materials find various applications, such as water purification and fuel cells. Introducing crosslinking can improve the mechanical integrity and control water sorption of the cells; however, this sacrifices conductivity. Here, a novel material is developed with a one-step cast/crosslinking method to incorporate the feature of chemically linked cations. This strategy significantly enhances the ionic conductivities.
      PubDate: 2017-12-22T21:36:43.538923-05:
      DOI: 10.1002/pola.28935
       
  • Ring opening metathesis polymerization (ROMP) and thio-bromo “click”
           chemistry approach toward the preparation of flame-retardant polymers
    • Authors: Jonathan Grubb; Federico Carosio, Mallikharjun Vasireddy, Salvador Moncho, Edward N. Brothers, Christopher E. Hobbs
      Abstract: This contribution describes our recent efforts geared toward the use of a general, thio-bromo “click” reaction as a post-polymerization method for the preparation of flame-resistant polymeric materials. α-bromo ester-containing polymers could easily be prepared using ROMP and a subsequent, facile thio-bromo click reaction was used for the installation of a phosphorus-moiety that was shown to impart flame-resistant/self-extinguishing properties to these polymers. The extent of their flame resistance was then ascertained by treating paper (previously coated with polymer) to standard burn tests as well as measuring the limiting oxygen index (LOI). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017This manuscript describes the preparation of new flame-retardant, phosphorus-containing polymers (PCPs) prepared using a general, thio-bromo “click” reaction as a post-polymerization functionalization route for modifying materials synthesized using ring opening metathesis polymerization (ROMP).
      PubDate: 2017-12-22T21:36:30.757207-05:
      DOI: 10.1002/pola.28939
       
  • Gel forming waterborne dispersion polymerization of sodium p-styrene
           sulfonate with glycidyl methacrylate
    • Authors: Roshan F. Dsouza; Anbanandam Parthiban
      Abstract: Water soluble monomer like sodium p-styrene sulfonate (SSS) is copolymerized with hydrophobic and reactive monomer glycidyl methacrylate (GMA). The polymerization proceeds as dispersion and forms gels. The gel forming nature prevails even with other hydrophobic and hydrophilic monomers to form ternary polymeric systems. The swelling is dependent on polymer composition as well as the treatment history of polymers. SSS also induces ring opening of GMA to form 1,2-diols as confirmed independently by various model reactions. The ability of hydrogels to absorb various dyes indicates that owing to the anionic nature, hydrogels absorb cationic dyes nearly quantitatively. Because of their strong affinity to cationic species these hydrogel forming polymers are potentially useful in water purification applications as well as purification of proteins. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017.Dispersion polymerization of sodium p-styrene sulfonate (SSS) with glycidyl methacrylate at 3:2 ratio yielded hydrogels. Ternary polymers formed by using hydrophobic monomers like MMA and hydrophilic monomers like sodium acrylate also yielded hydrogels with varying degree of swelling. Model experiments revealed that SSS-induced ring opening of GMA. Thus, ring opening occurred to form 1,2-diols simultaneously with copolymerization. The formation of hydrogel was mainly due to the presence of physical network formed through H-bonding interactions. Swelling in water was strongly dependent on the treatment of polymers.
      PubDate: 2017-12-22T01:47:08.703664-05:
      DOI: 10.1002/pola.28936
       
  • Controlled random copolymerization of rac-lactide and ɛ-caprolactone by
           well-designed phenoxyimine Al complexes
    • Authors: Tong Shi; Wenlong Luo, Shaofeng Liu, Zhibo Li
      Abstract: The random copolymers poly(LA-ran-CL) have improved properties of degradability, mechanical strength, elasticity, and permeability over the PLA and PCL homopolymers. However, the synthesis of such copolymers is still a great challenge in polymer chemistry. In this contribution, we develop a simple but well-designed phenoxyimine Al complex (4) with bulky Ph2CH groups, which achieves controlled random copolymerization of rac-LA and ɛ-CL in a living manner (Ð = 1.06–1.09). The reactivity ratios of rac-LA and ɛ-CL (rLA and rCL) are 1.09 and 1.05 and the average sequence lengths of the lactidyl unit (LLA) and the caproyl unit (LCL) are in the range of 1.9–2.0 at different stages of conversion. In marked contrast, Al complexes (1–3) having less bulky substituents on the ligands only produce gradient copolymers. Furthermore, this strategy of catalyst design would be readily extended to other catalytic systems including β-ketiminato Al complex (5). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017.Well-designed phenoxyimine Al complex with bulky steric Ph2CH groups could achieve strict random copolymerization of rac-LA and ɛ-CL. The reactivity ratios of rac-LA and ɛ-CL (rLA and rCL) are 1.09 and 1.05 as measured by NLLS method. The average sequence lengths of the lactidyl unit (LLA) and the caproyl unit (LCL) of resulted copolymers are in the range of 1.9–2.0 as indicated by 13C NMR spectroscopy.
      PubDate: 2017-12-22T01:45:45.535644-05:
      DOI: 10.1002/pola.28932
       
  • Cationic half-sandwich scandium complex for the synthesis of
           polyisobutylene with high molecular weight under mild conditions
    • Authors: Ke Yang; Tingting Li, Rui Tan, Kaihua Shen, Yang Li
      Abstract: The half-sandwich rare earth metal complex, [(C5Me4SiMe3)Sc(CH2SiMe3)2THF]/[Ph3C][B(C6F5)4], is an effective cationic initiator system to afford high-molecular-weight polyisobutylene and isobutylene–isoprene copolymer at relatively mild conditions.
      PubDate: 2017-12-22T01:45:39.481722-05:
      DOI: 10.1002/pola.28916
       
  • Substituent effect on supercapacitive performances of conducting
           polymer-based redox electrodes: Poly(3′,4′-bis(alkyloxy)
           2,2′:5′,2″-terthiophene) derivatives
    • Authors: Deniz Yiğit; Melis Aykan, Mustafa Güllü
      Abstract: This work reports the synthesis of novel poly(3′,4′-bis(alkyloxy)terthiophene) derivatives (PTTOBu, PTTOHex, and PTTOOct) and their supercapacitor applications as redox-active electrodes. The terthiophene-based conducting polymers have been derivatized with different alkyl pendant groups (butyl-, hexyl-, and octyl-) to explore the effect of alkyl chain length on the surface morphologies and pseudocapacitive properties. The electrochemical performance tests have revealed that the length of alkyl substituent created a remarkable impact over the surface morphologies and charge storage properties of polymer electrodes. PTTOBu, PTTOHex, and PTTOOct-based electrodes have reached up to specific capacitances of 94.3, 227.3, and 443 F g−1 at 2.5 mA cm−2 constant current density, respectively, in a three-electrode configuration. Besides, these redox-active electrodes have delivered satisfactory energy densities of 13.5, 29.3, and 60.7 W h kg−1 and power densities of 0.98, 1, and 1.1 kW kg−1 with good capacitance retentions after 10,000 charge/discharge cycles in symmetric solid-state micro-supercapacitor devices. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017The novel poly(terthiophene)-based redox-electrodes were prepared for the first time. Redox elecrode materials delivered specific capacitances of 94.3, 227.3, and 443 F g−1. The micro-supercapacitor devices reached energy densities of 13.5, 29, and 60.7 W h kg−1. The micro-supercapacitor devices also exhibited good capacitance retentions.
      PubDate: 2017-12-19T20:21:06.796399-05:
      DOI: 10.1002/pola.28927
       
  • RAFT synthesis of polystyrene-block-poly(polyethylene glycol monomethyl
           ether acrylate) for zinc phthalocyanine-loaded polymeric micelles as
           photodynamic therapy photosensitizers
    • Authors: Makoto Obata; Shuto Tanaka, Hiroshi Mizukoshi, Eika Ishihara, Masaki Takahashi, Shiho Hirohara
      Abstract: A series of polystyrene-block-poly(polyethylene glycol monomethyl ether acrylate) (PStm-b-PPEGAn) polymers were systematically synthesized as carriers for zinc phthalocyanine (ZnPc) for photodynamic therapy via reversible addition and fragmentation chain transfer polymerization. The degree of polymerization of the styrene (m) and PEGA units (n) of the resulting block copolymers were characterized to be n = 174, 40, and 18 for m = 52; and n = 200, 84, and 31 for m = 30. All the block copolymers formed micelles in water. The critical micelle concentration (CMC) of the PStm-b-PPEGAn was determined by fluorometry using pyrene as a hydrophobic probe. The CMC value increased from 4.5 to 20 mg·L−1 with an increase in the mole fraction of PEGA units. The median diameters of the micelles increased from 19 to 31 nm for PSt52-b-PPEGAn and from 15 to 23 nm for PSt30-b-PPEGAn with increasing n value. ZnPc-loaded micelles were prepared by dialysis of the block copolymer in the presence of ZnPc followed by removal of large aggregates by filtration. The encapsulation efficiency was dramatically changed in the range of 0–68%. The light-dose-dependent cytotoxicity of the ZnPc-loaded PSt30-b-PPEGA200 was clearly established in HeLa cell lines; while no cytotoxicity was confirmed under the dark. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017A series of polystyrene-block-poly(polyethylene glycol monomethyl ether acrylate) (PStm-b-PPEGAn) were systematically synthesized via RAFT polymerization for a carrier of ZnPc used in photodynamic therapy. Encapsulation efficiency of ZnPc in the block copolymer micelles was dramatically changed with changing the degree of polymerization of PPEGA segments. The light-dose-dependent photocytotoxicity of ZnPc-loaded block copolymer micelles was established in HeLa cell lines.
      PubDate: 2017-12-19T20:20:51.645324-05:
      DOI: 10.1002/pola.28929
       
  • O-Fmoc-protected 3-hydroxy-2-butenoate derivatives as thermal latent
           curing agents for thermosetting epoxy resins
    • Authors: Kenji Kudo; Masahiro Furutani, Koji Arimitsu
      Abstract: To improve the stability of epoxy resin-imidazole compositions, the authors have developed O-Fmoc-protected 3-hydroxy-2-butenoate derivatives to generate an imidazole via thermal deprotection and subsequent β-elimination reactions. The latent curing agents have good compatibility toward epoxy resins. It was found that high reactivity of the agents with epoxy resins is accomplished after their thermal decomposition reaction and that the composition shows long-term storage stability at room temperature.
      PubDate: 2017-12-19T20:20:29.73186-05:0
      DOI: 10.1002/pola.28926
       
  • Nonvolatile resistive memory devices based on ferrocene-terminated
           hyperbranched polyimide derived from different dianhydrides
    • Authors: Haiwei Tan; Huaxuan Yu, Ying Song, Shiyang Zhu, Bo Zhang, Hongyan Yao, Shaowei Guan
      Abstract: A series of ferrocene-terminated hyperbranched polyimides (HBPI-Fcs) were synthesized from a tetra-amine, bis(4-(3,5-bis (4-amino-2-(trifluoromethyl) phenoxy) phenoxy) phenyl) methanon, and various dianhydrides, followed by termination with (4-amino) phenyl ferrocene. All the HBPI-Fcs possessed good organo-solubility and high thermal stability. The devices based on HBPI-Fcs exhibited bipolar and nonvolatile write-once-read-many times (WORM) memory performance with various threshold voltages and the same ON/OFF current ratio of 104. Moreover, the devices possessed excellent bistability under a constant bias of −1.00 V during a test period of 104 s. The different charge trapping ability of the electron-accepting moiety endowed the devices with different the threshold voltages. Mechanism analysis showed that the switching behavior was dominated by the charge trapping effect and the charge transfer was well fitted with the space-current-limited-current (SCLC) and ohmic model. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017A series of ferrocene-terminated hyperbranched polyimides (HBPI-Fcs) were synthesized from a tetra-amine and various dianhydrides and followed by terminated with (4-amino) phenyl ferrocene. All the memory devices based on HBPI-Fc exhibited bipolar WORM behavior and the threshold voltage can be tuned by the chemical structure of the dianhydride.
      PubDate: 2017-12-11T00:31:22.967041-05:
      DOI: 10.1002/pola.28920
       
  • Careful investigation of the hydrosilylation of olefins at poly(ethylene
           glycol) chain ends and development of a new silyl hydride to avoid side
           reactions
    • Authors: Hyunseo Shin; Bongjin Moon
      Abstract: Hydrosilylation of olefin groups at poly(ethylene glycol) chain ends catalyzed by Karstedt catalyst often results in undesired side reactions such as olefin isomerization, hydrogenation, and dehydrosilylation. Since unwanted polymers obtained by side reactions deteriorate the quality of end-functional polymers, maximizing the hydrosilylation efficiency at polymer chain ends becomes crucial. After careful investigation of the factors that govern side reactions under various conditions, it was related that the short lifetime of the unstable Pt catalyst intermediate led to the formation of more side products under the inherently dilute conditions for polymers. Based on these results, two new chelating hydrosilylation reagents, tris(2-methoxyethoxy)silane (5) and 2,10-dimethyl-3,6,9-trioxa-2,10-disilaundecane (6), have been developed. It was demonstrated that the hydrosilylation efficiency at polymer chain ends was significantly increased by employing the internally coordinating hydrosilane 5. In addition, employment of the internally coordinating disilane species 6 in an addition polymerization with 1,5-hexadiene by hydrosilylation reaction yielded a polymer with high molecular weight (Mn = 9300 g/mol), which was significantly higher than that (Mn = 2600 g/mol) of the corresponding polymer obtained with non-chelating dihydrosilane, 1,1,3,3-tetramethyldisiloxane. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017Based on the careful analysis of hydrosilylation reactions of allyl-functionalized PEG with Karstedt catalyst, this research has elucidated that the inherently low concentration of the olefin group—due to its presence at polymer chain ends—decreases the hydrosilylation reaction relative to undesired side reactions such as olefin isomerization. To avoid this problem, weakly coordinating hydrosilanes were devised and employed to enhance the hydrosilylation selectivity over the undesired isomerization side reaction.
      PubDate: 2017-12-11T00:31:00.227351-05:
      DOI: 10.1002/pola.28924
       
  • Poly(N-vinyl imidazole) grafted silica nanofillers: Synthesis by RAFT
           polymerization and nanocomposites with polybenzimidazole
    • Authors: Satyanarayana Raju Kutcherlapati; Rambabu Koyilapu, Tushar Jana
      Abstract: In this report, we synthesized poly(N-vinyl imidazole) (PNVI) grafted silica nanoparticles (SiNP) by using RAFT polymerization through grafting-from approach to demonstrate that the self-assembled structure of SiNP is the key diving force in improving physical properties of SiNP based nanocomposites. In a multistep synthetic process, well-defined PNVI chains with tunable molecular weights and surface chain densities were grown from the RAFT agent anchored SiNP surface using N-vinyl imidazole (NVI) as a monomer. Spectroscopic and thermal analysis confirmed surface grafting of PNVI on SiNP surface and the amount of grafted PNVI chins were also quantified. The mean diameter of the PNVI grafted SiNP (PNVI-g-SiNP) particles altered between 50 and 100 nm with the variation of PNVI chain lengths. The present approach is metal-catalyst free, straight forward, and provides PNVI functionalized SiNP in a simple manner in comparison to the reported methods. Further, these PNVI-g-SiNP particles were used as a nanofiller to prepare nanocomposites with Poly(4,4′-diphenylether-5,5′-bibenzimidazole) (OPBI). These nanocomposites displayed significantly higher mechanical, proton conductivity and less acid leaching properties than the pristine OPBI. The anisotropic self-assembled ordered structure formation of nanofillers in the nanocomposites believed to be the driving force for the enhanced physical properties. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017A new and simple strategy to make nanofiller with surface anchored polymeric chain for the use in developing efficient proton exchange membrane.
      PubDate: 2017-12-08T05:05:59.22792-05:0
      DOI: 10.1002/pola.28917
       
  • Preparation of Cross-Linked Micelles from Glycidyl Methacrylate Based
           Block Copolymers and Their Usages as Nanoreactors in the Preparation of
           Gold Nanoparticles
    • Authors: Gökhan Kocak; Gökhan Solmaz, Zeynep Dikmen, Vural Bütün
      Abstract: This study reports the synthesis of poly(ethylene glycol)methyl ether-block-poly(glycidyl methacrylate) (MPEG-b-PGMA) diblock, and poly(ethylene glycol)methyl ether-block-poly(glycidyl methacrylate)-block-poly(methyl methacrylate) (MPEG-b-PGMA-b-PMMA) triblock copolymers via atom transfer radical polymerization and their self-assembly behaviors in aqueous media by using acetone as cosolvent. These block copolymers formed near monodisperse core–shell micelles having cross-linkable cores. Two types of cross-linked micelles, namely spherical MPEG-b-PGMA core cross-linked (CCL) micelles and MPEG-b-PGMA-b-PMMA interlayer cross-linked (ILCL) micelles, were also successfully prepared from these block copolymers by using various bifunctional cross-linkers such as hexamethylenediamine (HMDA), ethylenediamine (EDA), and 2-aminoethanethiol (AET). Cross-linking was successfully carried out via ring-opening reactions of epoxy residues of hydrophobic-cores with primary amine or thiol groups of bifunctional cross-linkers. Finally, these cross-linked micelles were successfully used as nanoreactors in the synthesis of gold nanoparticles (AuNPs) in aqueous media. Both CCL and ILCL micelles were found to be good stabilizers for AuNPs in aqueous media. Both CCL- and ILCL-stabilized AuNP dispersions were stable for a long time without any size changes and flocculation at room temperature. These cross-linked stabilized AuNPs exhibited good catalytic activities in the reduction of p-nitrophenol. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017.Hydrophilic–hydrophobic block copolymers, namely poly(ethylene glycol)methyl ether-block-poly(glycidyl methacrylate) and poly(ethylene glycol)methyl ether-block-poly(glycidyl methacrylate)-block-poly(methyl methacrylate), have been synthesized to form core–shell micelles with cross-linkable cores in aqueous media. Their cross-linking processes have been succeeded via ring-opening reactions of epoxy residues with bifunctional cross-linkers such as diamines. Resulted cross-linked micelles (CLMs) have been successfully used as nanoreactors for gold nanoparticle production. These CLM stabilized gold nanoparticles have exhibited good catalytic activity in the reduction of p-nitrophenol to p-aminophenol.
      PubDate: 2017-12-07T07:22:13.230986-05:
      DOI: 10.1002/pola.28922
       
  • Moisture-mediated intrinsic self-healing of modified polyurethane urea
           polymers
    • Authors: Anastassija Wittmer; Andreas Brinkmann, Volkmar Stenzel, Andreas Hartwig, Katharina Koschek
      Abstract: Functional materials having the ability to self-heal cracks or scratches after damage are of great interest for a huge scope of applications. Herein, we report a self-healing polyurethane urea-based material with implemented 1-(2-aminoethyl) imidazolidone (UDETA) as a chain terminating molecule and for hydrogen bond network formation. Both, UDETA content and moisture affected the self-healing process. The reversible change in the materials properties was proven by detailed analyses of hardness and thermomechanical behavior in dependence of the water uptake of the samples. FT-IR analysis revealed that water is able to act as a plasticizer interrupting hydrogen bonding interactions within the polymer network and thus, influencing glass transition temperature and hardness of the samples. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017.Polyurethane/urea-based polymers provide a huge number of hydrogen bonds and show moisture-mediated self-healing after damage at high relative humidity. Water molecules are able to interact through hydrogen bond interactions with the polymeric chains interrupting the chain–chain interactions for more freedom of movement for the self-healing process. IR-spectroscopy was used to simultaneously observe the destruction of chain–chain hydrogen bond interactions and the formation of strong interactions between heavy water molecules and the polymeric chains.
      PubDate: 2017-12-07T07:21:43.796013-05:
      DOI: 10.1002/pola.28925
       
  • Synthesis of helical polyisocyanides bearing aza-crown ether groups as
           pendant
    • Authors: Naoya Kanbayashi; Shingo Tokuhara, Tomoko Sekine, Yuki Kataoka, Taka-aki Okamura, Kiyotaka Onitsuka
      Abstract: We, herein, present a novel synthesis of responsive helical poly(aryl isocyanide)s bearing aza-crown ethers as pendant groups. Chiral aryl isocyanide monomers bearing an aza-crown ether as a pendant were designed and synthesized, piror to polymerization using a Pd-Pt µ-ethynediyl complex as an initiator to give the corresponding polymers in good yield. The resulting polyisocyanides adopted a stable helical structure in solution, as confirmed by circular dichroism spectroscopic analysis. In addition, the polymers were soluble in various solvents. Furthemore, the addition of suitable alkali metal ions to the crown ether of the sidechain on the helical polyisocyanide to form host-gest complexes resulted in deformation of the helix due to electrostatic repulsion, and these phenomena depended on the size of metal cations. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017.A novel synthesis of responsive helical poly(aryl isocyanide)s bearing aza-crown ethers as pendant groups are presented. Chiral aryl isocyanide monomers bearing an aza-crown ether as a pendant were designed and synthesized, and the resulting polyisocyanides adopted a stable helical structure in solution. The addition of suitable alkali metal ions to the crown ether of the sidechain on the helical polyisocyanide to form host-gest complexes resulted in deformation of the helix due to electrostatic repulsion.
      PubDate: 2017-12-07T07:20:57.43742-05:0
      DOI: 10.1002/pola.28919
       
  • Extending the Scope of Benign and Thermally Stable Organocatalysts:
           Application of Dibenzoylmethane for the Bulk Copolymerization of l-Lactide
           and ɛ-Caprolactone
    • Authors: Leila Mezzasalma; Julien De Winter, Daniel Taton, Olivier Coulembier
      Abstract: The use of dibenzoylmethane as benign and thermally stable new organocatalyst for the solvent-free ring-opening copolymerization of l-lactide and ɛ-caprolactone is reported here. Such β-diketone molecule allows preparing well-defined P(LA-co-CL) copolyesters exhibiting a gradient to a random structure at 155 C. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 00, 000–000The use of dibenzoylmethane as benign and thermally stable new organocatalyst for the solvent-free ring-opening copolymerization of l-lactide and ɛ-caprolactone is reported here. Such β-diketone molecule allows preparing well-defined P(LA-co-CL) copolyesters exhibiting a gradient to a random structure at 155 °C.
      PubDate: 2017-12-06T01:06:00.474866-05:
      DOI: 10.1002/pola.28921
       
  • Diphenylphenacyl sulfonium salt as dual photoinitiator for free radical
           and cationic polymerizations
    • Authors: Kerem Kaya; Johannes Kreutzer, Yusuf Yagci
      Abstract: Diphenylphenacylsulfonium tetrafluoroborate (DPPS+BF4–) salt possessing both phenacyl and sulfonium structural units was synthesized and characterized. DPPS+BF4– absorbs light at relatively higher wavelengths. The direct and sensitized initiation activity of the salt in both cationic and free radical photopolymerizations was investigated and compared with that of its analogue triphenylsulfonium tetrafluoroborate (TPS+BF4–). Differential scanning photocalorimetry and conventional gravimetric studies revealed that DPPS+BF4– showed higher efficiency for direct and sensitized photopolymerizations of most of the monomers investigated. Although, principally both homolytic and/or heterolytic cleavage is possible, theoretical studies suggested that homolytic pathway is more favored for the generation of reactive initiating species. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017A new photoinitiator having two chromophore groups (arylsulfonium and phenacyl units) was synthesized and proved to have superior absorbance characteristics and photoactivity over its triphenyl sulfonium analogue in both free radical and cationic polymerizations. The new initiator polymerizes the common monomers more efficiently and faster than its triphenyl analogue.
      PubDate: 2017-12-04T20:25:35.126253-05:
      DOI: 10.1002/pola.28918
       
  • Direct arylation synthesis of thienoisoindigo-based low-band-gap polymer
           from asymmetric donor–acceptor monomer
    • Authors: Kazuhiro Nakabayashi; Haruka Fukuzawa, Karin Fujita, Hideharu Mori
      Abstract: Thienoisoindigo (TIG) moiety has been paid numerous attentions as an excellent acceptor building block in low-band-gap polymers. Herein, a new TIG-dithiophene alternating copolymer (PTIG2T) was successfully synthesized from an asymmetric TIG-based donor–acceptor (D-A) monomer via the self-condensation-type direct arylation polymerization. PTIG2T exhibited the light absorption over 1000 nm owing to the intramolecular charge transfer in the thin film state, which corresponded to an optical band gap of 1.24 eV. The HOMO and LUMO levels of PTIG2T were determined to be −5.08 and −3.60 eV, respectively. Furthermore, the organic photovoltaic (OPV) with a PTIG2T/PC61BM active layer achieved a power conversion efficiency (PCE) of 3.19%, which is one of the highest PEC achieved by OPVs with TIG-based materials. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017A new thienoisoindigo (TIG)-based low-band-gap polymer (PTIG2T) was successfully synthesized from an asymmetric TIG-based donor–acceptor (D-A) monomer via the self-condensation-type direct arylation polymerization. Furthermore, an organic photovoltaic using PTIG2T as a donor material was investigated in detail.
      PubDate: 2017-11-30T01:40:42.903032-05:
      DOI: 10.1002/pola.28912
       
  • Semi-interpenetrating polymer networks based on crosslinked
           poly(N-isopropyl acrylamide) and methylcellulose prepared by frontal
           polymerization
    • Authors: A. Mariani; L. Nuvoli, D. Sanna, V. Alzari, D. Nuvoli, M. Rassu, G. Malucelli
      Abstract: In this work, semi-interpenetrating gels of poly(N-isopropyl acrylamide) and methylcellulose were successfully synthesized by using the Frontal Polymerization (FP) technique. The gels were obtained in the presence of dimethyl sulfoxide and trihexyltetradecylphosphonium persulfate, as polymerization solvent and radical initiator, respectively, hence avoiding the formation of bubbles during polymerization. Then, some of the gels containing dimethyl sulfoxide were thoroughly washed with water, hence obtaining the corresponding hydrogels. The effects of the ratio between poly(N-isopropyl acrylamide) and methylcellulose, the amount of crosslinker and solvent medium (i.e., dimethyl sulfoxide and water) were thoroughly studied, assessing the influence of temperature and velocity of FP fronts on the glass transition temperature values (dried samples), on the swelling behavior and on the dynamic-mechanical properties (gels swollen both in water and dimethyl sulfoxide). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017.The Frontal Polymerization technique was exploited to obtain polymer materials based on poly(N-isopropyl acrylamide) and methylcellulose. In the form of hydrogel, the former is a well-known polymer exhibiting a responsive behavior as a consequence of temperature variation, while the latter is derived from renewable sources and available in large amounts. The materials resulting from their combination prepared in this work show interesting and peculiar properties that can be useful in biomedical applications.
      PubDate: 2017-11-28T04:33:51.467866-05:
      DOI: 10.1002/pola.28914
       
  • Selective ethylene oligomerization with in-situ-generated chromium
           catalysts supported by trifluoromethyl-containing ligands
    • Authors: Eung Man Choi; Jong-Eun Park, Gyeong Su Park, Bonggeun Shong, Sung Kwon Kang, Kyung-sun Son
      Abstract: A series of pyrrole-containing diarylphosphine and diarylphosphine oxide ligands were prepared. The catalytic activity of the corresponding in-situ-generated chromium catalysts was investigated during selective ethylene oligomerization reactions. Variations in the ligand system were introduced by modifying the diarylphosphine and pyrrole moieties that affect the steric and electronic properties. Minor changes in the ligand structure and the composition of activators significantly changed the catalytic activity, selectivity toward linear alpha-olefins (LAO) versus polyethylene (PE), and the distribution of oligomeric products. The presence of trifluoromethyl groups on the diphenyl rings in ligand 3 promoted oxidation to form the corresponding phosphine oxide structure, 3o, which dramatically enhanced the catalytic activity of ethylene trimerization. The in-situ-generated chromium complex based on 3o activated by DMAO (dry methylaluminoxane)/TIBA (triisobutylaluminum) was used to achieve activity of about 1250 g (mmol of Cr)−1 h−1 with 98.5 mol % 1-hexene, along with a negligible amount of PE side product. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017.In-situ-generated chromium catalysts bearing a series of pyrrolyl-diarylphosphine and -diarylphosphine oxide ligands were prepared, and their influence on catalytic activity during selective ethylene oligomerization was studied. The ligand scaffold was varied by modifying the diarylphosphine substituents and the oxidation level of phosphine, which improved activity and selectivity for 1-hexene formation.
      PubDate: 2017-11-26T03:40:40.993046-05:
      DOI: 10.1002/pola.28915
       
  • Synthesis and electrochromic performance of oligoaniline-containing
           polyureas capped with various functional groups
    • Authors: Yanyan Li; Yan Zhou, Xiaoteng Jia, Xincai Liu, Ce Wang, Danming Chao
      Abstract: Tuning the molecular structure is an effective strategy to modulate the electrochromic behaviors of conducting polymers. In this contribution, a novel oligoaniline-containing polyurea ended with reactable isocyanate groups is designed and synthesized via nucleophilic polymerization. Then various functional groups such as o-toluidine, poly(ethylene glycol) (PEG), ethoxysilane, and congo red (CR) are introduced as end groups to modulate the electrochromic performance. Hydrophilic PEG could improve the switching speed due to the rapid electrolyte ions diffusion into polymer film through the hydrophilic region. An enhanced switching stability is afforded by crosslinkable ethoxysilane end groups, ascribed to crosslinked densified surface and great adhesion force between the electrochromic layer and ITO substrate through the hydrolysis reaction. Moreover, an ample color change is achieved by introducing colored CR as end groups. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017This article demonstrates the successful design and synthesis of a series of electrochromic polyureas capped with o-toluidine, PEG, ethoxysilane, and congo red end groups, respectively. The electrochromic properties, including color change, coloration efficiency, switching speed, and stability, have been effectively modulated.
      PubDate: 2017-11-22T00:00:52.227661-05:
      DOI: 10.1002/pola.28908
       
  • Self-assembly of block copolymers with an alkoxysilane-based core-forming
           block: A comparison of synthetic approaches
    • Authors: Guo Hui Teo; Rhiannon P. Kuchel, Per B. Zetterlund, Stuart C. Thickett
      Abstract: Polymerization-induced self-assembly (PISA) has become the preferred method of preparing self-assembled nano-objects based on amphiphilic block copolymers. The PISA methodology has also been extended to the realization of colloidal nanocomposites, such as polymer–silica hybrid particles. In this work, we compare two methods to prepare nanoparticles based on self-assembly of block copolymers bearing a core-forming block with a reactive alkoxysilane moiety (3-(trimethoxysilyl)propyl methacrylate, MPS), namely (i) RAFT emulsion polymerization using a hydrophilic macroRAFT agent and (ii) solution-phase self-assembly upon slow addition of a selective solvent. Emulsion polymerization under both ab initio and seeded conditions were studied, as well the use of different initiating systems. Effective and reproducible chain extension (and hence PISA) of MPS via thermally initiated RAFT emulsion polymerization was compromised due to the hydrolysis and polycondensation of MPS occurring under the reaction conditions employed. A more successful approach to block copolymer self-assembly was achieved via polymerization in a good solvent for both blocks (1,4-dioxane) followed by the slow addition of water, yielding spherical nanoparticles that increased in size as the length of the solvophobic block was increased. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017.Aqueous self-assembly of diblock copolymers that have an alkoxysilane-functional group was studied. Two different synthesis methods, namely polymerization-induced self-assembly (PISA) and addition of a selective solvent, yielded greatly different results for the preparation of polymer nanostructures. Due to hydrolytic instability of the monomer in water, PISA proved unsuccessful. Preformed polymers in an organic solvent were successfully used to form self-assembled nanospheres via slow addition of water.
      PubDate: 2017-11-21T23:26:59.016475-05:
      DOI: 10.1002/pola.28911
       
  • Synthesis and thermal properties of linear polydicyclopentadiene via
           ring-opening metathesis polymerization with a third generation grubbs-type
           ruthenium-alkylidene complex
    • Authors: Nicholas D. Steese; Dhruv Barvaliya, Xavier D. Poole, Donald E. McLemore, John C. DiCesare, Hans-Jörg Schanz
      Abstract: Linear polydicyclopentadiene was produced with a third generation Grubbs-type Ru–alkylidene complex. At high catalyst loadings, the polymer shows a portion of the polymer with a low degree of branching owing to secondary ROCM as seen in the SEC analysis. Distinct signals are observed via low angle scattering analysis for polymers with twice or another multiple of the average molecular weight of the linear polymer hence strongly affecting the controlled-living nature of the polymerization.
      PubDate: 2017-11-21T23:26:48.184987-05:
      DOI: 10.1002/pola.28909
       
  • Double thermoresponsive block–random copolymers with adjustable phase
           transition temperatures: From block-like to gradient-like behavior
    • Authors: Steffen Eggers; Tilman Eckert, Volker Abetz
      Abstract: Stimuli-responsive block–random copolymers are very useful “smart” materials as their switching behavior can be tuned by simply adjusting the composition of the random copolymer block. Because of that, we synthesized double thermoresponsive poly(N-acryloylpyrrolidine)-block-poly(N-acryloylpiperidine-co-N-acryloylpyrrolidine) (PAPy-b-P(APi-co-APy)) copolymers via reversible addition fragmentation chain transfer (RAFT) polymerization and investigated their temperature-induced self-assembly in aqueous solution. By varying the APi/APy ratio in the random copolymer block, its phase transition temperature (PTT1) can indeed be precisely adjusted while the temperature-induced collapse upon heating leads to a fully reversible well-defined micellization. By making the two blocks compositionally similar to more than 60%, the polymers' mechanistic thermoresponsiveness can furthermore be changed from block-like to rather gradient-like behavior. This means the micellization onset at PTT1 and the corona collapse at the PTT of the more hydrophilic pure PAPy block (PTT2) overlap resulting in one single broad transition. This work thus contributes to the detailed understanding of design, synthesis and mechanistic behavior of tailored “on-demand” switchable materials. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017.In this work, an example for the design and synthesis of smart on-demand materials is presented. The discussed block copolymers show a precisely and easily adjustable temperature-induced micellization in water. Besides the micellization temperature, the mechanistic behavior of the system can be switched from block-like (unimers–micelles–clusters) to gradient-like (unimers–broad transition to clusters). With this, it offers appealing options to adapt its temperature response to the requirements of specific applications.
      PubDate: 2017-11-19T07:35:42.834476-05:
      DOI: 10.1002/pola.28906
       
  • Dithienosilole–phenylquinoxaline-based copolymers with A-D-A-D and A-D
           structures for polymer solar cells
    • Authors: M. L. Keshtov; A. R. Khokhlov, S. A. Kuklin, A. Yu Nikolaev, E. N. Koukaras, Ganesh. D. Sharma
      Abstract: Two copolymers having D-A-D-A (P1) and D-A (P2) structures with quinoxaline acceptor unit and dithienosilole donor unit were synthesized and their optical and electrochemical (both experimental and theoretical) properties were investigated. The optical properties showed that these copolymers P1 and P2 exhibit optical bandgaps of 1.54 and 1.62 eV, respectively, with broader absorption profiles extending up to 800 nm and 770 nm, respectively. The electrochemical investigation of these two copolymers indicates that they exhibit suitable highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels for efficient exciton dissociation and high open circuit voltage in the resultant polymer solar cells (PSCs). These copolymers were used as donors along with the PC71BM as acceptor for the fabrication of solution processed bulk heterojunction PSCs. The optimized P1:PC71BM and P2:PC71BM active layers treated with solvent vapor treatment showed overall power conversion efficiency (PCE) of 7.16% and 6.57%, respectively. The higher PCE of P1-based device as compared to P2 might be attributed to higher crystallinity of P1 and good hole mobility resulting more balanced charge transport. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017The strategy of using donor (D) and acceptor (A) conjugated copolymers with alternating electron rich and electron deficient units is effective in achieving high-performing solar cells. Two copolymers having D- A-D-A (P1) and D-A (P2) quinoxaline acceptor units and a dithienosilole donor unit were used as a donor along with PC71BM as an acceptor for polymer solar cells (PSCs). The optimized PSCs based on P1:PC71BM and P2:PC71BM active layers achieved power conversion efficiencies (PCE) of 7.16% and 6.57%, respectively. The PCE for P1 is attributed to higher crystallinity of P1 and good hole mobility, resulting in a more balanced charge transport.
      PubDate: 2017-11-17T03:51:10.479636-05:
      DOI: 10.1002/pola.28904
       
  • Structural characterization of polybutadiene synthesized via cationic
           mechanism
    • Authors: Victor A. Rozentsvet; Olesya A. Stotskaya, Valentina P. Ivanova, Marianna G. Kuznetsova, Peter M. Tolstoy, Sergei V. Kostjuk
      Abstract: The microstructure of polybutadiene synthesized via cationic polymerization using TiCl4-based initiating systems has been investigated using 1D (1Н, 2Н, and 13С) and 2D (HSQC and HMBC) NMR spectroscopy. It was found that trans-1,4-unit is predominant structure of unsaturated part of polymer chain. Besides, the small amount of 1,2-structures was also detected, while cis-1,4-units were totally absent. The signals of carbon atoms of three types of head groups (trans-1,4-, 1,2-, and tert-butyl) and two types of end groups (trans-1,4-Cl and 1,2-Cl) were identified for the first time in macromolecules of cationic polybutadiene. It was showed that tert-butyl head groups were formed due to the presence in monomer of admixtures of isobutylene. The new methodology for calculation of the content of different structural units in polybutadiene chain as well as the head and end groups was proposed. It was established that main part of 1,2-units distributed randomly along the polybutadiene chain as separate units between trans-1,4-structures. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017.The assignment of all signals in NMR spectra to carbon and hydrogen atoms of cationic polybutadiene (CPB) has been made for the first time. Particularly, it was found that trans-1,4-units are predominant structure, while 1,2-units are presented in minor amounts and cis-1,4-units are totally absent. The signals of atoms of three types of head-groups (trans-1,4-, 1,2-, and tert-butyl) and two types of end-groups (trans-1,4-Cl and 1,2-Cl) were identified in microstructure of CPB.
      PubDate: 2017-11-14T06:00:43.110063-05:
      DOI: 10.1002/pola.28905
       
 
 
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