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A novel approach to preparing polymeric materials using elemental sulfur as a feedstock through the newly developed sulfur radical transfer and coupling (SRTC) reaction is reported herein. Polybenzoxazines with high sulfur contents are prepared using the SRTC reaction with benzoxazine compounds as the radical acceptors. The reactions between elemental sulfur and benzoxazine rings are analyzed with Fourier transform infrared (FTIR), 1 H NMR, and 13 C DEPT spectroscopies to elucidate the SRTC reaction mechanism. Moreover, the prepared polybenzoxazine-sulfur hybrid materials show attractive repairing properties based on the dynamic S-S linkages. An effective reaction mechanism and the prepared repairable sulfur-possessing polymeric materials are demonstrated., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This work demonstrates a new halogenation reaction through sequential radical and halogen transfer reactions, named as "radical and atom transfer halogenation" (RATH). Both benzoxazine compounds and poly(2,6-dimethyl-1,4-phenylene oxide) have been demonstrated as active species for RATH. Consequently, the halogenated compound becomes an active initiator of atom transfer radical polymerization. Combination of RATH and sequential ATRP provides an convenient and effective approach to prepare reactive and crosslinkable polymers. The RATH reaction opens a new window both to chemical synthesis and molecular design and preparation of polymeric materials., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this paper, self-assembled polymeric toroids formed by a temperature-driven process are reported. Rhodamine B (RhB) end-capped poly(N-isopropylacrylamide) (PNIPAAm) demonstrating a lower critical solution temperature (LCST) is prepared. In a two-phase system, the polymer in the aqueous phase could move to the chloroform phase on raising the temperature above its LCST. This temperature-driven process results in the formation of polymeric toroids in the chloroform phase, and the strategy affords a new pathway to toroidal self-assembly of polymers. Moreover, the photoluminescent behavior of the RhB end-capped PNIPAAm species formed by the process is also studied and discussed., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Multiwalled carbon nanotubes functionalized with poly(sulfone) (PSF) and poly(sulfobetaine methacrylate) (PSBMA) (MWNT-PSF/PSBMA) have been prepared through sequential atom transfer radical polymerization. The structure of MWNT-PSF/PSBMA hybrid has been characterized with FTIR, Raman spectroscopy, and high-resolution transmission electron microscopy. Incorporation of PSBMA chains to MWNTs introduces amphiphilic and protein-resistant properties to MWNT-PSF/PSBMA. Addition of 1 wt % MWNT-PSF/PSBMA to PSF films significantly improves their protein-resistant characteristic, as the composite films show a 4.4% of protein adsorption compared to poly(styrene) Petri dishes. The PSF/MWNT-PSF/PSBMA composite has been applied to prepare antifouling ultrafiltration membranes for protein separation. This work demonstrates an effective and convenient approach to prepare low-protein-adsorption surfaces and antifouling membranes.

This work reports white-light photoluminescent (PL) silica nanoparticles and their applications of preparation of PL polymer films and nanofibers. Rhodamine B (RhB) physically adsorbs or chemically bonds to silica nanoparticle (SNP) surfaces, resulting in PL SNPs. The RhB-modified SNPs exhibit white-light PL emissions under an excitation at 365nm, which is different from the inherent yellow light emission of RhB. The SNPs with physically-adsorbed RhB show stimuli-responsive properties. In solutions, the RhB molecules which physically adsorb to SNPs release from SNPs, consequently turning the PL emission from white-light to yellow. On the other hand, the SNPs having covalently-bonded-RhB molecules are effective additives for preparation of white-light PL polymer composites. Both PL poly(methylmethacrylate) (PMMA) films (from casting process) and nanofibers (from electrospinning process) showing white-light PL emission have been prepared., (Copyright 2010 Elsevier Inc. All rights reserved.)

Thermoresponsive statistical copolymers of zwitterionic sulfobetaine methacrylate (SBMA) and nonionic N-isopropylacrylamide (NIPAAm) were prepared with an average molecular weight of about 6.0 kDa via homogeneous free radical copolymerization. The aqueous solution properties of poly(SBMA-co-NIPAAm) were measured using a UV--visible spectrophotometer. The copolymers exhibited controllable lower and upper critical solution temperatures in aqueous solution and showed stimuli-responsive phase transition in the presence of salts. Regulated zwitterionic and nonionic molar mass ratios led to poly(SBMA-co-NIPAAm) copolymers having double-critical solution temperatures, where the water-insoluble polymer microdomains are generated by the zwitterionic copolymer region of polySBMA or nonionic copolymer region of polyNIPAAm depending on temperature. A high content of the nonionic polyNIPAAm in poly(SBMA-co-NIPAAm) exhibits nonionic aggregation at high temperatures due to the desolvation of polyNIPAAm, whereas relatively low content of polyNIPAAm in poly(SBMA-co-NIPAAm) exhibits zwitterionic aggregation at low temperatures due to the desolvation of polySBMA. Plasma protein adsorption on the surface coated with poly(SBMA-co-NIPAAm) was measured with a surface plasmon resonance (SPR) sensor. The copolymers containing polySBMA above 29 mol % showed extremely low protein adsorption and high anticoagulant activity in human blood plasma. The tunable and switchable thermoresponsive phase behavior of poly(SBMA-co-NIPAAm), as well as its high plasma protein adsorption resistance and anticoagulant activity, suggests a potential for blood-contacting applications.

This work demonstrates a general and effective approach to activate inert polymer chains for further reactions through electrochemically driven radical generation and radical transfer reactions. The generated radical-containing polymer chains show capacity for further polymer reactions and preparation of polymer hybrids. [ABSTRACT FROM AUTHOR]

Highlights • Transparent silk nanofibril/polyethylene terephthalate barrier films. • Barrier layer combine silk nanofibril with graphene oxide. • Morphology and microstructure of silk nanofibril coating layer. • OTR decreased by 76.8% and WVTR by 37.6% compared with PET film. • NSF/GO/PET film can be used in food, pharmaceutical and electronic device. Abstract Silk nanofibril was developed from Bombyx mori cocoons by thermodynamically driven, salts, and annealing processes. Silk nanofibril/polyethylene terephthalate composite films were produced by casting different concentrations and amounts of silk nanofibril solutions on polyethylene terephthalate film. Then oxygen and water vapor transmission rates were determined. The results showed that oxygen transmission rate at optimum concentration of 0.30 wt% silk nanofibril/polyethylene terephthalate film was reduced by 33.4%, while the water vapor transmission rate was decreased by 37.6%. Graphene oxide at different wt% were also mixed with silk nanofibril solutions to develop silk nanofibril/grapheme oxide/polyethylene terephthalate films. The silk nanofibril/grapheme oxide/polyethylene terephthalate film developed from 0.15 wt% grapheme oxide decreased the oxygen transmission rate by 76.8% but did not significantly affect the water vapor transmission rate. The morphology of the top surface of silk nanofibril based barrier film was investigated by using scanning electron microscope that showed micellar unit or nanofibril aggregates formation. Fourier transform infrared spectroscopy and X-ray diffraction showed high β-sheet regions and crystallinity in 0.30 wt% silk nanofibril/polyethylene terephthalate film. Besides, the silk nanofibril/polyethylene terephthalate and silk nanofibril/grapheme oxide/polyethylene terephthalate showed smaller cavity size than polyethylene terephthalate that can reduce the oxygen and water vapor permeation. Transparent silk nanofibril/polyethylene terephthalate and silk nanofibril/grapheme oxide/polyethylene terephthalate films might be a great potential material in flexible electronics or food and pharmaceutical packaging. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Porous and thermally stable membranes are attractive materials as separators in lithium-ion batteries. This work reports a new class of high-performance separators for Li-ion batteries based on a crosslinked polybenzoxazine electrospun fiber mat (CR-PBz-FbM). The CR-PBz-FbM separator shows a high ion conductivity of 2.92 mS cm−1 (5.2 times the value recorded for Celgard 2300), a low MacMullin number of 3.35, ultrahigh electrolyte uptake (≈825 %), and near-zero shrinkage at 150 °C. Consequently, the CR-PBz-FbM separator shows a high C-rate capacity and good cycle retention in the half-cell test. At a C-rate of 2.0, the CR-PBz-FbM-based Li-ion cell only exhibits a capacity loss of 16 % compared to a 40 % capacity loss found with the cell based on Celgard 2300. The results demonstrate that CR-PBz-FbM is an inexpensive, non-shutdown-type, thermally stable, and highly ion-conductive separator for Li-ion batteries. [ABSTRACT FROM AUTHOR]

The article presents a scalable approach for preparation of blood-inert materials and shape-reproducible electrospun polymeric mats. A mainchain polybenzoxazine (PBz) is used as the raw material and the surface energy measure with cured PBz plain film which is slow compared to the value of poly(tetrafluoroethylene) (PTFE). It states that it is noteworthy that the cured PBz electrospun fiber mat shows a more amphiphobic characteristic equated to plan crosslinked PBz film.

ABSTRACT The reactivity between the active species of atom transfer radical addition and the unsaturated groups of graphene oxides (GOs) has been demonstrated in this work. The reaction and the sequential surface-initiated atom transfer radical polymerization provide a convenient approach to anchor various polymer chains and to buildup various polymer architectures, such as linear polymer, V-shape block polymer, multibonded polymer layer, and hierarchical brush-on-layer polymer, on GO sheet surfaces. The chemical structures and morphology of the polymer-modified GOs have been characterized with Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. After organomodification, the GOs exhibit a good dispersion ability in organic solvent over 80 days, amphiphilic characteristics, and temperature-responsive properties. Reduction of the GOs has been performed to result in graphene-like materials showing certain extent of electron conductivities. An effective approach to synthesize GO/polymer hybrid materials possessing various polymer architectures and attractive properties has been developed. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1588-1596 [ABSTRACT FROM AUTHOR]

ABSTRACT A multifunctional ferrocene-modified poly(glycidyl methacrylate) (PGMA-Fc) and a difunctional β-cyclodextrin derivative (bis-CD) has been prepared for the construction of an electrically driven removable and self-healing polymeric materials based on the complexation reaction between ferrocene and β-CD groups. The chemical structures of PGMA-Fc and bis-CD have been characterized with Fourier transform infrared, 1H nuclear magnetic resonance, and X-ray photoelectron spectroscopy. The effects of electrical voltages and medium conductivity on the decrosslinking efficiency of the crosslinked PGMA-Fc/CD polymer have been examined. The PGMA-Fc/CD network has shown removable feature and properties for application as a reworkable crosslinked material. Moreover, the crosslinked PGMA-Fc/CD sample has shown electrically driven self-healing behavior. The self-healing performance could be enhanced with wetting the sample to increase the electrical conductivity. As a result, the material could serve as a self-healing agent for commercial painting products. Preparation and application of a novel and efficient self-healing polymer have been demonstrated. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3395-3403 [ABSTRACT FROM AUTHOR]

Matrix-polymer-functionalized multiwalled carbon nanotubes (MWCNTs) are demonstrated as a highly efficient toughening agent for matrix polymers. With poly(vinylidene fluoride) (PVDF) as the matrix polymer, the PVDF/MWCNT-PVDF nanocomposite films show high toughness. With a small load amount of MWCNT-PVDF (0.07 wt %), the nanocomposite film shows a yield point and a constant-stress extension region in stress-strain tests, compared with the typical low-extensibility feature of neat PVDF film. The PVDF/MWCNT-PVDF-0.7 film exhibits a 180-fold increase of toughness and about 38-fold increase in strain at break compared with neat PVDF film. This toughening effect is attributed to (a) homogeneous dispersion of MWCNT-PVDF in PVDF, (b) the high efficiency of load-transfer across MWCNT/PVDF interface, and (c) the long length of the MWCNTs. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 [ABSTRACT FROM AUTHOR]

Abstract: Both of the maleimide and carboxylic acid groups in 5-maleimidoisophthalic acid (MIPA) are reactive toward an amine group. The selective reaction between carboxylic acid and amine groups was successfully established and applied in preparation of polyamides (PA-MI) and copolyamides possessing maleimide pendants. The chemical structures of the polymers obtained were characterized with FTIR, 1H NMR, and elemental analysis. Some polyamides showed good solubility in organic solvents and are for further chemical modifications. Success of phosphorylation on PA-MI polymers demonstrated this kind of polyamide could be used as reactive polymers for further modification and functionalization. [Copyright &y& Elsevier]

Abstract: Cross-linked polyamides and polyamide gels were prepared from maleimide-containing polyamides and a tri-functional furan compound and showed thermal reversibility in cross-linking behavior and in gel formation through Diels–Alder (DA) and retro-DA reactions. The rate constant k of the DA cross-linking reaction were 1.25–4.83×10−5 dm3 mol−1 s−1 in the temperature range of 20–60°C with an activation energy of 32.1kJmol−1. The cross-linking densities, thermal properties, and thermal reversibility of the polyamides/furan polymers were adjustable with the contents of maleimide groups in polyamides. [Copyright &y& Elsevier]

Bismaleimides, having epoxy backbone linkages and various bridging groups, were prepared through reacting 4-(N-maleimidophenyl)glycidylether with various biphenol and silandiol compounds. The preparation route provided a convenient approach of introducing specific groups into the bridging groups of bismaleimides to alter their properties. The prepared bismaleimides in this study exhibited good oranosolubility, low melting points, and wide processing windows, further to indicate their excellent processability. The cured polymers were found having high glass transition temperatures above 210 °C and good thermal stability over 350 °C. The polybismaleimide having silicon group, which showed fairly good thermo-oxidative stability and low amount of volatiles, were suitably being considered as flame retardant for other polymeric materials. [Copyright &y& Elsevier]

The cover page of the journal "Advanced Materials Interfaces" is presented.

Efficient separation of both immiscible and emulsified oil/water mixtures is achieved by collaborating polybenzoxazine (PBz) with commercially available substrates in this work. Possessing intrinsic low surface energy, crosslinked PBz coating endows various substrates (sponges, filter paper, and ceramic membrane) with surface hydrophobicity and oleophilicity and enables oil-selective penetration. The as-prepared sponge (CR-PBz-sponge) could effectively remove oil floating on water and oil under water with high absorption capacities (up to 120 times its own weight) and good recyclability. The PBz-coated filter paper (CR-PBz-filter paper) is applicable to efficient large-scale oil/water separation based on its high fluxes (about 5000–6000 L m −2 h −1 ) on a wide range of organic solvents and oils. CR-PBz-ceramic membrane shows great effectiveness in removal of tiny water droplets from water-in-oil emulsion and reduces the water contents of the treated oil to the levels of the natural water solubility of the oils. Based on its separation efficiency, processing simplicity, substrate versatility and low cost, the technique of using PBz as coating material to fabricate oil/water separation materials is promising in practical and industrial concerns. [ABSTRACT FROM AUTHOR]

Polymeric membranes, compared with their inorganic counterparts, usually suffer from insufficient solvent resistance and thermal stability. In this study, an organic solvent–resistant thermally stable polymeric microfiltration membrane is prepared with a self-crosslinkable polybenzoxazine as a precursor. The obtained membranes have pore sizes of approximately 3.4 µm and superior antiswelling stability in organic solvents; thus, they exhibit excellent performance in terms of size-selective particle separation inorganic phases. The membranes are also effective in the gravity-driven separation of surfactant-stabilized water-in-oil emulsions. The water contents of the filtrate oil phases are close to the natural solubility of water in the solvents; for example, a water content of 350 ppm, which is comparable to the water solubility in toluene (330 ppm), has been found in the filtrate toluene from water-in-toluene emulsions. Moreover, the membrane demonstrates pH-induced changes in oil and water selectivity in oil–water separations. When treated with a strong base solution, the oil-selective membrane becomes water-selective and exhibits favorable performance in terms of separating organic solvents from surfactant-stabilized oil-in-water emulsions. These features effectively extend the application scope of the prepared membrane for oil–water separations. [ABSTRACT FROM AUTHOR]

Abstract: The molecular design concept of silicon-nitrogen synergistic effect for highly-efficient flame retardants has been demonstrated in the preparation of reactive type flame retardants which exhibits high flame retardation efficiency and property enhancement ability for developments of high performance polymers. In the synthetic route, a benzoxazine-containing triethoxysilane compound is obtained and used as a monomer together with diphenylsilanediol to result in branched benzoxazine-containing polysiloxanes (PBz-PSO) through a 3 + 2 condensation polymerization reaction. The chemical structures and properties of Bz-TES and PBz-PSO compounds have been characterized with Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. PBz-PSO samples are reactive polymers as they possess thermally-reactive benzoxazine groups. Thermally-crosslinking the PBz-PSO samples results in silicon-containing polymers which show high thermal stability and high flame retardancy (limited oxygen index > 45). Addition of 5 wt% PBz-PSO to a conventional benzoxazine resin could simultaneously improve its flame retardancy (passing the UL 94-V0 test) and increase its glass transition temperature from 145 °C to 205 °C. PBz-PSO samples are highly-efficient reactive-type flame retardants for preparation of halogen-free and phosphorus-free polymers. [Copyright &y& Elsevier]

Abstract: Introduction of cross-linked structure to sulfonated polymers is an effective approach to reduce the methanol permeability of the polymers for application in direct methanol fuel cells. In this work, a crosslinkable sulfonated polymer (sPBz) has been prepared through Diels–Alder reaction with a sulfonated bismaleimide and a benzoxazine-containing bisfuran as monomers. The polymer possesses both sulfonic acid groups and crosslinkable benzoxazine groups. The sulfonic acid group reduces the temperature of the thermal polymerization of benzoxazine groups, and the polymerization of benzoxazine group results in cross-linked sPBz polymer (CR-sPBz). CR-sPBz has showed good film formability, high mechanical strength, flexibility, and solvent resistance. The methanol permeability and proton conductivity of CR-sPBz is 2.52*10−7 cm2 s−1 and 48 mS cm−1 (60 °C), respectively, corresponding to a selectivity (proton conductivity/methanol permeability) of 1.86*105 S s cm−3. The selectivity of CR-sPBz is about 3.4 times of the value of the commercially-available Nafion 117 membrane. The high selectivity of CR-sPBz warrants its performance and suitability for use as a proton exchange membrane for direct methanol fuel cells. [Copyright &y& Elsevier]

Abstract: Polybenzimidazole (PBI) has been chemically bonded to silica nanoparticles (SNPs) through an ozone-mediated process using N-(p-carboxyphenyl)maleimide (pCPM) functionalized SNPs (SNP-pCPM) as precursors, to enhance the interfacial compatibility between SNPs and PBI in PBI/SNP nanocomposites. The PBI-functionalized SNPs (SNP-PBI) have been well characterized and used as inorganic nanofillers for preparation of PBI/SNP-PBI membranes for fuel cells. Addition of PBI-SNP to PBI membranes enhances their thermal and mechanical properties as well as decreases their phosphoric acid uptakes. For the PBI/SNP-PBI membrane with 10wt% of SNP-PBI, it shows a proton conductivity of about 50mScm−1 at 160°C, which is 25% higher compared to the pristine PBI membrane. Consequently, the PBI/SNP-PBI membrane demonstrates a maximum power density of 650mWcm−2 in a single cell test, compared to the value of 530mWcm−2 read from the test for pristine PBI membrane. [Copyright &y& Elsevier]

Abstract: In this study, we investigated various generations of waxy dendrons, dendritic side-chain polymers (varying the structure and polarity of the polymer backbone), and physical blends of dendrons with polymers for their ability to form honeycomb-like structures. Each waxy dendron comprises a focal part (possessing many hydrogen bonding sites) and a peripheral part (rich in units that undergo van der Waals interactions). Using a breath-figure process, we readily incorporated high-generation dendrons within polymer matrixes to form porous surfaces. When the high-generation waxy dendrons were grafted onto amino group – functionalized polystyrene or copolymerized with diisocyanates to form polyurethanes, the multiple long alkyl chains behaved as bristles of hydrophobic brooms, due to the presence of strong van der Waals forces. The formation of honeycomb-like patterns in the polymer films resulted from strong hydrogen bonding of the polymers to water droplets on the surfaces of substrates, with subsequent self-organization and phase separation. [Copyright &y& Elsevier]

A series of thermally stable nonlinear optical hyperbranched polyaspartimides were synthesized via the Michael addition reaction of a fluorine-containing trimaleimide, 1,1-tris[4-(4-maleimide-2-trifluoromethyl-phenoxy)-phenyl]ethane and two respective azobenzene dyes, namely bis(4-aminophenyl(4-(4-nitrophenyl)-diazenyl)phenyl)-amine and 2,4-diamino-4′-(4-nitrophenyl-diazenyl)-azobenzene, using p-toluenesulfonic acid as catalyst. The incorporation of fluorine-rich components within the hyperbranched polymers increased solubility in organic solvents and reduced optical loss. Owing to the three-dimensional, void-rich, topological structure of the highly branched polymers, the spatial separation of the dyes endows the polymers with a favorable site isolation effect, which thereby negates chromophoric aggregation. Using in situ contact poling, electro-optical coefficients, r 33 of 6.5–14.7pmV−1 and temporal stability at 80°C were obtained. Both the dynamic thermal and temporal stabilities of the hyperbranched polyaspartimides were superior to those of their linear analogues. [Copyright &y& Elsevier]