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This study evaluated the microhardness of two resin cements and a low-viscosity resin composite when light-cured under different ceramic thicknesses. A total of 20 samples (10.0 × 1.0 mm) of each material were polymerized by means of a LED light source with an intensity of 1,100 mW/cm2 for 20 seconds. For each experimental group, different ceramic thicknesses (0.5 mm, 1.0 mm, and 1.5 mm) were applied to each sample. For the control group, the samples were polymerized without the presence of ceramics. Each material was then stored in dry vials that inhibited the passage of light for a period of 24 hours. After that time, each sample underwent Vickers hardness test (HMV, Shimadzu: 25 g/10 seconds). The data were collected and analyzed using analysis of variance and Tukey test (P < .05). For the control group, RelyX Veneer (3m ESPE), Filtek Flow Z350XT (3M ESPE), and Allcem Veneer (FGM) showed mean microhardness values and standard deviations of 44.42 ± 4.9, 44.25 ± 2.4, and 31.71 ± 2.4, respectively. The lowest microhardness value (24.13) was found when the greatest ceramic thickness (1.5 mm) was used on the Allcem Veneer cement (P < .01). The microhardness of resin-based materials was affected when the 1.5-mm-thick ceramic material was interposed during photoactivation. [ABSTRACT FROM AUTHOR]

Polyaniline nanoparticle (nPANI) was successfully synthesized through ultrasonic-assisted reverse microemulsion polymerization method. The effect of four parameters including concentration of aniline (ANI) as monomer, molar ratio of dodecybenzene sulfonic acid (DBSA) as surfactant to ANI, molar ratio of ammonium peroxydisulfate (APS) as oxidant to ANI and polymerization temperaturewere systematically studied in terms of the structural characterizations of nPANI by applying the Taguchi method of experimental design. Data analysis indicated that there is a dependency between conductivity and particle size in the nanoscale; the maximum conductivity of nPANI was obtained when the diameter of the particles was 30 nm. [ABSTRACT FROM AUTHOR]

For the purpose of enhancing the hydrophilicity and antifouling property, styrene‐maleic anhydride copolymer (SMA) was successfully introduced on the surface of polypropylene hollow fiber membranes via in situ ultrasonic wave‐assisted polymerization. It was shown that how to avoid the hydrolysis and esterification of anhydride groups was the key for improving the hydrophilicity and antifouling property of membranes. Some factors were studied in detail, such as solvent, concentration of solution as well as time and temperature of ultrasonic treatment. Results showed that acetone and ethanol as solvents performed different functions during the process of the polymerization, and ethanol, a polar solvent, reacted with anhydride groups to hinder the formation of SMA and improvement of antifouling property. The modified membranes (PPM1 and PPM5) exhibit both high water flux and strong antifouling capability. Besides, antifouling property of modified membranes was very stable, which proved that they can work in reality. This study supplied a new approach to fabricate highly efficient polymeric membranes applicable to wastewater purification. POLYM. ENG. SCI., 59:E51–E58, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Two triarylamine derivatives, DPPA-2(NHCO-TPA) and DPPA-2(NHCO-NPC) , composed of a central diphenylpyrenylamine (DPPA) unit via amide groups linked to two triphenylamine (TPA) or N -phenylcarbazole (NPC) sides are developed as an electroactive precursor to prepare electrochromic films through electrochemical polymerization. The dilute solutions of these two DPPA-containing compounds showed notable fluorescence and solvatochromic shifts. Electroactive polymeric films could be electrodeposited on the ITO electrode surface by repetitive cyclic voltammetry scanning of their dichloromethane solutions containing dissolved 0.1 M tetrabutylammonium perchlorate (TBAP) between 0 and 1.5 V. The polymer films displayed multi-staged redox processes and color changes upon electrochemical oxidation. Spectroelectrochemistry and electrochromic switching stability of the polymers were investigated. Simple single-layer electrochromic devices were also fabricated and tested. [ABSTRACT FROM AUTHOR]

In this study, three new donor-acceptor-donor type monomers bearing 1,3-dibromo-5-(2-ethylhexyl)-4H-thieno[3,4- c ]pyrrole- 4,6(5H)-dione ( A ) as an acceptor unit and thiophene, 3,4-ethylenedioxythiophene (EDOT) and 3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine (didecyl-ProDOT) as donor units were synthesized via Stille cross-coupling reaction and their electrochemical polymerization by repetitive cycling was reported. The electrochemical and optical properties of the monomers (( 5-(2-ethylhexyl)-1,3-di(thienyl-2-yl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (TAT ), 1,3-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-5-(2-ethylhexyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione ( EAE ) and 1,3-bis(3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl)-5-(2-ethylhexyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione ( PAP )) and their corresponding polymers called PTAT, PEAE and PPAP were investigated and it was found that EDOT units containing monomer and polymer ( EAE and PEAE ) have lower oxidation potentials and lower band gap value as compared to didecyl-ProDOT and thiophene units containing monomers and polymers ( PAP , TAT and PPAP , PTAT ). Spectroelectrochemical investigations conducted on electrochemically obtained polymer films revealed that polymer films exhibited electrochromic behaviors: brick red to gray for PTAT , blue/violet to highly sky blue for PEAE and blue to highly light blue for PPAP in their neutral and oxidized states, respectively. Moreover, PAP was also polymerized chemically using FeCl 3 as an oxidizing agent. Both chemically and electrochemically obtained PPAP were found to be soluble in some organic solvents and their dichloromethane solutions can be reversibly oxidized and reduced using antimony pentachloride and hydrazine hydrate solutions, respectively. [ABSTRACT FROM AUTHOR]

Abstract: In this research, a series of random and block amphiphilic copolymers of norbornene derivatives containing biocompatible natural triterpenoid and oligo(ethylene glycol) pendants were synthesized by ring‐opening metathesis polymerization. These copolymers were heat and pH responsive, and could self‐assemble into core–shell spherical micelles in aqueous solution. Their hydrodynamic diameters corresponded to pH values and monomer sequences. By evaluating the loading and release capacity of hydrophobic molecules, it was found that 1) the higher the content of the hydrophobic triterpenoid, the higher the loading capacity; 2) the release speed could be trigged by the pH because of the deprotonation of the carboxyl groups on the triterpenoid. Additionally, the copolymers exhibited low cytotoxicity toward L929 cells, which makes them potential nanocarrier candidates for controlled drug delivery. [ABSTRACT FROM AUTHOR]

Proanthocyanidin (PAC) holds strong free radicals scavenging ability and is widely used as oxygen free radical scavenger. Huge demand, safety and economic aspect are forcing the PAC extraction to explore new resource and greener solvent. An efficient extraction method of PAC from Ginkgo biloba leaves was established by employing deep eutectic solvent (DES)-water mixture. After a rational design, a DES-water mixture (named as Ch-M 55 ) was chosen as the extraction solvent, which was prepared from choline chloride and malonic acid at a molar ratio of 1:2 with water addition of 55% (w/w). The main factors affecting the extraction yield were statistically optimized using a central composite design combined with response surface methodology (RSM). The optimal conditions were obtained as follows: extraction temperature of 65 °C, extraction time of 53 min and Ch-M 55 to solid ratio of 10.57:1 (v/w, mL/g). The PAC extraction yield was 22.19 ± 0.71 mg/g under the optimized conditions, which was much higher than those of conventional organic solvents. The antioxidant activity of PAC extracted by Ch-M 55 was similar to that of 70% acetone, but a little less than 70% methanol and 70% ethanol. The differences in constituent and polymerization degree of PAC extracted by different solvents might account for the difference in antioxidant activity. In consideration of biodegradability and pharmaceutical acceptability, the Ch-M 55 -based extraction method is obviously efficient, green and ecofriendly. Extraction of PAC from Ginkgo biloba leaves also provides a new PAC resource. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we demonstrate a simple approach to improve the electrochromic performances of polyaniline (PANI) by incorporating PANI nanofibers (PANI-NFs) synthesized by interfacial polymerization into water-soluble PANI:poly(styrene sulfonate) (PANI:PSS). The one-dimensional PANI-NFs endow spin-coated PANI film high electrochemical activities and electrochromic properties. The structures and morphologies of PANI-NFs were characterized by FTIR spectroscopy and SEM observation. The electrochemical behaviors of PANI/PANI-NFs composites were analyzed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochromic properties of composites were tested using electrochemical working station combining a UV-Vis spectrometer. The results show that the PANI-NFs with even diameter of ~ 30 nm can be synthesized easily using interfacial polymerization method. With the increasing of feeding amount of PANI-NFs, the oxidation peaks of CV curves shift to low potential direction, indicating enhanced electrochemical activities. The electrochromic test confirms that the PANI/PANI-NFs composites films have higher electrochromic contrast of 0.67 as comparison to 0.49 of PANI:PSS film. The PANI/PANI-NFs also exhibit excellent electrochromic stability. After 2000 cycles switching, only less than 4% contrast decay is observed. The enhanced electrochromic properties can be attributed to the small charge-transfer resistance and facile ion diffusion process brought by PANI-NFs. The EIS tests exhibit that with incorporating of highly conductive PANI-NFs, the PANI/PANI-NFs composites possess relatively lower charge-transfer resistance of 76 Ω as comparison to 94 Ω of neat PANI:PSS.Graphical abstract: [ABSTRACT FROM AUTHOR]

We used electron tomography to examine microtubules (MTs) growing from pure tubulin in vitro as well as two classes of MTs growing in cells from six species. The tips of all these growing MTs display bent protofilaments (PFs) that curve away from the MT axis, in contrast with previously reported MTs growing in vitro whose tips are either blunt or sheetlike. Neither high pressure nor freezing is responsible for the PF curvatures we see. The curvatures of PFs on growing and shortening MTs are similar; all are most curved at their tips, suggesting that guanosine triphosphate-tubulin in solution is bent and must straighten to be incorporated into the MT wall. Variations in curvature suggest that PFs are flexible in their plane of bending but rigid to bending out of that plane. Modeling by Brownian dynamics suggests that PF straightening for MT growth can be achieved by thermal motions, providing a simple mechanism with which to understand tubulin polymerization. [ABSTRACT FROM AUTHOR]

Here, a facile method for the preparation of polymeric particles from a sugar molecule, maltitol (ML) in single step was reported via microemulsion polymerization/crosslinking technique with a high yield, 89 ± 6%. Furthermore, poly(Maltitol) (p(ML)) particles were chemically modified to induce different physicochemical characteristic using different anionic and cationic modifying agents such as taurine (TA) and diethylenetriamine (DETA) to prepare m-p(ML)/TA and m-p(ML)/DETA. The blood compatibility of the p(ML) particles and their modified forms were tested with fresh blood, and found that p(ML) and m-(ML)/DETA particles are blood compatible with about 5% hemolysis, and above 80% blood clotting indices. Moreover, the cytotoxicity results against L929 fibroblast cell line revealed that p(ML) based particle are biocompatible up to 100 μg/mL with 85% cell viability regardless of their nature, and at 200 μg/mL dosage of p(ML), m-p(ML)/TA and m-p(ML)/DETA particles, the cell viabilities were determined as 83.33, 64.03 and 73.89% on for L929 fibroblast cells implying the slightly less biocompatibility nature of m-p(ML)/TA in accord with the blood compatibility results. Additionally, the apoptotic and necrotic indices were determination for p(ML) based particles on L929 fibroblast cells, and the results revealed that these particles do not induce any and stress on the cells. Also, it does not have genotoxic effect as determined against CHO cells. [ABSTRACT FROM AUTHOR]

A free radical polymerization method was adopted for the fabrication of hybrid hydrogel films based on acrylamide and polyethylene glycol dimethacrylate as plasticizing and crosslinking agents, respectively, to be employed as smart skin bandages. Electro-sensitivity, biocompatibility and proteolytic properties were conferred to the final polymer networks by introducing graphene oxide (0.5% w/w), gelatin or trypsin (10% w/w) in the polymerization feed. The physical chemical and mechanical characterization of hybrid materials was performed by means of determination of protein content, Raman spectroscopy, thermogravimetric analysis and measurement of tensile strength. The evaluation of both water affinity and curcumin release profiles (analyzed by suitable mathematical modelling) upon application of an external electric stimulation in the 0–48 voltage range, confirmed the possibility to modulate the release kinetics. Proper proteolytic tests showed that the trypsin enzymatic activity was retained by 80% upon immobilization. Moreover, for all samples, we observed a viability higher than 94% in normal human fibroblast cells (MRC-5), while a reduction of methicillin-resistant Staphylococcus aureus CFU mL −1 (90%) was obtained with curcumin loaded samples. [ABSTRACT FROM AUTHOR]

Nowadays, micellar polymerization is widely used in different fields of industry and research, including modern living polymerization technique. However, this process has many variables and there is no comprehensive model to describe all features. This research presents simulation methodology which describes key properties of such reactions to take a guide through a variety of their modifications. Dissipative particle dynamics is used in addition to Monte Carlo scheme to simulate initiation, propagation, and termination events. Influence of initiation probability and different termination processes on final conversion and molecular‐weight distribution are presented. We demonstrate that prolonged initiation leads to increasing in polymer average molecular weight, and surface termination events play major role in conversion limitation, in comparison with recombination. © 2018 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

ABSTRACT: In this work, a novel approach to improve the antifouling properties of membrane surfaces was developed. First, a polydopamine layer was attached onto the surface of an ultrahigh molecular weight polyethylene/fabric composite microporous membrane based on dopamine self‐polymerization and adhesive behavior. Then, methoxy polyethylene glycol amine was covalently bonded with the polydopamine layer via a Schiff base reaction. The physicochemical properties of the modified composite membrane surface were investigated, and the results indicated this modification could effectively enhance the membrane surface hydrophilicity. Furthermore, the protein fouling resistance of both dopamine‐coated and methoxy polyethylene glycol amine immobilized composite membranes was evaluated. It was found that a dopamine coating cannot obviously enhance the membrane antifouling properties due to its strong bioadhesion behavior. However, the antifouling properties of the composite membranes were significantly improved after being immobilized with a methoxy polyethylene glycol amine layer. Consequently, a layer‐by‐layer modified composite membrane with excellent antifouling property was obtained. The pure water flux and flux recovery ratio of the resultant membrane were 764 L m−2 h−1 and 83%, respectively. The aim of this paper was to provide an effective approach to optimizing the separation efficiency and antifouling performance of the ultrahigh molecular weight polyethylene/fabric composite membrane. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46428. [ABSTRACT FROM AUTHOR]

This paper conducted a study on the effects of polymerization condition, composition and chlorination degree of chlorinated polyethylene (CPE) rubber on the grafting rate of chlorinated polyethylene grafted with acrylonitrile and styrene (ACS resin) synthesized by high-temperature bulk polymerization. The results indicated that the grafting reaction mainly took place in the early stage at which the conversion was low than 50%. The grafting rate of ACS resin was significantly affected by polymerization temperature and the content of initiator and chain transfer agent. The improvement of polymerization temperature or the content of initiator and chain transfer agent resulted in a significant decrease in grafting rate. However, the weight ratio of styrene/acrylonitrile, the content and chlorination degree of CPE showed fewer effects. [ABSTRACT FROM AUTHOR]

Fabrication of Copper nanoparticles (CuNPs) on the Poly(glycidyl methacrylate) (PGMA) to prepare Poly(glycidyl methacrylate) core/copper nanoparticle shell nanocomposite (PGMA/Cu nanohybrid) by deposition method. The deposition method consists of two simple steps (i) The synthesis of PGMA beads by suspension polymerization followed by (ii) direct deposition of CuNPs on activated PGMA beads. The PGMA beads were used as a soft template to host the CuNPs without surface modification of it. Two different concentrations of copper salts (1% and 5%) were employed to know the effect of concentration on the shape and size of nanoparticles. The catalytic activity of PGMA/Cu nanohybrids were tested for the reduction of 4‐nitrophenol (4NP) to 4‐aminophenol (4AP) with an excess amount of sodium borohydride (NaBH4). The results showed that, the diverse sizes and shapes of CuNPs were deposited on the PGMA matrix. The X‐ray diffraction study revealed that the CuNPs were present on the surface of the PGMA matrix. The scanning electron microscopic images show that the fabrication of CuNPs on the PGMA matrix changes the morphology and nature of PGMA beads significantly. The catalytic studies have demonstrated that the PGMA/Cu nanohybrid 1% exhibit better catalytic activity than 5%. POLYM. COMPOS., 39:1913–1921, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

New heterobimetallic aluminates with well-defined structures bearing bidentate Schiff bases as ligands have been prepared. The ligands studied are PhO–CH=N–Ar (Ar = C6H5 (La) and 2,6-iPr-C6H3 (Lb)), with and without donor substituents in the ortho position of the arene ring bonded to the iminic nitrogen. To prepare the heterometallic species, the HL proligands were treated with the appropriate alkali metal precursor and then AlMe3 was added. In these reactions the alkali metal size has a substantial influence on the outcome. For lithium, the formation of [LiAlMe3(L)]21(a–b) compounds was straightforward and their nuclearity in the solid state was confirmed by X-ray studies. When moving to sodium, the analogous species [NaAlMe3(L)]n initially formed, quickly evolved to [NaAlMe2(L)2]n3(a–b) in solution. As well, for potassium, the initial derivatives formed [KAlMe3L] progressed very rapidly to the generation of [KAlMe2L2] as evidenced from the isolation of [KAlMe2(Lb)2] 4b as a crystalline product. Furthermore, for potassium the unique species [KAlMe(Lb)3] 5b was isolated which shows, as a striking feature, the presence of an unusual tripodal metalloligand. [ABSTRACT FROM AUTHOR]

A novel thin film composite (TFC) membrane was rationally originated using an interfacial polymerization (IP) process mediated by a rapid Cu 2+ /H 2 O 2 -induced co-deposition of PDA and piperazine (PIP). The co-deposition strategy distinctly shortens modification times while also promoting the high, stable loading of aqueous monomers through covalent bonding with PDA, thus being beneficial for subsequent crosslinking with trimesoyl chloride (TMC). The controlled diffusion of aqueous monomers during the IP process enabled the formation of a thin, smooth, and hydrophilic polyamide (PA) film at the top of a polyacrylonitrile (PAN) membrane substrate. ATR-FTIR, XPS, SEM, AFM, and water contact angle analyses confirmed the presence of the selective PA layer. Zeta potential measurements also revealed a negatively charged surface, which resulted in a salt retention order of NaCl < MgCl 2 < MgSO 4 < Na 2 SO 4 . The roles of the co-deposition time and the PIP/dopamine ratio in the membrane morphology and separation properties were systematically studied to explore the optimal functionalization parameters. A high-performance TFC membrane (TFC2.0_5) was achieved after identifying optimal conditions as 2/1 mass ratio for PIP/dopamine, 5 min co-deposition, 0.1% w/v TMC, and 30 s IP reaction. In addition to achieving high water permeability (14.5 LMH bar −1 ), this membrane also attained high mono/bivalent salt selectivity (NaCl/Na 2 SO 4 , 24.1) and long-term stability in treating saline solutions. This simple, and cost-effective strategy provides an improved guideline in designing high-performance TFC membranes with vast potential in water treatment. [ABSTRACT FROM AUTHOR]

Insight into self-assembly of CdX 2 (X = Cl and Br) with a mixture of L 1 and L 2 (L 1  = diallylbis(3-pyridyl)silane; L 2  = diallylbis(4-pyridyl)silane) was carried out. The self-assembly of CdCl 2 with the 1: 1 mixture of L 1 and L 2 produces only 2D [CdCl 2 (L 1 )(L 2 )] with heteroleptic ligands, whereas that of CdBr 2 with the 1: 1 mixture of L 1 and L 2 gives rise to the statistical mixture of 2D sheet [CdBr 2 (L 1 ) 2 ]·2H 2 O, 1D loop-chain [CdBr 2 (L 2 ) 2 ]·2CH 2 Cl 2 , and the 2D [CdBr 2 (L 1 )(L 2 )] with heteroleptic ligands. [ABSTRACT FROM AUTHOR]

This article presents a monolithic extraction unit with integrated stirring using carbon nanohorns and methacrylate-based compounds as monomers. The hybrid monolithic material was prepared by thermal polymerization at 70 °C for 24 h, and was applied for the extraction of UV-filters from waters and human urine samples. To achieve the integrated stirring unit, the monolith was grown over an ironware. Variables dealing with the polymerization mixture composition and the microextraction procedure were studied in depth. The resulting hybrid monolithic polymer was also characterized by scanning electron microscopy (SEM) and nitrogen intrusion porosimetry. The target analytes were quantified by UPLC-DAD, and the limits of detection were between 1 and 10 μg/L. The precision of the method (inter extraction units) expressed as relative standard deviation ranged from 5.4% and 7.9%. Also, relative recoveries values of the analyte spiked to swimming pool water and urine samples varied in the interval 72–124 and 71–114%, respectively. [ABSTRACT FROM AUTHOR]

Interfacial grafting was combined with aniline polymerization to modify nylon fibers for high and endurable conductivity. A large amount of acrylic acid grafted to the surfaces of nylon66 fibers. The grafted polyacrylic acid further promoted in situ polymerization of aniline within the interfacial layer of nylon fibers. The electric conductivity of the final nylon fibers reached an unprecedentedly value of 1.1 S/cm. The presence of strong adhesion between polyaniline layer and nylon fibers further significantly promoted the rub resistance and water resistance of conductive fibers. [ABSTRACT FROM AUTHOR]

In the present study, an adsorbent based on polyaniline-magnetic graphene oxide nanocomposite (MGO@PANI) was synthesized via in situ polymerization of an aniline monomer using ammonium persulfate as an oxidant in acidic medium for enhanced removal of ciprofloxacin (CIP) from aqueous solution. The surface functionality, morphology and elemental composition of the newly synthesized MGO@PANI were analyzed by FT-IR, FE-SEM, and EDX techniques. The adsorption efficacy of MGO@PANI was evaluated by monitoring the adsorption behavior of CIP antibiotic from aqueous samples. The effective factors on CIP adsorption such as solution pH, adsorbent dosage, contact time, concentration and temperature were investigated. The results revealed that MGO@PANI exhibits high adsorption efficiency with 97% removal of CIP (pH 6, dosage 20 mg, time 30 min at room temperature). The experimental data were well fitted to Freundlich adsorption isotherm suggesting multilayer pattern for adsorption process and the adsorption kinetics followed pseudo-second-order kinetics. Additionally, the thermodynamic study revealed that the CIP adsorption onto MGO@PANI was endothermic and indicated chemisorption mechanism. [ABSTRACT FROM AUTHOR]

Wettability-switchable bacterial cellulose/polyhemiaminal nanofiber aerogels were successfully prepared by a facile in situ polymerization of paraformaldehyde and 4,4′-diaminodiphenyl ether. The resultant aerogels displayed an interconnected porous structure, superior porosity, low density as well as hydrophobic-oleophilic properties. The aerogels could not only quickly and efficiently absorb the variety of oils or organic solvents from water, but also completely release the adsorbates in acid aqueous solutions by the aid of wettability switch (from hydrophobicity-oleophilicity to underwater superoleophobicity). Furthermore, the aerogels can continuously collect oils both on the water surface and in water-in-oil emulsions by a peristaltic pump. [ABSTRACT FROM AUTHOR]

A NaOH/urea (or thiourea) solvent system capable of dissolving cellulose at lower temperatures is a breakthrough in cellulose chemistry, but dissolution of cellulose with a degree of polymerization (DP) greater than 740 in NaOH/urea (or thiourea) at low temperature will be inadequate due to its limited dissolving capacity. It is known that the addition of additives to a precooled NaOH system enables the dissolution of more cellulose with a higher DP. Therefore, the development of new aqueous NaOH/additive solutions is of interest to the scientific community. Considering that sodium sulfamate has two hydrogen bond donors and four hydrogen bond acceptors, which is similar to urea (or thiourea) with its four hydrogen bond donors and three acceptors, in the present work a different source of commercial dissolving pulps with DP higher than 740 was selected as cellulose raw material, and the dissolving capacities of mixed aqueous solutions of 7 wt% NaOH and 0.05-0.6 wt% sodium sulfamate were examined. Dissolution of cellulose in dissolving pulps using a 7% NaOH/0.1% sodium sulfamate aqueous solution improved upon the addition of sodium sulfamate, and when the addition of sodium sulfamate was optimal, the amount of dissolved cellulose in three dissolving pulps was increased by 25.6, 28.7 and 17.9%, respectively. This effect is likely due to the participation of sodium sulfamate as a hydrogen bond-donating and hydrogen bond-accepting additive that promotes dissolution of cellulose in NaOH aqueous solution. [ABSTRACT FROM AUTHOR]

Developing facile and mild strategy to construct multi-enzymes immobilization system has attracted considerable attentions in recent years. Here a simple immobilization strategy called visible light induced graft polymerization that can simultaneously and separately encapsulate two kinds of enzymes on one polymer film was proposed. Two incompatible enzymes, trypsin and transglutaminase (TGase) were selected as model dual-enzymes system and simultaneously immobilized on two sides of low-density polyethylene (LDPE) film. After immobilization, it was found that more than 90% of the enzymes can be embedded into dual-enzymes loaded film without leakage. And the activities of both separately immobilized enzymes were higher than the activities of mixed co-immobilized enzymes or the sequential immobilized ones. This dual-enzymes loaded film (DEL film) showed excellent recyclability and can retain >87% activities of both enzymes after 4 cycles of utilization. As an example, this DEL film was used to conjugate a prodrug of cytarabine with a target peptide. The successful preparation of expected product demonstrated that the separately immobilized two enzymes can worked well together to catalyze a two-step reaction. [ABSTRACT FROM AUTHOR]

In this work, a novel kind of magnetic, core-shell structured and surface molecularly imprinted polymers (MMIPs) for the recognition of salicylic acid (SA) was facilely synthesized through a surface imprinting and sol-gel polymerization approach. The as-synthesized MMIPs exhibit uniform core-shell structure and favorable magnetic properties with a saturation magnetization of 22.8 emu g −1 . The binding experiments demonstrated that MMIPs possessed high binding and specific recognition capacity, as well as fast binding kinetics and phase separation rate. The maximum binding capacity of MMIPs is around 36.8 mg g −1 , nearly 6 times that of the magnetic non-imprinted polymers (MNIPs). Moreover, the selectivity experiments show that all the relative selectivity coefficients towards SA over its structure analogs are higher than 18, further indicating the markedly enhanced binding selectivity of MMIPs. Furthermore, the MMIPs were successfully applied for the determination of SA in environmental water samples with the recovery rates ranging from 94.0 to 108.0 %. This strategy may provide a versatile approach for the fabrication of well-defined molecularly imprinted polymers on nanomaterials for the analysis of complicated matrixes. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles have been widely used as support core for fast separation, which could be directly separated from complicated matrices using an external magnet in few minutes. Surface imprinting based on magnetic core has shown favorable adsorption and separation performance, including good adsorption capacity, fast adsorption kinetics and special selectivity adsorption. Reversible addition–fragmentation chain transfer (RAFT) is an ideal choice for producing well-defined complex architecture with mild reaction conditions. We herein describe the preparation of well-constructed magnetic molecularly imprinted polymers (MMIPs) for the recognition of benzimidazole (BMZ) residues via the microwave-assisted RAFT polymerization. The merits of RAFT polymerization assisting with microwave heating allowed successful and more efficient preparation of well-constructed imprinted coats. Moreover, the polymerization time dramatically shortened and was just 1/24th of the time taken by conventional heating. The results indicated that a uniform nanoscale imprinted layer was formed on the Fe 3 O 4 core successfully, and enough saturation magnetization of MMIPs (16.53 emu g −1 ) was got for magnetic separation. The desirable adsorption capacity (30.18 μmol g −1 ) and high selectivity toward template molecule with a selectivity coefficient ( k ) of 13.85 of MMIPs were exhibited by the adsorption isothermal assay and competitive binding assay, respectively. A solid phase extraction enrichment approach was successfully established for the determination of four BMZ residues from apple samples using MMIPs coupled to HPLC. Overall, this study provides a versatile approach for highly efficient fabrication of well-constructed MMIPs for enrichment and determination of target molecules from complicated samples. [ABSTRACT FROM AUTHOR]

We reported a novel and effective strategy to achieve higher continuity at a lower volume fraction of interphase by using compatibilizers in ternary blend consisting of PVDF, PS and HDPE. PVDF-g-PS was synthesized by electron beam radiation induced free radical graft copolymerization reaction and PVDF-g-PS was characterized by FTIR, DSC and 1 H NMR. PVDF-g-PS showed effective compatibilization in PVDF/PS binary blend. The phase size of PVDF/PS binary blend was decreased at addition of PVDF-g-PS. For phase morphology development, morphology of uncompatibilized PVDF/PS/HDPE (52/6/42 vol%) ternary blend revealed a part of PS droplets situated in PVDF/HDPE interface, the other part was located inside HDPE phase. Whereas, compatibilized blend showed more and more PS migrate to PVDF/HDPE interface. When adding 7% PVDF-g-PS, PS droplets formed into uniform layer self-assembly arrayed at interface, then tri-continuous morphology was formed and continuity of PS phase increased by 32%, ultralow percolation threshold ternary blend was successfully achieved. [ABSTRACT FROM AUTHOR]

In comparison to monometallic controls, bimetallic olefin polymerization catalysts often exhibit superior performance in terms of higher polyolefin Mw, higher comonomer incorporation, and higher polar comonomer tolerance. However, using cooperating catalyst centers to modulate stereoselectivity in α-olefin polymerizations is relatively unexplored. In this contribution, the monometallic Hf(IV) complex, L¹-HfMe2 (catalyst A, L¹ = 2,6-diisopropyl-N-{(2-isopropylphenyl)[6-(naphthalen-1-yl)pyridin-2-yl]methyl}aniline), and homo-bimetallic Hf(IV) complexes, L²-Hf2Me5 (catalyst B) and L²-Hf2Me4 (catalyst C) (L² = N,N'-{[naphthalene-1,4-diylbis(pyridine-6,2-diyl)]bis[(2-isopropylphenyl)methylene)]bis(2,6-diisopropylaniline}), are activated with Ph3C+B(C6F5)4- and investigated in propylene and 1-octene homopolymerizations. In propylene polymerizations, the conformationally flexible catalyst B-derived bimetallic dicationic catalyst produces higher Mw polypropylene (up to 7.8×), higher total stereo- and regiodefect densities (up to 3.5×), and lower Tm (by as much as ~14 °C) versus the monometallic catalyst A-derived control. In 1-octene polymerizations, the conformationally flexible catalyst B-derived bimetallic dicationic catalyst induces greatly reduced isotacticity (23% reduction in [mmmm]) versus the catalyst A-derived monometallic control ([mmmm] > 99%). Interestingly, conformationally flexible catalyst B-derived cationic bimetallic Hf catalysts are also known to undergo rapid intramolecular/intermetal methyl exchange and to exhibit strong Hf...Hf cooperative enchainment effects in ethylene homo- and copolymerizations. Steric effects and intramolecular intermetal chain transfer likely both contribute to the increased isotactic polyolefin stereo- and regiodefect content. [ABSTRACT FROM AUTHOR]

We have developed a novel poly-(1,4-anthraquinone)/carbon nanotube (P14AQ/CNT) nanocomposite via a simple in situ polymerization, to improve the rate performance of the lithium-ion battery. The characterization results show that CNT can be homogeneously distributed in the composite. When utilized as the cathode material for lithium-ion battery, the P14AQ/CNT composite exhibits excellent cycling stability with a specific capacity (233 mAh g −1 ) within 100 cycles, as well as the significantly enhanced rate performance (165 mAh g −1 at 5 C rate). [ABSTRACT FROM AUTHOR]

Composites containing conductive polymers and Au and Ag nanoparticles were introduced into the environmentally sensitive poly(N-isopropylacrylamide) hydrogel channels. The composites were synthesized directly in the channels by two phase polymerization procedure. In the first step the unmodified hydrogel was placed in a solution containing the oxidizing agent (HAuCl 4 or AgNO 3 ), and in the second step it was placed in a solution of aniline in nitrobenzene. The presence of polyaniline and metal nanoparticles increased conductivity of both types (ionic and electron) while the hydrogel properties, such as: flexibility, plasticity and ability to phase transition, were preserved. The presence of nobel-metal nanostructures added catalytical activity to the new materials. Optical and SEM investigations revealed that polymer-metal composites were uniformly distributed in the entire gel samples. NIPA-PANI-Au composites exhibited a sharp volume phase transition in response to changes in temperature and ionic strength. That behavior was similar to unmodified poly (N-isopropylacrylamide) hydrogel. The new material was electroactive and had electrocatalytical properties towards electrooxidation of ethanol. Electroactivity of the modified gel was a strong function of the swelling ratio; the shrinking process enhanced the voltammetric response. [ABSTRACT FROM AUTHOR]

Fluorescent molecularly imprinted polymers (MIPs) have received considerable attention for their promising applications in sensing, imaging and diagnostics. Different synthetic methods have been reported to prepare fluorescent MIPs. Here, one-pot polymerization method was developed to synthesize fluorescent MIP nanoparticles (NPs) bearing a suitable fluorescent label as the fluorescence acceptor. The MIP NPs can emit strong fluorescence based on fluorescence resonance energy transfer (FRET) when they bind to analytes acting as the fluorescence donor. The one-pot synthetic method is straightforward, less time-consuming and easy to optimize the loading of fluorescence acceptor. Additionally, a preliminary microfluidic reactor was designed for preparing such fluorescent MIP NPs with more uniform size in a continuous process for the first time. The fluorescent MIP NPs can be used for selective detection of the analytical target in a FRET-based turn-on fluorescence assay which is easy to carry out with no tedious separation steps. [ABSTRACT FROM AUTHOR]

Biobased thermoplastic elastomers are of interest for their merits, especially renewability and sustainability. In this work, a series of fully biobased linear comb poly(β-myrcene)- graft -poly( l -lactide) (PM- g -PLLA) copolymers consisting of interior rubbery block and exterior semicrystalline block were synthesized via ring-opening polymerization of l -lactide using hydroxylated poly(β-myrcene) as macroinitiator. To evaluate the effects of branch length and graft density of poly(β-myrcene) on the performances of these obtained copolymers, the chemical compositions and molecular weights, crystal structures and spherulite morphologies, phase morphologies, thermal and mechanical properties were systematically analyzed by various techniques. Analysis of NMR and GPC indicated that graft copolymers were successfully obtained as designed. Two distinct glass transitions corresponding to the two building blocks observed from both DMA and DSC measurements suggested the occurrence of microphase separation, which was further confirmed by SAXS and AFM morphological characterizations. Results of DSC, WAXD, and POM showed that the crystallization behavior of the graft copolymers depends on graft density and branch length. Tensile test suggested that the mechanical properties of graft copolymers depend on PM/PLLA composition, particularly graft density and branch length, which could be readily tailorable to different applications. [ABSTRACT FROM AUTHOR]

A series of polystyrenes (10-30k) end-functionalized with perfluoroalkyl (RF = C 7 F 16 , C 10 F 21 and C 13 F 27 ) groups were synthesized by atom transfer radical polymerization (ATRP) of styrene initiated by RF functionalized initiators and studied using optical transmission, differential scanning calorimetry and thermogravimetric analysis. Large decreases (≤40–50%) in optical transmission of the C 13 F 27 end functionalized PS were observed compared with the non-functionalized isobaric PS consistent with the formation of large RF domains. This association increases with RF concentration and length with the latter being especially significant. A melting endotherm attributed to semi-crystalline perfluorocarbon domains was seen only for a low MW(10k) C 13 F 27 end functionalized sample. Interestingly, compared with the matching PS, the glass transition temperatures of the RF-PS polymers were found to decrease by as much as 15 °C and with the RF lengths having the larger effects. [ABSTRACT FROM AUTHOR]

New aluminum(III) pentacoordinated compounds were obtained from reactions of 2-(2 H -benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol ( 1 ) and 2-(1 H -benzimidazol-2-yl)phenol ( 2 ) with two equivalents of Al(CH 3 ) 3 ( 3 and 4 respectively) or Al(CH 3 ) 2 Cl ( 5 and 6 ). Ligands are bidentate, the aluminum is the center of a spiranic structure bound to two fused and planar tetracyclic systems. Solution of compound 6 in DMSO afforded a new ionic compound ( 7 ), which has two bidentate ligands and two DMSO molecules bound to a cationic aluminum with chloride as counterion. Compounds were characterized by 1 H, 13 C and 27 Al NMR, mass spectrometry, elemental analysis and infrared spectroscopy. Crystals of compounds 3 , 4 and 7 were submitted to X-ray diffraction analysis. Intra and intermolecular weak interactions were analyzed using the Quantum Theory of Atoms in Molecules (QTAIM) and the noncovalent interaction plots (NCI). [ABSTRACT FROM AUTHOR]

Actin polymerization and assembly into stress fibers (SFs) is central to many cellular processes. However, how SFs form in response to the mechanical interaction of cells with their environment is not fully understood. Here we have identified Piezo2 mechanosensitive cationic channel as a transducer of environmental physical cues into mechanobiological responses. Piezo2 is needed by brain metastatic cells from breast cancer (MDA-MB-231-BrM2) to probe their physical environment as they anchor and pull on their surroundings or when confronted with confined migration through narrow pores. Piezo2-mediated Ca2+ influx activates RhoA to control the formation and orientation of SFs and focal adhesions (FAs). A possible mechanism for the Piezo2-mediated activation of RhoA involves the recruitment of the Fyn kinase to the cell leading edge as well as calpain activation. Knockdown of Piezo2 in BrM2 cells alters SFs, FAs, and nuclear translocation of YAP; a phenotype rescued by overexpression of dominant-positive RhoA or its downstream effector, mDia1. Consequently, hallmarks of cancer invasion and metastasis related to RhoA, actin cytoskeleton, and/or force transmission, such as migration, extracellular matrix degradation, and Serpin B2 secretion, were reduced in cells lacking Piezo2. [ABSTRACT FROM AUTHOR]

Thermal degradation and chemical degradation are among the key issues affecting mechanical properties and ultimately utilization of natural fibre reinforced polymer (NFRP) bio-composites. In our previous work, mathematical models were used to identify thermal processing boundaries and to recognize an optimized window for NFRP bio-composites. In this study, a correlation relating the tensile strength of flax/PLA bio-composite to the processing temperature history is proposed. For the first time, an existing linear model, which corresponds to the tensile strength of natural polymers and their degree of polymerization, has been combined with reaction kinetics to predict the tensile strength of NFRP bio-composites as a function of processing temperature history. In addition, a non-linear model has been proposed which shows a significant improvement for longer periods of time, compared with the linear model. The model is based on the underlying thermo-chemical degradation processes occurring during manufacture of NFRP bio-composites. The model is capable of predicting the tensile strength of the bio-composite within 10% error. [ABSTRACT FROM AUTHOR]

Solid–liquid suspensions are commonly encountered in industrial production processes. The dynamics of the solid–liquid suspension behaviors depends on both liquid–particle and particle–particle interactions. In this work, an Eulerian–Eulerian model is used to characterize the suspension dynamics and the role of particle–particle interactions in solid-liquid mixing vessels is studied. The collision and friction of coarse particles are considered by calculating solid pressure and viscosity based on a modified kinetic theory of granular flow (KTGF). The solid phase holdup and the velocity are predicted and compared with semi-empirical models. Effects of several key model parameters are investigated as well. The comparison between computational fluid dynamics simulations and experimental data shows a satisfactory agreement, which validates the robustness of the multi-fluid model. The proposed model is then applied to study the influences of particle size and solid loading for exploring the importance of particle–particle interactions. The obtained simulation results show that particle–particle interactions can influence suspension characteristics in the case of large particle size and high solid loading. [ABSTRACT FROM AUTHOR]

Hydrogels derived from 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) monomer are attractive materials for producing soft-biomimetic actuators, superabsorbents, and biomaterials. Here we present a simple synthetic strategy to prepare mechanically strong poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) hydrogels with self-healing ability. Initiator-free polymerization of AMPS in aqueous solution in the presence of Laponite nanoparticles and N , N ′-methylenebis(acrylamide) (BAAm) cross-linker produces hybrid-cross-linked hydrogels with excellent mechanical properties. The hydrogels exhibit a high modulus (~ 700 kPa), compressive strength (45 MPa at ~ 90% strain), good resilience, and self-healing. The results reveal that the incorporation of Laponite and BAAm separately into the physical PAMPS network weakens hydrogen bonding interactions while their combination enhances these interactions and generate water-insoluble hydrogels with a high modulus. The superior properties of hybrid cross-linked hydrogels are attributed to strengthening of the interactions between chemically cross-linked PAMPS chains and nanoparticles. The hybrid approach presented here might enable preparation of mechanically strong nanocomposite hydrogels consisting of strongly or weakly charged polymer chains of different architecture. [ABSTRACT FROM AUTHOR]

The impact of double bond modification by gem -difluorocyclopropanation (gDFC) in poly(norbornenes) backbone on their gas transport properties was studied for the first time. With this aim the research of gDFC of polynorbornene (PNB) and poly(5-trimethylsilylnorbornene) (PNBSi) in the conditions of sodium chlorodifluoroacetate thermolyses at 180–190 °C in methyl benzoate solution were carried out. The starting poly(norbornenes) were synthesized via ring-opening metathesis polymerization of the corresponding monomers mediated by the first generation Grubbs’ catalyst. The degree of double bonds conversion into the gem -difluorocyclopropane and the molecular weight of modified polymers could be controlled by adjusting the reaction time, sodium chlorodifluoroacetate amount, and polymer concentration in reaction mixture, as well as by addition of inhibitor. The bulky Me 3 Si-substituent hindered the modification of double bonds in poly(norbornenes)’ backbone. The gDFC decreased the thermal stability of poly(norbornenes). However, the films of modified polymers demonstrated high stability during storage at the ambient conditions, especially in comparison with unmodified polynorbornene. The introduction of gem -difluorocyclopropane in poly(norbornenes) backbone increased their gas permeability coefficients P especially strongly for PNB. Simultaneously the values of ideal selectivity α ij = P i /P j were not changed or slightly increased. The noted growth of P was caused by increases in the solubility coefficients S. To elucidate the role of the two types of modification fragment ( CF 2 and O ) of double bonds a sample was prepared that included both types of the fragments. It was distinguished by increased P and α ij values. So, a new and simple approach improving the gas permeation properties of metathesis polynorbornenes was developed. It may be extendable to broader families of polydienes and other polymers containing double bonds in the backbone. [ABSTRACT FROM AUTHOR]

Research on biodegradable films is a topic of strategical interest in the field of food science and technology. These films are membranes conformed by biopolymers that interact strongly with water and they generally require the addition of plasticizer in order to improve its integrity and mechanical properties. The study of the hydration and water transfer properties through these films, as well as understanding in what way the thickness and the addition of the plasticizer affect these properties, is essential for a better knowledge and optimization of the required protective function of these membranes. In this work the hydration kinetics and water transport through biodegradable films obtained from yeast biomass were studied, in order to know the performance against changes in thickness and glycerol content. Hydration kinetics experiments allowed obtaining solubility of water in the matrix film, and the diffusion coefficient. Results demonstrated that when glycerol content was increased, the solubility of water increased while diffusion remained constant. Moreover, when the film thickness was grown, the solubility of water decreased but the diffusion increased. Experimental water vapour permeability obtained through traditional cup method was compared to the theoretical permeability calculated by multiplying diffusion coefficient and water solubility. The good agreement observed between both values allowed the analysis of how solubility and diffusion contributed to permeability. As a result this study revealed that the increment of permeability with the plasticizer content was due to the increase in solubility, while the effect of the thickness increasing permeability was dominated by diffusion. [ABSTRACT FROM AUTHOR]

The preparation of a set of amphiphilic polystyrene-b-polyglycidol (PS-b-PGL) diblock copolymers and their characteristics in aqueous media are described. The copolymers were prepared via anionic polymerisation starting from the synthesis of a polystyrene macroinitiator terminated by ethylene oxide, followed by anionic polymerisation of glycidol 1-ethoxyethyl ether to obtain a poly(1-ethoxyethyl glycidyl ether) block. The ethoxyethyl blocking groups of the hydroxyls were subsequently removed by hydrolysis. The copolymers differed in polymerisation degree of the polyglycidol block with DP values equal to 13, 43, 68 and 125, whereas the DP of polystyrene was 29. Two different organic media, N,N-dimethylformamide and dioxane, were used to prepare copolymer solutions dialysed afterward against water. The behaviour of diblock copolymers in water, their self-assembly and the size parameters of their aggregated structures were determined using dynamic light scattering. The critical micelle concentration (CMC) did not depend on the initial solvent and linearly increased with increasing content of hydrophilic glycidol units in the copolymer chain. However, above the CMC, the dispersions obtained from DMF contained a significant fraction of large aggregates. In the case of dioxane after dialysis, only one population of particles of the sizes, which can be related to typical core–shell micelles, was observed. Cryogenic transmission electron microscopy images revealed the presence of spherical objects and confirmed their sizes. PS-b-PGL micelles were highly stable and did not dissociate even after dissolution of their dispersions to concentrations below the CMC. [ABSTRACT FROM AUTHOR]

The fabrication and biomedical applications of fluorescent polymeric nanoparticles (FPNs) with aggregation-induced emission (AIE) feature has attracted the most intensive research interest since the first discovery of AIE phenomenon by Tang' group. Although great attention has been devoted to preparation of AIE-active FPNs, an efficient, facile and versatile strategy is still highly desirable to advance their biomedical applications. In this work, a one-pot microwave-assisted multicomponent tandem polymerization was proposed to fabricate AIE-active FPNs based on a microwave-assisted Kabachnik–Fields (KF) reaction, which involves the conjugation of aldehyde group containing polyethylene glycol (CHO-PEG-CHO) and amino-group terminating AIE dye (H 2 N-PhE-NH 2 ) using diethyl phosphate as the lock. The KF reaction can occur under rather facile and mild experimental conditions (e.g. absent of catalyst and solvents, air atmosphere) with the assistance of microwave irradiation in 5 min. The resultant (PEG-DP-PhE) copolymers would self-assemble into FPNs that showed high water dispersibility and enhanced fluorescence intensity. The desirable cytocompatibility and cell uptake efficiency of PEG-DP-PhE FPNs endow their great potential for biomedical applications. Considering the convenience and effectiveness, the method should be promising for fabrication of many AIE-active functional materials with great application potential. [ABSTRACT FROM AUTHOR]

A chemoselective polymerization platform was designed for flow synthesis of telechelic thiol-functionalized polymers, amphiphilic block copolymers and noble metal nanoparticles. By assembling Novozyme435 packed tubular reactor, α-thiol-ω-hydroxyl telechelic poly(ε-caprolactone) were efficiently obtained via metal-free and protecting-group-free ring-opening polymerizations. Fast polymerization, high end group fidelity, controlled molecular weight and distribution were achieved under the flow conditions. The resultant mercapto-polymer solution derived from the enzymatic process was directly pumped into the subsequent microreactor system (isolation-step-free) to prepare amphiphilic poly( N -vinylpyrrolidone)- block -poly(ε-caprolactone). Relative narrower molecular weight distribution was observed in contrast to the batch mode. Moreover, silver nanoparticles were facilely fabricated in flow fashion by using mercapto-polymer solution as the stabilizer without isolation. The surface plasma resonance band absorption of nanoparticles could be adjusted by regulating the flow rates. This chemoselective polymerization platform would provide a powerful toolbox for the novel polymer and nanomaterial preparations. [ABSTRACT FROM AUTHOR]

A polymer-based adsorption medium with molecular recognition ability for homologs of pyrethroids was prepared by atom transfer radical polymer iration using a fragment imprinting technique. Phenyl ether-biphenyl eutectic was utilized as a pseudo-template molecule, and the adsorption medium prepared was evaluated by solid-phase extraction and gas chromatography. Selectivity of the medium for pyrethroids was evaluated using it as solid phase extraction packing by Gas Chromatography. The results demonstrated that the absorption amount of bifenthrin, fenpropathrin, permethrin, cypermethrin, fenvalerate, Dursban and pentachloronitrobenzene for molecularly imprinted polymers were 2.32, 2.12, 2.18, 2.20, 2.30, 1.30 and 1.40 mg g −1 , respectively, while the non-imprinted polymers were 1.20, 1.13, 1.25, 1.05, 1.20, 1.23 and 1.32 mg g −1 , respectively. The rebinding test based on the molecularly imprinted solid phase extraction column technique showed the recoveries of honey sample spiked with seven insecticides within 88.5–106.2%, with relative standard deviations of 2.38–5.63%. Finally, the method was successfully applied to the analysis of pyrethroids in a honey sample. [ABSTRACT FROM AUTHOR]

Presence of the tertiary amine in the reaction mixture during surface-initiated atom transfer radical polymerization (SI-ATRP) possess dual functionality, reduction of the graphene oxide (GO) and proceed the poly(methyl methacrylate) (PMMA) chain growth simultaneously. In the certain ratio between the ligand and GO, the slight reduction of the GO can be achieved and thus fine tuning of the conductivity is possible. Such benefits were utilized in the development of the novel dispersed phase based on GO-PMMA hybrid particles and their silicone oil suspensions for which their electro-responsive capabilities were investigated. This approach provides system which is very effective at very low particles concentrations (10 wt%) and serving the shear stresses from 5 to 95 Pa depending on the conductivity of particles and applied external electric field. [ABSTRACT FROM AUTHOR]

The physicochemical properties of gliadin upon mild thermal treatment were studied in terms of polymerization behavior, conformation and viscoelasticity. Gliadin samples were heated at 40, 60 and 90 °C for up to 20 min. Results showed that α-gliadin started to polymerize via disulfide (SS) bonds before γ-gliadin at 90 °C, resulting in the extractability loss in aqueous ethanol. β-Turn and specific β-sheet structures were partially conversed to α-helices during thermal treatment. Rearrangement of non-covalent forces might contribute to viscosity loss of gliadin at 40 and 60 °C. However, the elevated elasticity at 90 °C was mainly due to gliadin polymerization while the viscosity variation was resulted from combined effects of non-covalent forces and covalent SS bonds. This study could offer insight into the variation of gliadin characteristics during the early baking process. [ABSTRACT FROM AUTHOR]

To address the effect of absence of NaCl on myosin heavy chain polymerization during two-step surimi gelation (different setting temperatures/times −5 °C/24 h and 30 °C/30 min-followed by heating at 90 °C/30 min) were considered. In gel samples made without salt (Lot A), no myosin heavy chain (MHC) polymerization was observed, only aggregation, as indicated by the electrophoresis in polyacrylamide/agarose gel profile. Moreover, these gels were characterized by weakly stabilized protein networks as denoted by the dynamic oscillatory measurement and FTIR analysis, resulting in poor quality gels. On the other hand, in gels made with added salt, MHC polymerization occurred, as evidenced by the electrophoresis, and the gelation resulted in a well-stabilized protein network with good physicochemical properties. [ABSTRACT FROM AUTHOR]

A novel direct Z-scheme P-containing tungsten trioxide/polyimide (PWO/PI) photocatalyst was synthesized by an in-situ solid-state polymerization strategy to enhance the visible-light photocatalytic oxidation capacity of PI. The effects of polymerization temperature and PWO content on the physicochemical properties of PWO/PI composites and photocatalytic degradation efficiency of imidacloprid were investigated. The photocatalysts were characterized by X-ray powder diffraction, Fourier transformed infrared spectra, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, UV–vis diffused reflection spectra and N 2 adsorption-desorption isothermals. The results showed that the photocatalysts with visible-light photocatalytic activity can already be prepared at 300 °C. The PWO/PI composites exhibited a lamellar structure and PWO was wrapped by PI. After PWO was introduced, there was a significant interaction between PWO and PI, and the visible light response of photocatalysts was also improved. The visible-light photocatalytic degradation efficiency of imidacloprid on 3% PWO/PI-300 composite was about 3.2 times of commercial P25, and the corresponding pseudo-first-order rate constant was about 2.9 times of pristine PI. The Z-scheme photocatalytic system of PWO/PI composites was confirmed by the electron spin resonance technology, terephthalic acid photoluminescence probing technique, reactive species trapping experiments, X-ray photoelectron spectroscopy and photoluminescence of PWO/PI composites and pristine photocatalysts. [ABSTRACT FROM AUTHOR]

The oriented 1D nanostructure arrays of PANI have great potential applications in various devices. In this paper, we report a simple and facile one-step template-free way to assemble highly oriented arrays of PANI nanofibers using chemical oxidative polymerization on the glass and polymer flexible substrates. The diameters of the individual nanofibers range from 10 nm to 33 nm, and the average length of the aligned nanofibers is up to 48–139 nm. The PANI nanofiber arrays can be uniformly distributed on the whole substrates via this method, which are confirmed by the results of SEM images and Raman mapping. The as-prepared PANI nanofiber arrays can be potentially used in flexible low-voltage electronics, anti coatings, self-cleaning surfaces and chemical sensors, and so on. [ABSTRACT FROM AUTHOR]

Non-iridescent structural colors and lotus effect universally existing in the nature provide a great inspiration for artificially developing angle-independent and high hydrophobic structurally colored films. To this end, a facile strategy is put forward for achieving superhydrophobic structurally colored films with wide viewing angles and high visibility based on bumpy melanin-like polydopamine-coated polystyrene particles. Here, hierarchical and amorphous structures are assembled in a self-driven manner due to particles’ protrusive surfaces. The superhydrophobicity of the structurally colored films, with water contact angle up to 151°, is realized by combining the hierarchical surface roughness with a dip-coating process of polydimethylsiloxane-hexane solution, while angle-independence revealed in the films is ascribed to amorphous arrays. In addition, benefited from an essential light-absorbing property and high refractive index of polydopamine, the visibility of as-prepared colored films is fundamentally enhanced. Moreover, the mechanical robustness of the films is considerably boosted by inletting 3-aminopropyltriethoxysilane. This fabrication strategy might provide an opportunity for promoting the open-air application of structurally colored coatings. [ABSTRACT FROM AUTHOR]