Conjugated polymers with anionic dyes: Synthesis,properties, and sensing ability for nucleosides,DNA, and BSA

The reaction of N-(2,4-dinitrophenyl)pyridinium chloride (salt[Cl⁻]) with sodium salts of anionic dyes, such as acid red 52 (AR52), acid violet 49 (AV49), and coomassie brilliant blue G-250 (CBBG250) involves an anion exchange between the chloride anion of salt(Cl⁻) and sulfonium anion of the dyes, resulting in the generation of novel Zincke salts, namely, salt(AR52), salt(AV49), and salt(CBBG250), respectively. Reactions of salt(AR52), salt(AV49), and salt(CBBG250) with piperazine in the absence of catalysts resulted in the opening of the pyridinium ring to yield ionic polymers comprising units of 5-piperazinium-2,4-dienylideneammonium and the corresponding dye anion, namely polymer(AR52), polymer(AV49), and polymer(SBBG250), respectively. The corresponding model compounds for the polymers were also synthesized by reacting salt(AR52), salt(AV49), and salt(CBBG250) with piperidine. Polymer(AV49) and polymer(SBBG250) were found to be suitable for the detection of nucleosides, DNA, and proteins, realized by monitoring the changes in their UV–vis absorption spectra, arising from the anionic dyes within the polymers. The polymers and the model compounds were electrochemically oxidized in solution.     

Synthesis and properties of phenyl carboxyl polydimethylsiloxane for fabrics treatment

A series of phenyl carboxyl polydimethylsiloxane (PCPDMS) with different relative molecular mass, phenyl and carboxyl content was prepared through condensation reaction and equilibrium polymerization. The effects of reaction conditions on the conversion were investigated, to determine the optimum reaction conditions. According to the thermal gravity analysis of PCPDMS with different relative molecular mass and phenyl content, it was found that the large relative molecular mass can improve the thermal stability of PCPDMS. The thermal stability of PCPDMS was significantly higher than carboxyl polydimethylsiloxane. Moreover, the PCPDMS emulsions were also prepared for the fabrics treatment. The emulsions can improve the wrinkle resistance, smoothness, elasticity, and other properties of the fabrics. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45866.     

Characterization and dual functionalization of polystyrene with propionic anhydride and cyanate derivatives

First, Friedel–Crafts reactions were used for the acylation process. For this, polystyrene (PS) was reacted with propionic anhydride in the presence of Lewis acid catalyst. The amount of acyl group linked PS as a result of acylation has been identified as volumetric. Second, the bromination and lithiation reactions of acylated PS containing carbonyl groups were realized. Also, the lithiated PS containing acyl groups has been modified a second time with various isocyanates and isothiocyanate derivatives in the presence of n?BuLi catalyst. Some important reaction parameters were assigned in order to optimize the process. The structure all of the products were characterized by Fourier transform infrared, ¹H NMR (Proton Nuclear Magnetic Resonance), and thermogravimetric methods. In addition, reaction yields were determined according to the result of elemental analysis. Dual functionalization yields were realized between 62.2% and 69.9%. For kinetic analysis, the TG/DTG (Thermal Gravimetric Analysis/Differantial Thermal Analysis) data obtained at three different heating rates were processed by Kissinger–Akahira–Sunose method. The results demonstrated that the acylation reaction, bromination and lithiation reactions, and dual functionalization reactions with cyanate derivatives can be carried out to obtain a significantly functionalized polymer. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1351‐1362, 2013     

POSS‐based fluorinated azobenzene‐containing polymers: Photo‐responsive behavior and evaluation of water repellency

The photoresponsive polyhedral oligomeric silsesquioxanes (POSS) based fluorinated azobenzene‐containing polymers were prepared and characterized by NMR, FT‐IR, GPC, XRD, TG and UV–Vis spectra. The thermal property of the polymers was improved by the introduction of POSS cage. The trans‐cis photoisomerization of the polymers in solution was similar to that of the fluorinated azobenzene monomer and in accordance with the first‐order reaction kinetics equation within the first 250 seconds UV irradiation. The cotton fabrics coated with the polymers showed excellent water repellency and possessed switchable wettability under UV irradiation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43540.     

Poly(alkyl lactate acrylate)s having tunable hydrophilicity

Four alkyl lactates and alkyl lactate acrylates having methyl, ethyl, propyl, and butyl as alkyl moiety were synthesized by azeotropic distillation. Their formation was confirmed by Fourier transform infrared (FTIR), mass, ¹H nuclear magnetic resonance (NMR) and proton decoupled ¹³C NMR spectroscopic techniques. Solution polymerization was carried out for these alkyl lactate acrylates and the formed homopolymers were characterized by FTIR, ¹H NMR, proton decoupled ¹³C NMR spectroscopic, and gel permeation chromatographic techniques. Shear thinning behavior was observed for all the polymers. Wide angle X‐ray Diffraction studies showed that the polymers were amorphous in nature and also exhibited odd‐even effect among alkyl lactate groups with respect to average molecular interchain spacing. Depending on the length of the alkyl lactate groups, relative humidity and time, the hydrophilicity of the polymers decreased with increase in the length of the alkyl lactate group among the odd and even series. Among the studied polymers, poly(ethyl lactate acrylate) may have the potential for hydrogel applications, due to its highly hydrophilic nature. T_g decreased with increase in length of alkyl lactate groups. Trend observed on the thermal stabilities of poly(alkyl lactate acrylate)s could be explained on the basis of average molecular interchain spacing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40962.     

Reactive organophosphorus flame retardant for transparency,low-flammability,and mechanical reinforcement epoxy resin

To maintain transparency and improve flame retardancy and mechanical properties of epoxy resin, a reactive organophosphorus flame retardant (DPDDM) was designed and synthesized, which was derived from 3,4-dihydroxybenzaldehyde, 4, 4′- diamino diphenylmethane and 9,10-dihydro-9-oxa –10- phosphaphenanthrene-10-oxidein two steps. Compared with neat epoxy resin (EP), the tensile strength and flexural strength of the EP with 5% DPDDM increased by 28.6% and 42.8%, respectively, indicating that DPDDM can significantly improve the mechanical properties of EP materials. Meanwhile, the DPDDM modified EP materials have good transparency and the EP with 5% DPDDM passed the V-0 rating and had the limiting oxygen index as high as 34%. Cone calorimeter test results showed that the heat release and smoke generation of the modified materials were significantly lower than the unmodified materials, which were reduced by 32.6% and 64.6%, respectively, indicating that the modified materials can greatly improve the safety of fire prevention. This work provides a new approach to prepare transparent epoxy resin with good mechanical properties and excellent flame retardancy.     

Influence of chloroacetate group on physical properties of natural rubber and its interaction with fillers

Filler–rubber composites were prepared by mixing chloroacetated natural rubber (CNR) with silica, carbon black (CB), or calcium carbonate using a two‐roll mill. The interactions between the CNR and fillers, including silica, carbon black, and calcium carbonate, were characterized based on glass transition temperature (T_g) and shear storage modulus (G′). The results showed that both the T_g and G′ values of the CNR‐Si composite were found to be higher than those of the CNR–CB and CNR–CaCO₃ composites, indicating the existence of the CNR and silica interaction. The outstanding direct interaction between the CNR rubber matrix and silica without using a coupling agent was believed to be due to hydrogen bonds that formed between the hydroxyls of the silanol groups of silica and the carbonyls in the chloroacetate groups of CNR molecules. Moreover, it was also found that silica dispersed and distributed in the CNR matrix much better than in the natural rubber matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43076.     

Polyols production by chemical modification of autocatalyzed ethanol‐water lignin from Betula alnoides

Betula alnoides lignin, recovered as a byproduct in autocatalyzed ethanol‐water pulping process, was converted into viscous polyether polyols through oxypropylation and liquefaction methods, with the aim of adding value to this byproduct. The oxypropylation reaction was performed by reacting autocatalyzed ethanol‐water lignin (AEL) with propylene oxide under the acidic and alkaline conditions at room temperature, respectively. In contrast, the liquefaction reaction was carried out using the mixed solvents of polyethylene glycol and glycerol at 160°C with sulfuric acid as a catalyst. The resulting polyether polyols from each method was characterized by Fourier transform‐infrared (FTIR), ¹H and ³¹P nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), and thermogravimetric analysis. Quantitative ³¹P NMR indicated that all the aliphatic hydroxyl group values of polyols increased significantly by the above two methods. More secondary hydroxyl groups (2.016 mmol/g) were obtained in the alkaline oxypropylation reaction, whereas more primary hydroxyl groups (4.296 mmol/g) were found in the liquefied product. GPC analysis showed that the alkaline oxypropylated product (M_w 3130 g/mol, M_n 2080 g/mol) and liquefied product (M_w 4990 g/mol, M_n 4630 g/mol) have higher molecular weights than AEL (M_w 2560 g/mol, M_n 1530 g/mol). Thermal stability analysis suggested that the polyether polyols have a lower degradation temperature than AEL. These polyols used as precursors in polyurethane synthesis give promising properties, which open new avenues of exploitation of AEL. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Exactly alternating silarylene—siloxane polymers: 6. Thermal stability and degradation behaviour

The thermal stability and degradation behaviour of a series of twelve different exactly alternating silarylene—siloxane polymers were investigated by several different methods including thermal gravimetric analysis (t.g.a.) in air and in nitrogen, long term (up to 48 h) high temperature (600° and 900°C) isothermal degradation in nitrogen, and rapid pyrolysis in helium. No weight loss was observed by t.g.a. until about 400°C, and two distinctly different mechanisms were observed, one for degradation in nitrogen (a single step process), and the other in air (a three step process). Under nitrogen, black, insoluble, carbon-hydrogen-silicon containing degradation products were obtained, which were stable in pure oxygen to at least 1100°C. In air, pure SiO₂ was obtained after heating to above 730°C. Isothermal investigations revealed that at temperatures of 600°C and above, weight loss by thermal degradation under a nitrogen atmosphere was completed in less than an hour, and the polymeric products which remained thereafter did not change any further even after 48 h at 900°C.     

2‐Mercapto thioxanthone as a chain transfer agent in free‐radical polymerization: A versatile route to incorporate thioxanthone moieties into polymer chain‐ends

2‐Mercapto thioxanthone (TX‐SH) was used as a chain transfer agent in free‐radical polymerization of methyl methacrylate (MMA) and styrene (St), by using 2,2′‐azobisisobutyronitrile (AIBN) as an initiator at 70°C. Chain transfer constants were found to be 1.41 and 0.12 for St and MMA, respectively. The use of TX‐SH as a chain transfer agent leads to the formation of polymers with thioxanthone (TX) end groups. The incorporation TX moiety was confirmed by spectral measurements. Polymers obtained this way were used as triplet photosensitizer in free‐radical polymerization of MMA in the presence of a hydrogen donor such as N‐methyldiethanolamine (MDEA). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3766–3770, 2007     

Fast swelling behaviors of thermosensitive poly(N‐isopropylacrylamide‐co‐methacryloxyethyltrimethyl ammonium chloride)/Na2WO4 cationic composite hydrogels

A facile method was explored to synthesize thermosensitive poly[N‐isopropylacrylamide (NIPAM)‐co‐methacryloxyethyltrimethyl ammonium chloride (DMC)]/Na₂WO₄ cationic hydrogels via copolymerization of NIPAM and DMC in the presence of Na₂WO₄. Na₂WO₄ acted as both a physical crosslinking agent and a porogen precursor. The hydrogels were characterized by Fourier transform infrared spectroscopy, energy dispersive X‐ray, thermogravimetry, environmental scanning electron microscopy, and transmission electron microscopy. Effects of various salt solutions, pH solutions on swelling were investigated. Thermosensitivity of the hydrogels were also investigated in various polar solvents at different temperatures. The resultant hydrogel showed a fast swelling rate and good salt tolerance. The hydrogels reached the swelling equilibrium within 10 min. Moreover, the swelling ratio of the hydrogels increased with the increase of the polarity of the solvent. In the water, the swelling ratio decreased with the increasing of temperature, but remained at a high level even at 80 °C since the pore structure weaken the lower critical solution temperature effect of PNIPAM. The swelling ratio increased instead in low polar solvent, while it became negligible in nonpolar solvent with the increasing of temperature. The whole swelling kinetics was fit for Schott's pseudo‐second order model. The hydrogels have a great potential as catalysts and smart materials. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46375.     

Mechanical and barrier properties of thermoplastic whey protein isolate/ethylene vinyl acetate blends

Crude oil is becoming scarcer and more expensive, resulting in alternative biobased or partially biobased materials gaining importance in the field of plastic packaging and encouraging the development of naturally derived, protein‐based plastics (Endres, 2009; Jones and McClements, Compreh. Rev. Food Sci. Food Safety 2010, 9, 374; Khwaldia et al., Compreh. Rev. Food Sci. Food Safety 2010, 9, 374). A strategy to improve extrusion processing behavior of proteins is the blending with other polymers. In this study ethylene vinyl acetate (EVA) was used for such purpose. The aim of this study was to determine the properties of blends of thermoplastic whey protein (TPP) and ethylene vinyl acetate (EVA). Mechanical and barrier properties were tested. Blends of differing TPP/EVA ratio were produced and extruded into flat films. Morphological analysis of the blends shows immiscibility of the TPP and EVA, greatly influencing the mechanical properties. Young's modulus measurements shows the values approached that of pure EVA with increasing EVA ratios. At values of about 21 MPa, corresponding to EVA ratios of 30% (w/w) and above, continuous extrusion including material take‐off was possible. At higher whey protein ratios in the blends the water vapor transmission rate increased, i.e., the higher water vapor transmission rate of whey protein compared with EVA dominated this property. This study showed that whey proteins can be utilized for extrusion by blending with EVA. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41172.     

Multi‐stimuli responsive shape memory polymers synthesized by using reaction‐induced phase separation

Thermo‐induced multishape memory polymers are a growing focus of smart materials because of its promising applications. Multishape memory effect is generally attained by using polymers with broad phase transition and multiphase polymers. The latter is of particular interest for copolymerization and polymer compositing. One requirement has to be fulfilled to achieve multishape memory effect, which is to have two reversible phase transitions. In this study, we report synthesis of polymer composite composed of strong segregated polymers by using reaction‐induced phase separation. We demonstrate the method by using polyurethane (PU) and poly(methacrylic acid) (PMAA). With adjusting the weight ratio, the polymer composites exhibit a phase spectrum from phase separation to miscible composite. The composite with PU/PMAA =3:1 demonstrated triple‐shape memory effect. Based on the results, we argued the effect of segregation on the shape memory effect for polymer composites. With the addition of PMAA, the polymer composite also exhibits pH/water‐induced shape memory effect. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43534.     

Silica/poly(styrene-alt-maleic anhydride) hybrid particles as a reactive toughener for epoxy resin

Amino-modified silica nanoparticles (SiO₂─NH₂) were first prepared by hydrolytic condensation of tetraethyl orthosilicate and 3-aminopropylmethyldiethoxysilane. Then, organic–inorganic hybrid particles (SiO₂─SMA) were prepared by the amidation reaction between SiO₂─NH₂ and poly(styrene-alt-maleic anhydride) (SMA). Subsequently, SiO₂─SMA particles were employed for modifying bisphenol-A epoxy/anhydride thermoset. Compared with pure cured epoxy, the modified epoxy thermosets with only 1 wt % of SiO₂─SMA particles could achieve a simultaneous toughening and reinforcing performance. The tensile strength, impact strength, and fracture toughness of epoxy thermoset were increased by 14.1, 44.3, and 114.4%, respectively. Moreover, the modification also improved the thermal stability of epoxy thermosets, and the modulus and glass transition temperature of cured resin were not sacrificed. It can be attributed to the rigid structure of SiO₂, as well as the anhydride and carboxyl groups onto the surface of SiO₂─SMA particles participating in the epoxy curing reaction and effectively enhancing the crosslinking density of epoxy thermoset.     

Thermal and mechanical characterization of maleimide‐functionalized copoly(urethane‐urea)s

Maleimide functionalized copoly(urethane‐urea)s were prepared by the reaction of a binary mixture of dibenzyldiisocyanate and 5‐maleimidoisophthalic diisocyanate with a macrodiol (PEGA‐2000), using diethylene glycol and trimethylol‐propane as chain extender and crosslinkers in toluene‐dichloromethane solutions at the ratio NCO/OH = 1.2. Structures of polymers were confirmed by IR spectroscopy and properties were studied by thermal and mechanical analysis (dynamic mechanical analysis (DMA), differential scanning calorimetry, thermogravimetric analysis, stress‐strain) and other physical methods. Maleimide modification increased the storage modulus and Young's modulus of copoly(urethane‐urea)s, slightly increased their glass transition temperature from ?10.6°C to ?6.3°C. Copoly(urethane‐urea) networks obtained by thermal polymerization of maleimide functions showed significantly increased of the mechanical properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Thermal and mechanical properties of epoxy resin reinforced with modified iron oxide nanoparticles

Epoxy polymers, having good mechanical properties and thermal stability, are often used for engineering applications. Their properties can be further enhanced by the addition of iron oxide (Fe₃O₄) nanoparticles (NPs) as fillers to the resin. In this study, pristine Fe₃O₄ NPs were functionalized with polydopamine (PDA), (3-glycidoxypropyl)trimethoxysilane (GPTMS), and (3-aminopropyl)trimethoxysilane (APTES). X-ray diffraction and scanning electron microscopy (SEM) were used to study any changes in the crystal structure and size of the NPs while Fourier-Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) were used to ensure the presence of functional groups on the surface. The mechanical properties of the Fe₃O₄-based nanocomposites generally improved except when reinforced with Fe₃O₄/PDA. The maximum improvement in tensile strength (∼34%) and fracture toughness (∼13%) were observed for pristine Fe₃O₄-based nanocomposites. Dynamic mechanical analysis (DMA) showed that the use of any of the treated NPs improved the material's initial storage modulus and had a substantial impact on its dissipation potential. Also, it was observed that the glass transition temperature measurements by DMA and differential scanning calorimetry were below that of pure epoxy. SEM of the cracked surfaces shows that the incorporation of any NPs leads to an enhancement in its thermal and mechanical properties.     

PCM nanofibrous composites based on PEG/PVA incorporated by TiO2/Ag nanoparticles for thermal energy management

Herein, form-stable phase change material fibrous composite containing nanoparticles was prepared via a single-step green approach using single-nozzle electrospinning for the first time. Polyethylene glycol (PEG), polyvinyl alcohol (PVA), and water were used as PCM, polymeric support and safe solvent together with simultaneous formation of nanoparticles. The introduced manner not only is free from applying organic solvents, separate addition, or buying nanoparticles and coaxial electrospinning but also it is easy and cost-effective to use for different applications. Thermal energy storage capacity of the fabricated samples reached to 135.88 and 136.27 J/g in melting process for the nanofibers and nanofibers with nanoparticles, respectively, which are mostly higher than the reported works. Meanwhile supercooling temperature was decreased for (50% PVA/50% PEG/0.1% AgNO₃/1% TiO₂) nanofibers compared to the other fabricated composites and the pure PEG. The effects of different weight ratio of polymers in spinning solutions, amount of titanium dioxide nanoparticles and silver nitrate, range of phase change transition and thermal endurance and stability of the samples were further discussed in details. Altogether, this renders a single-step safe route for producing form-stable PCM nanofibrous composites and also a broad insight concerning the thermal behavior of such composites for diverse renewable energy applications.     

Gas permeation related to the moisture sorption in films of glassy hydrophilic polymers

The purpose of this article is to elucidate the effect of integral sorption of moisture on gas permeation in glassy hydrophilic polymers. The oxygen and the simultaneous moisture sorption into various hydroxypropyl methylcellulose (HPMC) films were measured under a wide range of relative humidities using sorption analyzer equipment. Correspondingly, the oxygen permeability at different ambient conditions was measured using an oxygen detector. The solubility of oxygen in the HPMC film was found to be affected by the amount of water and therefore by the water state. At low moisture content, the water molecules are present as bound water, which promotes the sorption of oxygen in the HPMC films. At moisture content higher than 5%, water clusters are rapidly formed, which increase the affinity of HPMC polymer towards water rather than towards oxygen molecules, resulting in a decrease of oxygen solubility in the polymer. This was found to be the governing factor for the reduction in the oxygen permeability in glassy HPMC films at high water activity. This proposes a specific interaction between moisture sorption and oxygen transport in coating films like HPMC, which is of important aspect in the coating design and formulation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,characterization, and dielectric properties of polymers functionalized with coumarone and diethanolamine

A series polymers of the poly(4‐{[bis(2‐hydroxyethyl)amino]methyl}‐2‐oxo‐2H‐chromen‐7‐yl‐2‐methylpropanoate), P(CIMMAOC)‐DEA, were synthesized by modification of poly(4‐(chloromethyl)‐2‐oxo‐2H‐chromen‐7‐yl‐2‐ethylpropanoate), P(CIMMAOC), with diethanolamine (DEA). All polymers were structurally characterized by FTIR, ¹H NMR, UV–vis, and Fluorescence spectra. The electronic features of the polymer, such as lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energies and electrostatic potential (ESP), and the vibrational frequencies were computed by the Becke3–Lee–Yang–Parr (B3LYP) functional using 3–21G* basis set. Dielectric measurements for P(CIMMAOC) and P(CIMMAOC)‐DEA were performed by means of an impedance analyzer as a function of frequency and temperature. It was found that the dielectric constant values decreased in the applied frequency range. The values of dielectric constant increased with a rise in concentrations of DEA in polymer for all temperatures. Dielectric constants of P(CIMMAOC) and P(CIMMAOC)‐DEA (60%) were calculated as 3.93 and 12.29 at 1 kHz, respectively. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42164.     

High temperature resistant silane/zirconium‐oxocluster hybrid copolymers containing “free” thiol/ene functionalities in the polymer matrix

Inorganic–organic hybrid copolymers are promising materials where the size of the inorganic/organic domains, the phase continuity and the interface between the domains play an important role in their behavior. Two types of hybrid copolymers composed of 3‐butynoate‐substituted zirconium‐oxoclusters covalently bonded to a (3‐mercaptopropyl)trimethoxysilane or a vinyltrimethoxysilane matrix are investigated in bulk. Their properties are directly correlated with the degree of condensation of the silanes and the alkyne‐3‐mercaptopropyl or alkyne‐vinyl interface. Both copolymers show storage moduli and glass‐transition temperatures (T_gG″) above 130 MPa and 230°C. However, the more impressive results are achieved with the (3‐mercaptopropyl)trimethoxysilane copolymer where a T_gG″ of about 300°C holds over six dynamical mechanical spectroscopy analyses. In addition to their excellent thermo‐mechanical proprieties, the copolymers show unreacted 3‐mercaptopropyl or vinyl groups which could be employed either in direct usage of the materials or for post‐functional modifications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013