UV‐curing synthesis of sulfonated polyaniline‐silver nanocomposites by an in situ reduction method

Sulfonated polyaniline‐silver (SPAni‐Ag) hybrid nanocomposites have been synthesized by the in situ reduction using a UV‐curing polymerization method without using any reducing or binding agent. An aqueous solution of aniline and orthoanilinic acid (OA) comonomers, a free‐radical oxidant and silver metal salts were irradiated by UV rays. Reduction of the silver salt in aqueous aniline and OA leads to the formation of silver particles which in turn catalyze the oxidation of comonomers to sulfonated polyaniline (SPAni). The resultant SPAni‐Ag nanocomposites were characterized by using different spectroscopy analyses like UV–visible (UV–Vis), X‐ray diffraction (XRD) and infrared spectroscopy. The absorption bands were revealed to be optically active and the peaks blue‐shifted due to the presence of metallic silver within the SPAni matrix. The XRD patterns displayed both the broad amorphous polymeric and sharp metallic peaks. Scanning electron microscopy and transmission electron microscopy of the nanocomposites showed a uniform size distribution with spherical and granular morphology. Thermogravimetric analysis revealed that the nanocomposites had a better thermal stability than the bulk SPAni. Copyright © 2008 John Wiley & Sons, Ltd.     

UV‐cured polyester‐acrylate nanocomposite films with silane‐grafted silica nanoparticles

UV‐curing technique was employed in this study to prepare polyester‐acrylate nanocomposite films with silane‐grafted silica nanoparticles. Methacryloxypropyl trimethoxysilane was grafted to the surfaces of silica nanoparticles to improve dispersion of silica nanoparticles as well as interfacial adhesion between the resin matrix and silica nanoparticles. The silane‐grafting was confirmed by nuclear magnetic resonance and infrared spectroscopy. The effects of the silane‐grafting on the mechanical and optical properties as well as UV‐curing behavior of the nanocomposite films were investigated. The tensile strength, transmittance, UV‐curing rate, and final chemical conversion of the nanocomposite films were increased by use of the grafted silica nanoparticles as compared to the use of neat silica nanoparticles. Copyright © 2011 John Wiley & Sons, Ltd.     

Effects of organic modifications of clay on the ultraviolet‐curing behavior and structure of a polyester‐acrylate/clay nanocomposite system

A pristine clay (Na⁺‐montmorillonite (MMT) and three different organoclays (20A‐MMT, vinylbenzyl dimethyldodecyl ammonium (VDA)‐MMT, and siloxane diamine ammonium (SDA)‐MMT) that originated from the pristine clay were used to prepare polyester‐acrylate (PEA)/clay nanocomposites by in situ ultraviolet (UV)‐curing. Except for the commercial organoclay (20A‐MMT), VDA‐MMT, and SDA‐MMT were prepared in this study by ion exchange method. The effects of organic modifications of the pristine clay on the UV‐curing behavior and structure of the nanocomposite system were investigated. The organic modifications of the clay affected considerably the UV‐curing behavior and structure of the nanocomposite system. Copyright © 2008 John Wiley & Sons, Ltd.     

Effect of polymerically‐modified clay structure on the morphology and properties of UV‐cured polyurethane acrylate/clay nanocomposites

Polyurethane acrylate (PUA)/clay nanocomposites were prepared by UV‐curing from a series of styrene‐based polymerically‐modified clays and PUA resin. Effect of the chemical structure of the polymeric surfactants on the morphology and tensile properties of nanocomposites has been explored. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) experimental results indicated that surfactants having hydroxyl or amino groups show better dispersion and some of the clay platelets were fully exfoliated. However, the composites formed from pristine clay and other polymerically‐modified clays without hydroxyl or amino groups typically contained both tactoids and intercalated structure. The mechanical properties of PUA composites were greatly improved where the organoclays dispersed well. Thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) were carried out to examine the thermal properties of the composites. The results showed that the loading of polymerically‐modified clays do not effect the thermal stability, but increased the Tgs of PUA/clay composites. Copyright © 2010 John Wiley & Sons, Ltd.     

New fluorinated acrylic monomers for the surface modification of UV‐curable systems

New fluorinated acrylates were synthesized and used as modifying additives for acrylic UV‐curable systems. Their chemical structure is: C_nF_2n+1 R—OCO—CHCH₂, where the linear perfluorinated chain contains from 4 to 10 carbon atoms, while R is a linear alkyl group containing or not a thioether group. Notwithstanding their very low concentration, the fluorinated monomers caused a dramatic change of the surface properties of the films, without changing their curing conditions and their bulk properties. X‐ray photoelectron spectroscopy measurements showed that the monomers were able to concentrate selectively on the surfaces of the films, depending on their chemical structure and on the kind of substrate employed. The synthesis of the fluorinated monomers and the relationship between their chemical structure and the final surface properties of the UV‐cured films will be discussed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 77–87, 1999     

Renewable epoxidized cardanol‐based acrylate as a reactive diluent for UV‐curable resins

A novel kind of biobased monomer, epoxidized cardanol‐based acrylate (ECA), was successfully synthesized from cardanol via acrylation and epoxidization. The chemical structure was confirmed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. Then, the ECA was employed to produce UV‐curable films and coatings copolymerized with castor oil‐based polyurethane acrylate. Compared to coatings from petroleum‐based diluent hydroxyethyl acrylate‐based castor oil‐based polyurethane acrylate resins, ECA‐based biomaterials exhibited a little inferior dilution ability but overcome the drawback of high volumetric shrinkage with a special lower value. Moreover, ultimate properties of the UV‐cured biomaterials such as thermal, mechanical, coating, swelling, and hydrophobic properties were investigated. The UV‐curing behavior was investigated using real‐time IR, and the overall double bond conversion was more than 90%. This biobased UV‐curable cardanol‐based diluent shows a promise in “green + green” materials technologies.     

Synthesis and characterization of UV‐curable ladder‐like polysilsesquioxane

Various ladder‐like structured poly(phenyl‐co‐methacryl silsesquioxane)s (LPMSQ)s with high molecular weight (M_w = 10,000 ～ 40,000) were synthesized by direct hydrolysis and polymerization in the presence of base catalyst at 25 °C. Synthesized LPMSQs mainly showed ladder‐like structure and photo‐cure reaction by 100 mW/cm² (360 nm) for 10 s without any photo‐cure initiators. Chemical composition and structural analysis of the obtained LPMSQs were characterized using ¹H NMR, ²⁹Si NMR, Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and X‐ray diffraction (XRD). Physical properties of LPMSQs before and after photcuring were analyzed by Nanoindentation. Surface modulus increased to 8GPa and hardness of thin films increased from 100 to 400 MPa. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Photoinitiating behavior of benzophenone derivatives covalently bonded tertiary amine group for UV‐curing acrylate systems

A series of benzophenone derivatives (N‐BPs) containing tertiary amine group used as hydrogen abstraction‐type (type II) photoinitiators were synthesized through the addition reaction of secondary amines with 4‐(2,3‐epoxypropyloxy) benzophenone. The chemical structures were characterized with ¹H NMR, FTIR spectroscopy, and UV spectrum measurements. The N‐BPs showed the higher absorption in 300–400 nm than benzophenone (BP). The photoinitiating activity was examined based on the photopolymerization of 1,6‐hexanediol diacrylate using photo‐DSC method. The results showed that the photoinitiating efficiency was negatively affected by the molecular structure of alkyl group connected to the tertiary amine with the order of isopropyl (N‐BPI) < methyl (N‐BPM) < ethyl (N‐BPE) < propyl (N‐BPP). Moreover, the diethanolamine‐modified benzophenone derivative (N‐BPOH) had the highest‐photoinitiating efficiency for free radical polymerization systems among the N‐BPs. Copyright © 2011 John Wiley & Sons, Ltd.     

Ultraviolet curing of acrylic systems: Real‐time Fourier transform infrared,mechanical, and fluorescence studies

The photopolymerization of acrylic‐based adhesives has been studied by Fourier transform infrared and fluorescence analysis in real time. Real‐time infrared spectroscopy reveals the influence of the nature of the photoinitiator on the kinetics of the reaction. Furthermore, the incident light intensity dependence of the polymerization rate shows that primary radical termination is the predominant mechanism during the initial stages of the curing of the acrylic system with bis(2,4,6‐trimethylbenzoyl) phenyl phosphine oxide (TMBAPO) as a photoinitiator. The fluorescence intensity of selected probes increases during the ultraviolet curing of the adhesive, sensing microenvironmental viscosity changes. Depending on the nature of the photoinitiator, different fluorescence–conversion curves are observed. For TMBAPO, the fluorescence increases more slowly during the initial stage because of the delay in the gel effect induced by primary radical termination. Mechanical tests have been carried out to determine the shear modulus over the course of the acrylic adhesive ultraviolet curing. In an attempt to extend the applications of the fluorescence probe method, we have undertaken comparisons between the fluorescence changes and shear modulus. Similar features in both curves confirm the feasibility of the fluorescence method for providing information about microstructural changes during network formation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4236–4244, 2002     

The effect of the curing agent content on the curing and liquid‐crystalline phase of liquid‐crystalline epoxy resin

The effect of the curing agent content on the curing behavior and liquid‐crystalline (LC) phase of the liquid‐crystalline epoxy (LCE) resin 4,4′‐di(2,3‐epoxypropyloxy)phenyl benzoate was studied. Diaminodiphenylester (DDE) was used as a curing agent. The curing behavior was observed via differential scanning calorimetry, and the LC phase was investigated with a polarized optical microscopy. The LC phase in the LCE/DDE mixture with a high DDE content was developed during curing. The onset time was inversely proportional to the DDE content. The mesophase stability of LCE/DDE was enhanced by the addition of large amounts of DDE. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 374–379, 2001     

The effect of zeolite on the curing of epoxy resin by polyaniline: a kinetic study

Polyaniline sulfate‐zeolite composite was prepared by emulsion polymerization. Epoxy resin was cured using polyaniline‐sulfate salt and various amounts of polyaniline sulfate‐zeolite composite. The kinetics of the cure reaction for an epoxy resin based on the diglycidyl ether of bisphenol A (DGEBA) with polyaniline‐sulfate and polyaniline sulfate‐zeolite composite have been studied using differential scanning calorimetry (DSC) under isothermal and dynamic conditions. Isothermal kinetics analysis was performed using the phenomenological model of Kamal. Dynamic kinetic analysis was performed using Kissinger's method. Copyright © 2002 John Wiley & Sons, Ltd.     

Effect of Polymerizable Photoinitiators on the UV‐polymerization behaviors of photosensitive polysiloxane

In this contribution, three polymerizable benzophenone photoinitiators containing maleimide group including 4‐maleimidebenzophenone (MBP), 4‐chlorine‐4′‐maleimide benzophenone (CMBP), and 4‐maleimide‐4′‐[(4‐maleimide)thiophenyl]benzophenone (MMTBP) were designed and synthesized to enhance the polymerization degree of photosensitive polysiloxane containing methacryloxy active groups (MAPSO). The polymerization behaviors of the MAPSO cured by different photoinitiators were investigated using Fourier transform infrared (FTIR). It was noted that the MAPSO initiated by MMTBP showed a high carbon–carbon double bond conversion above 80% because of the existence of thiophenyl group which could generate more radicals from the photolysis reaction at the C? S bond. In addition, the thermal stability of the UV‐cured MAPSO were studied by thermogravimetric analysis (TGA), the result showed that the initial 5% mass loss (T _5%) and residual weight percent at 800 °C in nitrogen of the UV‐cured MAPSO initiated by MMTBP systems was 200 °C and 33.8%. Thus, this work provides a new perspective and efficient strategy to improve the polymerization degree of UV‐curable polysiloxanes with carbon–carbon double bonds. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1696–1705     

Kinetics of thiol–ene and thiol–acrylate photopolymerizations with real‐time fourier transform infrared

We used real‐time Fourier transform infrared to monitor the conversion of both thiol and ene (vinyl) functional groups independently during photoinduced thiol–ene photopolymerizations. From these results, the stoichiometry of various thiol–ene and thiol–acrylate polymerizations was determined. For thiol–ene polymerizations, the conversion of ene functional groups was up to 15% greater than the conversion of thiol functional groups. For stoichiometric thiol–acrylate polymerizations, the conversion of the acrylate functional groups was roughly twice that of the thiol functional groups. With kinetic expressions for thiol–acrylate polymerizations, the acrylate propagation kinetic constant was found to be 1.5 times greater than the rate constant for hydrogen abstraction from the thiol. Conversions of thiol–acrylate systems of various initial stoichiometries were successfully predicted with this ratio of propagation and chain‐transfer kinetic constants. Thiol–acrylate systems with different initial stoichiometries exhibited diverse network properties. Thiol–ene systems were initiated with benzophenone and 2,2‐dimethoxy‐2‐phenylacetophenone as initiators and were also polymerized without a photoinitiator. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3311–3319, 2001     

Syntheses of conductive adhesives based on epoxy resin and polyanilines by using N‐tert‐butyl‐5‐methylisoxazolium perchlorate as a thermally latent curing reagent

Conductive composites consisted of epoxy resin and polyanilines (PANIs) doped with dodecylbenzenesulfonic acid ( 1 ), dodecylsulfonic acid (2), di(2‐ethylhexyl)sulfosuccinic acid (3), and HCl were synthesized by use of N‐tert‐butyl‐5‐methylisoxazolium perchlorate (5) under various reaction conditions. It was found that the composites with PANI doped with acid 2 (PANI‐2) prepared by curing with 10 mol % of reagent 5 at 80 °C for 12 h showed high electroconductivity along with the low conducting percolation threshold (3 wt % of PANI‐2). Furthermore, the composite with even ?10 wt % of PANI‐2 exhibited ?10^?1 S/cm of electroconductivity. The UV–vis and IR measurements indicated that the conductive emeraldine salt form of PANI‐2 in the composite was maintained after the curing reaction. The thermal stability was studied by TGA and DSC measurements, and then, the T_d10 and T_g of the composite with 5 and 10 wt % of PANI‐2 were found to be similar to those with the cured epoxy resin itself. In addition, the similar investigation with an oxetane resin instead of the epoxy resin was also carried out. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 718–726, 2006     

Free radical and thermal curing of terpyridine‐modified terpolymers

Terpolymers bearing terpyridine as well as (meth)acrylates as free radical curable groups (UV‐curing) or hydroxyl groups (thermal curing with bis‐isocyanates) were synthesized and characterized using ¹H NMR, IR and UV‐vis spectroscopy as well as GPC. Subsequently, the ability of covalent crosslinking via the UV‐initiated polymerization of the acrylate groups was investigated. Moreover, the thermal covalent crosslinking via the reaction of hydroxyl functionalized terpolymer and bis‐isocyanate compounds could be successfully achieved. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4028–4035, 2004     

Synthesis of core‐shell silver–polyaniline nanocomposites by gamma radiolysis method

Core‐shell silver (Ag)–polyaniline (PAni) nanocomposites have been synthesized by the in‐situ gamma radiation‐induced chemical polymerization method. Aqueous solution of aniline, a free‐radical oxidant, and/or silver metal salt were irradiated by γ‐rays. Reduction of the silver salt in aqueous aniline leads to the formation of silver nanoparticles which in turn catalyze oxidation of aniline to polyaniline. The resultant Ag‐PAni nanocomposites were characterized by using different spectroscopy analyses like X‐ray photoelectron, UV–visible, and infrared spectroscopy. The optical absorption bands revealed that the bands at about 400 nm are due to the presence of nanosilver and the blue‐shifted peak at ～ 555 nm is due to the presence of metallic silver within the PAni matrix. X‐ray diffraction pattern clearly indicates the broad amorphous polymer and the sharp metal peaks. Scanning electron microscopy and transmission electron microscopy of the nanocomposite showed a uniform size distribution with spherical and granular morphology. Thermogravimetric analysis revealed that the composites have a higher degradation temperature than polyaniline alone. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5741–5747, 2007     

Gold Tailored Photosensitive Elastin‐like Polymer: Synthesis of Temperature,pH and UV‐vis Sensitive Probes

Here, we describe a procedure to manufacture smart hybrid probes that exhibit tunable optical properties as a function of multiple environmental variations. Initially, we achieved a one‐pot synthesis of gold‐PREP (photo‐responsive elastin‐like polymer) conjugate Gold‐AzoGlu15 via reduction of auric acid in the presence of PREP AzoGlu15 . Outstandingly, Gold‐AzoGlu15 exhibited pH and temperature sensitiveness. However, Gold‐AzoGlu15 was not UV‐vis sensitive. We noticed that photo‐isomerisation of azobenzene moieties in Gold‐AzoGlu15 could not be detected by UV‐vis spectroscopy. In a subsequent step, we explored the use of cyclodextrins and the formation of alkanethiol mixed‐monolayers over mother Gold‐AzoGlu15 by thiol‐place exchange reactions in order to decouple photo‐isomerisation of azobenzene from the bulk phase absorption. In this sense we achieved the synthesis of β‐cyclodextrin capped Gold‐CD‐AzoGlu15 . Notable was that cis‐trans photo‐conversion of azobenzene groups in Gold‐CD‐AzoGlu15 could be successfully detected. Finally, we present the optical properties exhibited by multi‐sensitive probe Gold‐CD‐AzoGlu15 as a function of pH, temperature and UV‐vis irradiation. We think that gold‐PREP hybrids could be of great interest in the design of multi‐functional chromophore‐metal nanocomposites that operate in aqueous media for the development of multi‐stimuli sensitive detectors for biosensing applications.

     

Synthesis and properties of oxetane‐based polysiloxanes used for cationic UV curing coatings

The polysiloxanes end‐capped with oxetane group (PSiO‐H and PSiO‐L) were synthesized via hydrosilylation reaction based on α,ω‐dihydrogen‐terminated polydimethylsiloxanes with a higher (0.23%, PDSi‐H) and lower (0.12%, PDSi‐L) hydrogen amount. The molecular structures were characterized by FT‐IR and ¹H NMR spectroscopy. The polysiloxanes were added into a commercial oxetane‐based resin, 3,3′‐(oxydi(methylene)) bis(3‐ethyloxetane) (DOX), as an additive to prepare a series of cationic UV curable formulations. The photo‐DSC results showed that the maximum photopolymerization rate decreased while the oxetane conversion increased with the polysiloxane content increasing. The surface hydrophobic property of cured films was improved having the water contact angles of 97° and 99° compared with 82° of the cured DOX film with only 1 wt% PSiOs, respectively. The dynamic mechanical thermal analysis results showed that both the storage modulus on the rubbery plateau region and the glass transition temperature decreased with increasing PSiO‐H loading. Moreover, the decrease became more obvious as PSiO‐L was added instead of PSiO‐H due to its lower concentration of oxetane group. The thermal stability of cured films was enhanced by the addition of PSiOs from the thermogravimetric analysis. And the DOX/PSiO‐H film possessed higher thermal degradation temperatures than DOX/PSiO‐L film. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis of water‐soluble conductive copolymer based on polyaniline

Synthesis and characterization of polyaniline‐grafted poly(styrene‐alt‐maleic anhydride) (PANI‐g‐PSMA) was carried out to obtain conductive comb copolymers with highly improved processability. First, polyaniline (PANI) was prepared in nano‐scale by chemical synthesis under ultrasonic irradiation. Then the poly(styrene‐alt‐maleic anhydride) (PSMA) was synthesized by free radical polymerization. Moreover, the PANI was grafted on the PSMA backbone to prepare a comb‐like conductive copolymer for improving its processability as a new method. The products were characterized by Fourier transform infrared, ultraviolet–visible spectroscopy and X‐ray diffraction patterns. Morphology of the samples was also investigated by scanning electron microscopy images. Finally, the solubility and conductivity of the products were studied, and it resulted in high solubility of the products in water and other common organic solvents in comparison to the pure PANI. Copyright © 2015 John Wiley & Sons, Ltd.