Light‐curing of a sol–gel‐derived silicate‐based epoxy‐functional polymer nanocomposite material system

In an effort to explore the potential of certain types of polymer nanocomposites to be successful candidates as dental restoration/adhesion materials, a Ti‐ or Zr‐containing and organically modified silicate‐based material system with epoxy functionality was prepared by use of a sol–gel synthesis method, and ultraviolet light‐ and visible light (VL)‐curing processes. Comparative influences of certain synthesis/processing parameters on the properties of the system were detailed. It was shown that both Ti‐ and Zr‐containing species could play significant roles in determining the structure and hence the properties of the nanocomposites. VL‐curing was demonstrated to be a relatively advantageous process that could be employed in applications such as dental restoration/adhesion. Moreover, the mechanical properties of the nanocomposites were shown to be promisingly high. Overall observations and results indicated a prospective opportunity for this material system to be utilized in dental restoration/adhesion applications. POLYM. COMPOS., 35:1879–1887, 2014. © 2014 Society of Plastics Engineers     

Synthesis and modification of epoxy‐ and hydroxy‐functional microspheres

This article describes the synthesis and surface modification of epoxy‐ and hydroxy‐functional polymeric microspheres. The functionalized microspheres were synthesized using aqueous and nonaqueous cationic suspension photopolymerizations using multifunctional silicon‐containing epoxy monomers with iodonium salt photoinitiators. Although generally solid microspheres were obtained using these techniques, macroporous spheres could be obtained though the use of porogens. Various rapid and facile acid‐ and base‐catalyzed ring‐opening addition reactions were performed on the epoxy‐functional microspheres. These reactions include the additions of mercaptans, acid chlorides, isocyanates, amines, sodium azide, water, and alcohols. Similar functionalization reactions were performed on the hydroxy‐functional microspheres. The particle size and size distribution were determined using scanning electron microscopy. Fourier transform infrared spectroscopy was used to monitor the functionalization reactions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1574–1585, 2005     

Synthesis and characterization of epoxy‐acrylate composite latex

A waterborne epoxy‐acrylate composite latex was synthesized. The effects of the concentration of the initiator, surfactant, and epoxy resin on the particle size, molecular weight, and grafting ratios of the composite latex were investigated. The increase of the concentration of the initiator and epoxy resin led to the decrease of the weight‐average molecular weight. The graft ratios increased with an increase in the initiator level and a decrease in the epoxy resin concentration whereas the variation of the concentration of the surfactant did not have much influence on the graft ratios. The increase in the initiator level caused the aggrandizement of the particle size, and the increase of the concentration of the surfactant and epoxy resin caused a decrease in the latex particle size. Fourier transform IR spectroscopy with attenuated total reflectance indicated that the epoxy resin molecules were enriched in the mold‐facing surface in the film from the composite latex. The differential scanning calorimetry analysis, dynamic mechanical analysis, and Instron test showed that the polymer films cast by the composite latex had lower tensile strength and glass transition than those by the blend latex. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1736–1743, 2002     

Synthesis,formulation, and characterization of siloxane‐modified epoxy‐based anticorrosive paints

Diglycidyl ether of bisphenol A epoxy (E) was modified with hydroxyl‐terminated polydimethylsiloxane through a ring‐opening addition polymerization reaction. The structural elucidation of the siloxane‐modified epoxy resin (ES) was carried out with Fourier transform infrared, ¹H‐NMR, and ¹³C‐NMR spectroscopy techniques. The physicochemical characterization of the synthesized resin (ES) was performed with standard methods. E and ES were subjected to paint formulation with the help of a rutile (TiO₂) pigment. The formulated paint systems were cured at room temperature with 1,6‐diaminohexane (AH) and 1,3‐diaminopropane (AP), which were used as curatives. The E–AH, E–AP, ES–AH, and ES–AP paint systems were applied to mild steel strips. The physicomechanical and anticorrosive performance of the coated panels was evaluated with standard methods. The thermal analysis of these E–amine and ES–amine systems was carried out via thermogravimetric analysis. The effects of siloxane incorporation and amine curatives on the coating properties of the paint systems were also investigated. The ES–AP system exhibited good thermal and corrosion stability performance among all the E and ES paint systems. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4981–4991, 2006     

Synthesis and characterization of a calcium‐ and sodium‐containing acrylamide‐based polymer and its effect on soil strength

Soil degradation is a significant problem throughout the world. One strategy that can be used to improve soil physical properties is the use of soil conditioners, particularly anionic polyacrylamides. Synthetic water‐soluble anionic acrylamide‐based polymers have wide applications in agriculture, such as mulch and agrochemicals, and can also be used as soil modifiers for erosion control, nondesertification, and soil stabilization. In this study, anionic polyacrylamides containing cationic metal ions were prepared by free‐radical polymerization. Anionic polymer with negative charges was produced by the reaction of mono‐ and divalent inorganic salts with acrylamide monomer via solution polymerization. Hydrolysis of the polymer was carried out by using calcium chloride and sodium carbonate in their soluble forms, and the negative charges on the polymer were regulated by variation of the molar ratios of inorganic salts with respect to the acrylamide monomer concentration. The molecular weight and charge density of the anionic charged polymers were improved and manipulated by using these methods. The molecular structure of the polymers was characterized and confirmed by common techniques. The effect of the polymers on soil strength was evaluated, and the results showed that the addition of anionic polymer having a high molecular weight improved the behavior of soil components. J. VINYL ADDIT. TECHNOL., 19:140–146, 2013. © 2013 Society of Plastics Engineers     

Synthesis,characterization, and thermo mechanical properties of siloxane‐modified epoxy‐based nano composite

In this study, polymer hybrid composites were synthesized by sol‐gel process. 3‐Amino‐propyltrimethoxysilane [APTMS)/γ‐Glycidoxypropyl trimethoxy‐silane (GPTMS); (4, 4′‐Methylene‐dianiline (DDM)] and 1,4‐Bis(trimethoxysilylethyl) benzene (BTB) were added to DGEBA type epoxy resin for anticipated to exhibit excellent thermal stability. Boron trifluoride monoethylamine (BF₃MEA) was used as catalyst. The structure of nanocomposites was characterized by attenuated total reflectance (ATR) and solid‐state ²⁹Si NMR which suggest EP‐APTMS‐BTB/EP‐GPTMS‐BTB possesses T³; T¹–T⁰, and T¹ structures when the BTB content was lower than 10 wt % and higher 20 wt %, respectively. BF₃MEA was proved to be an effective catalyst for the sol‐gel reaction of APTMS, but it could not promote for GPTMS. From TEM microphotographs, EP‐APTMS‐BTB (10 wt %) possesses a dense inorganic structure (particle size around 5–15 nm) compare with the loose inorganic structure of EP‐GPTM‐/BTB (10 wt %). DSC, TGA were use to analyze the thermal properties of the nanocomposites and DMA was used to analyze the dynamic mechanical properties of hybrid composites. The T_gs of all nanocomposites decreased with the increasing BTB content. A system with BTB content lower than 10 wt % showed good dynamic mechanical property and thermal stability (Td₅ increased from 336°C to 371°C, char yield increased from 27.4 to 30.2%). The structure of inorganic network affects the Td₅ and dynamic mechanical properties of composite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40984.     

Fabrication of surface‐relief gratings on an azobenzene‐containing epoxy‐based polymer film using atomic force microscopy

Many studies have been reported on the photo‐fabrication of surface‐relief gratings (SRGs) in azo‐polymer films using the interference of two laser beams of appropriate polarization. However, there are few reports in the literature concerning the electro‐fabrication of SRGs on such types of polymer films. The goal of the work reported was the electro‐patterning of an azobenzene‐containing epoxy thermoplastic film. An epoxy‐based polymer functionalized with an azo‐chromophore was synthesized and characterized using thermal analysis. The reversible optical storage properties and photo‐induced dichroism were studied. SRGs were fabricated on a film of the synthesized azobenzene‐containing polymer using contact mode current‐sensing atomic force microscopy which locally applied an electric field that aligned the azobenzene moieties. The anisotropic mass transport of the azo‐polymer film was observed after applying an electric field. Additionally, the effect of the relief formation in the polymeric film surface was investigated by means of atomic force microscopy and electrostatic force microscopy. Copyright © 2010 Society of Chemical Industry     

Morphology and properties of layered silicate‐polyethylene nanocomposite blown films

Film grade ethylene vinyl acetate (EVA), low density polyethylene (LDPE), and high density polyethylene (HDPE) were melt compounded with an organically modified montmorillonite, then blown into films. The morphology studies showed that all three types of film involve intercalated clay particles. The dependence of intercalation extent on the matrix as well as on the molecular weight of compatibilizers is discussed. The tensile testing data showed that the clay enhancing effects apply mainly to the modulus, instead of to the strength. The EVA‐based nanocomposite films exhibit the most significantly improved modulus while the HDPE‐based films have the least. Lower molecular weight compatibilizers could promote the clay enhancing effects while higher molecular weight compatibilizers could increase the matrix properties. Steady shear viscosities of an intercalated and an exfoliated system were also investigated. Comparing our data with that from the literature lead us to conclude that: 1) the zero‐shear viscosity of a nanocomposite is mainly determined by clay loading instead of by clay intercalation/exfoliation structures and the matrix viscosity; and 2) the clay orientation during a shear flow is highly dependent on the matrix flow behavior and to a lesser extent on the clay structural state. POLYM. ENG. SCI., 45:469–477, 2005. © 2005 Society of Plastics Engineers     

Synthesis,characterization, and anticorrosive coating properties of waterborne interpenetrating polymer network based on epoxy‐acrylic‐oleic acid with butylated melamine formaldehyde

The present study reports the synthesis and characterization of waterborne interpenetrating network (IPN) of epoxy‐acrylic‐oleic acid (EpAcO) with butylated melamine formaldehyde (BMF). The effect of BMF on the formation of IPN was investigated in terms of physicochemical, spectral, morphological, and thermal analyses. The coating properties of the IPN were investigated for their physicomechanical, corrosion resistance, and antimicrobial activity. The formation of the IPN was confirmed by FTIR and ¹H NMR analyses as well as physicochemical properties. The EpAcO‐BMF IPN coatings were found to exhibit far superior corrosion resistance performance and good thermal stability when compared with the reported waterborne epoxy acrylic‐melamine formaldehyde systems [EpAc‐MF]. The preliminary antimicrobial investigations of the IPNs were carried out by agar diffusion method against some bacteria and fungi. The results revealed that antimicrobial activities were enhanced upon the formation of IPN. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of chiral side‐chain liquid‐crystalline polymer containing menthol ester

The synthesis of new chiral side‐chain liquid‐crystalline polysiloxanes containing p‐(allyoxy)benzoxy‐p‐chlorophenyl (ABCH) as mesogenic units and undecylenic acid menthol ester (UM) as chiral nonmesogenic units is presented. The chemical structures of monomers and polymers are confirmed by IR spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are used to measure thermal properties of those polymers. Mesogenic properties are characterized by polarized optical microscope (POM), DSC, and small‐angle X‐ray diffraction. Analytic results revealed that polymers P₀–P₆ are thermotropic liquid‐crystalline polymers with low glass transition; Polymers P₂–P₆ exhibit chiral smectic liquid‐crystalline properties with marble texture, optical rotation, and a sharp reflection at low angles in X‐ray diffraction; polymers P₀, P₁ only exhibit smectic liquid‐crystalline properties without chirality; and P₇ only exhibits chirality without liquid‐crystalline properties. All the polymers exhibit good thermal stability with temperature of 5% mass loss over 297°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2845–2851, 2003     

Processing and characterization of epoxy–anhydride‐based intercalated nanocomposites

A study of the kinetic and thermal characterization of an epoxy resin (DGEBA) polymerized with a methyl tetrahydrophthalic anhydride reinforced with montmorillonite‐layered silicates is presented. The nanoreinforcement used was compatibilized by exchanging the cations between the silicate layers with alkylammonium salts, containing long hydrocarbon chains. The aim of this study was to develop new nanocomposites based on thermoset resins with improved thermal stability, suitable for electronic applications. Differential scanning calorimetry was used here to produce the polymerization kinetics data, while thermogravimetric analysis was used to evaluate the effects of the nanoreinforcements on the thermal stability and to analyze the degradation kinetics. Unexpected strong effects of the nanocomposite on the polymerization kinetics of the epoxy–anhydride system were detected and evaluated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2532–2539, 2003     

Preparation and characterization of new nanocomposite polymer films containing NiO nanofillers

Nanocomposite solid polymer films based on the poly(exo‐N‐phenyl‐7‐oxanorbornene‐5,6‐dicarboximide) (PPhONDI)/LiClO₄/NiO system have been designed, and the effect of inorganic NiO nanofiller in different amounts on the film properties has been examined. The exo‐PPhONDI/LiClO₄/NiO polymer system is the first solid nanocomposite polymer electrolyte film example based on a ring‐opening metathesis polymerization (ROMP) host polymer. The NiO nanoparticles were prepared by two‐step chemical syntheses, and the thermoplastic host polymer, exo‐PPhONDI, was synthesized via ROMP. Composite polymer films were prepared by the solution‐casting method. The amount of nanoparticles was varied from 1 to 15 wt % of NiO. The conductivity of the nanocomposite solid polymer systems was influenced by the NiO nanofiller concentration. The composite films based on exo‐PPhONDI ROMP polymer with the highest conductivity were achieved for the composition with 8 wt % of NiO nanofiller and 10 wt % of LiClO₄ dopant. The prepared films were characterized using X‐ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy (SEM). The SEM results showed that the filler was well distributed in the polymer matrix. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45938.     

Synthesis and optical properties of a crosslinkable polymer system containing tricyanofuran‐based chromophores with excellent electro‐optic activity and thermal stability

Crosslinkable polymers with side‐chain systems were investigated in order to increase the content of nonlinear optical chromophores and improve the stability of oriented chromophores. A series of crosslinkable copolymers having varying concentrations of chromophores with tricyanofuran as an acceptor were successfully synthesized and characterized. The crosslinked electro‐optic (EO) polymers revealed the highest EO coefficient (r₃₃) of 47.0 pm V^?1 at 1310 nm, which was similar to r₃₃ of uncrosslinked systems. Compared to the uncrosslinked EO polymer systems, the crosslinked ones exhibited significantly enhanced temporal stability. The results of the EO coefficients and thermal properties indicated that the crosslinking effectively improved the stability and did not influence the r₃₃ values. Copyright © 2012 Society of Chemical Industry     

Synthesis and characterization of novel silver/L‐phenylalanine‐based optically active polyacrylate nanocomposite

Novel bioactive and optically active poly(N‐acryloyl‐L ‐phenylalanine) (PAPA) was synthesized by atom transfer radical polymerization. PAPA‐silver (Ag) nanocomposites have been successfully prepared via in situ reducing Ag⁺ ions anchored in the polymer chain using hydrazine hydrate as reducing agent in an aqueous medium. By controlling of the amount of Ag⁺ ions introduced, we have produced an organic/inorganic nanocomposite containing Ag nanoparticles with well controlled size. Nanocomposites were characterized by X‐ray diffraction (XRD), UV–Vis spectrophotometry, transmission electron microscopy, and Fourier transform infrared. XRD pattern showed presence of Ag nanoparticles. The PAPA/Ag nanocomposites with 1 : 10 silver nitrate (AgNO₃) : PAPA ratio revealed the presence of well‐dispersed Ag nanoparticles in the polymer matrix. All of these Ag nanoparticles formed are spherical and more than 80% of them are in the range of 15–25 nm. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of a novel siloxane‐imide‐containing polybenzoxazine

A novel siloxane‐imide‐containing polybenzoxazine based on N,N′‐bis(N‐phenyl‐3,4‐dihydro‐2H‐benzo[1,3]oxazine)‐5, 5′‐bis(1,1′,3,3′‐tetramethyldisiloxane‐1,3‐diyl)‐bis(norborane‐2,3‐dicarboximide) (BZ‐A1) was successfully synthesized. The thermal properties of BZ‐A1 are superior to those of conventional polybenzoxazines lacking siloxane groups. Polymerized BZ‐A1 possesses extremely low surface free energy (γ_s = 15.1 mJ m^?2) after curing at 230 °C for 1 h. Moreover, the surface free energy of polymerized BZ‐A1 is more stable than conventional bisphenol A‐type polybenzoxazine during thermal curing and annealing processes, indicating that polymerized BZ‐A1 is more suitable for applications requiring low surface free energy materials for high temperatures over long periods of time. Copyright © 2010 Society of Chemical Industry     

Synthesis and characterization of short Grewia optiva fiber‐based polymer composites

Natural fibers, such as Flax, Sisal, Hibiscus Sabdariffa, and Grewia optiva (GO) possess good reinforcing capability when properly compounded with polymers. These fibers are relatively inexpensive, easily available from renewable resources, and possess favorable values of specific strength and specific modulus. The mechanical performance of natural fiber‐reinforced polymers (FRPs) is often limited owing to a weak fiber‐ matrix interface. In contrast, urea–formaldehyde (UF) resins are well known to have a strong adhesion to most cellulose‐containing materials. This article deals with the synthesis of short G. optiva fiber‐reinforced UF polymer matrix‐based composites. G. optiva fiber‐reinforced UF composites processed by compression molding have been studied by evaluating their mechanical, physical, and chemical properties. This work reveals that mechanical properties such as: tensile strength, compressive strength, flexural strength, and wear resistance of the UF matrix increase up to 30% fiber loading and then decreases for higher loading when fibers are incorporated into the polymer matrix. Morphological and thermal studies of the matrix, fiber, and short FRP composites have also been carried out. The swelling, moisture absorbance, chemical resistance, and water uptake behavior of these composites have also been carried out at different intervals. The results obtained lay emphasis on the utilization of these fibers, as potential reinforcing materials in bio‐based polymer composites. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

Synthesis and characterization of novel polyurethanes based on fluorine‐containing polyphosphazene

Fluorine‐containing poly[bis‐(2,2,3,3,4,4,5,5‐octafluoro‐1‐pentanol)_1.6 (4‐hydroxybutaneoxy)_0.4 phosphazene] (OFHBP) was synthesized and characterized by Fourier transform infrared (FTIR) spectra, nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The obtained OFHBP was used as a cross‐linker to prepare a series of novel polyurethanes (PUPFs). The composition of the PUPFs was confirmed by FTIR and elemental analysis (EA). The crystalline structure and microstructure of the PUPFs were examined by X‐ray diffraction (XRD) and atomic force microscopy (AFM). The thermal and tensile properties of the PUPFs were characterized by differential scanning calorimetry (DSC) and tensile testing. In addition, the surface energy of the PUPFs was also evaluated by contact angle measurements (CA). The results showed that glass transition temperature of the PUPF‐4 was decreased by 15°C, elongation at break was improved by 61% and a 41% decrease in surface energy in comparison with conventional polyurethane. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Modeling and experimental investigation of polymer micropart demolding from a Zr‐based bulk metallic glass mold

Demolding is a necessary process in polymer micro molding, which requires energy for fracture of the bonds between the mold and the polymer. This often leads to structural defects due to an inappropriate combination of process parameters, including demolding temperature, embossing force or injection pressure, separation rate, and separation mode. In this article, we focus on the theoretical analysis and experimental optimization of the process parameters for polymer micro‐part demolding from a zirconium (Zr)‐based bulk metallic glass mold. We developed a theoretical model to predict the demolding work, in which we considered the effects of sidewall friction combined with deformation and adhesion. We also optimized the parameters for the demolding process based on the Taguchi method. The experimental results showed that the embossing force and the separation mode had significant effects on the demolding work of hot embossing. We determined the optimum process parameters and found that with these parameters the demolding work could be decreased to 10.36 mJ in this case. POLYM. ENG. SCI., 59:2202–2210, 2019. © 2019 Society of Plastics Engineers     

Synthesis and characterization of polyurethane urea based on fluorine‐containing bisphenoxydiamine

A fluorine‐containing bisphenoxydiamine, 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane (BAPF₆P), was synthesized and characterized by means of Fourier transform infrared spectrometry (FTIR), NMR, and elemental analysis. The obtained BAPF₆P was used as a chain extender to prepare polyurethane urea (PUU), whose morphology and properties were measured through FTIR, differential scanning calorimetry, thermogravimetric analysis, tensile measurements, and atomic force microscopy. The results show that the PUU elastomers based on BAPF₆P exhibited good mechanical properties and thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1863–1869, 2006