Development and characterization of a gelatin‐based coating with unique sealing properties

The experimental results on the development of thin (～ 1.5 μm) gelatin‐based coatings and the investigation on their sealing attribute when applied onto oriented polypropylene (OPP) are reported. The sealing performance, expressed as the strain energy required to separate the sealed joints, was studied as a function of three different influencing factors. pH of the hydrogel solution was varied between 5 and 11. The highest seal strength values were obtained for pH values beyond the isoelectric point (IEP) of the gelatin molecule. The effect of the plasticizer (glycerol) was studied by changing its concentration from 2.5 wt % to 7.5 wt % to the total weight of the hydrogel solution. Glycerol concentration = 7.5 wt % was found to be the best for achieving adequate strain energy values. The influence of a hydrophobic component on the capability of the coating to act as a sealant has also been assessed. The hydrophobic component had a positive effect only up to a certain level (1 wt %, weight percent), whereas beyond this value, it affected the seal strength attribute. According to the best setting conditions, seal strength values for the OPP biocoated films of ～ 61 N × mm were attained, with a corresponding maximum force required to break the joints of 2.4 N. These results are discussed by taking into consideration the modality of seals opening. Interestingly, the heat‐seal (temperature: 90°C; dwell time: 1 s; pressure: 4 bar) failed in both peeling and tearing mode failure, as confirmed by microscopy, spectrophotometric, and particle size analyzes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thin,highly crosslinked polymer layer synthesized via photoinitiated graft copolymerization on a self‐assembled‐monolayer‐coated gold surface

A thin, highly crosslinked layer was grafted onto an alkyl thiol self‐assembled‐monolayer (SAM)‐coated gold surface with N,N′‐methylene bisacrylamide (MBAA), a widely used crosslinker with two polymerizable groups, as the monomer. Surface‐initiated photografting copolymerization was achieved through the immobilization of the hydrogen‐abstraction photoinitiator benzophenone on the hydrophobic alkyl surface via physical adsorption and subsequent UV irradiation in the presence of an MBAA solution. The growth of the grafted poly‐MBAA layers seemed to produce dendritic structures with low surface coverage. At a higher monomer concentration (15 g/L of water), full coverage of the gold surface with a thin layer was obtained and proved by scanning force microscopy and contact‐angle measurements. The evaluation of the gold, gold–SAM, and gold–SAM/grafted poly‐MBAA layers with a surface plasmon resonance sensor system revealed that the photografted, thin, highly crosslinked polyacrylamide layers had a very low affinity toward the adsorption of protein. Therefore, this provides a very promising approach to tailoring materials for sensors and other applications. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 158–164, 2005     

Effect of heat‐treatment on the performance of gas barrier layers applied by atomic layer deposition onto polymer‐coated paperboard

The effect of heat treatment on the gas barrier of the polymer‐coated board further coated with an Al₂O₃ layer by atomic layer deposition (ALD) was studied. Heat treatment below the melting point of the polymer followed by quenching at room temperature was used for the polylactide‐coated board [B(PLA)], while over‐the‐melting‐point treatment was utilized for the low‐density polyethylene‐coated board [B(PE)] followed by quenching at room temperature or in liquid nitrogen. Heat treatment of B(PLA) and B(PE) followed by quenching at room temperature improved the water vapor barrier. However, because of the changes in the polymer morphology, quenching of B(PE) with liquid nitrogen impaired the same barrier. No improvement in oxygen barrier was observed explained by, e.g., the spherulitic structure of PLA and the discontinuities and possible short‐chain amorphous material around the spherulites forming passages for oxygen molecules. This work emphasizes the importance of a homogeneous surface prior to the ALD growth Al₂O₃ barrier layer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and application of an ultraviolet curable coating containing nanoscale α‐aluminum oxide

This study focuses on the preparation of an organic–inorganic ultraviolet (UV) curable coating containing the nanoscale α‐aluminum oxide (α‐Al₂O₃) powder and UV curable resin. This developed coating can form a protection film on the poly(vinyl chloride) (PVC) plastic tile surface. Thus, the abrasion resistance of the PVC plastic tile surface is improved. Besides, the adhesion between this UV cured film and the PVC plastic tile surface is well. After treatment with the UV curable coating that contains 6 wt % α‐Al₂O₃, the abrasion resistance of the PVC plastic tile surface can be improved up to 57%. From the result of a scanning electron microscopy (SEM) mapping photograph, it shows that the nanoscale α‐Al₂O₃ powder is well dispersed in the cured coating film. Under the wavelength of the visible light in the range of 400–800 nm, the degree of transparency for the coated film on poly(ethylene terephthalate) (PET) sheet is about 82–90%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5747–5752, 2006     

A simplified method to determine the 3D orientation of an injection molded fiber‐filled polymer

In short‐fiber reinforced composites, it is widely accepted that the fiber orientation plays an important role on their overall physical and thermomechanical properties. To predict the properties of such composite materials, a full 3D fiber orientation characterization is required. A variety of destructive and nondestructive techniques have been developed, but all the methods have the same common point that they are very tedious and time consuming. Knowing that the fiber orientation induced by the flow remains mainly in the flow plane, an easier method has been performed for injection molded fiber‐filled polymers. It is based on the simple 2D SEM image analysis of a specific 45°‐oblique section plane. Then, the indetermination of fiber orientation from an ellipse mark analysis does not exist anymore. This novelty also turns out to be much more accurate. To achieve measurements over large composite samples, the method has been fully automated. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

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     

Analysis of a liquid‐assisted molding process for coating microchannels with an ultraviolet curable polymer

Injection molding can be altered to form hollow parts by partially pre‐filling a mold with polymer melt and then injecting a gas into the mold before cooling. The gas will core the center section and in the process force melt into the unfilled portions of the mold. This process is called gas‐assisted injection molding (GAIM) and is a thoroughly studied polymer processing technique. Liquid‐assisted molding follows the same principles as GAIM, except the coring fluid is a liquid of low viscosity. Liquid‐assisted molding of an ultraviolet (UV) curable polymer can be used to coat microchannels, the benefit of which being a smooth and circular cross‐section. Presented here are experiments of the controlled microchannel flow of a long, immiscible liquid thread through a viscous UV curable polymer. The roles of channel geometry and bubble velocity are discussed for square, rectangular, and circular microchannels. Finally, a quasi‐analytical model for calculating the Newtonian coating fluid thickness, when the coring fluid is driven by a constant pressure, was developed using the equation for Poiseuille‐like flow within a square channel. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Optimization of powder injection molding of feedstock based on aluminum oxide and multicomponent water‐soluble polymer binder

Analyses crucial to optimize powder injection molding of feedstock based on aluminum oxide powder and multicomponent polymeric binder are provided with the aim to obtain defect‐free, high density parts. As the critical step of the process is the flow of highly filled (60 vol%) compound into a mold cavity, rheological properties supplemented by thermal and pressure‐volume‐temperature characteristics are measured and described. Upon shear deformation the feedstock undergoes structural changes, which are quantified in terms of yield stresses obtained using Herschel‐Bulkley and Casson methods. Further, the rheological model is developed to describe the flow behavior of the feedstock in the whole shear rate range measured. Thermogravimetric analysis is performed to optimize debinding step of the process, and two possible ways of the binder removal are proposed: purely thermal andcombined solvent/thermal. The quality of the final sintered parts is demonstrated on scanning electron microscopic images of their surfaces. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Characterization and properties of LDPE film with gallic‐acid‐based oxygen scavenging system useful as a functional packaging material

We prepared and characterized active, oxygen‐scavenging, low density polyethylene (LDPE) films from a non‐metallic‐based oxygen scavenging system (OSS) containing 1, 3, 5, 10, and 20% of gallic acid (GA) and potassium chloride (PC). We compared the surface morphology and mechanical, permeability, and optical properties of the oxygen‐scavenging LDPE film with those of pure LDPE film. The surface morphology, gas barrier, and thermal properties indicate that the OSS was well incorporated into the LDPE film structure. The surface roughness of the film increased with the amount of oxygen scavenging material. The oxygen and water vapor permeability of the developed film also increased with the amount of oxygen scavenging material, though its elongation decreased. The oxygen scavenging capability of the prepared film was analyzed at different temperatures. The initial oxygen content (%) in the vial headspace, 20.90%, decreased to 16.6% at 4 °C, 14.6% at 23 °C, and 12.7% at 50 °C after 7 days of storage with the film containing 20% OSS. The film impregnated with 20% organic oxygen scavenging material showed an effective oxygen scavenging capacity of 0.709 mL/cm² at 23 °C. Relative humidity triggered the oxygen scavenging reaction. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44138.     

Mechanical properties of (poly(L‐lactide‐co‐glycolide))‐based fibers coated with hydroxyapatite layer

This article presents the results of the experimental study on manufacturing and mechanical evaluation of poly(L ‐lactide‐co‐glycolide) (PLGA)‐based fibers modified with ceramic nanoparticles. Study was conducted to establish the effect of biomimetic formation of apatite layers on polymeric fibers on their mechanical properties. The tensile tests were performed to determine the influence of polymer crystallinity and the presence of hydroxyapatite nanoparticles (nanoHAp) on mechanical properties of PLGA fibers coated with hydroxyapatite (HAp) layer. HAp deposits on the surfaces of the fibers precipitated from simulated body fluid (SBF). Three types of fibers coated with HAp layers were compared in mechanical tests. The results indicated that by using a biomimetic fiber coating method the mechanical properties of the fibers are affected by their crystallinity. The nanoHAp modified polymer fibers after incubation in SBF were found to have a continuous HAp layer. The layer affected the mechanical behavior (force–strain function) of the fibers from nonlinear to linear, typical of ceramic materials. The tensile modulus of the fibers with a continuous layer was found to increase with the apatite layer thickness, whereas the tensile strength decreases. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of bio‐based PA/EP interpenetrating network polymer as coating material for controlled release fertilizers

A novel controlled release fertilizer was developed using interpenetrating polymer network (IPN) as the coating material. The IPN was successfully sprayed on the surface of the urea particles to form IPN‐coated fertilizers (IPNCU) for controlled nitrogen release. The IPN was synthesized by bio‐based polyamide (PA) from d ‐glucaric acid and epoxy (EP) through network interpenetrating. The chemical structure and microscopic morphology characteristics of IPN were examined by Fourier transform infrared spectroscopy, ¹H‐nuclear magnetic resonance, and scanning electron microscopy. The property of IPN with the different PA/EP mass ratios were investigated and compared with that of EP‐coated fertilizers (EPCU). The nutrient release behaviors of IPNCU in water and soil were detected. The results showed that the IPNCU with 5% PA content increased the nitrogen release longevity by 41 days, raised the water contact angle of surface by 23.9°, and then significantly slowed the nitrogen release rate of the IPNCU. The nutrient release mechanism of IPNCU was discussed in detail. This work indicated that the environment‐friendly IPN with superior controlled release properties could be especially useful in horticultural and agricultural applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46052.     

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     

Degradation of La0.6Sr0.4CoO3-based cathode performance in solid oxide fuel cells due to the presence of aluminum oxide deposited through atomic layer deposition

Aluminum oxide was deposited into the porous cathode compartment of the (Sc,Al)-doped ZrO₂ electrolyte cell through atomic layer deposition involving trimethyl aluminum and water as aluminum and oxygen sources, respectively. The deposited aluminum oxide had a detrimental effect on the cell performance of the zirconia-based SOFC unit cells in terms of the output power but did not change the open-cell voltage. Based on impedance spectroscopy, the open-cell voltage, and the output performance, the resultant degradation is attributed to the geometrical blockade of functional triple phase boundaries in La_0.6Sr_0.4CoO₃ (LSCo)-based cathode materials of mixed ionic electronic conduction, indicating that there is a disruption at the interface between the charge collector and cathode that is proportional to the amount of deposited Al₂O₃.     

Development of an electrochemical‐surface plasmon dual biosensor based on carboxylated conducting polymer thin films

A biosensing platform based on the covalent attachment of biomolecules on electropolymerized carboxylated conducting polymers, poly(3‐aminobenzoic acid) and poly(3‐pyrrole carboxylic acid), were developed for the selective simultaneous detection of two biomolecules using electrochemical‐surface plasmon resonance (EC–SPR) spectroscopy. The surface morphology of the developed biosensors was studied by scanning electron microscopy and atomic force microscopy. The EC–SPR dual biosensor was developed for the label‐free, simultaneous, and selective detection of glucose and human immunoglobulin G (IgG). A change in current density was clearly observed after the injection of glucose, whereas a change in SPR reflectivity was clearly observed after the injection of human IgG. The present work demonstrates the potential of this biosensing platform for real sample analysis in the future. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45641.     

Surface structure and properties of water‐based polymer coating materials prepared by the complexation of two polymer latices with chemically complementary structures

In this study, water‐based polymer coating materials used for the surface coating of substrates with lower surface energies were prepared by the complexation of two‐component polymer latices containing polydimethylsiloxane (PDMS) and having chemically complementary structures. The film‐forming performance of the polymer latices and the surface structures and properties of the coatings formed by the polymer latices were studied by means of scanning electron microscopy and by the measurement of mechanical strength, thermal performance, water absorbability, and contact angle. When the two‐component polymer latices [the poly(methyl methacrylate‐co‐butyl acrylate‐co‐methyl acrylic acid)/polydimethylsiloxane system (PA latex) and the poly(methyl methacrylate‐co‐butyl acrylate‐co‐pyrrolidone)/polydimethylsiloxane system (PB latex)] were compared, the complex polymer latex formed by the complexation of the PA latex with the PB latex had the best film‐forming performance, with formed coatings that were more smooth and had fewer less cracks. Also, compared to the two coatings formed by the two‐component polymer latices, the coatings formed by the complex polymer latex had a unique structure, a higher mechanical strength and elongation, a higher decomposing temperature, and better water resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1748–1754, 2003     

Adhesion of microorganisms to polymer membranes: a photobactericidal effect of surface treatment with TiO2

The adhesion of Escherichia coli, Pseudomonas putida and Acinetobacter calcoaceticus cells to Microdyn-Nadir ultrafiltration membranes of various chemical nature: PS100 (polysulfone), P005 (polyethersulfone), C100 (regenerated cellulose) was studied. It was shown that an adhesiveness of the microorganisms to the membranes essentially depends on hydrophobic/hydrophilic properties of both the cells and membranes. In particular, it was found that the adhesion of relatively hydrophilic E. coli to membrane surfaces is essentially lower comparing with the adhesion of more hydrophobic P. putida, or A. calcoaceticus cells. In a turn the microorganisms attachment to more hydrophobic polyethersulfone and polysulfone membranes is higher than to hydrophilic cellulose one. It was shown that the volume fluxes of membranes with adhesive microorganisms dropped while samples were kept in contact with natural surface water due to increasing of cell number on membrane surface. In attempts to reduce membrane biofouling, TiO₂ particles were deposited on membrane surface with following ultraviolet (UV) irradiation at 365 nm. It was shown that due to photobactericidal effect the fluxes of surface modified membranes were 1.7–2.3 times higher comparing with those for control membrane samples (without TiO₂ deposition and UV treatment).     

Preparation of high‐k composites with low dielectric loss based on the double‐layer coaxial structure of inorganic/polymer

This study presents a novel and simple modification of cladding multiwalled carbon nanotubes (MWCNTs) using organic polymer and inorganic nanoparticles to synthesize a product, which has a double‐cladding coaxial structure and can be applied as filler in the dielectric field. The first layer of MWCNTs was coated with polyaniline (PANI) through the oxidation–reduction reaction mechanism using Ce(NH₄)₂(NO₃)₆ as oxidizing agent and metal precursor of cerium oxide. Cerium ions on the second cladding layer of MWCNTs were directly deposited from the solution to the surface of the PANI layer forming the double‐cladding hybrid (CeO₂/PANI@MWCNTs). The external inorganic layer provides an insulating shell, which can prevent the contact between the conductive particles and hinder the migration of electrons between the MWCNTs. The intermediate layer of PANI provides the bonding between CeO₂ and the conductive core of MWCNTs, which also shows lower conductivity than carbon nanotubes. The CeO₂/PANI@MWCNTs were compounded with epoxy (EP) resin and formed a dielectric material with the advantage of reducing dielectric loss while ensuring high dielectric constant. The dielectric constant of the coated MWCNTs/EP composites was 194.90 at 10³ Hz with the content of fillers reaching 30 wt %, which is 28 times that of the pure EP. Accordingly, the dielectric loss of 30 wt % coated MWCNTs/EP composites was only 0.09 at 10³ Hz, which is only 2.25 times that of the pure EP. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46299.     

Polypropylene separator coated with a thin layer of poly(lithium acrylate‐co‐butyl acrylate) for high‐performance lithium‐ion batteries

In this paper, poly(lithium acrylate‐co‐butyl acrylate) [P(AALi‐co‐BA)] was synthesized, and a P(AALi‐co‐BA)‐coated polypropylene (PP) separator was prepared by a simple dip‐coating process. In contrast to the conventional thick, dense gel polymer coating layer, a thin P(AALi‐co‐BA) layer was formed on the PP separator, which had less influence on the pore structure of the original PP separator and was beneficial for the migration of lithium ions through the separator. Furthermore, the AALi units in the copolymer could improve the wettability of the separator, while the BA units provided the separator with strong adhesion to the electrodes. As expected, the modified separators showed good wettability, high ionic conductivity, and excellent interface stability. In addition, the cycle stability and rate performance were also improved significantly. This facile, affordable, and effective method has great application potential for the modification of polyolefin‐based separators. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46423.     

Preparation of phosphor coated with a polymer by emulsion polymerization and its application in low‐density polyethylene

The long‐afterglow phosphor SrAl₂O₄ : Eu²⁺, Dy³⁺ is liable to hydrolyze in water with deterioration of its luminescent properties. In this study, in situ emulsion polymerization was first used to prepare phosphor coated with poly(methyl methacrylate‐co‐butyl acrylate) [P(MMA‐co‐BA)] to improve water resistance. Fourier transform infrared spectra suggested that the polymer attached to the phosphor by chemical bonding. Observation by scanning electron microscopy (SEM) showed that a polymer layer formed on the surface of the phosphor. The resistance to water of the phosphor coated with the polymer layer was much better than that of the uncoated phosphor because the transparent polymer layer could suppress its hydrolysis process. Low‐density polyethylene (LDPE) plastics, doped with long‐afterglow phosphors, were manufactured with an extrusion technique. Through coating with P(MMA‐co‐BA), the compatibility of phosphor with the LDPE matrix was improved, as determined by SEM. The luminous LDPE plastics blended with the phosphor coated with polymer showed long and strong phosphorescence with little loss of persistence phosphorescence compared to the uncoated phosphor. The LDPE plastics still retained their mechanical properties through doping with 3% (mass fraction) of the phosphors. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of an acrylate‐copolymer‐based antistatic agent composed of a single‐ion conductive polymer electrolyte

Monomethoxy poly(ethylene glycol) acrylate (MPEGA) was synthesized through the esterification reaction of acrylic acid and methoxy poly(ethylene glycol)s (MPEGs) of different molecular weights. Then, MPEGA was copolymerized with methyl methacrylate, butyl acrylate, and β‐carboxyethyl acrylate neutralized with potassium hydroxide via conventional solution polymerization. In this way, a single‐ion conductive polymer‐electrolyte‐based antistatic agent (PEAA), in which potassium (K) ions were used as charge carriers, was obtained. The molecular structure, coordination effects between ether oxygen (EO) groups and K cations, ionic conductivity, and crystallization ability of the copolymer were characterized with Fourier transform infrared, conductivity measurements, polarizing optical microscopy, and differential scanning calorimetry, respectively. The crystallinity of the synthesized PEAA apparently decreased with the molecular weight of MPEG and the EO/K molar ratio decreasing, and this led to a corresponding enhancement of the conductivity. The dependence of the conductivity of the copolymer on temperature could be divided into different linear parts, and each was in good agreement with the Arrhenius equation. Moreover, the dependence of the conductivity on the relative humidity (RH) revealed that the PEAA could maintain high ionic conductivity (∼10⁻⁶ S/cm) even at the low RH of 10%. This implies the potential widespread application of PEAAs for the preparation of antistatic composites and especially poly(vinyl chloride)‐ and poly(methyl methacrylate)‐related composites because of their considerable miscibility. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011