Vapor‐Phase Transport Crystallization of Micro‐HZSM‐5 Zeolite Coatings

A novel structured catalyst of binderless micro‐HZSM‐5 zeolite coating was prepared on stainless‐steeled tubes (i.d. 2 mm) through wash coating and vapor‐phase transport (VPT) crystallization method. The subsequent crystallization of amorphous SiO₂ binders improved the coatings adhesion tremendously by more than 10 times with the least amount of binders (<20% by weight), attributed to the remarkably enhanced interlock by the formed Mordenite Framework Inverted structure between zeolite particles. Catalytic cracking of supercritical n‐dodecane (500°C, 4 MPa) was used to examine the catalytic performance of the coatings as prepared, indicating that MZC‐V0.2 exhibited a catalytic activity improvement by 8% and a decreased deactivation rate by 48%. The improved catalytic performance may result from its high acid sites amount by incorporating extra‐framework Al into HZSM‐5 framework, and the possible depressing of pore‐mouth deactivation through partial modification of surface acid sites during VPT treatment. This work provides a potential technique to prepare mechanically stable zeolite coatings with high catalytic activity but less binder usage.     

Catalytic combustion kinetics of isopropanol over novel porous microfibrous‐structured ZSM‐5 coating/PSSF catalyst

Porous thin‐sheet cobalt–copper–manganese mixed oxides modified microfibrous‐structured ZSM‐5 coating/PSSF catalysts were developed by the papermaking/sintering process, secondary growth process, and incipient wetness impregnating method. Paper‐like sintered stainless steel fibers (PSSF) support with sinter‐locked three‐dimensional networks was built by the papermaking/sintering process, and ZSM‐5 coatings were fabricated on the surface of stainless steel fibers by the secondary growth process. Catalytic combustion performances of isopropanol at different concentrations over the microfibrous‐structured Co–Cu–Mn (1:1:1)/ZSM‐5 coating/PSSF catalysts were measured to obtain kinetics data. The catalytic combustion kinetics was investigated using power–rate law model and Mars–Van Krevelen model. It was found that the Mars–Van Krevelen model provided fairly good fits to the kinetic data. The catalytic combustion reaction occurred by interaction between isopropanol molecule and oxygen‐rich centers of modified microfibrous‐structured ZSM‐5 coating/PSSF catalyst. The reaction activation energies for the reduction and oxidation steps are 60.3 and 57.19 kJ/mol, respectively. © 2014 American Institute of Chemical Engineers AIChE J, 61: 620–630, 2015     

Synthesis and characterization of polyhydroxylated polybutadiene binding 2,2′‐thiobis(4‐methyl‐6‐tert‐butylphenol) with isophorone diisocyanate

A macromolecular hindered phenol antioxidant, polyhydroxylated polybutadiene containing thioether binding 2,2′‐thiobis(4‐methyl‐6‐tert‐butylphenol) (PHPBT‐b‐TPH), was synthesized via a two‐step nucleophilic addition reaction using isophorone diisocyanate (IPDI) as linkage. First, the ? OH groups of PHPBT reacted with secondary ? NCO groups of IPDI to form the adduct PHPBT‐NCO, then the PHPBT‐b‐TPH was obtained by one phenolic ? OH of 2,2′‐thiobis(4‐methyl‐6‐tert‐butylphenol) (TPH) reacting with the PHPBT‐NCO. The PHPBT‐b‐TPH was characterized by Fourier transform infrared spectroscopy, ¹H nuclear magnetic resonance (¹H‐NMR), ¹³C‐NMR, and thermogravimetric analysis, and its antioxidant activity in natural rubber was studied by an accelerated aging test. Influences of reaction conditions on the two nucleophilic reactions between ? OH group and ? NCO group were investigated. In addition, catalytic mechanism for the reaction between PHPBT‐NCO and TPH was discussed. The results showed that the adduct PHPBT‐NCO could be obtained by using dibutyltin dilaurate (DBTDL) as catalyst, and the suitable temperature and DBTDL amount were 35°C and 3 wt %, respectively. However, triethylamine (TEA) was more efficient than DBTDL to catalyze the reaction between PHPBT‐NCO and TPH because of steric hindrance effect. In addition, it was found that the thermal stability and antioxidant activity of PHPBT‐b‐TPH were higher than those of the low molecular weight antioxidant TPH. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40942.     

Preparation and Performances of Hierarchical Structured HZSM‐5 Washcoating on Stainless‐Steel Substrates

The washcoats of the hierarchical HZSM‐5 zeolite (through desilication) were prepared on the inner surface of SS304 stainless‐steel tubes. The properties of slurries and coatings were characterized by analysis of particle size, measurements of rheological property, loading, adhesion, and finally the catalytic cracking test. It was found that introducing mesoporosity on the zeolite crystals was beneficial for reducing the particle size during ball milling for slurries preparation, which was helpful for improving loading due to a significant change in the rheological property. As the interaction between the particles with different sizes was enhanced after ball milling, the adhesion of the prepared coatings was improved. The catalytic activity and stability of the hierarchical HZSM‐5 coatings for the catalytic cracking of n‐dodecane were 56% and 75% higher than that of the conventional one, respectively. This probably resulted from the enhanced diffusion rate of reactant and products in the crystals and the coatings.     

Copper(I)‐Catalyzed [3+2] Cycloaddition/Ring‐Opening Rearrangement/[4+2] Cycloaddition/Aromatization Cascade: An Unprecedented Chemo‐ and Stereoselective Three Component Coupling of Sulfonyl Azide,Alkyne and N‐Arylidenepyridin‐2‐ amine to Pyrido[1,2‐a]pyrimidin‐4‐imine

A novel synthetic protocol for the one‐pot chemo‐ and stereoselective construction of diversely functionalized pyrido[1,2‐a]pyrimidin‐4‐imines via copper(I)‐catalyzed [3+2] cycloaddition/ring‐opening rearrangement/[4+2] cycloaddition/aromatization cascade of sulfonyl azides, alkynes and N‐arylidenepyridin‐2‐amines under mild reaction conditions is reported. In addition, the catalytic activity of copper(I)‐modified zeolite, a recyclable, heterogeneous catalyst is also investigated, which gives improved yield compared to its homogeneous equivalents.     

Chemical kinetic modeling of i‐butane and n‐butane catalytic cracking reactions over HZSM‐5 zeolite

A chemical kinetic model for i‐butane and n‐butane catalytic cracking over synthesized HZSM‐5 zeolite, with SiO₂/Al₂O₃ = 484, and in a plug flow reactor under various operating conditions, has been developed. To estimate the kinetic parameters of catalytic cracking reactions of i‐butane and n‐butane, a lump kinetic model consisting of six reaction steps and five lumped components is proposed. This kinetic model is based on mechanistic aspects of catalytic cracking of paraffins into olefins. Furthermore, our model takes into account the effects of both protolytic and bimolecular mechanisms. The Levenberg–Marquardt algorithm was used to estimate kinetic parameters. Results from statistical F‐tests indicate that the kinetic models and the proposed model predictions are in satisfactory agreement with the experimental data obtained for both paraffin reactants. © 2011 American Institute of Chemical Engineers AIChE J, 58: 2456–2465, 2012     

Vegetable oil based polyurethanamide/organo‐montmorillonite bio‐nanocomposite

The present work describes the synthesis and characterization of polyurethanamide/organo‐montmorillonite bio‐nanocomposites (OBNC) from Linseed oil‐a renewable resource. The aim of the work is (i) to widen the scope of application and improve the performance of vegetable oil based polymers, and (ii) to investigate the effect of introduction of modified clay on their structure, morphology, thermal stability, and coating properties. OBNC has been prepared by in situ polymerization of Linseed oil derived diol fattyamide and tolulylene‐2,4‐diisocyanate in the presence of different contents of OMMT (0.5–2.5 mass % in minimum amount of dimethylformamide) at room temperature. OBNC has been characterized by optical microscopy, FTIR, XRD, TEM, and TGA, which confirm the formation of OBNC. OBNC produced tough, scratch‐resistant, impact resistant, flexibility retentive coatings, which cure at room temperature with improved coating performance and thermal stability than virgin polymer. Amongst all the compositions, OMMT‐1.5 showed the best coating properties, with good scratch hardness (3.5 kg), impact (passes 200 lb/inch.) and bent test values (passes 1/8 inch). It can be commercially used as effective green coating material in future. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40278.     

Kinetic and catalytic performance of a BI‐porous composite material in catalytic cracking and isomerisation reactions

Catalytic behaviour of pure zeolite ZSM‐5 and a bi‐porous composite material (BCM) were investigated in transformation of m‐xylene, while zeolite HY and the bi‐porous composite were used in the cracking of 1,3,5‐triisopropylbenzene (TIPB). The micro/mesoporous material was used to understand the effect of the presence of mesopores on these reactions. Various characterisation techniques, that is, XRD, SEM, TGA, FT‐IR and nitrogen sorption measurements were applied for complete characterisation of the catalysts. Catalytic tests using CREC riser simulator showed that the micro/mesoporous composite catalyst exhibited higher catalytic activity as compared with the conventional microporous ZSM‐5 and HY zeolite for transformation of m‐xylene and for the catalytic cracking of TIPB, respectively. The outstanding catalytic reactivity of m‐xylene and TIPB molecules were mainly attributed to the easier access of active sites provided by the mesopores. Apparent activation energies for the disappearance of m‐xylene and TIPB over all catalysts were found to decrease in the order: E_BCM > E_ZSM‐5 and E_BCM > E_HY, respectively. © 2012 Canadian Society for Chemical Engineering     

Influence of MA‐g‐HDPE compatibilizer content on quality and adhesion/bending strength of polyethylene/O‐MMT coating films

High density polyethylene/organo‐modified montmorillonite composites whit various concentrations of maleic anhydride grafted high density polyethylene (MA‐g‐HDPE) as compatibilizer (5–20 wt %) have been prepared by melt process. The extruded composite powders are applied on the treated steel surfaces using spray electrostatic powder technique, followed by oven curing at various temperatures (180°C–220°C) and times (15–45 min). The surface uniformity of produced coating films is studied by scanning electron microscopy. Comparison of micrographs of the coatings shows the composite coating films are measured using standard methods. The uniformity, adhesion, and bending strength of the coating films are compared to select high performance coatings. The results indicate that the presence of 15 wt % MA‐g‐HDPE in the coatings shows the highest properties (adhesion and bending strength) and more surface uniformity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40926.     

Synthesis,characterization, and catalytic behavior of copper complexes with fluorosubstituted β‐ketoimine ligands

A series of β‐ketoimine ligands with various fluorine substitutions on the N‐aryl ring and the corresponding copper complexes were synthesized. The fluorosubstituents exerted significant effects on the structures and catalytic activities of the copper complexes. X‐ray diffraction revealed that the copper(II) central ions were coordinated by two trans‐oriented β‐ketoimino ligands with delocalized double bonds. Complex 2b (with mono‐o‐fluorosubstitution on the N‐aryl moiety) adopted a central symmetric square planar structure, whereas complex 2f (with bis‐o‐fluorosubstitution) had a distorted square planar structure with a dihedral angle of 28.2°. The Cu? N bond length in 2f was appreciably shorter than that in 2b . When activated by modified methylaluminoxane, the copper complexes effectively polymerized methyl acrylate. Furthermore, substitution with more fluorine atoms resulted in a higher activity. The catalytic activity of the pentafluorosubstituted complex 2h reached 57.5 kg (mol of Cu)^?1·h^?1 under optimized conditions; this was the highest value reported up to this point for copper complexes in acrylic monomer polymerization. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41178.     

Influence of alumina binders on adhesion and cohesion during preparation of Cu‐SAPO‐34/monolith catalysts

The adhesion and cohesion between the coating layers and the ceramic honeycombs are usually one of the key issues in the preparation of high‐performance zeolite‐based/Monolith catalysts. In this work, we investigate the deposition of high‐efficiency Cu‐SAPO‐34 catalyst on a cordierite monolith with special focus on the impact of alumina binders on the structure, mechanical adhesion and cohesion, and catalytic performance of the monolithic catalyst. Two kinds of alumina nanoparticles, α‐alumina and γ‐alumina, have no significant impacts on the Cu‐SAPO‐34 crystal structure, micropore morphology and catalytic activity. But washcoating experiments showed that the mass loss rate of the coating was less and the loading of the catalyst was higher when α‐alumina was used as the binder. The reason of improving the adhesion and cohesion strength is the suitable thermal shrinkage, the uniform distribution and densification structure of α‐alumina. Furthermore, optimization of the coating formulation with α‐alumina as the binder has been performed. Finally, the catalyst prepared under the optimal conditions was tested by SCR and a maximum conversion rate of 97.4% was obtained. It was concluded that the use of the washcoating method with α‐alumina does not affect catalytic performance while it increases bonding strength between substrate and catalysts.     

Pervaporation of n‐butanol aqueous solution through ZSM‐5‐PEBA composite membranes

Composite membranes were prepared by incorporating ZSM‐5 zeolite into poly(ether‐block‐amide) (PEBA) membranes. These composite membranes were characterized by TGA, XRD, and SEM. The results showed that the zeolite could distribute well in the polymer matrix. And when the zeolite content reached 10%, the agglomeration of zeolite in the membranes was found. The composite membranes were used to the pervaporative separation of n‐butanol aqueous solution. The effect of zeolite content on pervaporation performance was investigated. With the contribution of preferential adsorption and diffusion of n‐butanol in the polymer matrix and zeolite channel, the 5% ZSM‐5‐PEBA membrane showed enhanced selectivity and flux. The effects of liquid temperature and concentration on separation performance were also investigated. All the composite membranes demonstrated increasing separation factor and permeation flux with increasing temperature and concentration. Incorporation of ZSM‐5 could decrease the activation energy of n‐butanol flux of the composite membrane. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Zeolite A‐polypropylene and silver‐zeolite A‐polypropylene composite films for antibacterial and breathable applications

Polypropylene (PP) composite films were successfully prepared using melt blending by directly mixing PP pellets with zeolite A or silver‐zeolite A powder and then blowing. All the prepared films were characterized in terms of their physical, mechanical, optical, and gas permeability properties. The structure of each composite film was similar to that of the pure PP film. The crystallinity and glossy quality of the composite films were increased by the addition of silver, zeolite, and maleic anhydride grafted PP (PP‐g ‐MA). The composite PP film with zeolite A and PP‐g ‐MA exhibited a level of oxygen and carbon dioxide permeation (6438 and 15,087 cc m^?2 day^?1 atm^?1, respectively). Finally, all the films were evaluated for their antibacterial activity and fruit packaging applications. Silver‐zeolite A‐PP composite films exhibited a bactericidal activity of 79% against Staphylococcus aureus and 52% against Escherichia coli , while the zeolite A‐PP film could extend the shelf‐life of bananas for over a week. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45450.     

Antimicrobial cytocompatible pentaerythritol triacrylate‐co‐trimethylolpropane composite scaffolds for orthopaedic implants

As of 2010, 5.3 million orthopedic surgeries are performed each year, and this number is expected to increase to 6.2 million by 2020. On average, 27.7% of all orthopedic surgeries result in infection which often leads to osteomyelitis and the loss of supporting bone. In this study, we describe two synthetic bone grafts, or augmentation methods, for a biodegradable, silver nanoparticle (SNPs) containing antimicrobial scaffolds composed of pentaerythritol triacrylate‐co‐trimethylolpropane tris (3‐mercaptopropionate) (PETA) and hydroxyapatite (HA). This osteoinductive and degradable material is designed to stimulate proliferation of bone progenitor cells, and provide controlled release of antimicrobial components. The first method, denoted as the “incorporating method,” involves dissolving SNPs in ethanol, butanol, or isopropanol and directly incorporating the particles into the scaffold prior to polymerization. The second method, “coating method,” involves submerging fabricated scaffolds into their respective SNPs‐solution and mixing for 24 h. The coating method allowed better distribution and release of SNPs from the surface of the composites when exposed to extracellular media. The in vitro release of silver for both methods was quantified by inductively coupled plasma optical emission spectroscopy (ICP‐OES). The scaffolds made by means of the coating method showed increased release of silver with respect to time; no silver leached from the scaffolds formed by the incorporating method. Use of Alamar Blue assay demonstrated that the SNPs incorporation did not affect cell viability when tested with hASCs. The scaffolds formed by the coating method inhibited the proliferation of Staphylococcus aureus 99.5% and Escherichia coli by 99.9% within 24 h. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41099.     

Gold‐nanoparticle‐decorated thermoplastic polyurethane electrospun fibers prepared through a chitosan linkage for catalytic applications

Thermoplastic polyurethane (TPU)‐electrospun‐fiber‐mat‐supported gold catalysts were prepared by the adsorption of gold nanoparticles (AuNPs) onto a TPU electrospun fiber mat after functionalization with chitosan (CS) by a dip‐coating method. The mechanism for the adsorption of AuNPs was electrostatic interaction between the positive charge of CS (? N ) and the negative charge of the AuNP surface (? COO^?) and coordination between the amine groups of CS and gold. The mat was crosslinked with glutaraldehyde vapor to strengthen the adhesion between the CS coating and TPU fibers after the adsorption of AuNPs. The catalytic activity of the supported gold catalyst was evaluated with the reduction of 4‐nitrophenol by NaBH₄ to demonstrate the excellent catalytic performance and its reusability for at least 10 cycles without a loss in activity. The rate constant increased with both an increase in the amount of supported catalyst and an increase in the ratio of the mat surface area to AuNP within the investigated scope. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 44336.     

Synthesis,self‐assembly,and drug release behavior of star‐shaped poly(ε‐caprolactone)‐b‐poly(ethylene oxide) block copolymer with porphyrin core

A serial of star‐shaped poly(ε‐caprolactone)‐b‐poly(ethylene oxide) (SPPCL‐b‐PEO) block copolymers with porphyrin core were successfully synthesized from ring‐opening polymerization (ROP) of ε‐caprolactone (CL) initiated with porphyrin core, followed by coupling reaction with a hydrophilic polymer poly(ethylene oxide) (PEO) shell. The structure of this novel copolymer were synthesized and thoroughly characterized by Nuclear Magnetic Resonance (NMR), Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR). Notably, the as‐prepared porphyrin‐cored star‐shaped copolymer could self‐assembly into different structures determined by transmission electron microscopy (TEM) and dynamic lighting scattering (DLS), which provides the great potential of using this well‐defined photodynamic therapy material for drug delivery system. Particularly, the doxorubicin‐loaded SPPCL‐b‐PEO nanosphere exhibits property of pH‐induced drug release. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40996.     

Preparation and properties of phase‐change heat‐storage UV curable polyurethane acrylate coating

Phase‐change heat‐storage UV curable polyurethane acrylate (PUA) coating was prepared by applying microencapsulated phase change materials (microPCMs) to PUA coating. MicroPCMs containing paraffin core with melamine‐formaldehyde shell were synthesized by in situ polymerization. The effect of stirring speed, emulsification time, emulsifier amount, and core/shell mass ratio on particle size, morphology, and phase change properties of the microPCMs was studied by using laser particle size analyzer, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopic analysis, scanning electron microscopy, and differential scanning calorimetry. The results showed that the diameter of the microcapsules decreased with the increase of stirring speed, emulsification time, and emulsifier amount. When the mass ratio of emulsifier to paraffin is 6%, microcapsules fabricated with a core/shell ratio of 75/25 have a compact surface and a mean particle size of 30 μm. The sample made under the above conditions has a higher efficiency of microencapsulation than other samples and was applied to PUA coating. The dispersion of microPCMs in coating and heat‐storage properties of the coating were investigated. The results illustrated that the phase‐change heat‐storage UV curable PUA coating can store energy and insulate heat. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41266.     

Gradient and weather resistant hybrid super‐hydrophobic coating based on fluorinated epoxy resin

A weather resistant super‐hydrophobic coating that can offer good substrate adhesion and yet to be easily processed at large scale can be of practical use in emerging fields of self‐cleaning and anti‐icing paint, combing all these properties together remains challenging task. Here we describe a composite coating composed of a fluorinated epoxy resin emulsion with embedded in situ surface‐modified dual‐scale nano‐silica, which displayed durable super‐hydrophobicity and excellent adhesive strength. The as‐prepared coating possesses water contact angle of 158.6 ± 1°, sliding angle around 3.8 ± 0.2° which remain stable even under acidic/alkaline, heat/cool, and accelerated aging treatment. The results demonstrate that surface roughness had a micron‐ and nanometer scale distribution with increased particle loading beyond 40 wt %. Through quantitative comparison of surface Attenuated Total Reflection (ATR) with bulk FT‐IR transmission spectra, a gradient coating with surface enrichment of hydrophobic groups was determined. The air‐side fluorinated polysiloxane‐rich layer endows coating with weather‐resistance and ultra‐hydrophobicity while bottom epoxy resin layer enhances substrate adhesion. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40955.     

High‐performance zeolite T membrane for dehydration of organics by a new varying temperature hot‐dip coating method

A new seeding method, namely, varying‐temperature hot‐dip coating (VTHDC), is proposed for synthesis of zeolite T membranes by secondary hydrothermal growth. The VTHDC method is composed of hot‐dip coating at higher temperature, rubbing off the superfluous crystals, and hot‐dip coating at lower temperature. It was found that the method was flexible and effective for combined control over the seed suspension concentration, seed size, and coating temperature, leading to combined control of properties of the seed layer over the seed size, thickness, coverage, and defect. A thin continuous, smooth defect‐free asymmetric seed layer was achieved consisting of large and small zeolite T seed crystals. The resulting zeolite T membrane M5 exhibited high pervaporation performance with the flux reaching 2.12 and 2.52 kg/m² h for the dehydration of 90 wt % EtOH/H₂O and IPA/H₂O mixture, respectively, at 348 K. The corresponding separation factor was up to 1301 and 10,000, respectively. © 2012 American Institute of Chemical Engineers AIChE J, 59: 936–947, 2013     

Tribological properties of polyimide coatings filled with PTFE and surface‐modified nano‐Si3N4

Polyimide (PI) coatings filled with PTFE and nano‐Si₃N₄ were prepared by a spraying technique and successive curing. Nano‐Si₃N₄ particles were modified by grafting 3‐aminopropyltriethoxysilane to improve their dispersion in the as‐prepared coatings. Friction and wear performances and wear mechanisms of the coatings were evaluated. The results show that the incorporations of PTFE and modified nano‐Si₃N₄ particles greatly improve the friction reduction and wear resistance of PI coating. The friction and wear performance of the composite coating is significantly affected by the filler mass fraction and sliding conditions. PI coating incorporated with 20 wt % PTFE and 5 wt % modified nano‐Si₃N₄ displays the best tribological properties. Its wear rate is more than one order of magnitude lower and its friction coefficient is over two times smaller than that of the unfilled PI coating. Differences in the friction and wear behaviors of the hybrid coatings as a function of filler or sliding condition are attributed to the filler dispersion, the characteristic of transfer film formed on the counterpart ball and the wear mechanism of the coating under different sliding conditions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40410.