Polyaniline‐functionalized magnetic nanoparticles for the removal of toxic dye from wastewater

A novel and inexpensive approach was adopted to develop a magnetic nanocomposite for the adsorption of cationic dye from an aqueous solution. This nanocomposite, which was based on a superparamagnetic iron oxide nanocore, was functionalized with a hydrophilic coating of polyaniline (PANI). The nanoparticle size, colloidal stability, surface chemistry, and magnetic properties were studied extensively by transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. The polymeric functionalized magnetic nanocomposite had an average core size of 20–40 nm and a shell size of 6–10 nm. To evaluate the potential of such nanocomposites for dye adsorption, malachite green (MG) was exposed with different operational parameters, such as the pH, temperature, initial concentration of the dye, contact time, and reusability. The rate of the adsorption followed pseudo‐second‐order kinetics with the adsorption isotherm fit the Langmuir isotherm model well. The maximum adsorption capacity was 240 mg of MG/g of adsorbent. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40840.     

Polyaniline‐supported platinum‐hydrous ruthenium oxide nanocomposite as electrocatalyst for methanol oxidation

A novel composite electrode is fabricated through the electrodeposition of hydrous ruthenium oxide (RuO₂·xH₂O) and platinum (Pt) particles into the matrix of polyaniline (PANI). Scanning electron microscopy reveals that RuO₂·xH₂O and Pt particles are homogeneously distributed into the matrix of PANI. A comparison of the sizes of Pt and RuO₂·xH₂O particles incorporated into the PANI film reveals that Pt particles are smaller in sizes as compared with the sizes of RuO₂·xH₂O particles. The catalytic activity of composite electrodes was evaluated for the oxidation of methanol by using cyclic voltammetry and chronoamperometry. A relatively high catalytic current was noticed for the oxidation of methanol (2.37 mA/cm²) at PANI‐Pt‐RuO₂·xH₂O electrode (+0.6 V (V vs. Ag/AgCl) in comparison to oxidation current at PAN‐Pt (1.27 mA/cm²) electrode. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Polyaniline‐modified cellulose nanofibrils as reinforcement of a smart polyurethane

Segmented polyurethanes exhibiting shape memory properties were modified by the addition of polyaniline (PANI)‐coated cellulose nanofibrils (CNFs). The two‐phase structure of the polymer is responsible for the material's ability to ‘remember’ and autonomously recover its original shape after being deformed in response to an external thermal stimulus. PANI was grown on the surface of the CNFs via in situ polymerization. Modified nanocrystals were added to the segmented polyurethane in concentrations ranging from 0 to 15 wt%. The changes in the material properties associated with the percolation of the coated fibrils appear at higher concentrations than previously observed for non‐modified CNFs, which suggests that fibril agglomeration is occurring due to the PANI coating. The shape memory behavior of the composites is maintained at about the same level as that of the unfilled polyurethane only up to 4 wt% of fibrils. At higher concentrations, the rigidity of the nanofibrils as well as their interaction with the hard‐segment phase and the increasing difficulty of dispersing them in the polymer collaborate to produce early breakage of the specimens when stretched at temperatures above the melting point of the soft segments. Copyright © 2010 Society of Chemical Industry     

Amine‐functionalized mesoporous silica: A material capable of CO2 adsorption and fast regeneration by microwave heating

The surface of ordered mesoporous (MCM‐48) silica has been subjected to covalent grafting with silane molecules containing one to three amino groups. The dielectric properties of the materials were studied in detail, and the functionalized materials were used for CO₂ adsorption at room temperature, followed by regeneration under either conventional heating or microwave irradiation. It has been found that, as the intensity of functionalization with amino groups increases (from mono‐ to tri‐amino silanes) both the CO₂ load and the dielectric response at microwave frequencies increase. In particular, functionalization with a tri‐amino silane derivative gave the highest CO₂ adsorption and the fastest microwave heating, resulting in a fourfold acceleration of adsorbent regeneration. The grafted material was fully stable for at least 20 adsorption‐regeneration cycles, making it an ideal candidate for microwave‐swing adsorption (MWSA) processes. © 2015 American Institute of Chemical Engineers AIChE J, 62: 547–555, 2016     

Designing acrylamide‐ and methacrylate‐based novel supports for lipase immobilization

To design efficient polymeric supports for lipase immobilization, two series of hydrogels based on acrylamide and three methacrylates were prepared via crosslinking with ethylene glycol methacrylate and N,N‐methylenebisacrylamide. The three methacrylates used to prepare these hydrogels had different alkyl chain lengths: C₁ (methyl methacrylate), C₁₂ (dodecyl methacrylate), and C₁₈ (octadecyl methacrylate). In the reaction scheme, only the feed concentration of the hydrophobic component (methacrylate) was varied. The characterization of the hydrogels was carried out with Fourier transform infrared, scanning electron microscopy, and nitrogen analysis to establish their structural aspects and to obtain evidence for network formation; the swelling and water uptake of the hydrogels were studied as functions of the time, temperature, and pH. Lipase immobilization on selected hydrogels was studied as a function of the concentration of the methacrylate used in the feed and the nature of the crosslinker. The activity of the hydrogel series that showed the highest activity of the immobilized lipase was investigated further as a function of the methacrylate feed concentration, pH, and temperature. Some organic solvents were studied to investigate the effect of the nature of the solvent on the activity of the immobilized lipase. The activity of the immobilized lipase was more than that of the free lipase and was affected by the structural attributes of the polymeric supports and by the nature of the solvent. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

氨基硅烷功能化磁性材料固定化琼胶酶的性能

利用3-氨丙基三乙氧基硅烷(APTES)对制备的SiO₂包覆Fe₃O₄复合粒子(Fe₃O₄@SiO₂)进行改性，制备了氨基硅烷功能化磁性材料Fe₃O₄@SiO₂-NH₂，将Fe₃O₄@SiO₂-NH₂作为载体用于固定化琼胶酶。采用SEM、FTIR、VSM对Fe₃O₄@SiO₂-NH₂和固定化琼胶酶进行了表征，对琼胶酶的固定化条件进行了优化，评价了固定化琼胶酶的性能。结果表明，琼胶酶成功固定在载体上。Fe₃O₄@SiO₂-NH₂的磁化饱和强度为48.4 emu/g，固定化琼胶酶的磁化饱和强度为42.8 emu/g...     

介孔分子筛SBA-15表面改性对脂肪酶固定化的强化作用

引言 脂肪酶可以催化酯水解或醇解、酯合成、酯交换、多肽合成及高聚物合成等多种有机反应,已被广泛应用于食品、精细化工及制药工业中[1].作为重要的生物催化剂,脂肪酶应用的有效性和经济性很大程度上取决于酶的固定化.     

Polyaniline–maleicacid–dodecylhydrogensulfate salt as sensor material for toxic gases

This article reports the results of novel polyaniline material as gas sensor, capable of operating at room temperature for toxic gases. Polyaniline–maleicacid–dodecylhydrogensulfate salt (PANI‐MA‐DHS) was prepared by emulsion polymerization pathway, which is soluble in N, N‐dimethyl formamide. PANI‐MA‐DHS was coated on a ceramic bead by simple brush coating method and used as sensor material. The resistance change of PANI‐MA‐DHS material for NH₃, CO₂, SO₂, and H₂S gases at different concentrations (10, 100, 1000, and 10,000 ppm level) was monitored for sensor characteristics. The stability of the polyaniline material under continuous exposure of gas level from 10 to 10,000 ppm was also studied. This novel gas sensor material has advantages such as excellent sensing ability, low cost, fast regeneration time (～ 1–2 min), simple experimental setup, and operable at room temperature. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Vertically oriented polyaniline‐graphene nanocomposite based on functionalized graphene for supercapacitor electrode

Polyaniline functionalized reduced graphene oxide (PORGO) is prepared by interfacial polymerization and then vertically oriented polyaniline‐graphene (PANI‐PORGO) nanocomposites based on PORGO are developed successfully by in situ polymerization. The morphology and structure are characterized by field emission scanning electron microscopy (FE‐SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FT‐IR), Raman spectra and X‐ray diffraction (XRD). The electrochemical tests indicate that the specific capacitance of PORGO and PANI‐PORGO is as high as 291 and 369 F/g, respectively, at the current density of 1 A/g. PANI—PORGO nanocomposite exhibits high electrochemical activity and enhanced cycle stability with a capacitance retention of 81.2% after 500 cycles at 10 A/g. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44808.     

Structure‐property relationship of substituted pyrrolidine functionalized CNT epoxy nanocomposite

Carbon nanotubes (CNTs) based polymer nanocomposites hold the promise of delivering exceptional mechanical properties and multifunctional characteristics. However, the realization of exceptional properties of CNT based nanocomposites is dependent on CNT dispersion and CNT‐matrix adhesion. To this end, we modified MWCNTs by Prato reaction to yield aromatic (phenyl and 2‐hydroxy‐4‐methoxyphenyl) substituted pyrrolidine functionalized CNTs (fCNT1 and fCNT2) and aliphatic (2‐ethylbutyl and n‐octyl) substituted pyrrolidine functionalized CNTs (fCNT3 and fCNT4). The functionalization of CNTs was established by Thermogravimetric analysis (TGA), Raman Spectroscopy, and XPS techniques. Optical micrographs of fCNT epoxy mixture showed smaller aggregates compared to pristine CNT epoxy mixture. A comparison of the tensile results and onset decomposition temperature of fCNT/epoxy nanocomposite showed that aliphatic substituted pyrrolidine fCNT epoxy nanocomposites have higher onset decomposition temperature and higher tensile toughness than aromatic substituted pyrrolidine fCNT epoxy nanocomposites, which is consistent with the dispersion results of fCNTs in the epoxy matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42284.     

Microwave‐assisted immobilization of lipase from Candida rugosa on Eupergit® supports

BACKGROUND: Immobilization of lipase (triacylglycerol acylhydrolase EC 3.1.1.3) from Candida rugosa on Eupergit^® C and Eupergit^® C 250L was performed under microwave irradiation in order to reduce immobilization time. Lipase loading, hydrolytic activity, esterification activity and operational stability in organic solvent of immobilized lipase preparation were determined. RESULTS: The microwave‐assisted procedure resulted in a 29% lower lipase loadings, compared with immobilized lipase obtained without microwaves. In hydrolytic activity assay, lipase immobilized under microwaves exhibited a 23% higher specific activity. Slight activation of lipase by microwave‐assisted immobilization was observed, since specific activity was around 5% higher than for free lipase. Lipase of highest activity was obtained after 2 min immobilization on Eupergit^® C. The same preparation exhibited high esterification activity in organic medium and a half life of 212 h was determined in multiple use assay. CONCLUSION: The application of microwave irradiation leads to reduction of immobilization time from 2 days to only 2 min. The immobilized lipase obtained has prospects for further application due to its high retained activity and stability. Copyright © 2009 Society of Chemical Industry     

Preparation of aldehyde‐, amino‐, and hydrazide‐functionalized polymer particles for direct immobilization of the sugars

The reaction of poly(vinyl alcohol) with glutaraldehyde (GA) at different molar ratio was systematically studied. By this reaction, white particles functionalized with aldehyde groups were obtained and their diameters were found to be between 50 and 150 nm. The amount of free ? CHO groups on the surface of the particles reached more than 1.6 mmol/g by adjusting the ratio of n(GA)/n(? OH). The free ? CHO groups were then converted into alkyl amino, aromatic amino, and hydrazide groups by coupling with hexamethylene diamine, m‐phenylene diamine, and adipic dihydrazide, respectively, and the length of the spacer was also prolonged. Finally, a series of sugar‐particle conjugates were prepared by directly coating the functionalized particles with maltose, D ‐(+)‐glucosamine, and heparin. The anticoagulant experiments show that the heparin immobilized on the aldehyde‐ and hydrazide‐functionalized particles is still biologically active. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

粒径对磺酸官能化介孔材料性能的影响

以聚乙氧基-聚丙氧基-聚乙氧基三嵌段共聚物(P123)为模板剂、正硅酸乙酯(TEOS)为硅源,保持P123和TEOS的浓度比,改变P123和TEOS在合成体系中的浓度,水热法合成了系列具有不同粒径的介孔分子筛SBA-15.采用后合成法,将3-巯基丙摹三甲氧基硅烷(MPTMS)嫁接到具有不同粒径的介孔分子筛SBA-15表面上,经氧化后得到含有强酸性的磺酸基因的固体酸样品SBA-15-SO_3H.采用SEM、XRD、FT-IR、TG-DTA、N_2吸附以及酯化反应考察了粒径对所制备的SBA-15-SO_3H的物化性能和催化性能的影响.结果表明,SBA-15的粒径大小对MPTMS在其上的嫁接量没有很人影响,但对后续氧化过程有较大的影响,SBA-15粒径的减小有利于巯基被氧化为磺酸基,导致磺酸的负载量随着粒径的减少而增大.SBA-15-SO_3H在乙酸和乙醇的酯化反应中表现出不同的催化性能,催化性能的差异是粒径大小、酸量及磺酸基和巯基相互作用的综合结果.     

Spirulina platensis‐capped mesoporous magnetic nanoparticles for the adsorptive removal of chromium

The magnetic nanoparticles prepared through the co‐precipitation method were surface modified using Spirulina platensis. The mesoporous and superparamagnetic nature of the adsorbent was confirmed by Brunauer‐Emmett‐Teller (BET) and vibrating sample magnetometer (VSM) analyses, respectively. Further, an increased specific surface area of 75.3 m²/g was reported in the BET studies. Parameters such as pH, contact time, concentration, and temperature were studied to optimize the operating conditions influencing adsorption. Thermodynamic studies justified the spontaneity and endothermic nature of adsorption. The adsorbent exhibited a better performance at 1.5 pH and 120 minutes of contact time. The monolayer adsorption capacity of the material was found to be 29.23 mg/g from the evaluation of Langmuir adsorption isotherm. The second‐ order kinetic studies suggest the predominance of chemisorption. Further, the X‐ray photoelectron spectroscopy (XPS) studies confirmed that the adsorption mechanism is electrostatic attraction accompanied by reduction. Notably, a regeneration efficiency of 75.26% was achieved with NaOH as the desorbing agent.     

Architecture and performance of mesoporous silica‐lipase hybrids via non‐covalent interfacial adsorption

To investigate the effects of surface property of mesoporous supports on the lipase immobilization and the performance of immobilized lipase, the mesoporous molecular sieve SBA‐15 is functionalized with three organic moieties, dimethyl (DM), diisopropyl (DIP), and diisobutyl (DIB), respectively, by post‐synthesis grafting and one‐pot synthesis methods. Porcine pancreas lipase (PPL) is immobilized on SBA‐15 supports through hydrogen bonding and hydrophobic interaction. The hydrophobic adsorption involves no active sites of PPL, and neither hyper‐activation nor total inactivation occurs. The study on the intrinsic stability of PPL, including thermal stability, pH stability, and storage stability, indicates that the entrapment in mesoporous supports, and especially in organic‐functionalized supports, makes PPL more resistant to temperature increment but more sensitive to pH change. The reusability investigation shows that the organic modification of mesoporous surface inhibits the enzyme leaching to some extent, resulting in a better operational stability. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

Silver nanoparticles decorated polypyrrole/graphene nanocomposite: A potential candidate for next‐generation supercapacitor electrode material

In the present study, we report a simple method to synthesize silver (Ag)‐polypyrrole (PPy)/graphene (Gr) nanocomposite as efficient electrode materials for supercapacitor application. The probable interaction between Ag nanoparticles with both PPy and Gr were characterized by FTIR, UV–visible, and Raman spectroscopies. The morphological analysis confirmed that the Gr sheets are uniformly coated by PPy and in the coated Gr sheets there is the presence of Ag nanoparticles. The Ag‐PPy/Gr nanocomposite achieved the highest specific capacitance of 472 F/g at a 0.5 A/g current density. Better energy and power density also obtained for the nanocomposite. The presence of both Ag nanoparticles and Gr is the main reason for the enhancement of the electrochemical properties of the nanocomposite. Based on the superior electrochemical properties, the nanocomposite can be used for next‐generation supercapacitor electrode material. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44724.     

Utilization of rice hull ash as a support material for immobilization of Candida cylindracea lipase

Rice hull ash was heated in a muffle furnace at 700°C for 2 h and metallic oxides were leached with 10% sulfuric acid. The acid-activated ash was then examined for immobilization of Candida cylindracea lipase. Immobilization was carried out by direct addition of the enzyme solution to the activated ash suspended in hexane. The immobilized lipase retained 30% of its hydrolytic activity, but thermal stability was greatly increased. Half-lives of the immobilized enzyme at 50, 60, and 70°C were 45, 17, and 4 min, respectively. Optimal pH of the immobilized enzyme was 7.2. The apparent K_m and V_max for olive oil were 41 mM and 99.5 μmol/h-mg solid, respectively.     

Incorporating functionalized silica nanoparticles in polyethersulfone‐based anion exchange nanocomposite membranes

In order to investigate for anion exchange membranes (AEMs) with improved properties, four series of polyethersulfone‐based composite AEMs are fabricated by incorporating pristine and three functionalized silica nanoparticles containing propylamine, trimethylpropylamine, and melamine‐based dendrimer amine groups. The results show that by choosing appropriate functional agent, anion exchange membranes with improved parameters can be achieved. The polymeric matrix of the membranes is synthesized by chloromethylation of polyethersulfone using thionyl chloride followed by amination with trimethylamine (TMA). The effectiveness of chloromethylation process is confirmed by ¹H NMR analysis. The effects of functional groups on characteristic and transport properties of the prepared composite membranes i.e., SEM, IEC, water uptake, porosity transport properties, and conductivity are investigated. The scanning electron microscope images illustrates that the synthesized membranes possess dense structures. Ion exchange capacity (IEC), water uptake, transport properties, and conductivity of the composite membranes are measured. In addition, the morphology and thermal stability are characterized. IECs and ion conductivities of up to 1.45 meq g^?1 and 45.46 mS cm^?1 and moderate transport characteristics are obtained from the modified membranes which confirm that these membranes are appropriate for applying in electro‐membrane processes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44596.     

Properties of ultrahigh‐molecular‐weight polyethylene nanocomposite films containing different functionalized multiwalled carbon nanotubes

We compared the thermomechanical properties, morphologies, gas permeabilities, and electrical conductivities of ultrahigh‐molecular‐weight polyethylene (UHMWPE) nanocomposite films containing two types of functionalized multiwalled carbon nanotubes (functionalized MWNTs). Both 2‐hydroxyethyl triphenyl phosphonium‐MWNT (Ph3P‐MWNT) and 1,1,1,3,3,3‐hexafluoro‐2‐phenyl‐2‐propanol‐MWNT (CF3‐MWNT) were used as reinforcing fillers in the fabrication of UHMWPE hybrid films. UHMWPE nanocomposites with various functionalized MWNT contents were solution‐cast to produce the films. The thermomechanical properties and morphologies of the UHMWPE hybrid films were then characterized using differential scanning calorimetry, thermogravimetric analysis, electron microscopy, and mechanical tensile analysis. Transmission electron microscopy studies showed that some of the MWNT particles were dispersed homogeneously within the polymer matrix (on the nanoscale), whereas others were agglomerated. We also found that the addition of only a small amount of functionalized MWNTs was sufficient to improve the thermomechanical properties and the gas barrier of the UHMWPE hybrid films. Even, those hybrid films with low functionalized MWNT contents (i.e., <1 wt%) were found to exhibit much better thermomechanical properties than the pure UHMWPE films. On the other hand, the values of the electrical conductivity remained constant, regardless of the amount of functionalized MWNTs. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers