Preparation of Mesoporous Carbons from Acrylonitrile-methyl Methacrylate Copolymer/Silica Nanocomposites Synthesized by in-situ Emulsion Polymerization

Acrylonitrile-methyl methacrylate (AN-MMA) copolymer/silica nanocomposites were synthesized by in-situ emulsion polymerization initiated by 2,2'-azobis(2-amidinopropane) dihydrochloride absorbed onto colloidal silica particles, and the mesoporous carbon materials were prepared through carbonization of the obtained AN-MMA copolymer/silica nanocomposites, followed by HF etching. Thermogravimetric analysis of AN-MMA copolymer/silica nanocomposites showed that the carbon yield of copolymer was slightly decreased as silica particle incorporated. N₂ adsorption-desorption, scan electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and morphology of the mesoporous carbon materials. Both SEM and TEM results showed that disordered mesopores were formed in the obtained carbon material mainly through templating effect of silica nanoparticles. The diameter of mesopores was mainly distributed in the range from 5 nm to 15 nm. The mean pore diameter and total pore volume of the material increased as the mass fraction of silica in the nanocomposites increased from 0 to 24.93%. The significant increase of the mean pore diameter and the decrease of surface area for the carbon material prepared from the nanocomposite with 24.93% silica were caused by partial aggregation of silica nanoparticles in the polymer matrix.     

Preparation and properties of poly[styrene‐co‐(butyl acrylate)‐co‐(acrylic acid)]/silica nanocomposite latex prepared using an acidic silica sol

BACKGROUND: Polyacrylate/silica nanocomposite latexes have been fabricated using blending methods with silica nanopowder, in situ polymerization with surface‐functionalized silica nanoparticles or sol–gel processes with silica precursors. But these approaches have the disadvantages of limited silica load, poor emulsion stability or poor film‐forming ability. RESULTS: In this work, poly[styrene‐co‐(butyl acrylate)‐co‐(acrylic acid)] [P(St‐BA‐AA)]/silica nanocomposite latexes and their dried films were prepared by adding an acidic silica sol to the emulsion polymerization stage. Morphological and rheological characterization shows that the silica nanoparticles are not encapsulated within polymer latex particles, but interact partially with polymer latex particles via hydrogen bonds between the silanol groups and the ? COOH groups at the surface of the polymer particles. The dried nanocomposite films have a better UV‐blocking ability than the pure polymer film, and retain their transparency even with a silica content up to 9.1 wt%. More interestingly, the hardness of the nanocomposite films increases markedly with increasing silica content, and the toughness of the films is not reduced at silica contents up to 33.3 wt%. An unexpected improvement of the solvent resistance of the nanocomposite films is also observed. CONCLUSION: Highly stable P(St‐BA‐AA)/silica nanocomposite latexes can be prepared with a wide range of silica content using an acidic silica sol. The dried nanocomposite films of these latexes exhibit simultaneous improvement of hardness and toughness even at high silica load, and enhanced solvent resistance, presumably resulting from hydrogen bond interactions between polymer chains and silica particles as well as silica aggregate/particle networks. Copyright © 2009 Society of Chemical Industry     

Creating polymer templates and their use in the in-situ synthesis of biodegradable composite networks

A biodegradable polyethyleneoxide–polycaprolactone–polyethyleneoxide (PEO–PCL–PEO or PECE) triblock polymer was synthesized as a structure-directing agent for high-surface area silica formation. Systematic end-group functionalization of the triblock polymer, prior to its use as a structure-directing agent for high-surface area silica growth, imparts an additional reactive function that is exploited to grow a continuous organic phase within and around the silica particles. Hence, the biodegradable triblock also acts as a macromer whose dual function leads to in-situ generation of intimately mixed biopolymer/nanoporous–silica composite networks. This composite can be both biodegradable and biocompatible, and the modulus is comparable to other non-biodegradable materials.     

Vinyl carbazole (VC) functionalized mesoporous silica polymer nanocomposites (SBA/VC) for the antibacterial activity studies

Vinyl carbazole (VC) functionalized ordered mesoporous silica polymer nanocomposites (SBA/VC) were synthesized by in situ radical polymerization of monomers inside the mesoporous framework and characterized for the antibacterial activity studies against gram positive and gram negative bacteria. Powder X-ray diffraction and N₂ adsorption isotherms of SBA/VC nanocomposites showed the presence of mesoporous nature. The antimicrobial activity results showed increasing trend with the increase in the concentration of vinyl carbazole (VC) and the maximum antibacterial activity was achieved with SBA/VC₆₄ nanocomposites.     

Electrochemical synthesis and In situ spectroelectrochemistry of conducting NMPy‐TiO2 and ZnO polymer nanocomposites for Li secondary battery applications

Poly(N‐methylpyrrole) (PNMPy), poly(N‐methylpyrrole‐TiO₂) (PNMPy‐TiO₂), and poly (N‐methylpyrrole‐ZnO) (PNMPy‐ZnO) nanocomposites were synthesized by in situ electropolymerization for cathode active material of lithium secondary batteries. The charge–discharging behavior of a Li/LiClO₄/PNMPy battery was studied and compared with Li/LiClO₄/PNMPy‐nanocomposite batteries. The nanocomposites and PNMPy films were characterized by cyclic voltammetry, in situ resistivity measurements, in situ UV–visible, and Fourier transform infra‐red (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The differences between redox couples (ΔE) were obtained for polymer nanocomposites and PNMPy films. During redox scan, a negative shift of potential was observed for polymer nanocomposite films. Significant differences from in situ resistivity of nanocomposites and PNMPy films were obtained. The in situ UV–visible spectra for PNMPy and polymer nanocomposite films show the intermediate spectroscopic behavior between polymer nanocomposites and PNMPy films. The FTIR peaks of polymer nanocomposite films were found to shift to higher wavelengths in PNMPy films. The SEM and TEM micrographs of nanocomposite films show the presence of nanoparticle in PNMPy backbone clearly. The result suggests that the inorganic semiconductor particles were incorporated in organic conducting PNMPy, which consequently modifies the properties and morphology of the film significantly. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41526.     

Facile preparation of superhydrophobic polyester surfaces with fluoropolymer/SiO2 nanocomposites based on vinyl nanosilica hydrosols

A facile method to prepare superhydrophobic fluoropolymer/SiO₂ nanocomposites coating on polyester (PET) fabrics was presented. The vinyl nanosilica (V? SiO₂) hydrosols were prepared via one‐step water‐based sol‐gel reaction with vinyl trimethoxy silane as the precursors in the presence of the base catalyst and composite surfactant. Based on the V? SiO₂ hydrosol, a fluorinated acrylic polymer/silica (FAP/SiO₂) nanocomposite was prepared by emulsion polymerization. The FAP/SiO₂ nanocomposites were coated onto the polyester fabrics by one‐step process to achieve superhydrophobic surfaces. The results showed that silica nanoparticles were successfully incorporated into the FAP/SiO₂ nanocomposites, and a specific surface topography and a low surface free energy were simultaneously introduced onto PET fibers. The prepared PET fabric showed excellent superhydrophobicity with a water contact angle of 151.5° for a 5 μL water droplet and a water shedding angle of 12° for a 15 μL. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40340.     

Preparation and characterization of nanocomposite materials based on polyamide‐6 and modified ordered mesoporous silica KIT‐6

Ordered mesoporous silica has been drawn great interest in many areas of modern science and technology. In this study, mesoporous silica KIT‐6 was modified with 3‐mercaptopropyl‐trimethoxysilane by sono‐chemical method and reflux. Low‐angle powder X‐ray diffraction (XRD) and transmission electron microscopy (TEM) images confirmed the presence well‐ordered arrangement of large pores and a relatively ordered mesostructure for the functionalized materials. The nanocomposites of polyamide‐6 and modified‐KIT (3 and 6 wt %) were prepared under reflux and followed by sonication for 2h. The prepared hybrid nanocomposites were characterized by Fourier transform‐infrared spectroscopy, XRD, field emission‐scanning electron microscopy and TEM techniques. Thermogravimetric analysis data showed that the onset of decomposition temperature of the nanocomposites was higher than that of pristine polyamide‐6, shifting toward higher temperatures as the amount of modified‐KIT was increased. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43098.     

High performance nanocomposite electrodes of mesoporous silica platelet‐polyaniline synthesized via impregnation polymerization

A novel high specific capacitance mesoporous polyaniline (PANI)/silica platelet nanocomposite electrode material for supercapacitors was prepared by an impregnation polymerization. The initiator was embedded firstly in the mesoporous silica pores and channels and then initiated the polymerization of aniline (AN). Compared with the other mesoporous silica materials, the mesoporous silica platelets possess a relative shorter mesoporous channels, leading an easier penetration process of initiator and AN to the inner of mesoporous silica platelets. The structures, morphologies, and electrochemical properties of the nanocomposites were thoroughly studied by a series of methods, such as X‐ray diffractometry, scanning electron microscope, nitrogen adsorption‐desorption tests, infrared spectroscopy, thermogravimetric analysis, and electrochemical measurements. The results revealed that the PANI existed both in the inner and surface of the mesoporous silica platelets, leading a continual conductive network and a large specific surface area. These features provide the nanocomposites an excellent electrochemical performance. The biggest specific capacitance is 1,598 F g⁻¹ at a current density of 0.5 A g⁻¹. POLYM. COMPOS., 38:1616–1623, 2017. © 2015 Society of Plastics Engineers     

Preparation of polycarbonate/poly(acrylonitrile‐butadiene‐styrene)/mesoporous silica nanocomposite films and its rheological,mechanical, and sound absorption properties

The homogeneous polycarbonate/poly(acrylonitrile‐butadiene‐styrene) (PC/ABS) nanocomposite thin films were prepared by a facile solvent casting method using phenylene modified‐mesoporous silica materials as additives and dichloromethane as a solvent. The physicochemical analyses using small‐angle X‐ray scattering, nitrogen adsorption–desorption, solid‐state ¹³C and ²⁹Si nuclear magnetic resonance, and scanning electron microscope were investigated to provide clear physical and chemical properties for modified‐mesoporous materials and nanocomposite films. Tensile tests were performed at room temperature according to ASTM D638. Rheological properties were also analyzed to observe any variance of solid–liquid property. As a compatibilizer and a reinforcing filler, mesoporous (organo‐)silicas showed enhanced features in rheological and mechanical properties. The sound absorption coefficient was measured by the impedance tube up to 6400 Hz according to ISO 10534‐2. It was found that the PC/ABS nanocomposites containing mesoporous materials can be used as a sound‐proofing support material depending on fabrication process. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45777.     

Microwave‐Assisted Reversible Coordination‐Mediated Polymerization for Self‐Healing Hybrid Materials: RGO@PDA Simultaneous as Catalyst and Nanocomposites in One‐Pot

In this article, polydopamine (PDA) is efficiently adhered on the surface of graphene oxide (GO) by mussel‐inspired chemistry. The obtained reduced GO/PDA (RGO@PDA) nanocomposites are used for catalyzing reversible coordination‐mediated polymerization under microwave radiation. Well‐defined and iodine‐terminated polyacrylonitrile‐co‐poly(n‐butyl acrylate) (PAN‐co‐PnBA) is successfully fabricated by using RGO@PDA nanocomposites as catalysts. Importantly, green and novel strategy of PAN‐co‐PnBA‐type self‐healing nanocomposite materials is further fabricated with RGO@PDA as additive after polymerization as catalyst in one‐pot. As a reinforcement agent, RGO@PDA can also improve the mechanical and self‐healing properties of hybrid materials, which opens up a novel and green methodology for the preparation of self‐healing hybrid materials.     

Synthesis and properties of mesoporous carbons with high loadings of inorganic species

A series of mesoporous carbons with high loading of silica has been synthesized by acid-catalyzed polymerization of resorcinol and formaldehyde in the presence of tetraethyl orthosilicate (TEOS), colloidal silica (silica source) and poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (soft template) followed by carbonization. This synthesis route can be considered as a combination of soft-templating and hard templating strategies. The resulting mesoporous silica-carbon composites contained spherical silica colloids in addition to uniformly distributed silica originated from TEOS. Dissolution of silica led to high surface area carbons, which in addition to the primary mesopores formed by thermal degradation of block copolymer template possessed spherical mesopores after dissolution of silica colloids and fine pores after removal of TEOS-generated silica species. This approach can be used to incorporate other inorganic nanoparticles into mesoporous carbons with extra microporosity created after dissolving TEOS-generated silica species.     

Ordered mesoporous polymer-silica and carbon-silica nanocomposites co-templated by amphiphilic polydimethylsiloxane-poly(ethylene oxide) block copolymer

Polydimethylsiloxane-poly(ethylene oxide) (PDMS-PEO) has been successfully used as the co-template to prepare ordered mesoporous polymer-silica and carbon-silica nanocomposites with diverse mesostructures by using Pluronic F127 or P123 as main templates and phenolic resol polymer as a carbon precursor via the strategy of evaporation-induced self-assembly (EISA). The structures of resulting mesoporous materials have been characterized by small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and nitrogen-sorption measurements. Experiments show that the ordered mesoporous polymer-silica and carbon-silica nanocomposites of two-dimensional hexagonal (p6m) and body-centered cubic (Im[`3]m Im\bar{3}m ) mesostructure have been achieved. A novel lamellar polymer-silica mesostructure stable up to 350 °C calcination is also obtained. Higher hydrophobicity of PDMS than PPO is believed to be the key factor that influences the swelling of F127 micelles and their further self-assembly behaviors into ordered mesostructures, resulting in different symmetries of the mesostructures. Surfactant removal and subsequent carbonization creates ordered mesoporous polymer-silica and carbon-silica nanocomposites, respectively. This simple one-pot route provides a pathway for large-scale convenient synthesis of polymer-silica and carbon-silica nanocomposites.     

有序介孔碳材料的模板化构筑及水处理应用研究

介孔碳材料是指孔径介于2 nm-50 nm的一类多孔碳材料。有序介孔碳材料，具有比表面积高、孔道结构规则有序、孔径分布狭窄、孔径大小可调控、表面易于修饰等结构特点和高机械强度、强吸附能力、化学惰性等性能特点，在诸多领域得到了广泛应用，特别是其作为新型吸附剂在水处理领域具有广阔的发展前景。有序介孔炭材料的制备方法主要有硬模板法和软模板法。模板和碳源的选择是控制有序介孔碳材料结构和性能的关键因素。本文从有序介孔硅、天然矿物、MOFs材料、嵌段共聚物等不同模板的角度对有序介孔碳、多级有序微/介孔碳、多级有序大/介孔碳的制备方法进行综述，并对有序介孔碳材料在水处理领域的应用进行简单介绍。     

Novel conducting nanocomposite based on polypyrrole and modified poly(styrene‐alt‐maleic anhydride) via emulsion polymerization: Synthesis,Characterization, Antioxidant,and heavy metal sorbent activity

Novel polypyrrole/modified poly(styrene‐alt‐maleic anhydride) conducting nanocomposites were prepared via emulsion polymerization using sodium dodecyl sulfate as an emulsifier and ammonium persulfate as an oxidant. Modified poly(styrene‐alt‐maleic anhydride) was used as an external dopant for conductivity enhancement of polypyrrole. The conductivity of nanocomposites was measured with a four‐probe method. The maximum electrical conductivity of the nanocomposite was 1.40 S/cm. The data from this research showed that the novel nanocomposite presents good tendency for the removal of heavy metal ions from aqueous solutions. Also the prepared nanocomposites were analyzed for their antioxidant activity using 2,2‐diphenyl‐1‐picrylhydrazyl assay. The results showed that the antioxidant activity of the nanocomposite was 60%. The nanocomposites were characterized by Fourier transform infrared, ultraviolet–visible, X‐ray diffraction, field emission scanning electron microscopy, and differential scanning calorimetry measurements. POLYM. COMPOS., 36:138–144, 2015. © 2014 Society of Plastics Engineers     

Polyaniline‐functionalized magnetic mesoporous nanocomposite: A smart material for the immobilization of lipase

Magnetically separable mesoporous silica nanocomposites with polyoaniline functionalization (Pani‐MS@Fe₃O₄) were synthesized for the immobilization of lipase via electrostatic adsorption. The as‐prepared Pani‐MS@Fe₃O₄ nanocomposites as well as immobilized lipase were characterized by FTIR, XRD, HRTEM, FESEM, BET, and TGA techniques. The BET surface area was calculated to be 779.27 m²/g, 425 m²/g, and 230.45 m²/g for magnetic mesoporous nanoparticle (MS@Fe₃O₄), Pani‐MS@Fe₃O₄ nanocomposite, and lipase immobilized Pani‐MS@Fe₃O₄ nanocomposite respectively. The comparison experiments verified that the immobilized lipase exhibited slightly higher optimal pH and temperature value with a wider pH‐activity and temperature stability in comparison with the free lipase. From Michaelis–Menten kinetic study, the lower K_m value (0.25 mM) and higher V_max value (0.0341 mM/min) for the immobilized lipase revealed the higher affinity of immobilized lipase toward the substrate. Further, reusability studies of the immobilized lipase indicated that up to 70% of the original activity was retained after having been recycled seven times. POLYM. COMPOS. 37:1152–1160, 2016. © 2014 Society of Plastics Engineers     

Effects of fluoride ion on the formation of earthworm‐like mesoporous silica

In a strong acidic environment, ordered earthworm‐like mesoporous silica has been synthesized with CTAB templating and fluoride ion (F^?) as a counterion. The synthesized products were characterized by small‐angle X‐ray diffraction (SXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption‐desorption isotherms, and Fourier‐transform infrared spectroscopy (FTIR). The effects of F/Si mole ratio on the morphology, surface area, and the pore size of the sample were discussed. It was found that a F/Si mole ratio at 0.083 induced the formation of 3D hexagonal mesophase, whereas higher F/Si mole ratios led to the formation of 2D hexagonal mesoporous silica, the optimum molar ratio of F/Si for the formation of delicate earthworm‐like mesoporous silica was observed at 0.250. The effects of the F/Si mole ratio, surfactant chain length, acid concentration, and shear flow on morphology were also studied.     

Fabrication of new ordered mesoporous carbons from petroleum pitch by triblock copolymer direct templating method

A highly ordered mesoporous carbon nanocage (OMC) direct synthesis method is introduced in this article. Petroleum pitch is chosen as a hydrophobic carbon precursor, tetrahydrofuran (THF) is used as solvent, the triblock copolymer F127 as structure directing agent, while the liquid crystal templating (LCT) is used as the templating mechanism, and the OMC was obtained via a one-step nanocasting method. Experimental results showed that the introduction of proper amounts of petroleum pitch and THF ratio does not hamper the synthetic process of the structure of OMC, thus a uniform carbon composite is finally formed. It was found that the as-prepared nanoporous carbon has a three-dimensional 7.5 nm-sized carbon nanocage network. Such a uniform mesoporous carbon material exhibits a high Brunauer–Emmett–Teller (BET) surface area (446.9 m² g^??1) and a total pore volume (0.6 cm³ g^??1).     

Synthesis,characterization, and properties of new conducting polyaniline/copper sulfide nanocomposites

This article reports the facile synthesis of copper sulfide (CuS)/polyaniline (PANI) nanocomposites by in situ polymerization. The composites were characterized by scanning electron microscopy (SEM), UV–visible and Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). SEM analysis showed that the metal sulfide nanoparticles were uniformly dispersed in the polymer matrix. The characteristic peaks in FTIR and UV–vis spectra of PANI were found to be shifted to higher wave numbers in PANI/CuS composite, which is attributed to the interaction of CuS nanoparticles with PANI chain. XRD pattern revealed the structurally ordered arrangement of polymer composite and this regularity increases with increase in concentration of nanoparticles. Glass transition temperature of the nanocomposite increased with increase in the concentration of nanoparticles and it indicated the ordered arrangement of the polymer composite than PANI. TGA studies indicated excellent thermal stability of polymer nanocomposite. The electrical properties of nanocomposites were studied from direct current and alternating current resistivity measurement. Conductivity, dielectric constant, and dissipation factor of the nanocomposite were significantly increased with the increase in CuS content in the nanocomposite. The enhancement of these properties suggests that the proposed PANI/CuS nanocomposites can be used as multifunctional materials for nanoelectronic devices. POLYM. ENG. SCI., 54:438–445, 2014. © 2013 Society of Plastics Engineers     

Synthesis of poly(arylene disulfide)–vermiculite nanocomposites via in situ ring‐opening polymerization of macrocyclic oligomers

Exfoliated poly(4, 4′‐oxybis(benzene)disulfide)/vermiculite (POBDS/VMT) nanocomposites were successfully synthesized via in situ melt intercalation of cyclo(4, 4′‐oxybis(benzene)disulfide) oligomers (COBDS) into octadecylammonium‐exchanged VMT (organo‐VMT). The POBDS/VMT nanocomposites were melt fabricated in a two‐step process. First, the COBDS/VMT nanocomposite precursor was fabricated by melt delaminating organo‐VMT with COBDS at a temperature slightly higher than its melting point. Subsequently, exfoliated POBDS‐VMT nanocomposites can be prepared in situ via instant melt ring‐opening polymerization of the COBDS‐VMT nanocomposite precursor. The nanoscale dispersion of VMT layers within POBDS polymer was confirmed by X‐ray diffraction, scanning electron microscopy and transmission electron microscopy. High molecular weight POBDS polymer was formed in a few minutes at the same time as the nanocomposite formation. The results of dynamic mechanical analysis showed that the storage modulus and glass transition temperature of the nanocomposites are much higher than those of the POBDS matrix, even with a very small amount of VMT addition. This methodology provides a potential approach to synthesize high‐performance polymer/clay nanocomposites. Copyright © 2004 Society of Chemical Industry     

Graphene oxide reinforced chitosan/polyvinylpyrrolidone polymer bio‐nanocomposites

Bio‐nanocomposite films based on chitosan/polyvinylpyrrolidone (CS/PVP) and graphene oxide (GO) were processed using the casting/evaporation technique. It has been found that the three components of bio‐nanocomposites can be easily mixed in controlled conditions enabling the formation of thick films with high quality, smooth surface and good flexibility. Structural and morphological characterizations showed that the GO sheets are well dispersed in the CS/PVP blend forming strong interfacial interactions that provide an enhanced load transfer between polymer chains and GO sheets thus improving their properties. It has been found that the water resistance of the CS/PVP blend is improved, and the hydrolytic degradation is limited by addition of 0.75 and 2 wt % GO. The modulus, strength, elongation and toughness of the bio‐nanocomposites are together increased. Herein, the steps to form new bio‐nanocomposite films have been described, taking the advantage of the combination of CS, PVP and GO to design the aforementioned bio‐nanocomposite films, which allow to have extraordinary properties that would have promising applications as eventual packaging materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41042.