Poly(vinyl chloride‐co‐vinyl acetate‐co‐maleic anhydride)/silica nanocomposites derived from in situ suspension polymerization

Poly(vinyl chloride‐co‐vinyl acetate‐co‐maleic anhydride) (PVVM)/silica nanocomposites were prepared by the suspension radical copolymerization of the monomers in the presence of fumed silica premodified with γ‐methylacryloxypropl trimethoxy siliane. Morphological observation showed that the silica particles of nanometer scale were well dispersed in the copolymer matrix of the nanocomposites films, whereas silica particles tended to agglomerate in the composites films prepared by the solution blending of PVVM with silica. The experimental results show that the thermal stability, glass‐transition temperature, tensile strength, and Young's modulus were significantly enhanced by the incorporation of silica nanoparticles. The enhancement of properties was related to the better dispersion of silica particles in polymer matrix and the interaction between the polymer chains and the surfaces of the silica particles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Grafting of polystyrene chains on surfaces of nanosilica particles via peroxide bulk polymerization

This article describes an in situ bulk polymerization process of styrene in the presence of silica nanoparticles. In this peroxide bulk polymerization process, two polystyrene fractions are formed: A polystyrene (PS) fraction attached to the particle's surface, which cannot be detached by hot xylene extraction, and an unattached PS fraction which dissolves in xylene. Solvent extraction and TGA measurements have confirmed the existence of grafted PS chains to the silica surfaces. FTIR measurements have indicated the existence of Si O C bonds connecting the PS grafts to the silica surface. Polypropylene (PP) was blended with the extracted PS‐g‐silica particles to produce concentrations of 1–3% nanoparticles in the PP composites. A remarkably improved dispersability of the nanoparticles was achieved, thus grafting reduces re‐agglomeration and increases the affinity of the grafted surface to the polymer matrix. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Grafting of water‐soluble sulfonated monomers onto functionalized fumed silica nanoparticles via surface‐initiated redox polymerization in aqueous medium

Sulfonated polymer/fumed silica hybrid nanoparticles were prepared via surface‐initiated free radical polymerization of 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid (PAMPS‐g‐FSN), styrene sulfonic acid sodium salt (PSSA‐g‐FSN) and vinyl sulfonic acid sodium salt (PVSA‐g‐FSN) from the surface of aminopropyl‐functionalized fumed silica nanoparticles (AFSNs) dispersed in aqueous medium. Cerium(IV) ammonium nitrate/nitric acid and sodium dodecyl sulfate were used as redox initiator and stabilizer respectively. AFSNs were prepared by covalently attaching 3‐aminopropyltriethoxysilane onto the surface of fumed silica nanoparticles. Sulfonated monomers (AMPS, SSA or VSA) were then grafted onto the AFSNs ultrasonically dispersed in water via redox initiation at 40 °C. Structure, thermal properties, particle size and morphology of the AFSNs and PAMPS‐g‐FSN, PSSA‐g‐FSN and PVSA‐g‐FSN hybrid nanoparticles were characterized by Fourier transform infrared spectroscopy, TGA, SEM, transmission electron microscopy (TEM) and dynamic light scattering (DLS). The results indicated that the sulfonated monomers were successfully grafted onto the fumed silica nanoparticles. Grafting amounts of the sulfonated polymers onto the fumed silica nanoparticle surface were estimated from TGA thermograms to be 59%, 13% and 29% for the PAMPS, PSSA and PVSA, respectively. From SEM, TEM and DLS analysis, polymer‐grafted fumed silica nanoparticles with an average diameter smaller than 70 nm and a (semi‐) spherical shape were observed. A significant bimodal particle size distribution was observed only for the PAMPS‐g‐FSN with average diameters of 39.6 nm (84.1% per number) and 106 nm (15.9% per number). The hydrophilic sulfonated polymer/grafted fumed silica obtained from the redox graft polymerization gave a stable colloidal dispersion in acidic aqueous medium. Copyright © 2012 Society of Chemical Industry     

Improving mechanical properties of poly(vinyl chloride) by doping with organically functionalized reactive nanosilica

Nanosilica particles are functionalized by in situ surface‐modification with trimethyl silane and vinyl silane. Resultant reactive nanosilica (coded as RNS) contains double bonds and possesses good compatibility with vinyl chloride (VC) and polyvinyl chloride (PVC). This makes it feasible for RNS to copolymerize with VC generating RNS/PVC composites via in situ suspension polymerization. As‐prepared RNS/PVC composite resins are analyzed by means of FTIR. The tensile strength and impact strength of compression‐molded RNS/PVC composites are measured and compared with that of compression‐molded PVC composites doped with dispersible nano‐SiO₂ particles (abridged as DNS) surface‐modified with trimethyl silane alone. Moreover, the thermal stability of compression‐molded RNS/PVC and DNS/PVC composites is evaluated by thermogravimetric analysis. It has been found that RNS/PVC composites possess greatly increased impact strength and tensile strength than PVC matrix, while DNS/PVC composites possess higher impact strength than PVC matrix but almost the same tensile strength as the PVC matrix. This implies that DNS is less effective than RNS in improving the mechanical strength of PVC matrix. Particularly, RNS/PVC composites prepared by in situ suspension polymerization have much higher mechanical strength than RNS/PVC composites prepared by melt‐blending, even when their nanosilica content is only 1/10 of that of the melt‐blended ones. Besides, in situ polymerized RNS/PVC and DNS/PVC composites have better thermal stability than melt‐blended nanosilica/PVC composites. Hopefully, this strategy, may be extended to fabricating various novel high‐performance polymer‐matrix composites doped with organically functionalized nanoparticles like RNS. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Studies on electro‐optical properties of polymer matrix/LC/SiO2 nanoparticles composites

Polymer‐dispersed liquid crystal (PDLC) films were prepared by ultraviolet light‐induced polymerization of photopolymerizable monomers in nematic liquid crystal (LC)/monomers/SiO₂ nanoparticles composites, and the effect of SiO₂ nanoparticles on the electro‐optical properties of PDLC films was studied. The observed effect showed that by the adjustment of the SiO₂ nanoparticles content, the refractive index ratio of the LC and polymer could be modulated, and the electro‐optical properties of the polymer matrix/LC/SiO₂ nanoparticles composites could be optimized. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Thermally and mechanically enhanced epoxy resin‐silica hybrid materials containing primary amine‐modified silica nanoparticles

In this article, a series of hybrid materials consisted of epoxy resin matrix and well‐dispersed amino‐modified silica (denoted by AMS) nanoparticles were successfully prepared. First of all, the AMS nanoparticles were synthesized by performing the conventional acid‐catalyzed sol–gel reactions of tetraethyl orthosilicate (TEOS), which acts as acceded sol–gel precursor in the presence of 3‐aminopropyl trimethoxysilane (APTES), a silane coupling agent molecules. The as‐prepared AMS nanoparticles were then characterized by FTIR, ¹³C‐NMR, and ²⁹Si‐NMR spectroscopy. Subsequently, a series of hybrid materials were prepared by performing in situ thermal ring‐opening polymerization reactions of epoxy resin in the presence of as‐prepared AMS nanoparticles and raw silica (RS) particles (i.e., pristine silica). AMS nanoparticles were found to show better dispersion capability in the polymer matrices than that of RS particles based on the morphological observation of transmission electron microscopy (TEM) study. The better dispersion capability of AMS nanoparticles in hybrid materials was found to lead enhanced thermal, mechanical properties, reduced moisture absorption, and gas permeability based on the measurements of thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and gas permeability analysis (GPA), respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

In‐situ formation of metal nanoparticle/acrylic polymer hybrid and its application to miniemulsion polymerization

We present in‐situ formation of metal nanoparticle/acrylic polymer hybrid and its application to prepare hybrid latex particles by miniemulsion polymerization. On the surface of a silver nanoparticle/silica nanoparticle/acrylic polymer hybrid layer formed in‐situ on a polyethylene terephthalate (PET) substrate, a copper film is deposited using electroless copper deposition. Silver nanoparticles, which are formed in‐situ via the reduction of silver ion by radical species and subsequent annealing, work as a catalyst for the electroless deposition. Miniemulsion polymerization via the in‐situ formation of nanoparticles affords nanoparticle/acrylic polymer hybrid latex particles and polymer particles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42675.     

Carbon nanomaterial‐based copolymer of styrene–divinylbenzene resins: Efficient interaction through graphene/CNTs polymer network

Carbon nanotubes (CNTs) and graphene were separately incorporated into the cross‐linked network of styrene–divinylbenzene composites via in situ suspension polymerization. The prepared copolymers were first chloromethylated and then aminated with trimethylamine to obtain ion exchange resins (IERs). The CNTs‐based and graphene‐based composites exhibited good dispersion throughout the polymer matrix with strong interaction within the network. Remarkable enhancement in antiswelling properties and thermal stabilities confirmed that graphene showed better compatibility and stronger interfacial adhesion than CNTs. The structural and thermal properties of the CNTs‐based and graphene‐based IERs were also significantly improved even at low loadings of 0.4 wt % compared with those when no CNTs and graphene were added. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41234.     

Formation of silver nanoparticles created in situ in an amphiphilic block copolymer film

In this work, silver nanoparticles were synthesized with an amphiphilic diblock copolymer, polystyrene‐block‐poly(1‐vinyl‐2‐pyrrolidone) (PS‐b‐PVP), as a template film. First, microphase‐separated amphiphilic PS‐b‐PVP (70 : 30 wt %) was synthesized through atom transfer radical polymerization. The self‐assembled block copolymer film was used to template the growth of silver nanoparticles by the introduction of a silver trifluoromethanesulfonate precursor and an ultraviolet irradiation process. The in situ formation of silver nanoparticles with an average size of 4–6 nm within the block copolymer template film was confirmed with transmission electron microscopy, ultraviolet–visible spectroscopy, and wide‐angle X‐ray scattering. Fourier transform infrared spectroscopy also demonstrated the selective incorporation and in situ formation of silver nanoparticles within the hydrophilic poly(1‐vinyl‐2‐pyrrolidone) domains, which were mostly due to the stronger interaction strength of the silver with the carbonyl oxygens of poly(1‐vinyl‐2‐pyrrolidone) in the block copolymer. This work provides a simple route for the in situ synthesis of silver nanoparticles within a polymer film. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Preparation and characterization of acrylic latex/nano‐SiO2 composites

Acrylic/nano‐silica composite latexes were prepared by blending via high shear stirring (SS) or ball milling (BM) and in situ polymerization (IS). For comparison, composites filled with micro‐silica were also prepared. The mechanical and optical properties of the polymers formed by the composite latex filled with nano‐ or micro‐silica were investigated using an Instron testing machine, by dynamic mechanical analysis, ultraviolet–visible spectrophotometry and transmission electron micrography. The results showed that SS and BM methods could obtain better nanocomposite latex and polymers than the IS method, characterized by better dispersion of nanoparticles, higher tensile strength and T_g for SS and BM than for IS. The increase in absorbance and reduction in transmittance of UV (290–400 nm wavelength) were observed as nano‐silica content increased, whereas the UV absorbance or transmittance basically were kept unchanged for the composites filled with micro‐silica. © 2002 Society of Chemical Industry     

Polymerizable ionic liquids for the preparation of polystyrene/clay composites

Polymerizable ionic liquids (ILs) 1‐methyl‐3‐(4‐vinylbenzyl)imidazolium chloride, 1‐hexyl‐3‐(4‐vinylbenzyl)imidazolium chloride and 1‐dodecyl‐3‐(4‐vinylbenzyl)imidazolium chloride were prepared and used as new surfactants for the modification of montmorillonite (MMT). Functionalized MMTs were prepared by cationic exchange between sodium MMT and each of the ILs. Polystyrene (PS)/MMT composites were subsequently prepared by in situ intercalative free radical polymerization of styrene containing dispersed organophilic MMT. Exfoliation of MMT in the PS matrix was achieved only for MMT functionalized with the 1‐dodecyl‐3‐(4‐vinylbenzyl)imidazolium‐based IL as revealed by X‐ray diffraction and electron microscopy. The exfoliated composites showed good transparency and higher decomposition temperature than virgin polymer matrix, particularly pronounced under air atmosphere (ΔT_max = 66 °C), data comparable to or even greater than those reported in the literature for exfoliated PS nanocomposites. Copyright © 2012 Society of Chemical Industry     

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     

Study on ultrasonic induced encapsulating emulsion polymerization in the presence of nanoparticles

In this paper, the ultrasonic induced encapsulating emulsion polymerization technique was used to prepare polymer/inorganic nanoparticle composites. The main affecting factors in ultrasonic induced encapsulating emulsion polymerization were studied systematically. The experimental results suggested that the pH value, the type of monomers, the type, content, and surface properties of nanoparticles, the type and concentration of surfactant have great influence on the ultrasonic induced encapsulating emulsion polymerization and the obtained latex stability. If selecting cationic emulsifier (such as cetyl trimethylammonium bromide), low water soluble monomer (such as n‐butyl acrylate and styrene), and hydrophobic nano silica, the inorganic nanoparticles could be encapsulated by polymers through ultrasonic irradiation successfully under alkalescent condition, forming a novel polymer/inorganic nanoparticles composite. The mechanism of ultrasonic induced encapsulating emulsion polymerization and the composite latex stabilization are proposed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1130–1139, 2001     

Characterization of stabilized porous magnetite core–shell nanogel composites based on crosslinked acrylamide/sodium acrylate copolymers

Stabilized and dispersed superparamagnetic porous nanogels based on sodium acrylate (AA‐Na) and acrylamide (AM) in a surfactant‐free aqueous system were synthesized via solution polymerization at room temperature. The formation of magnetite nanoparticles was confirmed and their properties characterized using Fourier transform infrared spectroscopy. Extensive characterization of the magnetic polymer particles using transmission electron microscopy (TEM), dynamic light scattering and zeta potential measurements revealed that Fe₃O₄ nanoparticles were incorporated into the shells of poly(AM/AA‐Na). The average particle size was 5–8 nm as determined from TEM. AM/AA‐Na nanoparticles with a diameter of about 11 nm were effectively assembled onto the negatively charged surface of the as‐synthesized Fe₃O₄ nanoparticles via electrostatic interaction. Crosslinked magnetite nanocomposites were prepared by in situ development of surface‐modified magnetite nanoparticles in an AM/AA‐Na hydrogel. Scanning electron microscopy was used to study the surface morphology of the prepared composites. The morphology, phase composition and crystallinity of the prepared nanocomposites were characterized. Atomic force microscopy and argon adsorption–desorption measurements of Fe₃O₄.AM/AA indicated that the architecture of the polymer network can be a hollow porous sphere or a solid phase, depending on the AA‐Na content. © 2013 Society of Chemical Industry     

Effect of flake size on thermal properties of graphene oxide/poly(methyl methacrylate) composites prepared via in situ polymerization

The effect of graphene oxide (GO) flake size on thermal properties of GO/poly(methyl methacrylate) (GO/PMMA) composites prepared via in situ polymerization was investigated. Two styles of GO sheets were synthesized from different sizes of graphite powders by modified Hummers' method and GO/PMMA composites with GO of different sizes were prepared via in situ polymerization. Transmission electron microscopy verified that GO sheets produced from large graphite powders was obviously larger than that from small graphite powders. The similar number of layers and disorder degree of two types of GO sheets were proved by X‐ray diffraction and Raman, respectively. X‐ray diffraction and scanning electron microscopy results of GO/composites proved the homogenous dispersion of both two types of GO sheets in polymer matrix. Dynamic mechanical analysis and thermogravimetric analysis results showed that large GO sheets exhibit better improvement than small GO sheets in thermal properties of the composites. Compared with neat PMMA, the glass transition temperature and decomposition temperature of the composites with large GO sheets (0.20 wt %) were increased by 15.9 and 25.9 °C, respectively. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46290.     

Effects of mesoporous SBA-15 contents on the properties of polystyrene composites via in-situ emulsion polymerization

Different loading of mesoporous molecular sieve SBA-15 was used to prepare polystyrene (PS)/SBA-15 composite materials via in-situ emulsion polymerization. The influence of SBA-15 silica on the styrene emulsion polymerization was studied regarding to the monomer conversion, particle size and particle size distribution, stability and viscosity of the resulting emulsion. The structure and properties of the composites were investigated by infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and gel permeation chromatography (GPC). In addition, the glass transition temperature (T_g), thermal mechanical property and thermal stability of the composite film were measured by differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), respectively. The results indicated that the composite emulsion showed high monomer conversion, thick viscosity, low coagulum, uniform particle size and broad size distribution. Molecular weight of the polymer decreased with the increase of mesoporous silica. SBA-15 silica was dispersed evenly in PS matrix at a loading of 5 %. The PS/SBA-15 composite material containing 10 % silica maintained a certain ordered structure. DMA results demonstrated that PS/SBA-15 composite exhibited greater storage modulus and high T_g compared to pure PS. The improved thermal stability and T_g of the composite were also confirmed by the TGA and DSC.     

Effective enhancement of anticorrosive properties of polystyrene by polystyrene–clay nanocomposite materials

A series of polymer–clay nanocomposite (PCN) materials consisting of polystyrene (PS) and layered montmorillonite (MMT) clay was prepared by effectively dispersing the inorganic nanolayers of MMT clay in the organic PS matrix via in situ thermal polymerization. Organic styrene monomers were first intercalated into the interlayer regions of organophilic clay hosts, followed by a typical free radical polymerization with BPO as the initiator. The as‐synthesized PCN materials were characterized by infrared spectroscopy (IR), wide‐angle powder X‐ray diffraction (XRD) and transmission electron microscopy (TEM). PCN coatings with low clay loading (1 wt %) on cold‐rolled steel (CRS) were found to be superior in anticorrosion to those of bulk PS, based on a series of electrochemical measurements of corrosion potential, polarization resistance and corrosion current in a 5 wt % aqueous NaCl electrolyte. The molecular weights of PS extracted from PCN materials and bulk PS were determined by gel permeation chromatography (GPC) with tetrahydrofuran (THF) as the eluent. The effects of material composition on molecular barrier and thermal stability of PS and PCN materials, in the form of both free‐standing films and fine powders, were also studied by molecular permeability analysis, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1970–1976, 2004     

Polystyrene/calcium carbonate nanocomposites prepared by in situ polymerization in the presence of maleic anhydride

Polystyrene (PS)/calcium carbonate (CaCO₃) nanocomposites were prepared by in situ polymerization in the presence of maleic anhydride (MA). The composites were characterized by Fourier transform infrared spectra, gel permeation chromatography, differential scanning calorimetry, controlled stress rheometer, scanning electron microscope (SEM), small‐angle X‐ray scattering (SAXS), and mechanical test. Results show that the copolymer of styrene (St) and MA formed during the polymerization acts as a compatibilizer between PS and nanometer calcium carbonate (nano‐CaCO₃) particles, resulting in an increase in the glass transition temperature of the composite. The complex modulus and the impact strength of the PS/nano‐CaCO₃ composite show an increase with the addition of MA on account of the enhanced interfacial adhesion and the increased molecular weight. SEM and SAXS analyses indicate that a finer dispersion of nanoparticles and an increased homogeneity of the PS/nano‐CaCO₃ composites are obtained with application of a small amount of MA. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013     

Monodisperse platinum nanoparticles of well-defined shape: synthesis, characterization, catalytic properties and future prospects

Monodisperse platinum nanoparticles with well-defined faceting have been synthesized by a modified polyol process with the addition of silver ions. Pt nanoparticles are encapsulated in mesoporous silica during in situ hydrothermal growth of the high surface area support. Removal of the surface regulating polymer, poly(vinylpyrrolidone), was achieved using thermal oxidation-reduction treatments. Catalysts were active for ethylene hydrogenation after polymer removal. Rates for ethylene hydrogenation decreased in accordance with the amount of Ag retained in the Pt nanoparticles after purification. Ag is most likely present on the Pt particle surface as small clusters. Future prospects for these catalysts for use in low temperature selective hydrogenation reactions are discussed.     

Polystyrene/attapulgite nanocomposites prepared via in situ suspension polymerization with redox initiation system

A series of polymer–clay nanocomposites consisting of polystyrene (PS) and attapuglite (ATP) were prepared successfully. First, silane coupling agent containing aromatic tertiary amine groups was synthesized to functionalize ATP (M‐ATP). Then, PS nanocomposites with varied clay loadings were prepared via in situ suspension polymerization process with a redox initiation system consisting of aromatic tertiary amine and benzoyl peroxide. The synthesis of silane coupling agent and functionalization of ATP were confirmed by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectra, and X‐ray photoelectron spectroscopy. Mechanical properties, morphology, thermal stability, and rheological behavior of nanocomposites were investigated to illuminate the effects of M‐ATP on the structure and properties of nanocomposites. Field‐emission scanning electron microscope images revealed an ideal dispersion of M‐ATP and an enhanced toughness of nanocomposites. The improved interface interaction between M‐ATP and PS matrix endowed the nanocomposites with outstanding mechanical properties and thermal stability. The formation of hybrid network in the nanocomposites containing 3 wt % M‐ATP resulted in higher complex viscosity (η*), storage modulus (G′), and lower loss factor (tanδ) compared with the pristine PS and PS/ATP nanocomposites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41567.