Preparation of silica/polyurethane nanocomposites by UV‐induced polymerization from surfaces of silica

UV‐curable nanocomposites were prepared by the in situ photopolymerizaton with nanosilica obtained from sol–gel process. The photoinitiator 2‐hydroxy‐2‐methyl‐1‐phenylpropane‐1‐one (1173) was anchored onto the surface of the nanosilica with or without methacryloxypropyltrimethoxysilane (MAPS) modification. The photopolymerization kinetics was studied by real‐time Fourier transform IR (RTIR), and the microstructure and properties of the nanocomposite were investigated using transmission electron microscopy and UV–visible (UV–vis) transmistance spectra. RTIR analysis indicated that the nanocomposites without MAPS had higher curing rates and final conversion than those with MAPS. The nanocomposites with an uniformal dispersion of nanosilica had high UV–vis transmittance. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

In situ fabrication of polyaniline‐silver nanocomposites using soft template of sodium alginate

Polyaniline (PANI)‐Ag nanocomposites were synthesized by in situ chemical polymerization approach using ammonium persulfate and silver nitrate as oxidant. Characterizations of nanocomposites were done by ultraviolet–visible ( UV–vis), Fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy (TEM). UV–vis, XRD and FTIR analysis established the formation of PANI/Ag nanocomposites and face‐centered‐cubic phase of silver. PANInanofibers were of average diameter ～ 30 nm and several micrometers in length. Morphological analysis showed that the spherical‐shaped silver nanoparticles decorate the surface of PANI nanofibers. Silver nanoparticles of average diameter ～ 5–10 nm were observed on the TEM images for the PANI‐Ag nanocomposites. Such type of PANI‐Ag nanocomposites can be used as bistable switches as well as memory devices. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Structure and properties of polyurethane/nanosilica composites

Nanosilica particles were directly introduced into polyester polyol resins through in situ polymerization and blending methods, then cured by isophorone diisocyanate (IPDI) trimers to obtain nanocomposite polyurethanes. FTIR and TGA analyses indicated that more polyester segments had reacted with silica particles during in situ polymerization than during the blending method, accompanied by higher T_g and more homogeneous dispersion of nanosilica particles in the polymer matrix from in situ polymerization. Maximum values in T_g, tensile properties, macrohardness, abrasion resistance, and UV absorbance were obtained when the particle size of silica was about 28 nm. The polyurethane/nanosilica composites obtained by in situ polymerization generally had better mechanical properties than those by the blending method except for some unexpected macrohardness at relatively high silica content. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1032–1039, 2005     

Synthesis of polycarbonate‐co‐poly(p‐ethylphenol) and CdS nanocomposites

The enzyme‐catalyzed synthesis of poly(p‐ethylphenol) (PEP) was modified by copolymerization with polycarbonates through triphosgene at low temperature to form polycarbonate‐co‐poly(p‐ethylphenol) (PC‐co‐PEP). FTIR, NMR, GPC, and thermal analysis verified the formation of PC‐co‐PEP. The copolymers have an optical absorption in the UV range. CdS semiconductor nanocrystallites were synthesized in reversed micelles with subsequent in situ enzymatic copolymerization of p‐ethylphenol and 4‐hydroxythiophenol in the same medium. TEM and ATR–FTIR showed that the polymer precipitated in spherical morphologies, incorporating CdS nanocrystals into the polymer matrix, with surface hydroxyl groups. The polymer/CdS core was then dispersed into polycarbonate. The polymer/CdS nanocomposites showed higher optical aborbance in the UV‐vis range when compared to the polymer matrix without CdS. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1851–1868, 1999     

Crystallization behavior and UV‐protection property of PET‐ZnO nanocomposites prepared by in situ polymerization

The aim of this study was to investigate the crystallization behavior and UV‐protection property of polyethylene terephthalate (PET)‐ZnO nanocomposits. PET‐ZnO nanocomposites containing 0.5–3.0 wt % of ZnO were successfully synthesized by in situ polymerization. The Fourier transformed infrared (FTIR) spectroscopy indicated the silane coupling agent was anchored onto the surface of ZnO. Scanning electron microscope (SEM) images showed ZnO particles were dispersed homogeneously in PET matrix with amount of 0.5–1.0 wt %. Differential scanning calorimetry (DSC) results exhibited that the incorporation of ZnO into PET resulted in increase of the melting transition temperature (T_m) and crystallization temperature (T_c) of PET‐ZnO nanocomposites. The crystallization behavior of PET and PET‐ZnO nanocomposites was strongly affected by cooling rate. ZnO nanoparticles can act as an efficient nucleating agent to facilitate PET crystallization. UV–vis spectrophotometry showed that UV‐ray transmittance of PET‐ZnO nanocomposites decreased remarkably and reached the minimum value of 14.3% with 1.5 wt % of ZnO, compared with pure PET whose UV‐ray transmittance was 84.5%. PET‐ZnO nanocomposites exhibited better UV‐protection property than pure PET, especially in the range of UVA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

In situ polymerization and characterization of polyester‐based polyurethane/nano‐silica composites

Polyester‐based polyurethane/nano‐silica composites were obtained via in situ polymerization and investigated by Fourier‐transform infrared spectroscopy (FTIR), or FTIR coupled with attenuated total reflectance (FTIR‐ATR), Transmission electron microscopy (TEM), atomic force microscopy (AFM), an Instron testing machine, dynamic mechanical analysis (DMA) and ultraviolet‐visible spectrophotometry (UV‐vis). FTIR analysis showed that in situ polymerization provoked some chemical reactions between polyester molecules and nano‐silica particles. FTIR‐ATR, TEM and AFM analyses showed that both surface and interface contained nano‐silica particles. Instron testing and DMA data showed that introducing nano‐silica particles into polyurethane enhanced the hardness, glass temperature and adhesion strength of polyurethane to the substrate, but also increased the resin viscosity. UV‐vis spectrophotometry showed that nano‐silica obtained by the fumed method did not shield UV radiation in polyurethane films. Copyright © 2003 Society of Chemical Industry     

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.     

Development of nanocomposites of bentonite with polyaniline and poly(methacrylic acid)

Nanocomposites of bentonite with polyaniline (PANI), poly(methacrylic acid) (PMAA), and poly(aniline‐co‐methacrylic acid) (PANI‐co‐PMAA) were prepared by in situ intercalative polymerization technique. The nanocomposites were characterized by FTIR and UV–visible spectroscopies, XRD, SEM, TEM, as well as TG‐DTA studies. The in situ intercalative polymerization of PANI, PMAA, and PANI‐co‐PMAA within bentonite layers was confirmed by FTIR, XRD, SEM, as well as TEM studies. XRD confirmed the intercalation of polymers and copolymer in bentonite. The average particle size of the nanocomposites was found to be in the range of 250–500 nm. The thermal stability was found be the highest for PANI‐co‐PMAA‐bentonite. The swelling behavior studies suggest that these nanocomposites hold potential for their utilization in absorption of toxic materials from waste water. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3299–3306, 2007     

Synthesis and characterization of poly(o‐anisidine)/V2O5 and poly(o‐anthranilic acid)/V2O5 nanocomposites

Poly(o‐anisidine)/V₂O₅ and poly(o‐anthranilic acid)/V₂O₅ nanocomposites were prepared by in situ intercalative polymerization, and the structure and electrical properties of these nanocomposites were investigated using GPC, TGA, XRD, TEM, FTIR, UV‐vis as well as conductivity measurement. The results show that the steric effect and nature of the substituting groups in the aromatic ring has an influence on the structure and electrical properties of the nanocomposites. Poly(o‐anisidine) or poly(o‐anthranilic acid) exists as a monolayer of outstretched chains in the gallery of the V₂O₅ xerogel owing to the confined environment in the nanometer‐size gallery. And intercalation of poly(o‐anisidine) or poly(o‐anthranilic acid) can improve the conductivity of V₂O₅ xerogel. Copyright © 2005 Society of Chemical Industry     

Kinetic investigations on the UV‐induced photopolymerization of nanocomposites by FTIR spectroscopy

The kinetics of the photopolymerization for nanocomposites containing nanosilica with 2,2‐dimethoxy‐1,2‐diphenylethan‐1‐one or benzophenone/n‐methyl diethanolamine (BP/MDEA)as photoinitiators were studied by FTIR spectroscopy. It was found that nanocomposites containing nanosilica had higher conversion in comparison with pristine EA. The presence of MPS and ethanol accelerated the photopolymerization of nanocomposites, while the presence of water decelerated it. The photopolymerization of nanocomposites was more sensitive to oxygen than that of pristine EA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99:1429–1436, 2006     

Thermomechanical properties of styrene‐butyl acrylate/organo‐silica nanocomposite films prepared by seed emulsion polymerization

Organo‐silica nanoparticles were prepared by sol–gel technique of triethoxyvinylsilane (VTES) in aqueous solution. The vinyl groups located on the surface of organo‐silica were used to induce the polymerization process and the encapsulation into styrene‐butyl acrylate copolymer emulsion. The prepared latex samples were characterized using FTIR, ¹HNMR, UV–visible, thermal analysis, field emission‐SEM and TEM. Results of TGA revealed that nanosilica has retarded the decomposition of nanocomposite polymers with at least 10°C higher than that of pure emulsions. DSC has shown an increase in the nanosilica ratio up to 5% which leads to a dramatic decrease in the glass transition (T _g) of nanocomposite polymer due to the formation of silica nanoparticles homopolymer. DMTA results indicated that the storage modulus of pure polymer is less than nanocomposite, which proves the reinforcing role of nanosilica in the matrix of polymer. Water resistance and UV‐blocking ability have improved by introducing the nanosilica into the matrix of prepared polymer. POLYM. COMPOS., 38:61–67, 2017. © 2015 Society of Plastics Engineers     

Surface‐modified silica nanoparticles for reinforcement of PMMA

Polymethyl methacrylate (PMMA) was introduced onto the surface of silica nanoparticles by particle pretreatment using silane coupling agent (γ‐methacryloxypropyl trimethoxy silane, KH570) followed by solution polymerization. The modified silica nanoparticles were characterized by Fourier‐transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Sedimentation tests and lipophilic degree (LD) measurements were also performed to observe the compatibility between the modified silica nanoparticles and organic solvents. Thereafter, the PMMA slices reinforced by silica‐nanoparticle were prepared by in situ bulk polymerization using modified silica nanoparticles accompanied with an initiator. The resultant polymers were characterized by UV–vis, Sclerometer, differential scanning calorimetry (DSC). The mechanical properties of the hybrid materials were measured. The results showed that the glass transition temperature, surface hardness, flexural strength as well as impact strength of the silica‐nanoparticle reinforced PMMA slices were improved. Moreover, the tensile properties of PMMA films doped with silica nanoparticles via solution blending were enhanced. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and characterization of hydrogel‐silver nanoparticle‐curcumin composites for wound dressing and antibacterial application

Hydrogel silver nanocomposites are found to be excellent materials for antibacterial applications. To enhance their applicability novel hydrogel‐silver nanoparticle‐curcumin composites have been developed. For developing, these composites, the hydrogel matrices are synthesized first by polymerizing acrylamide in the presence of poly(vinyl sulfonic acid sodium salt) and a trifunctional crosslinker (2,4,6‐triallyloxy 1,3,5‐triazine, TA) using redox initiating system (ammonium persulphate/TMEDA). Silver nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating the silver ions and subsequent reduction with sodium borohydride. Curcumin loading into hydrogel‐silver nanoparticles composite is achieved by diffusion mechanism. A series of hydrogel‐silver nanoparticle‐curcumin composites are developed and are characterized by using Fourier transform infrared (FTIR) and UV–visible (UV–vis) spectroscopy, X‐ray diffraction, thermal analyses, as well as scanning and transmission electron microscopic (SEM/TEM) methods. An interesting arrangement of silver nanoparticles i.e., a shining sun shape (ball) (～ 5 nm) with apparent smaller grown nanoparticles (～ 1 nm) is observed by TEM. The curcumin loading and release characteristics are performed for various hydrogel composite systems. A comparative antimicrobial study is performed for hydrogel‐silver nanocomposites and hydrogel‐silver nanoparticle‐curcumin composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of reactive copolymeric microgels

Hydrogels whose diameters range in the nanosize scale were synthesized by precipitation copolymerization of 4‐nitrophenol acrylate (NPA) with methacrylamide (MeAM) and N‐isopropylacrylamide (NIPAM). The polymerization reaction process was followed by attenuated total reflectance Fourier‐transform infrared spectrometry (ATR‐FTIR) and the conversion was studied by UV‐vis spectrometry. Poly(NPA‐co‐MeAM) and poly(NPA‐co‐NIPAM) microgels were characterized by proton nuclear magnetic resonance (¹H‐NMR) spectrometry. The thermal properties were studied by both thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. Transmission electron microscopy (TEM) of these microgels showed that the copolymer is located in spherical particles with a moderate polydispersity. The average particle diameter and the particle size distribution were measured in acetone by quasi‐elastic light scattering (QELS), which indicated a mean diameter close to 50 nm. Copyright © 2005 Society of Chemical Industry     

Preparation,crystallization, and spinnability of poly(ethylene terephthalate)/silica nanocomposites

Poly(ethylene terephthalate) (PET)/silica nanocomposites were successfully prepared by in situ polymerization. Silica nanoparticles were uniformly dispersed in the process of polymerization. By means of hot‐stage polarization microscope and DSC, the influence of nanosilica on the crystallization of PET/silica nanocomposites has been clarified. The results show that nanosilica does not behave as a nucleating agent in PET but postpones the appearance of crystallite. This phenomenon is very favor to improve spinnability. The investigation on melt spinning of PET/silica nanocomposites also shows that it is advantageous to spinning with descending the spinning temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2564–2568, 2007     

Synthesis and characterization of cationic gemini surfactant modified Na–bentonite and its applications for rubber nanocomposites

A cationic gemini surfactant (N‐isopropyl‐N , N‐dimethyldodecan 1‐aminium bromide) was synthesized by quaternization reaction. The synthesized surfactant was characterized by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. Modified Na–bentonite (organoclay) was obtained by the intercalation of a gemini surfactant between the layers of sodium bentonite and characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), FTIR, thermogravimetry–differential thermal analysis (TGA–DTA) and differential scanning calorimetry (DSC) techniques. The results of XRD, TEM, FTIR, TGA, and corresponding DSC analysis indicate that gemini surfactant has been successfully intercalated into the clay layers. Rubber‐based nanocomposites have been prepared by incorporating various concentration of organically modified bentonite on to natural rubber/styrene–butadiene rubber (NR/SBR) rubber blend (75/25) using two roll mill. Effect of organoclay content on XRD, curing, mechanical, and scanning electron microscopy (SEM) properties of the nanocomposites are investigated. The morphological study showed the intercalation of nanoclay in NR/SBR blend chain. It was found that the organoclay decrease the optimum and scorch time of the curing reaction, increase maximum torque and the curing rate, which was attributed to the further intercalation during vulcanization process. Mechanical properties such as tensile strength, modulus and elongation at break have improved. POLYM. COMPOS., 38:396–403, 2017. © 2015 Society of Plastics Engineers     

Towards transparent PMMA/SiO2 nanocomposites with promising scratch‐resistance by manipulation of SiO2 aggregation followed by in situ polymerization

Poly(methyl methacrylate) grafted silica (SiO₂‐g‐PMMA) was synthesized via in situ suspension polymerization. To achieve better uniform dispersion, hexadecyltrimethylammonium bromide (CTAB) was introduced into xylene to manipulate SiO₂ aggregation. SiO₂‐g‐PMMA or SiO₂ was incorporated into PMMA matrix by in situ polymerization to prepare PMMA‐based nanocomposites. The effect of CTAB amount, in the range 0–35 wt %, on the modification was evaluated by DLS, TGA, and FTIR. Furthermore, morphology, optical, mechanical, and thermal properties of PMMA nanocomposites was characterized by SEM, UV–vis, DMA, and TGA. Owing to surface functionalization, SiO₂‐g‐PMMA exhibited far more excellent compatibility and dispersion in matrix compared with SiO₂. Surface hardness and thermal properties of nanocomposites were enhanced significantly under the premise in high transparency. It is expected that transparent nanocomposites with promising scratch‐resistance could have wide applications, such as airplane shielding window and daily furniture. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44612.     

Synthesis and properties of nanosilica‐reinforced polyurethane for grouting

A polyurethane/nanosilica (PU/SiO₂) hybrid for grouting was prepared in a two‐step polymerization using poly(propylene glycol) diols as the soft segment, toluene 2,4‐diisocyanate (TDI) as the diisocyanate, 3,3′‐dichloro‐4,4′‐diaminodiphenylmethane (MOCA) as the chain extender, and acetone as the solvent. The size and dispersion of nanosilica, the molecular structure, mechanical properties, rheological behavior, thermal performance, and the UV absorbance characteristic of the PU/SiO₂ hybrid were investigated by transmission electron microscopy (TEM), FTIR, mechanical tests, viscometry, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and UV spectroscopy. Nanosilica dispersed homogeneously in the PU matrix. The maximum values of mechanical properties such as tensile strength, elongation break, and adhesive strength showed an addition of nanosilica of about 2 wt %. Resistance to both high and low temperatures was better than with PU. And the UV absorbance of the PU/SiO₂ hybrid increased in the range of 290–330 nm with increasing nanosilica content. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4333–4337, 2006     

Poly (styrene‐n‐butyl acrylate‐methyl methacrylate)/silica nanocomposites prepared by emulsion polymerization

Poly (styrene‐n‐butyl acrylate‐methyl methacrylate) (PSBM)/silica nanocomposite was prepared by emulsion polymerization in the presence of oleic acid surface modified nanosilica. The structure, morphology, size, and size distribution were characterized by Fourier transform infrared (FTIR), transmission electron microscopy (TEM), and dynamics laser scattering. The chemical bond was formed between PSBM and nanosilica revealed by FTIR and TEM studies. The composite particles with an averaged diameter ranging from 30 to 80 nm have the core‐shell structure. The effect of silica content on the glass transition temperature T_g, pyrolyze temperature, and rheological behavior of PSBM composites was systematically investigated. The results indicated that the addition of nanosilica could effectively inhibit chain movement, and improved the pyrolyze temperature of PSBM. The steady viscosity and dynamic modulus were strongly dependent on the content and distribution of nanosilica in PSBM nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Morphology,thermal, and crystallization properties of poly(butylene succinate)‐grafted Nanocrystalline Cellulose by polymerization in situ

The compounds 1,4‐butanediol, succinic anhydride, and nanocellulose (NCC) were used to synthesize poly(butylene succinate)‐grafted Nanocrystalline Cellulose (PBS‐g‐NCC) nanocomposites via polymerization in situ. The resulting structures were examined by transmission electron microscopic (TEM), scanning electron microscope (SEM), ¹H and ¹³C‐nuclear magnetic resonance spectroscopic (NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X‐ray diffraction (XRD) analyses. TEM showed the cellulose to be nanoscale and SEM analysis indicated that 3 wt% NCC dispersed well in PBS matrix. ¹H and ¹³C‐NMR analyses indicated the product to possess peaks characteristic of PBS. DSC analysis clearly showed that the NCC increased the PBS crystallinity when 3 wt% NCC was introduced into PBS matrixes by polymerization in situ, compared to pure PBS. TGA illustrated that the thermal stability of PBS‐g‐NCC was better than that of pure PBS, when 3 wt% NCC was added. XRD analysis suggested that 3 wt% NCC improved PBS crystallinity, which was in good agreement with the present DSC results. POLYM. ENG. SCI., 59:928–934, 2019. © 2018 Society of Plastics Engineers