Preparation and characterization of polyhydroxyurethane/silica nanocomposites via in situ surface‐initiated polymerization

The polyhydroxyurethane/silica nanocomposite (PHU/SN) was prepared by the in situ surface‐initiated polymerization of a five‐membered cyclic carbonate, 2,2‐bis[p‐(1,3‐dioxolan‐2‐one‐4‐yl‐methoxy)phenyl]propane (B5CC) and hexamethylene diamine, from the surfaces of the aminopropyl silica nanoparticles (APSN) for the first time. The percentage of grafting (PG%) and the grafting efficiency (GE%) of 27% and 19% were calculated from the results of thermogravimetric analysis (TGA), respectively, after the free polyhydroxyurethane was washed off. The chemical grafting of the polymer was also confirmed using Fourier transform infrared (FTIR) and the morphology of the silica nanoparticles in the nanocomposite was characterized by transmission electron microscope (TEM). POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Preparation and characterization of polystyrene‐grafted attapulgite via surface‐initiated redox polymerization

Polystyrene‐grafted attapulgite (ATP‐g‐PS) was prepared using surface‐initiated redox initiation via graft from approach. ATP was modified with (3‐ aminopropyl) triethoxysilane (APTES) to anchor amine on the surface (ATP‐NH₂), and then ATP‐NH₂ was further treated with 4‐(diethylamino) salicylaldehyde (DEAS) to give aromatic tertiary amine groups functional ATP (ATP‐ATA). Subsequently, the surface‐initiated redox polymerization of styrene in the presence of ATP‐ATA and benzoyl peroxide (BPO) was performed to afford ATP‐g‐PS . The chemical grafting of PS on the surface of ATP was confirmed by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and thermogravimetric analysis . The crystal structure of PS‐grafted ATP was characterized by X‐ray diffraction (XRD) analysis. The morphology of ATP‐g‐PS was observed by scanning electron microscopy (SEM) . POLYM. ENG. SCI., 55:889–895, 2015. © 2014 Society of Plastics Engineers     

Synthesis and characterization of poly(acrylonitrile)/montmorillonite nanocomposites from surface‐initiated redox polymerization

We have developed a facile method to prepare polyacrylonitrile/montmorillonite (PAN/MMT) nanocomposites using the surface‐initiated redox polymerization of acrylonitrile (AN) in the aqueous phase. The MMT silicate surfaces were first treated with diethanolamine, and the modified MMT (DEA‐MMT) was subsequently used together with the Ce(IV) salt to serve as a redox system. The PAN chains growing on a surface‐tethered DEA expand the interlayer space, and thus lead to intercalated/exfoliated nanocomposites. The nano‐morphology of the prepared nanocomposites depends on the AN/OH molar ratio in feed. An exfoliated PAN/MMT nanocomposite was obtained when the feeding AN/OH molar ratio = 300 was used. The molecular weight of PAN in the nanocomposites prepared by the present method is also dependent on the AN/OH molar ratio in feed and can be up to ca. 160,000 g/mol. The differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) analyses show that the increasing fraction of exfoliated silicate structures should enhance the contact interface between the silicate and polymer, resulting in the higher glass transition temperature and thermal stability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of copolymer grafted magnetic nanoparticles via surface‐initiated nitroxide‐mediated radical polymerization

“Grafting from” surface‐initiated nitroxide‐mediated radical polymerization (SI‐NMRP) techniques were used to synthesize poly[styrene‐co‐(maleic anhydride)] copolymer brushes from the Fe₃O₄ surfaces. Well‐defined polymer chains were grown from the Fe₃O₄ surfaces to yield particles with a Fe₃O₄ core and a polymer outer layer. The observed narrow molecular weight distributions (M_w/M_n), linear kinetic plots and linear plots of molecular weight (M_n) versus conversion for the free polymer indicated that the chain growth from the Fe₃O₄ surface was a controlled process by adding an excess of 2,2,6,6‐tetramethylpiperidinyloxy (TEMPO). The modified nanoparticles were subjected to detailed characterization using XRD, TEM, FT‐IR, and TGA. The analyses of vibration sample magnetometer (VSM) verified that the nanoparticles owned good magnetic property. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Preparation and characterization of coaxial halloysite/polypyrrole tubular nanocomposites for electrochemical energy storage

Halloysite nanotubes/polypyrrole (HNTs/PPy) nanocomposites with coaxial tubular morphology for use as electrode materials for supercapacitors were synthesized by the in situ chemical oxidative polymerization method based on self-assembled monolayer amine-functionalized HNTs. The HNTs/PPy coaxial tubular nanocomposites were characterized with transmission electron microscope (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), electrical conductivity measurement at different temperatures, cyclic voltammetry (CV), and galvanostatic charge-discharge measurements. The coaxial tubular nanocomposites showed their greatest conductivity at room temperature and a weak temperature dependence of the conductivity from 298 K to 423 K. A maximum discharge capacity of 522 F/g after correcting for the weight percent of the PPy phase at a current density of 5 mA cm⁻² in a 0.5 M Na₂SO₄ electrolyte could be achieved in a half-cell setup configuration for the HNTs/PPy composites electrode, suggesting its potential application in electrode materials for electrochemical capacitors.     

Synthesis and characterization of CTAB‐intercalated graphene/polyaniline nanocomposites via in situ oxidative polymerization

Polyaniline/graphene (PANI/GN) nanocomposites were fabricated via in‐situ oxidative polymerization of aniline in the presence of cetyltrimethylammonium bromide (CTAB) modified graphene (CGN) in 1M hydrochloric acid (HCl) solution. The morphology and structure of PANI/GN samples were investigated by Fourier transform infrared spectrum, X‐ray diffraction, ultraviolet and visible spectrum, thermogravimetric analysis, field‐emission scanning microscope (FE‐SEM), and transmitting electron microscopy (TEM). The conductivities of the PANI/GN nanocomposites were measured using four‐probe electrical conductivity measurement. The results indicated that the GN sheets disperse into the form of monolayer or stack few layers in PANI matrix. The GN sheets serve as a support material for PANI particles and the structure of GN covered with PANI nanoparticles were confirmed by FE‐SEM and TEM. The electrical conductivities of the PANI/GN samples have been improved compared with pure PANI prepared in the similar condition. POLYM. COMPOS., 36:1767–1774, 2015. © 2014 Society of Plastics Engineers     

Preparation of monodispersed and lipophilic attapulgite and polystyrene nanorods via surface‐initiated atom transfer radical polymerization

A new kind of initiator, 3‐(2‐bromo‐2‐methylacryloxy)propyltriethysiliane (MPTS‐Br), was prepared with a simply hydrobrominated commercial silane coupling agent (3‐methacryloxy‐proplytriethysilane, MPTS). It has been one‐step self‐assemble onto the surface of attapulgite (ATP) nanorods in the dispersion system, and by using this initiator‐modified nanorod (MPTS‐Br‐modified ATP nanoparticles, ATP‐MPTS‐Br) as macroinitiator for atom transfer radical polymerization (ATRP). Structurally well‐defined homopolymer polystyrene (PS) and block polymer poly(styrene‐b‐methyl methacrylate) (PS‐b‐PMMA) chains were then grown from the needle‐shaped nanorods surface to yield monodispersed nanorods composed of ATP core and thick‐coated polymer shell (ATP and PS). The graft polymerization parameters exhibited the characteristics of a controlled/”living” polymerization. The PS‐grafted ATP nanorods could be dispersed well in organic solvent with nanoscale. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Fabrication of conducting polyaniline‐coated halloysite coaxial structure nanocomposites via in situ oxidative graft polymerization

The preparation of conducting γ‐aminopropyltriethoxysilane halloysite (APHNTs)/polyaniline (PANI) coaxial tubular nanocomposite was conducted via in situ oxidative polymerization after the surface modification of the halloysite nanotubes' (HNTs) surface with γ‐aminopropyltriethoxysilane (γ‐APTES) as modifier and aniline as monomer in the presence of hydrochloric acid (HCl). The products were characterized by Fourier transform infrared spectroscopy analysis, X‐ray diffraction, and thermogravimetric analysis. The surface coatings of the γ‐APHNTs and the γ‐APHNTs/PANI hybrids were characterized with X‐ray photoelectron spectroscopy. The morphology of γ‐APHNTs/PANI nanocomposites were examined by scanning electron microscopy and transmission electron microscopy. The electrical conductivities of the γ‐APHNTs/PANI were measured using SDY‐4 Four‐Point Probe Meter. The results showed that the concentration of HCl had no effect on the morphologies and the electrical conductivities of the γ‐APHNTs/PANI nanocomposites increased with more HCl added. POLYM. COMPOS., 36:1759–1766, 2015. © 2014 Society of Plastics Engineers     

Synthesis and characterization of chlorine‐containing flame‐retardant polyurethane nanocomposites via in situ polymerization

We have developed flame‐retardant polyurethanes (FRPUs) and polyurethane (PU) nanocomposites via in situ polymerization. Three series of thermoplastic elastomeric PUs were synthesized to investigate the effect of incorporating 3‐chloro‐1,2‐propanediol (CPD) and nanoclay on mechanical, thermal properties, and also resistance to burning. PU soft segments were based on poly(propylene glycol). Hard segments were based on either CPD or 1,4‐buthane diol (BDO) in combination with methyl phenyl di‐isocyanate named PU or FRPU, respectively. In the third series, CPD was used as chain extender also nanoclay (1% wt) and incorporated and named as flame‐retardant polyurethane nanocomposites (FRPUN). Mechanical properties and LOI of PUs and nanocomposites have been evaluated. Results showed that increasing the hard segment (chlorine content) leads to the increase in flame retardancy and burning time. Addition of nanoclay to CPD‐containing PUs leads to obtain self‐extinguish PUs using lower CPD contents, higher Young's modulus, and strength without any noticeable decrease in elongation at break. Investigation of the TGA results showed that copresence of nanoclay and chlorine structure in the PU backbone can change thermal degradation pattern and improve nanocomposite thermal stability. X‐ray diffraction and transmission electron microscopy studies confirmed that exfoliation and intercalation have been well done. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and characterization of flame‐retardant melamine cyanurate/polyamide 6 nanocomposites by in situ polymerization

This article focuses on an improved method, i.e., improved in situ polymerization of ε‐caprolactam in the presence of melamine derivatives to prepare flame‐retardant melamine cyanurate/polyamide 6 (MCA/PA6) nanocomposites. The chemical structures of these synthetic flame retardant composites are characterized by Fourier‐transform infrared spectroscopy and X‐ray diffraction. Morphologies, mechanical properties, and thermal properties also are investigated by the use of transmission electron microscopy, mechanical testing apparatus, differential scanning calorimetry, and thermogravimetric analysis, respectively. Through transmission electron microscopy photographs, it can be found that the in situ‐formed MCA nanoparticles with diametric size of less than 50 nm are nanoscaled, highly uniformly dispersed in the PA6 matrix. These nanocomposites, which have good mechanical properties, can reach UL‐94 V‐0 rating at 1.6‐mm thickness even at a relatively low MCA loading level. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and properties of the self‐crosslinked acrylic rubber via gamma ray initiated emulsion polymerization

In this study, a series of self‐crosslinked acrylic rubbers were prepared by gamma ray initiated emulsion copolymerization. Acrylic acid and N‐hydroxymethl acrylamide were used as the cure‐site monomers. The vulcanizing properties, tensile properties, and dynamic mechanical analysis of the self‐crosslinked acrylic rubbers were investigated. It was found that the curing characteristics could be influenced significantly by the content and species of the cure‐site monomers. Improvement in mechanical properties like tensile strength, modulus and elongation at break was observed in the prepared self‐crosslinked rubber. The structure‐property correlation of the self‐crosslinked acrylic rubber was discussed. POLYM. ENG. SCI. 46:1748–1753, 2006. © 2006 Society of Plastics Engineers.     

Preparation and characterization of Pani and Pani‐Ag nanocomposites via interfacial polymerization

Polyaniline (Pani) and Polyaniline‐silver nanocomposites (Pani‐Ag) were prepared by employing interfacial polymerization using ammonium persulphate as an oxidizing agent. During the polymerization, the Ag+ is reduced to Ag⁰, and the formations of regular nanocomposite materials were studied by Fourier transform infrared spectroscopy and UV–visible spectroscopy techniques. Scanning electron microscopy and transmission electron microscopy images were conducted to characterize the morphology. Thermogravimetric and differential thermal analysis were carried out to study the thermal stability of the resulting composites. Formation of conducting emeraldine salt form was concluded by electrical conductivity. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Synthesis and characterization of polystyrene/layered double‐hydroxide nanocomposites via in situ emulsion and suspension polymerization

Polystyrene (PS)/ZnAl layered double‐hydroxide (LDH) nanocomposites were synthesized via in situ emulsion and suspension polymerization in the presence of N‐lauroyl‐glutamate surfactant and long‐chain spacer and characterized with elemental analysis, Fourier transform infrared spectrum, X‐ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis. The XRD and TEM results demonstrate that the exfoliated ZnAl–LDH layers were well dispersed at molecular level in the PS matrix. The completely exfoliated PS/LDH nanocomposites were obtained even at the 20 and 10 wt % LDH loadings prepared by emulsion polymerization and suspension polymerization, respectively. The PS/LDH nanocomposites with a suitable amount of LDH showed apparently enhanced thermal stability. When the 50% weight loss was selected as a comparison point, the decomposition temperature of the exfoliated PS/LDH sample prepared by emulsion polymerization with a 5 wt % LDH loading was about 28°C higher than that of pure PS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3758–3766, 2006     

Preparation of conductive polypyrrole composites by in‐situ polymerization

Two kinds of conductive polypyrrole composites were prepared by in‐situ polymerization of pyrrole in a suspension of chlorinated polyethylene powder or in a natural rubber latex using ferric chloride as oxidizing agent. The preparation conditions were studied and the results showed that it is better to swell the chlorinated polyethylene powder with the monomer first, followed by addition of the oxidant, than to add the oxidant first, and that conversion can reach 98% for 6 h at room temperature. The conductivity percolation threshold of the composite is about 12%. The composites can be processed repeatedly, exhibiting a maximum tensile strength over 9 MPa and a maximum conductivity near 1 S cm⁻¹. The polypyrrole/natural rubber composites were prepared successfully by using a nonionic surfactant (Peregal O) as stabilizer at pH less than 3 with a molar ratio of FeCl₃/pyrrole = 2.5 below 45 °C. The latter composites show a low conductivity percolation threshold about 6%, a maximum tensile strength over 10 MPa and a maximum conductivity over 2 S cm⁻¹. The composites were characterized by FTIR and TGA. The polypyrrole/chlorinated polyethylene composites are very stable in air and almost no decrease of conductivity was observed for over 10 months examined. © 1999 Society of Chemical Industry     

Microwave‐assisted preparation of polylactide/organomontmorillonite nanocomposites via in situ polymerization

Microwave technology was introduced to assist the synthesis of polylactide (PLA)/organomontmorillonite (OMMT) nanocomposites in bulk by the in situ ring‐opening polymerization of D,L ‐lactide. Factors that influenced the polymerizing effects, such as the microwave power, irradiation time, and dosages of the catalyst and OMMT, were studied in terms of tensile strength. The polymerization time was decreased dramatically to 10 min under 90 W of microwave irradiation, and the mechanical and thermal properties of the PLA/OMMT nanocomposites were significantly improved. The composite with the highest mechanical properties was obtained when the dosages of the OMMT and the catalyst were 1.0 and 0.6 wt % of the lactide, respectively. The initial decomposition temperature of the PLA/OMMT(1.0 wt % OMMT) nanocomposite was heightened 11.5°C compared with that of pure PLA. The results of scanning electron microscopy confirmed an improvement in the toughness with the addition of OMMT. The transmission electron microscopy and X‐ray diffraction results indicate that an exfoliated and intercalated nanocomposite was successfully prepared. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of PET/clay nanocomposites via in situ polymerization in the presence of monomer‐activated organoclay

Various polyethylene terephthalate (PET)/clay nanocomposites containing a commercial organoclay (organophilic montmorillonite nanoclay [OMMT]) and a monomer‐activated OMMT (remodified OMMT) were prepared via in situ interlayer polycondensation of dimethyl terephthalate and ethylene glycol. In order to remodify the commercial OMMT nanoparticles, a diacid chloride monomer was applied. The prepared nanocomposites were characterized by diverse methods, including X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and intrinsic viscosity measurements. The results of the study revealed that the PET/(remodified OMMT) nanocomposites possess a better state of clay dispersion as well as significantly better thermal properties as compared with the PET/OMMT nanocomposites. Moreover, the PET/(remodified OMMT) nanocomposites showed higher crystallization temperature, degree of crystallinity, maximum degradation temperature, and lower half‐time of crystallization than that of the PET/OMMT nanocomposites. It was found that the remodification process for OMMT led to less of a foaming problem during in situ polymerization. J. VINYL ADDIT. TECHNOL., 21:70–78, 2015. © 2014 Society of Plastics Engineers     

Preparation and characterization of epoxy nanocomposites containing surface‐modified graphene oxide

A three‐step grafting procedure has been used to graft the epoxy monomers (DER332) and the curing agents (diamino diphenyl methane (DDM), onto graphene oxide (GO) surface. The surface modification of GO has been performed by grafting of Jeffamine D‐2000, followed with subsequent grafting of DER332 and DDM, respectively. Fourier transform spectroscopy and thermogravimetric analysis indicate successful surface modification. The resulting modified GO, that is, (DED)‐GO, can be well dispersed in the epoxy monomers. The epoxy nanocomposites containing different GO contents can then be prepared through curing processes. The dispersion of GO in the nanocomposites is characterized by transmission electron microscopy. It is found that the tensile strength and elongation at break of epoxy nanocomposite with only 0.2 wt % DED‐GO are increased by 30 and 16% as compared with the neat epoxy resin, respectively. Dynamic mechanical analysis results show that 62% increase in storage modulus and 26°C enhancement in the glass transition temperature of the nanocomposite have been achieved with the incorporation of only 0.2 wt % of DED‐GO into the epoxy. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40236.     

Comb‐like polymer‐graphene nanocomposites with improved adhesion properties via surface‐initiated atom transfer radical polymerization (SI‐ATRP)

The synthesis and properties of comb‐like polymer‐graphene nanocomposites via surface initiated atom transfer radical polymerization is reported. The crystallization temperature (T_c) and melt temperature (T_m) of the comb‐like homopolymer increases from −18 to −8 °C and 1 to 11 °C, respectively, in the nanocomposite synthesized with 0.6 wt % graphene initiator. The rheological properties like modulus and complex viscosity of the nanocomposite show a twofold increase. Transmission electron microscopy results of the nanocomposite show a well‐intercalated structure with nanoscale distribution of graphene domains and in scanning electron microscopy a sheet‐like structure with corrugations, and crumples are seen. The hydrophobicity, as measured by water contact angle, increases from 101° in the homopolymer to 118° in the nanocomposite. The nanocomposites exhibit substantial increase in adhesive strength on different substrates, with peel strength increasing by more than 1000 times, as compared to the homopolymer. The improved tack and adhesion properties of the nanocomposites suggest them as novel materials for adhesive applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45885.     

Shape control synthesis of polymeric hybrid nanoparticles via surface‐initiated atom‐transfer radical polymerization

Polymeric hybrid nanoparticles were synthesized via surface‐initiated atom‐transfer radical polymerization (SI‐ATRP) method on the surface of gold nanoparticles in cyclohexanone. Tetraoctyl ammonium bromide (TOAB) as a phase transfer agent was used to transfer the gold nanoparticles into cyclohexanone, which will be replaced by disulfide initiator on the surface of gold nanoparticles. Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and UV–vis spectroscopy were utilized to characterize the product to make sure the experiment had been conducted. The results showed that the polymeric gold hybrid nanoparticles with different structures could be controlled by adjusting the ratio of initiator and gold nanoparticles in ATRP. If the ratio is very little, asymmetric polystyrene–gold hybrid nanoparticles were synthesized, and a single gold nanoparticle was attached with a polystyrene sphere. If the ratio becomes larger, core–shell polystyrene–gold nanocomposite particles were obtained resulting in gold nanoparticle encapsulated by a uniform polymer shell. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43584.