“Grafting through” approach for synthesis of polystyrene/silica aerogel nanocomposites by in situ reversible addition-fragmentation chain transfer polymerization

Sobani, Masoud; Haddadi‐Asl, Vahid; Salami‐Kalajahi, Mehdi; Roghani‐Mamaqani, Hossein; Mirshafiei-Langari, Seyed-Ataollah; Khezri, Khezrollah

doi:10.1007/s10971-013-3015-8

Cited by 44 publications

(19 citation statements)

References 21 publications

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“…Sobani et al [39] have employed RAFT polymerization to synthesize welldefined polystyrene/silica aerogel nanocomposites. According to their report, double bond containing modifier was firstly attached on silica aerogel surface (surface modification) and the grafting through technique was applied to attach polystyrene on the surface of silica aerogel.…”

Section: Introductionmentioning

confidence: 99%

SR&NI atom transfer radical random copolymerization of styrene and butyl acrylate in the presence of MPS-functionalized silica aerogel nanoparticles

Sarsabili

Kalantari

Khezri

2016

J Therm Anal Calorim

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Hydrophilic silica aerogel nanoparticles' surface was functionalized with 3-(trimethoxysilyl)propyl methacrylate (MPS). Then, the resultant functionalized nanoparticles were used in grafting through copolymerization of styrene and butyl acrylate by simultaneous reverse and normal initiation technique for atom transfer radical copolymerization (SR&NI ATRP) to synthesize tailor-made random poly (styrene-co-butyl acrylate) nanocomposites with twofold chains. Successful surface modification of hydrophilic silica aerogel nanoparticles with MPS is demonstrated by Fourier transform infrared spectroscopy and thermogravimetric analysis (TG). Nitrogen adsorption/desorption isotherm is applied to examine surface area and structural characteristics of the synthesized silica aerogel nanoparticles. Evaluation of size distribution and morphological studies were also performed by scanning and transmission electron microscopy. Conversion and molecular weight determinations were carried out using gas and size exclusion chromatography, respectively. Addition of MPS-functionalized nanoparticles by 3 mass% results in a decrease in conversion from 71 to 46 %. Molecular weight (M n ) of the free poly (styrene-cobutyl acrylate) chains decreases by adding 3 mass% MPSfunctionalized silica aerogel nanoparticles; however, polydispersity index (PDI) value increases from 1.17 to 1.48. Although PDI values of the attached poly (styrene-cobutyl acrylate) chains are increased from 1.54 to 1.76, M n values reveal an increment by adding silica aerogel nanoparticles. 1 H NMR spectroscopy results indicate that the molar ration of each monomer in the copolymer chains is approximately similar to the initial selected mole ratio of the monomers. Increasing thermal stability of the nanocomposites is demonstrated by TG. Differential scanning calorimetry also shows a decrease in glass transition temperature by increasing modified silica aerogel nanoparticles.

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Section: Introductionmentioning

confidence: 99%

SR&NI atom transfer radical random copolymerization of styrene and butyl acrylate in the presence of MPS-functionalized silica aerogel nanoparticles

Sarsabili

Kalantari

Khezri

2016

J Therm Anal Calorim

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“…In physical methods, adsorption of polymer chains on a substrate is applied by physical bonds. However, in chemical methods, polymer chains are covalently attached to the surface via three common ways of Bgrafting from^, Bgrafting through^, and Bgrafting to^ [9][10][11][12][13][14][15][16][17]. Therein, grafting from is preferable to other methods because of its higher grafting density and thicker polymer layers.…”

Section: Introductionmentioning

confidence: 99%

Nanofibers of poly (hydroxyethyl methacrylate)-grafted halloysite nanotubes and polycaprolactone by combination of RAFT polymerization and electrospinning

2015

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Halloysite nanotubes (HNTs) were functionalized with (3-Chloropropyl)triethoxysilane (CPTS) and sodium ethyl xanthate (NaEtX) to yield HNT-CPTS and HNT-RA respectively. Subsequently, HNT-RA was used as a substrate to graft poly (hydroxyethyl methacrylate) (PHEMA) to yield HNT-PHEMA. Then, HNT and polycaprolactone (PCL), HNT-PHEMA and PCL, and neat PCL in ethanol were electrospun. Successful grafting of CPTS, RA, and PHEMA on HNTs was evaluated by FTIR, TGA, and TEM. Stretching vibrations of C-H, C-O, and C=O bonds confirm the attachment of CPTS, NaEtX, and PHEMA respectively. Formation of PHEMA on the lumen, outer, and inner surface of HNTs is displayed by TEM. Cylindrical morphology of HNTs was revealed by SEM. DLS shows that grafting PHEMA at the surface of HNTs results in breaking of HNTs agglomerates. Surface roughness and morphology of nanofibers were evaluated by TEM. By surface grafting of HNTs with PHEMA, its dispersion in PCL is improved and HNTs removal from the nanofibers is reduced.

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“…In this method, stable dispersion of colloidal particles in a solvent (sol) forms a three-dimensional continuous network (gel) in acidic, basic, or acidic-basic conditions [14,15]. The content of water, metal alkoxides, and solvent, pH value, temperature, and drying methods are important factors in microstructure of gel [16].…”

Section: Introductionmentioning

confidence: 99%

Incorporation of epoxy resin and graphene nanolayers into silica xerogel network: an insight into thermal improvement of resin

Najafi-Shoa

Roghani‐Mamaqani

Salami‐Kalajahi

2016

J Sol-Gel Sci Technol

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Three well-tuned procedures were used for thermal improvement of epoxy resin (E). Accordingly, graphene xerogel (GX) was used as nanofiller in the matrix of E. Additionally, (3-isocyanatopropyl)triethoxysilanemodified E (IE) or tetraethyl orthosilicate (TEOS) oligomer-modified E (TE) was incorporated into a hybrid structure of graphene-containing silica/siloxane network. For this purpose, a bifunctional silane coupling agent of 1,1 0 -(hexane-1,6-diyl)bis(3-(3-(trimethoxysilyl)propyl)urea) (HDBTMSPU) was synthesized. GX was obtained by incorporation of HDBTMSPU-modified graphene oxide (FGO) into xerogel structure using HDBTMSPU and TEOS. Modified resins, FGO, HDBTMSPU, and TEOS were also used in preparation of hybrid products. Thermal stability and char residue of the composites were compared. GO modification was approved by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman, X-ray diffraction, and thermogravimetric analysis results. Hybrid composite of IE, FGO, and silica/siloxane network shows higher thermal properties. Char residue is increased by 16.93 % by loading of only 1 wt% of FGO in this hybrid product. Graphical Abstract

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“Grafting through” approach for synthesis of polystyrene/silica aerogel nanocomposites by in situ reversible addition-fragmentation chain transfer polymerization

Cited by 44 publications

References 21 publications

SR&NI atom transfer radical random copolymerization of styrene and butyl acrylate in the presence of MPS-functionalized silica aerogel nanoparticles

SR&NI atom transfer radical random copolymerization of styrene and butyl acrylate in the presence of MPS-functionalized silica aerogel nanoparticles

Nanofibers of poly (hydroxyethyl methacrylate)-grafted halloysite nanotubes and polycaprolactone by combination of RAFT polymerization and electrospinning

Incorporation of epoxy resin and graphene nanolayers into silica xerogel network: an insight into thermal improvement of resin

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