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ABSTRACT The surface grafting of attapulgite (ATP) with polystyrene (PS) was established via a simultaneous reverse and normal initiation atom transfer radical polymerization (SR&NIATRP). 4-(chloromethyl)phenyltrimethoxysilane (CMPTMS) chemical bounded on the surface of ATP (ATP-Cl, Cl-I) was prepared via one-step self-assembly. SR&NI ATRP of styrene was conducted using CuCl2 complex tris(2-(dimethylamino)ethyl)amine (Me6-TREN) as the catalytic system, initiated by 2,2-azobis(isobutyronitrile) (AIBN) and ATP-Cl. FT-IR, XRD, XPS, TGA and TEM data were consistent with the grafting of benzyl chloride groups and PS chains on ATP surface. The controllability of polymerization was investigated by the kinetics behavior under different molar ratio of AIBN and CuCl2. The obtained polymer possessed a uniform distribution of molecular weights with a lower polydispersity index of 1.2∼1.4. The relationship between polymerization on the surface of ATP and in solution was discussed in detail based on TGA data of hybrid particles and GPC trace of free polymer in solution. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1508-1516 [ABSTRACT FROM AUTHOR]

ABSTRACT Hybrid nanocomposites consisting of polydimethylaminoethyl methacrylate (PDMAEMA) and attapulgite (ATP) were prepared by using a surface thiol-Ce (IV) redox initiation system via graft from approach. Initially, ATP was chemically modified with γ-mercaptopropyltrimethoxysilane (MTS) to anchor thiol groups on the surface (ATP-MTS). Subsequently, surface-initiated polymerization of dimethylaminoethyl methacrylate was performed by using ATP-MTS and cerium (IV) ammonium nitrate (CAN) in aqueous nitric acid (HNO3) to afford hybrid particles (ATP-g-PDMAEMA). Evidence of grafting of PDMAEMA was confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Thermogravimetric Analysis (TGA). The crystal structure of PDMAEMA grafted ATP was characterized by X-ray diffraction (XRD) analysis. Morphology of ATP-g-PDMAEMA was observed by transmission electron microscopy (TEM). The effects of concentration of Ce (IV), HNO3, and reaction temperature were examined by determining the percentage of grafting (PG). With other condition kept constant, the optimum conditions were obtained as follows: the reaction temperature was 50°C, Ce (IV) and HNO3 concentrations were 12.5 mmol/L and 1 mol/L, respectively, when 0.2 g of ATP-MTS, 1 mL of DMAEMA, and 4 mL of aqueous solution were used. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42762. [ABSTRACT FROM AUTHOR]

ABSTRACT The Core-shell hybrid particles with attapulgite (ATP) as the core and polymethylmethacrylate (PMMA) as the shell (ATP- g-PMMA) were prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization method. The diameter of ATP- g-PMMA was increased to 50-60 nm, and the surface hygroscopicity was decreased observably after surface grafting. Then, ATP- g-PMMA hybrid particles were filled into the polycarbonate (PC) by melt mixing to afford nanocomposites, and the mechanical properties, microstructures, thermal stability, and rheological behavior of nanocomposites were investigated by varying ATP- g-PMMA concentration in the range 1, 3, 5, and 7 wt % in PC. Fourier Transform infrared spectroscopy (FTIR) suggested that there is no esterification reaction between particles and matrix. Slight changes in tensile strength, and noticeable decrease of elongation and impact strength were observed with the increase in ATP- g-PMMA particles loading. The morphology evaluated by field-emission scanning electron microscopy (FESEM) indicated that ATP- g-PMMA was dispersed with a diameter range of 80-100 nm, and phase separation was appeared with increasing ATP- g-PMMA loadings. Thermogravimetric analysis (TGA) results revealed the thermal stability of composites was strengthened. The disentanglement and interface slip induced by preferred orientation and directional arrangement of ATP- g-PMMA resulted in lower complex viscosity (η*) and higher loss factor (tan δ) compared with the pristine PC. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42262. [ABSTRACT FROM AUTHOR]

ABSTRACT 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. [ABSTRACT FROM AUTHOR]

ABSTRACT Poly(methyl methacrylate) (PMMA) was bonded on the surface of attapulgite (ATP) by using an ammonium persulfate amine redox initiation system via grafting from approach. ATP was modified with (3-aminopropyl)triethoxysilane to anchor amine groups on the surface, and then the amine-functionalized ATP was further treated with methacryloyl chloride and 4,4′-azobis(4-cyanovaleric acid) to give methacryl- and azo-functionalized ATP, respectively. Subsequently, surface-initiated graft polymerization of MMA in a soap-free emulsion was performed to afford ATP/PMMA hybrids. Meanwhile, graft polymerizations on the surface of methacryl- and azo-functionalized ATP were carried out for comparison. The grafting of PMMA on the surface of ATP was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis (TGA). The crystal structure of hybrids was characterized by X-ray diffraction analysis. The morphology of hybrids was observed by scanning electron microscopy and transmission electron microscopy. The degree of grafting obtained from surface-initiated graft polymerization in a soap-free emulsion was found to be the greatest (29.4%) estimated from TGA. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41062. [ABSTRACT FROM AUTHOR]