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

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.

Single-chain folding via intramolecular noncovalent interaction is regarded as a facile mimicry of biomacromolecules. Single-chain folding and intramolecular crosslinking is also an effective method to prepare polymer nanoparticles. In this study, poly(methyl methacrylate-co−2-ureido-5-deazapterines functionalized ethylene methacrylate) (P(MMA-co-EMA-DeAP)) is synthesized via free radical polymerization. The single-chain folding of P(MMA-co-EMA-DeAP) and the formation of the nanoparticles in diluted solution (concentration <0.005 mg/mL) are achieved via supramolecular interaction and intramolecular collapsing during the disruption-reformation process of the hydrogen bonding triggered by water. The size and the morphology of the nanoparticles are characterized by dynamic light scattering, transmission electron microscope, and atomic force microscope. The results show that the size of the nanoparticles depends on the molecular weight of the polymer and the loading of 2-ureido-5-deazapterines functionalized ethylene methacrylate (EMA-DeAP) on the polymer backbone. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1832–1840

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.

Amphoteric polymers have been studied for various applications such as separation of low molecular weight organic molecules from inorganic salt mixtures, selective ion transport, drug delivery through membranes of biological interest, separation of ionic drugs and proteins, and separation of alcohol and water. Typical amphoteric polymers consist of weak base and weak acid groups. In present study, the copolymerization of 5-vinyltetrazole (VT) and diisopropyl-p-vinylbenzyl phosphate (DIPVBP) via free radical polymerization is studied. The reactivity ratio of VT and DIPVBP, which is calculated from Kelen-Tudos plot, is 0.251 and 0.345, respectively. The amphoteric copolymer of VT and diisopropyl-p-vinylbenzyl phosphonic acid (poly(VT-co-VBPA)) is obtained from hydrolysis of the copolymer of VT and DIPVBP (poly(VT-co-DIPVBP)). Poly(VT-co-VBPA) is thermally stable under 190 °C. The anhydrous proton conductivity of amphoteric poly(VT-co-VBPA) can reach 1.54 × 10^-4 S cm⁻¹ at 170 °C with an activation energy of 114.7 kJ mol⁻¹. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3486–3493

Poly(N-methyl-5-vinyltetrazole-co-5-vinyltetrazole) (P(MVT-VT)) with different N-methyl-5-vinyltetrazole (MVT) contents was synthesized via the method of click chemistry and the methylation thereafter. The chemical structure of the copolymers was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). Compared with that of poly(5-vinyltetrazole) (PVT), the solubility of P(MVT-VT) is improved. The chemical oxidation stability of the copolymer increases with increasing substitution value of the methyl group on the tetrazole ring. H₃PO₄ and imidazole (Imi) blended PVT and P(MVT-VT) composite membranes were prepared. The proton conductivity of P(MVT-VT)/H₃PO₄ and P(MVT-VT)/Imi composite membranes decreases with increasing MVT content. After the methylation of the tetrazole ring, the amphoteric properties of P(MVT-VT) is improved, which means either acid or base blended P(MVT-VT) can exhibit suitable proton conductivity. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

Controlled intramolecular collapse of linear polymer chains with crosslinkable groups is an efficient way to prepare single-chain nanoparticles in the size range of 5–20 nm. However, the nature of the crosslinking group is critical. In present study, poly(styrene-co-chloromethyl styrene) [P(St-co-CMS)] was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization and then was converted into polystyrene azide (PSN₃). Polystyrene containing benzoxazine side groups [P(St-co-BS)], which can be used as the precusor for the later intramolecular collapse, was obtained from PSN₃ and 3-(4-(prop-2-ynyloxy)phenyl)-3,4-dihydro-2H-benzo[e][1,3]oxazine (P-APPE) via the method of click chemistry. The sub-20 nm polymeric nanoparticles with well-defined structure via thermally intramolecular crosslinking of P(St-co-BS) were prepared. The structure change from the linear polymers to the single-chain nanoparticles was confirmed by nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), and gel permeation chromatography (GPC). The morphology and the dimension of the nanoparticles were characterized by using transmission electron microscope (TEM), atomic force microscopy (AFM), as well as dynamic light scattering (DLS). The results reveal that the size of the nanoparticles can be regulated by changing the molecular weight of the precursors and the amount of pendant benzoxazine groups by the use of controlled polymerization techniques. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Two new kinds of fluorine-containing polybenzimidazoles (PBI), poly(2,2′-(tetrafluoro-p-phenylene)-5,5′-bibenzimidazole) and poly(2,2′-tetradecafluoroheptylene-5,5′-bibenzimidazole), were synthesized by condensation polymerization of 3,3′-diaminobenzidine and perfluoroterephthalic acid (or perfluoroazelaic acid), with polyphosphoric acid as solvent. Thermogravimetric analysis results show that the fluorine-containing polymers synthesized exhibit promising thermal stability. The film-forming properties of the fluorine-containing polymers are improved over nonfluorinated PBI. The introduction of fluorine into the backbone of the polymers has significant positive affection on their chemical oxidation stability demonstrated by Fenton test. Compared with poly(2,2′-(m-phenylene)-5,5′-bibenzimidazole)/phosphoric acid (PA) composite membrane, the resulting fluorinated membranes with a same PA doping level exhibit better flexibility and higher proton conductivity. The maximum proton conductivity gained is 3.05 × 10⁻² S/cm at 150 °C with a PA doping level of 7. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2115–2122, 2010