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Juan Zhang

Bio: Juan Zhang is an academic researcher from Sichuan University. The author has contributed to research in topics: Solution polymerization & Polymerization. The author has an hindex of 2, co-authored 5 publications receiving 28 citations.

Papers
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Journal ArticleDOI
Zheng Yi1, Kai Pan1, Long Jiang1, Juan Zhang1, Yi Dan1 
TL;DR: Xylene/N,N-dimethylformamide (DMF) and xylene/ethanol were employed as mixed solvents, respectively, for the reverse atom transfer radical polymerization (R-ATRP) of styrene with the azobisisobutyronitrile (AIBN)/CuBr2/N.

13 citations

Journal ArticleDOI
TL;DR: In this article, a series of copper-based reverse atom transfer radical polymerizations (ATRP) were carried out for methyl methacrylate (MMA) at same conditions (in xylene, at 80°C) using N,N,N′, N′-teramethylethylendiamine (TMEDA), N, N, n′,N-N′-N-pentamethyldiethylentriamine (PMDETA), 2-2′-bipyridine, and 4,4′-Di(
Abstract: A series of copper-based reverse atom transfer radical polymerizations (ATRP) were carried out for methyl methacrylate (MMA) at same conditions (in xylene, at 80°C) using N,N,N′,N′-teramethylethylendiamine (TMEDA), N,N,N′,N′,N′-pentamethyldiethylentriamine (PMDETA), 2-2′-bipyridine, and 4,4′-Di(5-nonyl)-2,2′-bipyridine as ligand, respectively. 2,2′-azobis(isobutyronitrile) (AIBN) was used as initiator. In CuBr2/bpy system, the polymerization is uncontrolled, because of the poor solubility of CuBr2/bpy complex in organic phase. But in other three systems, the polymerizations represent controlled. Especially in CuBr2/dNbpy system, the number-average molecular weight increases linearly with monomer conversion from 4280 up to 14,700. During the whole polymerization, the polydispersities are quite low (in the range 1.07–1.10). The different results obtained from the four systems are due to the differences of ligands. From the point of molecular structure of ligands, it is very important to analyze deeply the two relations between (1) ligand and complex and (2) complex and polymerization. The different results obtained were discussed based on the steric effect and valence bond theory. The results can help us deep to understand the mechanism of ATRP. The presence of the bromine atoms as end groups of the poly(methyl methacrylate) (PMMA) obtained was determined by 1H-NMR spectroscopy. PMMA obtained could be used as macroinitiator to process chain-extension reaction or block copolymerization reaction via a conventional ATRP process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

12 citations

Journal ArticleDOI
Juan Zhang1, Kai Pan1, Long Jiang1, Zheng Yi1, Yi Dan1 
TL;DR: In this article, the controllability of atom transfer radical polymerization of methyl methacrylate in the polar solvent N,N-dimethylformamide and the nonpolar solvent xylene with 4-(chloromethyl)phenyltrimethoxysilane as an initiator and with CuCl/2,2′-bipyridine and CuCl 4,4′-di(5-nonyl)-2, 2.2
Abstract: The controllability of the atom transfer radical polymerization of methyl methacrylate in the polar solvent N,N-dimethylformamide and the nonpolar solvent xylene with 4-(chloromethyl)phenyltrimethoxysilane as an initiator and with CuCl/2,2′-bipyridine and CuCl/4,4′-di(5-nonyl)-2,2′-bipyridine as catalyst systems was studied. Gel permeation chromatography analysis established that in the nonpolar solvent xylene, much better control of the molecular weight and polydispersity of poly(methyl methacrylate) was achieved with the CuCl/4,4′-di(5-nonyl)-2,2′-bipyridine catalyst system than with the CuCl/2,2′-bipyridine as catalyst system. In the polar solvent N,N-dimethylformamide, unlike in xylene, the polymerization was more controllable with the CuCl/2,2′-bipyridine catalyst system than with the CuCl/4,4′-di(5-nonyl)-2,2′-bipyridine catalyst system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2751–2754, 2007

2 citations

Journal ArticleDOI
TL;DR: In this article, the mass ratio of CaCO 3 /SiO 2 two-component composite particles to methyl methacrylate (MMA) was studied in detail, and the results showed that increasing the mass ratios of the two components will decrease the overall rate of polymerization under standard reverse ATRP conditions.
Abstract: We previously discovered that structurally well-defined polymer/inorganic composite particles, i.e., poly(methyl methacrylate) (PMMA)/CaCO 3 /SiO 2 three-component composite particles, can be achieved via reverse atom transfer radical polymerization (ATRP), using 2,2'-azo-bis-isobutyronitrile as initiator and Cu I I bromide as catalyst. In the present study, the influence of the mass ratio of CaCO 3 /SiO 2 two-component composite particles to methyl methacrylate (MMA) on the rate and behavior of the polymerization was studied in detail. The results illustrate that increasing the mass ratio of CaCO 3 /SiO 2 two-component composite particles will decrease the overall rate of polymerization of MMA under standard reverse ATRP conditions. Thermal properties of the obtained well-defined particles were characterized and determined by thermogravimetric analysis (TGA). The results indicate that well-defined PMMA chains grafted on the surface of CaCO 3 /SiO 2 particles were only degraded by random chain scission of C-C linkages within the PMMA chain, which is different from the degradation of PMMA chains prepared via traditional radical polymerization. This difference is reasonably ascribed to the difference between the end groups of PMMA prepared via reverse ATRP and that via traditional radical polymerization, which has been confirmed by end group analysis measured by 1 H-NMR spectroscopy.

2 citations

Journal ArticleDOI
TL;DR: In this paper, the reverse atom transfer radical polymerization of methyl methacrylate was investigated in different solvents: xylene, N,N-dimethylformamide, and pyridine.
Abstract: The reverse atom transfer radical polymerization of methyl methacrylate was investigated in different solvents: xylene, N,N-dimethylformamide, and pyridine. The polymerizations were uncontrolled, using 2,2′-bipyridine as a ligand in xylene and pyridine because the catalyst (CuBr2/2,2′-bipyridine complex) had poor solubility in the xylene system. In the pyridine system, the solubility of the catalyst increased, but the solvent could complex with CuBr2, which influenced the control of the polymerization. In the N,N-dimethylformamide system, the catalyst could be dissolved in the solvent completely, but the N(CH3)2 group in N,N-dimethylformamide could also complex with CuBr2, so the polymerization could not be well controlled. The ligand of 4,4′-di(5-nonyl)-2,2′-bipyridine was also investigated in xylene; the introduction of the CH(C4H9)2 group enabled the CuBr2/4,4′-di(5-nonyl)-2,2′-bipyridine complex to easily dissolve in xylene, and the polymerizations were well controlled. The number-average molecular weight increased linearly with the monomer conversion from 4280 to 14,700. During the whole polymerization, the polydispersities were quite low (1.07–1.10). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

2 citations


Cited by
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Journal ArticleDOI
TL;DR: The reaction solvent in surfaces-initiated ATRP affected the grafting configuration of PIPAAm on porous silica-bead surfaces, leading to the different separation efficiency of stationary phase for bioactive compounds.

44 citations

Journal ArticleDOI
TL;DR: In this paper, a general method for tuning the dispersity of polymers synthesized via atom transfer radical polymerization (ATRP) was described, and it was shown that adding varying amounts of phenylhydrazine (PH) to the ATRP of tert-butyl acrylate led to significant deviations in the reaction kinetics.

37 citations

Journal ArticleDOI
TL;DR: In this article, the structural chemistry of copper(I) and copper(II) with a range of multidentate N-donor ligands employed in atom transfer radical polymerisation (ATRP) is illustrated and discussed in the context of both its solid state and solution structures.

27 citations

Journal ArticleDOI
TL;DR: In this paper, mesoporous diatomite platelets were used for in situ polymerization of methyl methacrylate by RATRP to synthesize tailor-made poly (methyl methcrylate) nanocomposites.
Abstract: Mesoporous diatomite was employed to synthesize different poly (methyl methacrylate)/diatomite composites. Diatomite platelets were used for in situ polymerization of methyl methacrylate by RATRP to synthesize tailor-made poly (methyl methacrylate) nanocomposites. FTIR spectroscopy, TGA, nitrogen adsorption/desorption isotherm, SEM, and TEM were employed for evaluating some inherent properties of pristine diatomite platelets. Conversion and molecular weight determinations were carried out using GC and SEC, respectively. Addition of 3 wt% pristine mesoporous diatomite leads to increase of conversion from 84 to 95%. Molecular weight of poly (methyl methacrylate) chains increases from 8600 to 9400 g mol−1 by addition of 3 wt% pristine mesoporous diatomite; however, polydispersity index values increase from 1.34 to 1.54. Increasing thermal stability of the nanocomposites is demonstrated by TGA. Differential scanning calorimetry shows an increase in glass transition temperature from 75.8 to 81.1 °C by adding 3 wt% of mesoporous diatomite platelets.

20 citations

Journal ArticleDOI
TL;DR: In this paper, the atom transfer radical polymerization (ATRP) of n-butyl acrylate (nBA) using initiators for continuous activator regeneration (ICAR) was successfully carried out in ionic liquid in the presence of a catalyst system of FeCl3·6H2O/succinic acid using 2-bromoisobutyrate as the initiator and 2,2′-azobisisobutyronitrile as the reducing agent.
Abstract: The atom transfer radical polymerization (ATRP) of n-butyl acrylate (nBA) using initiators for continuous activator regeneration (ICAR) was successfully carried out in ionic liquid in the presence of a catalyst system of FeCl3·6H2O/succinic acid using 2-bromoisobutyrate as the initiator and 2,2′-azobisisobutyronitrile as the reducing agent. The ICAR ATRP of nBA was proved a ‘living’/controlled polymerization such as a linear increase of molecular weights of polymers with monomer conversion and relatively narrow polydispersities (<1.25) when the conversion was beyond 30% and its kinetics in this system was investigated. The polymerization rate increased with temperature and the apparent activation energy was calculated to be 32.84 kJ mol−1. The chain extension experiment was carried out to confirm the controlled manner of the polymerization system. The resultant was characterized by nuclear magnetic resonance and gel permeation chromatography.

17 citations