Xubao Jiang

University of Jinan (Jinan, China), Chi-nan-shih, Shandong Sheng, China

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Publications (7)9.64 Total impact

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    ABSTRACT: Porous polyurea (PPU) is prepared through a simple protocol by reacting toluene diisocyanate (TDI) with water in binary solvent of water-acetone, and the process is optimized. Porosimetric test demonstrates that PPU possesses typical properties of porous materials. The structure of the material is characterized by Fourier transform infrared (FTIR), NMR (1H & 13C) and X-ray diffraction (XRD). FTIR analysis shows that TDI is full reacted. Microstructure analysis of PPU by NMR reveals that PPU is consisting of short polyurea chains with degree of polymerization about 15. The presence of crystallinity in PPU is confirmed by XRD, which shows three diffraction peaks, for which the corresponding chain conformations, based on interplanar spaces owing to different hydrogen-bonding, are depicted. TGA analysis demonstrates that PPU is of high thermal stability, and no degradation is seen before 270 °C. DSC test reveals that no obvious glass transition is observed owing to intensive hydrogen-bonding.
    RSC Advances 07/2014; · 3.71 Impact Factor
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    ABSTRACT: A novel type of hollow polymer particles, polyurea (PU) microspheres with uniform morphology, is prepared via precipitation polymerization of isophorone diisocyanate (IPDI) in acetone–H2O as the solvent in three steps. In the first step, IPDI reacts with H2O to form the core particles consisting of linear PU, followed, in the second step, by addition of triethylene tetramine (TETA) and supplementary IPDI; the microspheres of core–shell structure are therefore obtained with a shell consisting of crosslinked PU thanks to the copolymerization of TETA with IPDI. Hollow microspheres are finally obtained by dissolving the core template of linear PU. The influence of the amounts of TETA, IPDI and their molar ratio on the formation and the morphology of the core–shell and the hollow microspheres are studied. The morphologies of the core–shell and of the hollow microspheres are characterized by scanning electron microscopy. The polymers are examined using Fourier-transform infrared spectra, differential scanning calorimetry and thermogravimetric analysis.
    Polym. Chem. 11/2013; 4(24).
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    ABSTRACT: Uniform polymer microspheres with neat surface are of high interests. Precipitation polymerization of vinylic monomers remains a very limited process owing to very low monomer concentration allowed. Here, a fully novel protocol for the production of uniform polymeric microspheres is presented. Using one single monomer, isophorone diisocyanate, highly monodisperse polyurea microspheres were achieved with very high yield in a very short time period via precipitation polymerization in water–acetone mixed solvent. Results demonstrated that the ratio of water–acetone and polymerization temperature played important roles in the process. The size of the microspheres was readily adjustable by varying monomer concentration, water/acetone ratio or polymerization temperature. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
    Journal of Polymer Science Part A Polymer Chemistry 10/2011; 49(20). · 3.54 Impact Factor
  • Macromolecular Chemistry and Physics 09/2010; 211(20):2201 - 2210. · 2.39 Impact Factor
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    ABSTRACT: Cationic latexes based on styrene and butyl acrylate using cetyl trimethyl ammonium bromide (CTAB) as surfactant were carried out using both batch and semicontinuous emulsion polymerization. Monomer conversion, particle size and its distribution, ζ potential, latex surface tension were determined as function of CTAB levels. Evolutions of these properties were followed, and the results from batch compared to those from semicontinuous process. It was revealed that polymerization rate in batch process was enhanced with CTAB, and the polymerization rate was controlled by addition rate of the preemulsion in semicontinuous process. Molecular adsorption area of CTAB on latex particle surface was calculated, which showed clearly that ζ potential and surface tension in the latex were directly related with surfactant adsorption on the particle surface. The molecular surface adsorption area of CTAB on latex particle could be used to explain the evolution of latex properties such as ζ potential and latex surface tension.
    Polymer. 01/2009; 50(17):4220-4227.
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    ABSTRACT: Polyurethane–acrylic (PU–AC) hybrid latexes were prepared. Main monomers for PU preparation were isophorone diisocyanate, DMPA (dimethylol propanic acid) and polypropylene oxides (PPO) of different molecular weights. Acrylic monomers included butyl acrylate, methyl methacrylate and a crosslinker, trihydroxymethyl propane triacrylates (TMPTA). Several important ingredients in PU–AC latex preparation, such as surfactants, initiator, DMPA and PU/AC ratio, etc., were varied, and their effects on latex properties studied. Compared with surfactant free latexes, a sharp increase in particle size was observed in latexes done with 0.1% of surfactant regardless of the nature of the surfactants used (anionic, nonionic and anionic with long chain of amphiphilic alkylphenyl polyethoxylate). Further increase in surfactant content, however, led to latexes with smaller particle size and narrower particle size distribution when compared between latexes prepared using a same surfactant. When amount of the oil soluble initiator, azobisisobutyronitrile, was increased, AC monomers conversion was increased. It is interesting to observe that PPO with long propylene oxides brought about larger particle size combined with broader size distribution and less charge on particle surface; whereas lower DMPA levels led to latexes also of larger size combined with broader size distribution but more charges on particle surface. AC monomer crosslinker, TMPTA, contributed to reduce particle size, narrower size distribution and lower particle surface charges. By increasing AC amount in PU–AC latex, latex particle size significantly increased accompanied by a remarkable increase in particle surface charges. Mechanisms of particle formation and of DMPA stabilization were discussed in order to understand the experimental results.
    Progress in Organic Coatings - PROG ORG COATING. 01/2008; 62(3):251-257.
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    ABSTRACT: This paper presents a novel and facile route to preparation of highly uniform polymeric microspheres through a quiescent polymerization with the reactor standing still without any stirring. Using one single monomer, isophorone diisocyanate (IPDI), highly uniform polyurea microspheres are achieved with high yield via precipitation polymerization of IPDI with water in water–acetone mixed solvent. Full conversion of IPDI to polymer is readily achieved thanks to the step polymerization mechanism involved. The monomer concentration can go up to 11 wt.% with the polymerization accomplished within 2 h, with a much higher yield of microspheres in a much shorter time than those reported with vinyl monomers. The size of the microspheres is adjustable by changing IPDI concentration, acetone/H2O ratio in the solvent or polymerization temperature. Without need of any stirring or shaking during the polymerization, the protocol renders the fabrication of uniform microspheres more practical and economical, particularly for large scaled production.
    Chemical Engineering Journal. 213:214–217.