Co-reporter:Chenting Cai;Zhihua Xu;Xiling Niu;Lunguo Kang;Zhendong Zhang
Industrial & Engineering Chemistry Research October 30, 2013 Volume 52(Issue 43) pp:15124-15130
Publication Date(Web):2017-2-22
DOI:10.1021/ie402557r
In this experiment, silicon oxide groups (SixOy(OH)z) and carbon–carbon double bonds (C═C) were introduced onto the PA molecular chains. In the first step, acrylic resins (PA), grafted by organosilicon groups, were prepared by solution polymerization. In the second step, UV curable SixOy(OH)z/PA aqueous dispersions, with a high silicon content, were prepared by hydrolyzation and condensation of PA and silane coupling agents (KH-570). Aqueous dispersions possess certain stability when the KH-570 consumption ranges from 0 wt % to 30.0 wt %. With increased content of C═C, the water absorption of UV cured SixOy(OH)z/PA aqueous dispersion films soaked in the water for 24 h was decreased from 78% to 0%. Furthermore, heat curing further improved the water tolerance of the UV cured aqueous dispersion films. The water absorption change of the films caused by heat curing could reach up to 17%.
Co-reporter:Xiling Niu, Lixia Huo, Chenting Cai, Jinshan Guo, and Hui Zhou
Industrial & Engineering Chemistry Research 2014 Volume 53(Issue 42) pp:16359-16365
Publication Date(Web):2017-2-22
DOI:10.1021/ie502869c
To improve the dispersion stability of attapulgite (ATT) in epoxy (EP), acrylic resin (AC) containing trimethoxysilyl and carboxyl was employed to form a covalent link between attapulgite and epoxy. The rod-like attapulgite was first efficiently activated by means of removing the adsorbed water to release the structural channels under reflux and subsequently functionalized by the bifunctional acrylic resin obtaining grafting efficiency as high as 11 wt %. The improvement of the hydrophobic nature of attapulgite was demonstrated by the fact that the contact angle of organically modified attapulgite (108.6°) was much higher than that of the pristine attapulgite (29.9°). Modified attapulgite exhibited homogeneous dispersion in epoxy matrix in forms of monodispersion or agglomeration by several nanorods. Compared to pristine epoxy, AC-ATT/EP nanocomposites containing only 3 wt % AC-ATT exhibited a significantly increase of 128.9% in storage modulus. In addition, the nanocomposites exhibited remarkable enhancement in the impact strength, Young’s modulus, and the tensile strength relative to the pristine epoxy.
Co-reporter:Zhengfeng Ma;Xiling Niu;Zhihua Xu
Journal of Applied Polymer Science 2014 Volume 131( Issue 11) pp:
Publication Date(Web):
DOI:10.1002/app.40352
ABSTRACT
A new kind of macrophotoinitiator (MPI) was synthesized through the copolymerization of acrylic monomers and the polymerizable photoinitiator monomer 2959-AA. Monomer 2959-AA was obtained by an esterification reaction between acrylic acid (AA) and the water-soluble photoinitiator Irgacure 2959 [2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone]. By adjusting the monomer proportions in the MPIs, two series of MPIs with different 2959-AA contents and different glass transition temperatures were obtained. The molecular structure of 2959-AA was characterized by Fourier-transform infrared spectroscopy, nuclear magnetic spectrometry, and mass spectrometry. Polymerization of 1, 6-hexanediol diacrylate was initiated using Irgacure 2959 and 2959-AA, and two series of MPIs to be polymerized were studied with a photo-DSC test. Results showed that 2959-AA had higher chemical reactivity than Irgacure 2959 because of the higher solubility of the former. It was evident from the experiments that 2959-AA content in the MPI progressively increased the polymerization rate and monomer conversion when the glass transition temperatures of MPIs were similar. At the same 2959-AA content, the polymerization rate slightly slowed down with increased glass transition temperature. However, the radical lifetime and polymerization time were prolonged. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40352.
Co-reporter:Lihui Zhang;Limin Zang;Hong Zhang
Iranian Polymer Journal 2013 Volume 22( Issue 2) pp:93-100
Publication Date(Web):2013 February
DOI:10.1007/s13726-012-0107-1
A core–shell structure of fluorine-containing polyacrylate latex was synthesized by UV-initiated two-stage microemulsion polymerization from styrene (St) and hexafluorobutyl acrylate (HFA) in the presence of Irgacure 2959 as hydrophilic photoinitiator at room temperature. The first polymerization stage took 12 min and the second stage took 10 min. The conversions of the first and the second polymerization stages were about 60 and 85 %, respectively. Fourier transform infrared (FTIR) spectra, transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and contact angle analysis were used to characterize the properties of latexes and their films. The DLS analysis results indicated that the size of the fluorine-containing nanoparticle is about 20 nm. The TEM photos showed that the particles have core–shell structure and some of the cores are located in the center and the others deviate from the center of particles. From the FTIR and XPS results, we can infer that the fluorine monomer could be introduced into the copolymer and the fluorine-containing polyacrylate mainly occupies the shell part. The TGA results indicated that the fluorine-containing polyacrylate copolymers exhibited higher thermal stability than that of the fluorine-free one. The contact angle analysis results showed that fluorine monomers make the film surface more hydrophobic.
Co-reporter:Lihui Zhang, Hong Zhang, and Jinshan Guo
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 25) pp:8434-8441
Publication Date(Web):June 5, 2012
DOI:10.1021/ie3000248
In this study, environmentally friendly UV-curable polyester-based waterborne polyurethane (WPU)/functionalized silica nanocomposites were successfully prepared. The functionalized silica was combined with WPU by chemical bonds and existed as effective cross-link points to form composites. Because of the existence of organic molecule chains from the functionalized silica, the compatibility of WPU with silica was improved obviously. This makes the composite latex possesses certain stability when the silica content rose up to 17.5 wt %. The composite latex particles kept the structure where the functionalized silica was covered by WPU during the film formation process, which could greatly decrease the aggregation of silica. What’s more, the existence of functionalized silica improved thermo-stability, hardness, and water resistance of composite films effectively and the composite films possessed good transparency.
Co-reporter:Limin Zang;Jiahe Luo ;Hong Zhang
Polymers for Advanced Technologies 2012 Volume 23( Issue 1) pp:15-20
Publication Date(Web):
DOI:10.1002/pat.1819
Abstract
A core–shell fluorine-containing polyacrylate emulsion was successfully prepared by UV-initiated seeded emulsion polymerization in two stages in the presence of two photoinitiators. The water-soluble photoinitiator for the core polymerization and the oil-soluble photoinitiator was used for the shell polymerization. Both of the two stage polymerizations could be completed within 15 min and displayed a conversion above 94%. The emulsion and the films were characterized by Fourier transformed infrared spectrometry, transmission electron microscopy, dynamic light scattering, X-ray photoelectron spectroscopy (XPS), contact angle (CA), and thermogravimetry analysis, respectively. The analysis results indicated that the fluorine-containing latex particles had very small particle size (40 nm) with a core–shell structure and a narrow particle size distribution. XPS analysis revealed that a gradient concentration of fluorine excited in fluorine-containing emulsion film from the film–air interface to the film–glass interface. In addition, the film formed from the fluorine-containing emulsion exhibited not only higher thermal stability but also better hydrophobicity than that of the fluorine-free emulsion. Copyright © 2010 John Wiley & Sons, Ltd.
Co-reporter:Fei Chen, Fengying Ye, Guangcheng Chu, Jinshan Guo, Lixia Huo
Progress in Organic Coatings 2010 Volume 67(Issue 1) pp:60-65
Publication Date(Web):January 2010
DOI:10.1016/j.porgcoat.2009.09.014
With acrylic acid, butyl acrylate and methyl methacrylate as the monomers, acrylate modified vinyl chloride and vinyl isobutyl ether copolymers were prepared by solution polymerization. Firstly, vinyl chloride and vinyl isobutyl ether copolymers were grafted with acrylic monomers to obtain a product containing acrylate grafted vinyl chloride and vinyl isobutyl ether copolymers and polyacrylate, which was then neutralized by triethylamine and dispersed into water to get a self-emulsified emulsion. The acrylate modified vinyl chloride and vinyl isobutyl ether copolymers were characterized by Fourier transform infrared spectroscopy. The mean molecular weight of grafted polymer was determined by gel permeation chromatography, and the particle sizes and their distributions of the dispersions were measured by laser light scattering. The influences of initiator concentration, acrylate content, acrylic acid content and neutralization degree upon the properties of the modified copolymers were discussed. The results show that the emulsion will be with good storage stability, and the modified polymer will be with high water resistance, impact resistance and excellent adhesion when initiator concentration is 1.5%, acrylate content is 50%, acrylic acid content ranges from 9% to 11%, and neutralization degree is between 80% and 100%.
Co-reporter:Limin Zang;Jiahe Luo;Hangong Liu;Jing Ru
Polymer Bulletin 2010 Volume 65( Issue 7) pp:669-680
Publication Date(Web):2010 October
DOI:10.1007/s00289-009-0241-x
Vermiculite (VMT) was readily intercalated by hexadecyl trimethyl ammonium bromide to yield organo-vermiculite (OVMT), which was confirmed by X-ray diffraction measurement and Fourier transform infrared spectroscopy. Poly(ethylene glycol)/organo-vermiculite (PEG/OVMT) nanocomposites were prepared by using the direct melt intercalation method, and its intercalation state was confirmed by transmission electron microscope. Thereafter, a lithium salt was dissolved in the PEG/OVMT nanocomposites to prepare composite polymer electrolytes. The highest conductivity was 2.1 × 10−5 S cm−1 at room temperature, which was obtained by AC impedance analysis when the amount of OVMT based on PEG was 1 wt%.
Co-reporter:Zhaobin Tang;Peng Liu;Zhixing Su
Polymer International 2009 Volume 58( Issue 5) pp:552-556
Publication Date(Web):
DOI:10.1002/pi.2566
Abstract
BACKGROUND: Recently, conducting polymers have attracted much attention, since they have interesting physical properties and many potential applications, such as in conductive coating charge storage. Hence the synthesis of conducting polymer nanocomposites is also an area of increasing research activity.
RESULTS: Vermiculites (VMTs) were successfully delaminated using an acid treatment. Polyaniline (PANI)/VMT nanocomposites were prepared by in situ chemical oxidative grafting polymerization.
CONCLUSION: The chemical grafting of PANI/VMTs was confirmed by Fourier transform infrared and UV-visible spectroscopy. The percentage of grafted PANI was 142.7 wt% as a mass ratio of the grafting PANI and charged nano-VMTs, investigated using thermogravimetric analysis. In addition, characteristic agglomerate morphology of PANI was observed in the composites using scanning electron microscopy. Thermal analyses indicated that the introduction of VMT nanosheets had a beneficial effect on the thermal stability of PANI. The electrical conductivity of the nanocomposites was 3.9 × 10−3 S cm−1, a value typical for semiconductors. Copyright © 2009 Society of Chemical Industry
Co-reporter:Zhaobin Tang;Peng Liu;Zhixing Su
Polymer Composites 2009 Volume 30( Issue 4) pp:445-450
Publication Date(Web):
DOI:10.1002/pc.20575
Abstract
The polyhydroxyurethane/silica nanocomposite (PHU/SN) was prepared by the in situ surface-initiated polymerization of a five-membered cyclic carbonate, 2,2-bis[p-(1,3-dioxolan-2-one-4-yl-methoxy)phenyl]propane (B5CC) and hexamethylene diamine, from the surfaces of the aminopropyl silica nanoparticles (APSN) for the first time. The percentage of grafting (PG%) and the grafting efficiency (GE%) of 27% and 19% were calculated from the results of thermogravimetric analysis (TGA), respectively, after the free polyhydroxyurethane was washed off. The chemical grafting of the polymer was also confirmed using Fourier transform infrared (FTIR) and the morphology of the silica nanoparticles in the nanocomposite was characterized by transmission electron microscope (TEM). POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Co-reporter:Zhaobin Tang, Dan Lu, Jinshan Guo, Zhixing Su
Materials Letters 2008 Volume 62(Issue 26) pp:4223-4225
Publication Date(Web):15 October 2008
DOI:10.1016/j.matlet.2008.06.044
Serials of vermiculites/polystyrene (VMTs/PS) nanocomposites with different contents of organo-modified vermiculites (organo-VMTs) were successfully prepared by the in-situ bulk polymerization of styrene with the organo-VMTs as macromonomers. The thermogravimetric analysis TGA results showed that the thermal stabilities of the VMTs/PS nanocomposites prepared via the bulk polymerization were better than the pure polystyrene. And the maximum thermal degradation temperature of the nanocomposites increased with the increasing of the amount of the VMTs fillers added. The polymer grafted nanoparticles had lower thermal stabilities than the pure polystyrene because of the lower molecular weight of the grafted polymers. This also showed that the crosslink reactions occurred in the grafted polystyrene chains.
