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Wu J.,Taiyuan University of Technology | Wu J.,Shanxi Research Institute of Applied Chemistry | Ma G.,Shanxi Research Institute of Applied Chemistry | Ling L.,Taiyuan University of Technology | Wang B.,Taiyuan University of Technology
Polymer Bulletin | Year: 2015

The nanosilica is first treated with 3-mercaptopropyl trimethoxysilane (MPTMS) to introduce mercapto groups as growth points, and then hyperbranched polymer is grafted on the nanosilica surface via repeated step of thiol-ene click reaction between the acrylate double bond of trimethylolpropane triacrylate (TMPTA) and mercapto groups of trimethylolpropane tris 3-mercaptopropionate (Trithiol). FTIR results confirm that the grafting procedure is feasible, and TGA results indicate the grafting ratio is as high as 45.0 %. The curing kinetic, monitored by photo-DSC, shows that both terminal acrylate double bonds and mercapto groups can accelerate the curing speed of the UV-curing organic–inorganic hybrid coatings. The mechanical and physical properties of UV-curable hybrid coatings containing modified nanosilica at different generations are also investigated. © 2015 Springer-Verlag Berlin Heidelberg


Wu J.,Taiyuan University of Technology | Wu J.,Shanxi Research Institute of Applied Chemistry | Xie J.,Taiyuan University of Technology | Ling L.,Taiyuan University of Technology | And 2 more authors.
Journal of Coatings Technology Research | Year: 2013

This paper describes surface modification of commercial nanosilica with 3-mercaptopropyl trimethoxysilane (MPTMS) and its effect on the properties of UV curable coatings. The mercapto groups were grafted onto nanosilica surface by a condensation of the surface Si-OH with the hydrolysized Si-OH of MPTMS. Fourier transform infrared spectroscopy, thermal gravimetric analysis, and particle size distribution were employed to characterize nanosilica and modified nanosilica. It was demonstrated that the mercapto groups were successfully grafted onto the nanosilica surface with the grafting ratio of 16.8% and the mercapto groups content of 0.9 mmol/g. The dispersion and self-aggregation of nanosilica in UV curable coatings were improved significantly. The photopolymerization kinetics of UV curable coatings, containing various amounts of nanosilica and modified nanosilica, were evaluated by the photo differential scanning calorimetry technique. This indicated that nanosilica both before and after modification decreased UV curing speed and ultimate percentage conversion; however, in comparison with the coatings containing unmodified nanosilica, the coatings containing modified nanosilica exhibited higher curing speeds and conversion ratios. It can be ascribed that the mercapto groups on the nanosilica surface reduced oxygen inhibition during the UV curing process via the thiol-ene click reaction. The mechanical properties of UV curable coatings were also compared. © 2013 American Coatings Association & Oil and Colour Chemists' Association.


Ma G.,Shanxi Research Institute of Applied Chemistry | Zhang T.,Shanxi Research Institute of Applied Chemistry | Zhang T.,Taiyuan University of Technology | Wu J.,Shanxi Research Institute of Applied Chemistry | And 4 more authors.
Journal of Applied Polymer Science | Year: 2013

Tung oil modified rosins (TR) were prepared by reaction rosin with different amount of tung oil via Diels-Alder addition reaction and further used in the formulation of glycerin ester of tung oil modified rosins (GTR) with flexible characteristics. The effects of the amount of tung oil on the bromine value, molecular weight, thermostability, physical, and tackifying properties of GTRs were studied. The results showed that the bromine value of GTRs decreased and molecular weight of GTRs increased with the increase in the amount of tung oil. Meanwhile, increasing the amount of tung oil resulted in a significant decrease in both the softening points and viscosities of GTRs, but a slight increase in the thermostability of GTRs due to the incorporation of the flexible fatty chains into the rigid hydrophenanthrene units in rosins. Applied in PU adhesive as tackifier, the increase of the flexible chains content in GTRs led to an increase first and then decrease in both the miscibility of GTRs with PU and the T-peel strength of adhesives. The elongation at break of films increased monotonously, but their tensile strengths increased first and then decreased with increasing the flexible chains content in GTRs. GTRs with desired properties were prepared when the tung oil/rosin weight ratios were in the range from10/100 to 40/100. © 2013 Wiley Periodicals, Inc.


Wu J.,Taiyuan University of Technology | Wu J.,Shanxi Research Institute of Applied Chemistry | Zhang T.,Taiyuan University of Technology | Zhang T.,Shanxi Research Institute of Applied Chemistry | And 4 more authors.
Journal of Applied Polymer Science | Year: 2013

A Diels-Alder adduct of rosin with tung oil was effectively prepared for use as a filler and adhesion promoter in UV-curable adhesives. The characteristics of the adduct were analyzed by Fourier transform infrared (FTIR) spectroscopy and ultraviolet-visible (UV-vis) absorption spectra. The reaction mechanism was studied with gel permeation chromatography, thermogravimetric analysis, 1H-NMR, and the density functional theoretical method. The FTIR and 1H-NMR results showed that the Diels-Alder addition occurred between the rosin and tung oil. The still-existing characteristic peaks of the conjugated diene in the adduct, as shown in the FTIR and UV-vis absorption spectra, indicated that the most favorable reaction between the rosin and tung oil was when the rosin was used as the conjugated diene and the tung oil was used as the dienophile. The molecular weights of the adduct with different molar ratios showed that the most possible addition molar ratio between the rosin and tung oil was 3:1. The favorable addition mechanism was further proved by a comparison of the relative energies of different isomers of the adduct with theoretical calculation, and the most stable structure of adduct showed that the addition position of tung oil was the terminal C=C double bond. The properties analysis indicated that the adduct could improve the adhesion of UV-curable adhesives and reduce the curing shrinkage rate. Copyright © 2013 Wiley Periodicals, Inc.


Wu J.,Taiyuan University of Technology | Wu J.,Shanxi Research Institute of Applied Chemistry | Ma G.,Shanxi Research Institute of Applied Chemistry | Li P.,Shanxi Research Institute of Applied Chemistry | And 2 more authors.
Journal of Coatings Technology Research | Year: 2014

In order to improve the dispersion of nanosilica and the mechanical properties of UV-curable coating, nanosilica was modified with acrylsilane-containing tertiary amine structure, which was synthesized by the Michael addition reaction between 3-aminopropyl triethoxysilane and tripropylene glycol diacrylate. The prepared acrylsilane was characterized by 1H NMR, 13C NMR, and FTIR. The modified nanosilica was characterized by FTIR, TGA, and SEM. The TGA analysis showed that the grafting percentage of acrylsilane based on nanosilica was 72.4 wt%. The SEM results showed that the agglomeration of nanosilica was reduced and the dispersion was improved due to the acrylsilane modification. The viscosities of UV-curable coatings with modified nanosilica were determined and it was found that the viscosities of the coatings decreased in comparison with the viscosities of coatings with unmodified nanosilica. The photo-DSC results indicated that both nanosilica and modified nanosilica also decreased the UV-curing speed and final percentage conversion, while the conversion of the coatings containing modified nanosilica was faster than that with unmodified nanosilica owing to the tertiary amine structure and acrylate structure on the surface of the modified nanosilica. © 2014 American Coatings Association & Oil and Colour Chemists' Association.


Wu J.,Taiyuan University of Technology | Wu J.,Shanxi Research Institute of Applied Chemistry | Ling L.,Taiyuan University of Technology | Ma G.,Shanxi Research Institute of Applied Chemistry | Wang B.,Taiyuan University of Technology
Journal of Coatings Technology Research | Year: 2014

Nanosilica was modified and functionalized with acrylsilane by the "grafting to" method via different grafting steps, i.e., prepared-grafting step and step-wise propagation. The prepared-grafting step was achieved by grafting the nanosilica surface with the prepared acrylsilane, which was obtained by thiol-ene click reaction between 3-mercaptopropyl trimethoxysilane (MPTMS) and trimethylolpropane triacrylate (TMPTA). The step-wise propagation was achieved by first grafting MPTMS onto the nanosilica surface and then using the mercapto groups as initiators to react with TMPTA. The acrylsilane was characterized by FTIR. The modified nanosilica was characterized by FTIR, TGA, and contact angle analysis. It was demonstrated that the thiol-ene click reaction can easily occur between MPTMS and TMPTA. The grafting ratio of modified nanosilica via prepared-grafting step was higher than that of step-wise propagation. The SEM images of fractured films containing modified nanosilica also indicated that the former is more effective than the latter in reducing the self-aggregation of nanosilica. The effects of modified nanosilica on the viscosity and hardness of UV-curable coatings were also investigated. © 2014 American Coatings Association.


Wu J.,Taiyuan University of Technology | Wu J.,Shanxi Research Institute of Applied Chemistry | Ling L.,Taiyuan University of Technology | Xie J.,Taiyuan University of Technology | And 2 more authors.
Chemical Physics Letters | Year: 2014

Surface modification of nanosilica with 3-mercaptopropyl trimethoxysilane (MPTMS) has been investigated. FTIR, TGA, CA, 29Si NMR and DFT method have been applied to study the interaction between nanosilica and MPTMS. The results show that the organic functional groups are successfully grafted onto the nanosilica surface and the grafting ratio firstly increases and then decreases with the increasing MPTMS. In addition, four different grafting modes between nanosilica surface and MPTMS have been studied by DFT method. It indicated that the favorable grafting structures are mono-, di-grafting mode when the MPTMS is lower and ladder-like grafting mode when the MPTMS is higher. © 2013 Elsevier B.V. All rights reserved.


Wang G.,Shanxi Research Institute of Applied Chemistry | Wang G.,Taiyuan University of Technology | Ma G.,Shanxi Research Institute of Applied Chemistry | Hou C.,Shanxi Research Institute of Applied Chemistry | And 4 more authors.
Journal of Applied Polymer Science | Year: 2014

Waterborne polyurethane (WPU) was prepared from toluene diisocyanate, polypropylene glycol, 2,2-bis(hydroxymethyl)propionic acid and a diol containing triethoxysilane group as the chain extender which was synthesized via Michael addition between 3-triethoxysilylpropylamine and 2-hydroxyethylacrylate. Different amounts of nanosilica were incorporated into the WPU to prepare WPU/nanosilica composites. The results showed that the particle size of the emulsions increased and their viscosity decreased first and then increased with increasing the amount of nanosilica. Incorporation of nanosilica into WPU enhanced the water contact angle and thermal stability of the composites films, meanwhile, their tensile strength and hardness increased first and then decreased. However, increasing the amount of nanosilica resulted in reduction in the elongation at break of the films. It suggested that nanosilca was anchored into the side chain of WPU due to the condensation process between the triethoxysilane group in the side chain of WPU molecular and the silanols group on the surface of nanosilica. © 2014 Wiley Periodicals, Inc.


Wu J.,Taiyuan University of Technology | Wu J.,Shanxi Research Institute of Applied Chemistry | Ma G.,Shanxi Research Institute of Applied Chemistry | Li P.,Shanxi Research Institute of Applied Chemistry | And 2 more authors.
Journal of Applied Polymer Science | Year: 2014

The multifunctional thiol- and acrylate-terminated polyurethane (PU) has been successfully prepared for using as the main resin in the UV curable coatings. The structure and molecule weight of prepared PUs were analyzed by fourier transformed infrared spectroscopy (FTIR) and gel permeation chromatography, respectively. The results showed that the different terminal multifunctional groups have been grafted onto the PU and their difference in molecule weight was significant. Used as the main resin in coatings, the curing kinetic and percentage conversion of the different UV curing coatings system were investigated by real-time FTIR method, and the effects of terminal functional groups and photoinitiator on the final conversion percentage and conversion rate were also compared. It is observed that the thiol-terminated PU had higher conversion speed and final conversion percentage due to the remarkable effect of mercapto groups on reducing oxygen inhibition during UV curing process. The shrinkage, viscosity, and adhesion of UV curable coatings with thiol- and acrylate-terminated PUs were also investigated and compared, and the results indicated that the former exhibited lower shrinkage and higher adhesion performances than the latter, along with the lower viscosity. © 2014 Wiley Periodicals, Inc.


Ji X.,Shanxi Research Institute of Applied Chemistry | Zhang X.,Texas Tech University | Zhang X.,Hefei University of Technology
Journal of Nanomaterials | Year: 2015

In recent years, three-dimensional (3D) graphene-based nanomaterials have been demonstrated to be efficient and promising electrocatalysts for oxygen reduction reaction (ORR) in fuel cells application. This review summarizes and categorizes the recent progress on the preparation and performance of these novel materials as ORR catalysts, including heteroatom-doped 3D graphene network, metal-free 3D graphene-based nanocomposites, nonprecious metal-containing 3D graphene-based nanocomposites, and precious metal-containing 3D graphene-based nanocomposites. The challenges and future perspective of this field are also discussed. © 2015 Xuan Ji et al.

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