Yong He

Name: 何勇; He, Yong

Organization: Key Laboratory of Carbon Fiber and Functional Polymers (Beijing University of Chemical Technology) , China

Department: Key Laboratory of Carbon Fiber and Functional Polymers (Beijing University of Chemical Technology)

Title: (PhD)

TOPICS

Material Chemistry

Organic Chemistry

Polymer

Photopolymerization

Chemicals
References

α-hydroxyalkyl ketones derivatives used as photoinitiators for photografting field

Co-reporter:Yuxuan Zhang, Yong He, Xueqin Zhang, Jun Nie

Journal of Photochemistry and Photobiology A: Chemistry 2017 Volume 349(Volume 349) pp:

Publication Date(Web):1 December 2017

DOI:10.1016/j.jphotochem.2017.08.065

•A facile method was used to determine the free radical activity difference between benzoyl radical and hydroxyalkyl radical.•Two fluorinated and silanated α-hydroxyalkyl ketones derivatives were used as photoinitiators and were used to prepare photoinitiatable surface.•The prepared surface could be used in surface modification areas and to prepare coatings with long-termed stability.•During polymerization, the fluorinated free radical would initiate polymerization in the solution while the silanated free radical could only initiate on the substrate surface.Two fluorinated and silanated photoinitiators are synthesized and the photoinitiatable surface is prepared via hydrolysis of silane groups. To investigate the reactivity difference between benzoyl radicals and hydroxyalkyl radicals, Real Time FTIR and XPS are used and the results convince that hydroxyalkyl radicals are more active than benzoyl radicals. And this method may be used in other radical research and find its potential applications in photografting fields.Download high-res image (114KB)Download full-size image

Investigation on the photopolymerization possibility of 1,6-hexanediol diacrylate in crystalline-state

Co-reporter:Miao Yao, Lili Ji, Jun Nie, Yong He

Journal of Photochemistry and Photobiology A: Chemistry 2017 Volume 346(Volume 346) pp:

Publication Date(Web):1 September 2017

DOI:10.1016/j.jphotochem.2017.06.006

•The single crystal of 1,6-Hexanediol Diacrylate (HDDA) was grown and the crystal structure was analyzed.•Two models to study the possibility of polymerization in crystal region were built.•The polymerization possibility of HDDA in crystal region is denied.•The place where the polymerization of HDDA occur is inferred as amorphous region.1,6-hexanediol diacrylate (HDDA) single crystal was grown by slow cooling method. The grown crystal was characterized by single crystal X-ray diffraction, and it showed that HDDA crystallizes in the triclinic system with space group P-1. The cell parameters are a = 6.4885 (9) Å, b = 6.945 (2) Å, c = 7.4890 (12) Å, α = 96.43 (2) °, β = 98.369 (13) °, γ = 109.96 (2) ° and Z = 1. The thermal properties of the HDDA was studied by differential scanning calorimetry (DSC) and showed just one crystalline form existed. A modelization method to judge the possibility of photoinitiating free-radical chain-reaction polymerization in crystal region was established based on the single crystal data, with which the polymerize possibility of HDDA in crystal region was studied.Download high-res image (138KB)Download full-size image

From rosin to high adhesive polyurethane acrylate: Synthesis and properties

Co-reporter:Baihua Liu, Jun Nie, Yong He

International Journal of Adhesion and Adhesives 2016 Volume 66() pp:99-103

Publication Date(Web):April 2016

DOI:10.1016/j.ijadhadh.2016.01.002

A high adhesion polyurethane acrylate (HPUA) was synthesized from isophorone diisocyanate (IPDI), hydroxyethyl acrylate (HEA) and hydrogenated rosin. The chemical structure was characterized by 1H NMR and FTIR; storage modulus and glass transition temperature (Tg) were measured with dynamic mechanical analyzer. Real time infrared spectroscopy (RTIR) was used to investigate the effect of different concentrations of photoinitiator on the double bond conversion of HPUA. Real time volume shrinkage and adhesion on glass, poly(ethylene terephthalate) (PET), polycarbonate (PC) and polyvinyl chloride (PVC) substrates were also measured by laser micrometer and universal testing machine. Results showed that this kind of HPUA has a high photopolymerization rate, low volume shrinkage and high adhesion compared with commercial polyurethane acrylate competitor.

High compatible free radical UV-curable fluorine-containing polyacrylic acrylate prepolymer

Co-reporter:Cui Liu, Jun Nie, Yong He

Journal of Fluorine Chemistry 2015 Volume 173() pp:47-54

Publication Date(Web):May 2015

DOI:10.1016/j.jfluchem.2015.02.012

•A novel kind of fluorine-containing polyacrylic acrylate prepolymer were successfully synthesized.•Very good compatibility with solvents and acrylate monomers was achieved.•Very low surface tension and good photopolymerization kinetic were realized.Fluorine-containing polyacrylic acrylate prepolymers, with different molecular weight and fluorine content, were successfully synthesized by solution radical polymerization of acrylate monomer and following esterification. The compatibility of the prepolymers with solvents and acrylate monomers could be improved markedly with introduction of butyl acrylate as co-monomer and decreasing the polymer molecular weight. It could form homogeneous solution in solvents and monomers and transparent cured film combined with commercial photoinitiator and monomer, evidenced with vision, transmittance, dynamic mechanic and graphic analysis. At the same time, this kind of prepolymers could perform rapid photopolymerization and reach about 95% double bond conversion after 90 s ultraviolet irradiation. It also showed unique surface tension as low as 24.9 dyn/cm and lower glass transition temperature (Tg) with higher fluorine concentration. This kind of novel prepolymer could be widely used in photopolymerization for low surface tension and high optical demands.A novel kind of fluorine-containing polyacrylic acrylate prepolymer were successfully synthesized with very good compatibility, low surface tension and good photopolymerization kinetic.

Synthesis and properties of polyurethane acrylate modified by different contents of stearyl alcohol

Co-reporter:Lili Qin;Jun Nie

Journal of Coatings Technology and Research 2015 Volume 12( Issue 1) pp:197-204

Publication Date(Web):2015 January

DOI:10.1007/s11998-014-9625-4

Polyurethane acrylates (PUAs) modified by different amounts of stearyl alcohol were synthesized from stearyl alcohol (SA), isophorone diisocyanate, 2-hydroxyethyl acrylate, and polycaprolactone triol. The molecular structure was characterized by Fourier transform infrared spectroscopy. Real time infrared spectroscopy was used to investigate the kinetics of photopolymerization of synthesized PUAs. The volume shrinkage was measured by laser displacement sensor. The adhesion on glass, polycarbonate (PC), and polyvinyl chloride (PVC) was tested by the laser micrometer and universal testing machine. The glass transition temperature (Tg) and storage modulus (E′) were measured by dynamic mechanical analyzer (DMA). The pendulum hardness, pencil hardness and flexibility were also measured. The results showed that the greater the amount of SA in synthesized PUAs, the lower the volume shrinkage and the better the adhesion to glass, PC, and PVC substrates.

Thiol–epoxy/thiol–acrylate hybrid materials synthesized by photopolymerization

Co-reporter:Yu Jian, Yong He, Yukun Sun, Haitao Yang, Wantai Yang and Jun Nie

Journal of Materials Chemistry A 2013 vol. 1(Issue 29) pp:4481-4489

Publication Date(Web):17 Jun 2013

DOI:10.1039/C3TC30360H

Thiol–epoxy/thiol–acrylate hybrid networks with systematic variations (100/0, 75/25, 50/50, 25/75, 0/100, w/w) were prepared by free-radical photoinitiator (ITX) and photo-base generator (TBD·HBPh4) induced photopolymerization. The enhanced spectral sensitivity of TBD·HBPh4 at long wavelengths (320–500 nm) with aid of ITX was capable of in situ generation of a strong base (TBD) to achieve the relatively fast and essentially quantitative thiol–epoxy click reaction. The ITX/TBD·HBPh4 photoinitiating system, which generated both the free radicals and the strong base upon UV exposure, could induce thiol–epoxy/thiol–acrylate hybrid polymerizations. The kinetics investigated with real-time IR indicated that the thiol–acrylate reactions were faster and more efficient than the thiol–epoxy reactions (>95% conversion in a matter of seconds and minutes, respectively), and the thiol conversion increased with an increase in the epoxy concentration. The incorporation of the thiol–epoxy reaction offered several advantages: the polymerization shrinkage decreased with the increase in the thiol–epoxy content due to the low shrinkage factor for the thiol–epoxy system (every mole of epoxy group polymerized produces 6.3 mL of shrinkage). The glass transition temperature of the thiol–epoxy/thiol–acrylate hybrid networks progressively increased as a function of the thiol–epoxy content, also resulting in enhanced mechanical and physical properties. This work will be helpful to make optical and electronic devices with low shrinkage and stress, decreased residual monomers, and improved mechanical properties.

Rapid photopolymerization of octadecyl methacrylate in the solid state

Co-reporter:Yu Jian, Yong He, Jie Wang, Bingbing Xu, Wantai Yang and Jun Nie

New Journal of Chemistry 2013 vol. 37(Issue 2) pp:444-450

Publication Date(Web):12 Nov 2012

DOI:10.1039/C2NJ40557A

Mobility restrictions in solid-state photopolymerization give extremely poor polymerization kinetics. However, photopolymerization of octadecyl methacrylate in the solid state exhibits unique polymerization kinetics and molecular weight distributions. The solid state (at low temperature) in comparison with liquid state (at high temperature) gives significantly improved polymerization kinetics and double bond conversion. More notably, the conversion and polymerization rate of crystalline octadecyl methacrylate were higher than that of liquid dimethacrylates (DEGDMA and EGDMA) studied comparatively. XRD, Real-time FTIR and DSC analysis has illustrated that octadecyl methacrylate polymerized in the solid state without destroying the hexagonal packing of crystalline long alkyl chains. It has been concluded that crystallization occurred in such a manner that acrylic double bonds were arranged in a structure that facilitated rapid minimally activated propagation. Molecular weight distributions were significantly decreased by solid-state photopolymerization. The molecular weight distribution of polymer samples synthesized by solid-state polymerization was independent of reaction conditions i.e. photoinitiator concentration, irradiation wavelength and light intensity.

Effect of Monomer Structure on Real-Time UV-Curing Shrinkage Studied by a Laser Scanning Approach

Co-reporter:Yu Jian;Liyan Zhao;Agnieszka Kowalczyk;Wantai Yang;Jun Nie

Advances in Polymer Technology 2013 Volume 32( Issue 1) pp:

Publication Date(Web):

DOI:10.1002/adv.21331

ABSTRACT

The very fast curing rate, low coating thickness (<100 µm), and a wide range of viscosity of ultraviolet (UV) systems hindered the study of UV-curing shrinkage. A recently developed laser scanning method provided a chance to directly measure the real-time (UV-curing shrinkage. The effect of monomer chain lengths (degree of ethoxylation), monomer functionality, and monomer type (acrylate vs. methacrylate) on the shrinkage rates and shrinkage of UV monomers was systematically investigated. The concentration of double bonds and degree of conversion played the dominant role in the photopolymerization shrinkage and shrinkage rate. The main reason for the low shrinkage of methacrylate was that the low reactivity of methacrylate decreased the degree of conversion. The ethoxylation was an attractive way to lower the shrinkage and decrease the shrinkage rate due to significant reduction of the concentration of double bonds. The reduction of functionality was not obvious in decreasing the shrinkage or maximum shrinkage rate due to the combination effect of the concentration of double bonds and the degree of conversion. Besides, heat expansion attributed to polymerization could bring forward the maximum shrinkage rate from the shrinkage stage to the expansion stage. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 2013, 32, 21331; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21331

Volume shrinkage of UV-curable coating formulation investigated by real-time laser reflection method

Co-reporter:Yu Jian;Tongzhou Jiang

Journal of Coatings Technology and Research 2013 Volume 10( Issue 2) pp:231-237

Publication Date(Web):2013/03/01

DOI:10.1007/s11998-012-9446-2

Volume shrinkage is one of the main drawbacks of UV-cured coatings and can lead to premature coating failures. Due to the rapid polymerization during UV-curing, real-time volume shrinkage has been challenging to measure accurately. In this article, the shrinkage process of UV-curable formulations was systematically investigated by a recently developed laser reflection method. The influence of oligomers, monomers, and photoinitiators on shrinkage process has been evaluated. Compared with the oligomers, the monomer was the main contributor to shrinkage due to the high concentration of double bonds. Polymerization shrinkage could be reduced by increasing the oligomer/monomer ratio. Because monomers were the main contributors of shrinkage, the chemical structure of monomers was important for decreasing shrinkage. Methacrylate monomers decreased the final shrinkage but unfortunately reduced the conversion. Monomers with a high degree of ethoxylation lowered the shrinkage and simultaneously increased the conversion. The concentration of photoinitiators had no obvious effect on the normalized shrinkage. Thus, the low shrinkage caused by the low concentration of photoinitiators was only attributed to the significant drop of the conversion.

Solid photopolymerization and polymer properties of octadecyl vinyl ether

Co-reporter:Jie Wang, Yu Jian, Jun Nie, Yong He

Journal of Photochemistry and Photobiology A: Chemistry 2013 Volume 271() pp:105-110

Publication Date(Web):1 November 2013

DOI:10.1016/j.jphotochem.2013.08.011

•We have demonstrated that the fast photopolymerization of octadecyl vinyl ether can be performed in the solid-state.•Compared with the liquid photopolymerization, the solid photopolymerization of octadecyl vinyl ether has advantages in reducing shrinkage.•Compared with the liquid photopolymerization, the solid photopolymerization of octadecyl vinyl ether is less sensitivity to hydroxyl compound.The UV initiated solid-state polymerization of octadecyl vinyl ether (ODVE) was explored in this article. The crystallization process and crystal structure were investigated by XRD, DSC and FTIR. The kinetic results obtained from real time FTIR showed that ODVE performed quick cationic photopolymerization in crystalline form at about 25 °C and the conversion of double bond reached about 70% in 10 min. This advantage is attributed to the local amorphous phase of double bond and same crystalline configuration of monomer with polymer. This kind of solid-state photopolymerization could lead to polymer which will show more ordered and lower molecular weight. At the same time, it resulted in less volume shrinkage and less sensitivity to hydroxyl compound.

Exploration for decreasing the volume shrinkage for photopolymerization

Co-reporter:Tongzhou Jiang, Yong He, Yu Jian, Jun Nie

Progress in Organic Coatings 2012 Volume 75(Issue 4) pp:398-403

Publication Date(Web):December 2012

DOI:10.1016/j.porgcoat.2012.07.007

This article explored one method to decrease the volume shrinkage for photopolymerization including synthesis of a series of methacrylate–vinyl ether hybrid monomer, combination initiator system and introduction of chain transfer agent. Its photopolymerization kinetics was monitored by Fourier transform real-time infrared spectroscopy (FTIR) and the volume shrinkage is measured by using laser displacement sensor (LDS), the adhesion strength is also evaluated. The results indicated that the volume shrinkage could be adjusted in some degree on demand which is good for adhesion strength.Highlights► A series of methacrylate–vinyl ether hybrid monomer was synthesized successfully. ► The volume shrinkage is real time measured by laser displacement sensor (LDS). ► Combination of initiator and chain transfer agent could adjust volume shrinkage. ► Adhesion strength of new developed formula to PVC is improved obviously.

Synthesis and properties of novel polyurethane acrylate containing 3-(2-hydroxyethyl) isocyanurate segment

Co-reporter:Yong He, Mengbo Zhou, Bo Wu, Zhanglin Jiang, Jun Nie

Progress in Organic Coatings 2010 Volume 67(Issue 3) pp:264-268

Publication Date(Web):March 2010

DOI:10.1016/j.porgcoat.2009.11.005

Novel UV curable multi-functional polyurethane acrylate (PUA) containing 3-(2-hydroxyethyl) isocyanurate (THEIC) segment was synthesized through three step reactions, the ring-opened reaction of ɛ-caprolactone with THEIC under the catalysis of tetrabutyl titanate (TBT), the polyaddition reaction between formed hydroxyl compounds and isophorone diisocyanate (IPDI) and condensation reaction between the product of the second step and pentaerythritol triacrylate (PETA). The chemical structure of PUA oligomer and some influence factors in synthesis process were characterized with GPC, 1H NMR and FTIR. And its photopolymerization process and properties of cured films were also investigated.

Preparation and properties of different photoresponsive hydrogels modulated with UV and visible light irradiation

Co-reporter:Jianwei Liu, Jun Nie, Yufei Zhao, Yong He

Journal of Photochemistry and Photobiology A: Chemistry 2010 Volume 211(Issue 1) pp:20-25

Publication Date(Web):5 March 2010

DOI:10.1016/j.jphotochem.2010.01.016

Two different types of hydrogel containing azo group were designed and prepared via UV and visible light initiating photopolymerization technology respectively. The obtained two hydrogel showed different swelling properties and control release behaviors with Ribavirin as model drugs. Upon additional irradiation, they exhibited different photo response characters, which may be due to the different isomer states of azo group under different light irradiations and the interior morphology of hydrogel investigated by scanning electron microscopy (SEM).

Investigation of stabilizer-free dispersion polymerization process of styrene and maleic anhydride copolymer microspheres

Co-reporter:Pengzong Liang;Zhun Meng;Zhanglin Jiang;Jun Nie

Journal of Polymer Science Part A: Polymer Chemistry 2010 Volume 48( Issue 24) pp:5652-5658

Publication Date(Web):

DOI:10.1002/pola.24321

Abstract

The copolymer microspheres of styrene (St) and maleic anhydride (MA) were synthesized by stabilizer-free dispersion polymerization, and the polymerization process was explored in detail. The results showed that the homopolymerization of St formed in initial polymerization period served as stabilizer, and reaction solvent of closer solubility parameter would benefit the stabilizer-free dispersion polymerization. In addition, some principal factors affecting the microspheres size, such as reaction time, reaction temperature, monomer concentration, molar feed ratio, reaction media, and cosolvent, were investigated as well. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Synthesis and photopolymerization of 4-(1-propenyl)oxybutyl acrylate

Co-reporter:S. J. Li;Y. He;J. Nie

Journal of Applied Polymer Science 2008 Volume 110( Issue 6) pp:3388-3394

Publication Date(Web):

DOI:10.1002/app.28924

Abstract

Hybrid monomer, 4-(1-propenyl)oxybutyl acrylate, with cationic and free radical polymerizable group was synthesized. Real-time Fourier transform infrared spectroscopy (FTIR) was used to monitor the photopolymerization kinetics of the monomer. Photopolymerization processing conditions, such as light intensity, photoinitiator concentrations have been evaluated. It was found that hybrid monomer showed higher efficiency of photopolymerization in comparison with the blend system. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Thiol–epoxy/thiol–acrylate hybrid materials synthesized by photopolymerization

Co-reporter:Yu Jian, Yong He, Yukun Sun, Haitao Yang, Wantai Yang and Jun Nie

Journal of Materials Chemistry A 2013 - vol. 1(Issue 29) pp:NaN4489-4489

Publication Date(Web):2013/06/17

DOI:10.1039/C3TC30360H