Zhen Ge

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Organization: Beijing Institute of Technology

Department: School of Materials Science and Engineering

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Chemicals
References

Properties and application of a novel type of glycidyl azide polymer modified double-base spherical powders

Co-reporter:Yanguang Wu;Yunjun Luo

Journal of Thermal Analysis and Calorimetry 2016 Volume 124( Issue 1) pp:107-115

Publication Date(Web):2016 April

DOI:10.1007/s10973-015-5122-y

GAP modified double-base powder was prepared by an internal solution method and applied in cross-linked modified double-base propellants. It was found that if GAP content was not more than 30 %, the modified double-base powders had high roundness rate, no bonding between the particles and excellent fluidity. The median diameter (d50) of powders was decreased from 90.24 to 72.41 μm when the amount of GAP increased from 0.0 to 30.0 %. The thermal decomposition peak temperatures of –N3 and GAP’s main chain were found to be lower for the 10.0, 20.0 and 30.0 % GAP modified powders than the corresponding peak temperatures for pure GAP. The drop mass impact sensitivity of the modified powders is reduced as the mass ratio of GAP increases. It was experimentally shown that GAP modified double-base powders can improve the mechanical characteristics of the propellant with a maximum tensile strength (σm) between 0.45 MPa < σm < 1.18 MPa and an elongation at maximum tensile strength (εm) between 29.80 % < εm < 52.60 % at temperatures of −40, +20 and +50 °C.

Fabrication and thermal decomposition of glycidyl azide polymer modified nitrocellulose double base propellants

Co-reporter:Benbo Zhao;Tianfu Zhang;Yunjun Luo

Science China Chemistry 2016 Volume 59( Issue 4) pp:472-477

Publication Date(Web):2016 April

DOI:10.1007/s11426-015-5538-z

Glycidyl azide polymer (GAP) with the advantages of non-volatility and excellent thermal stability is a candidate as a replacement for nitroglycerine (NG) in a double base propellant. The GAP-NC double base propellants were formulated with GAP and nitrocellulose (NC) fibers. Tensile test and SEM characterization indicated that GAP-NC propellants had a homogeneous structure. Thermogravimetric analysis of GAP-NC propellants revealed that the onset decomposition temperature reached a high level ranging from 192.9 to 194.6 °C, which indicated that the substitution of NG with GAP contributed to the safe storage and process operations for double base propellant. The result analysis of decomposition products of GAP-NC propellants showed that the main gas decomposition products of the propellants were NO, NO2, CO, CO2, NH3, CH4, HCN, N2, CH2O and C2H4O. The thermal decomposition process of the specimens was proposed.

Synthesis and characterization of novel energetic thermoplastic elastomers based on glycidyl azide polymer (GAP) with bonding functions

Co-reporter:Zaijuan Zhang;Gang Wang;Zhen Wang;Yilu Zhang;Yunjun Luo

Polymer Bulletin 2015 Volume 72( Issue 8) pp:1835-1847

Publication Date(Web):2015 August

DOI:10.1007/s00289-015-1375-7

The energetic thermoplastic elastomers (ETPE) of glycidyl azide polymer with bonding functions were synthesized by using mixture of chain extenders including 1,4-butanediol and N-(2-cyanoethyl) diethanolamine. From FTIR results, the ability of ETPEs to form hydrogen bond weakened with the percentage of N-(2-cyanoethyl) diethanolamine increasing, which further lead to the decrease of maximum stress of ETPEs and increase of elongation at break. On the other hand, the interfacial interactions between solid ingredients and ETPEs were enhanced owing to the more –CN content. With the percentage of N-(2-cyanoethyl) diethanolamine increasing, two factors affect the adhesion between binder and fillers at the same time. The RDX/ETPE propellants were synthesized and the mechanical properties of them showed that the ETPE-50 with bonding functions can effectively prevent the dewetting, and then improve the mechanical properties of propellants. That is, when the percentage of N-(2-cyanoethyl) diethanolamine was 50 %, the synthesized ETPEs had not only binding function but also bonding interaction.

Synthesis and characterization of siloxane-modified two-component waterborne polyurethane

Co-reporter:Zhen Ge, Yunjun Luo

Progress in Organic Coatings 2013 Volume 76(Issue 11) pp:1522-1526

Publication Date(Web):November 2013

DOI:10.1016/j.porgcoat.2013.06.007

•The prepared siloxane-modified 2K WPUs are promising antifouling coatings.•Thermal stability of 2K WPUs was improved by introducing siloxane segment.•The siloxane-modified 2K WPUs with higher DHPDMS content have shorter dry time.•The gloss of siloxane-modified 2K WPU coatings decreased with the increment of DHPDMS.A series of siloxane-modified two-component waterborne polyurethane (2K WPU) was synthesized by the reaction between siloxane-modified hydroxyl-functional polyurethane aqueous dispersion and the hydrophilic-modified polyisocyanate. The siloxane-modified 2K WPUs were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and surface contact angle measurement. The effect of DHPDMS content on the application properties (water and chemical resistance, flexibility, impact resistance, dry time, gloss, hardness and adhesion) of siloxane-modified 2K WPU coatings was also investigated. The results showed that the siloxane-modified 2K WPUs had better thermal stability owing to the forming of SiOSi crosslinking network and good surface properties due to the enrichment of siloxane chains on the surface of films compared with conventional 2K WPU. The application properties of the siloxane-modified 2K WPUs are satisfactory for their use in coatings.

Synthesis, characterization and properties of a novel fluorinated polyurethane

Co-reporter:Zhen Ge, Xingyuan Zhang, Jiabing Dai, Weihu Li, Yunjun Luo

European Polymer Journal 2009 Volume 45(Issue 2) pp:530-536

Publication Date(Web):February 2009

DOI:10.1016/j.eurpolymj.2008.11.008

A novel fluorinated polyurethane (FPU) was prepared by fluorinated polyether glycol (PTMG-g-HFP) as a soft segment, 1,6-hexamethylene diisocyanate (HDI) or toluene diisocyanate (TDI) as a hard segment and 1,4-butanodiol (BDO) as a chain extender. Fourier transform infrared spectroscopy (FTIR), 1H NMR, 13C NMR and gel permeation chromatography (GPC) were used to characterize the structure of the fluorinated polyurethane. The thermal stabilities of the fluorinated polyurethane and the corresponding hydrogenated polyurethane were studied by thermogravimetric analysis (TGA). X-ray photoelectron spectroscopy (XPS) analysis at two different sampling depths for the fluorinated polyurethane was used to investigate the surface compositions of FPU. And the mechanical properties of the fluorinated polyurethane and the corresponding hydrogenated polyurethane were also measured. Chemical resistance of polyurethane films was estimated through spot tests with different solvents. The results showed that FPU had high thermal stability, strain-hardening property and good chemical resistance. The XPS measurements showed the fluorine enrichment on the surface of FPU.

Synthesis, characterization, and properties of amphiphilic block copolymer of acrylamide-styrene by self-emulsifying microemulsion method

Co-reporter:Zhen Ge;Yunjun Luo

Journal of Applied Polymer Science 2009 Volume 114( Issue 3) pp:1457-1463

Publication Date(Web):

DOI:10.1002/app.30577

Abstract

The copolymerization system of acrylamide (AM) and styrene (St) was acquired by using amphiphilic block copolymer PAM-b-PSt with lower molecular weight as polymeric surfactant, and then the microemulsion phase diagram was drawn. The appropriate copolymerization systems were chosen in the phase diagram, and higher molecular weight amphiphilic block copolymers PAM-b-PSt were prepared by self-emulsifying microemulsion method. The chemical composition and structure of the products were analyzed by FTIR, ¹H-NMR, ¹³C-NMR, GPC, and UV; the block structure of products was characterized by DSC, and the hydrophobic association property of the products was studied by the fluorescence probe and rotating viscosity measurement. The results showed that O/W microemulsion was also acquired by using the polymeric surfactant; 3 g polymeric surfactant was only used to disperse 0.25 g St into aqueous solution, which showed higher emulsifying efficiency. At the same time, the use of self-emulsifying microemulsion copolymerizing system can avoid back treatment of small molecular surfactant and the purified block polymer was prepared in one step; the prepared copolymers have good hydrophobic association properties and their aqueous solution showed evident viscosity increment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Synthesis and characterization of fluorinated polyurethane with fluorine-containing pendent groups

Co-reporter:Zhen Ge, Xing Yuan Zhang, Jia Bing Dai, Wei Hu Li, Yun Jun Luo

Chinese Chemical Letters 2008 Volume 19(Issue 11) pp:1293-1296

Publication Date(Web):November 2008

DOI:10.1016/j.cclet.2008.07.014

A novel fluorinated polyurethane (FPU) with fluorine-containing pendent groups was prepared by using fluorinated polyether glycol (PTMG-g-HFP) as a soft segment, 1,6-hexamethylene diisocyanate (HDI) or toluene diisocyanate (TDI) as a hard segment and 1,4-butanodiol (BDO) as a chain extender. FTIR, 1H NMR, 13C NMR and GPC were used to characterize the structure of the fluorinated polyurethane. Thermal stabilities of the fluorinated polyurethane and the corresponding hydrogenated polyurethane were studied by TGA. XPS analysis at two different sampling depths for the fluorinated polyurethane was used to investigate the surface compositions of FPU. The results showed the fluorine enrichment on the surface of FPU.