Density,viscosity and ultrasonic v elocity of solutions of four Schiff bases in 1,4-dioxane and dimethylfor -mamide(DMF )were measured at 308.15K.Various acoustical properties such as specific impedance(Z),adiabatic c...Density,viscosity and ultrasonic v elocity of solutions of four Schiff bases in 1,4-dioxane and dimethylfor -mamide(DMF )were measured at 308.15K.Various acoustical properties such as specific impedance(Z),adiabatic compressibility(κ s ),Rao’s molar sound function(R m ),the van der Waals constant (b),molar compressibility(W),intermolecular free length(L f ),relaxation strength(r),solvation number(S n ),were calculated.The results are in terpret-ed in terms of molecular interactions occurring in the solutions.展开更多
A method for the determination of 1,4-dioxane in washing food has been developed by using solid-phase microextraction technology coupled with gas chromatography-mass(SPME/GC-MS).The different SPME fibers were studied,...A method for the determination of 1,4-dioxane in washing food has been developed by using solid-phase microextraction technology coupled with gas chromatography-mass(SPME/GC-MS).The different SPME fibers were studied,in which the SPME of DVB/CAR/PDMS(50/30 μm) showed high sensitivity and selectivity for the determination of 1,4-dioxane.The calibration curve was y=3.53×105x+397 with the correlation coefficient of 0.998 8.The linear range was range of 0.05-50 mg/kg and the detection limit of 1,4-dioxane was 0.05 mg/kg with RSD of 1.01%(n=6).展开更多
In this paper,high cis-1,4 content hydroxyl-terminated polybutadiene(cis-HTPB)with different molecular weights was prepared through the oxidative cracking process using cis-butadiene rubber as raw material.Firstly,thi...In this paper,high cis-1,4 content hydroxyl-terminated polybutadiene(cis-HTPB)with different molecular weights was prepared through the oxidative cracking process using cis-butadiene rubber as raw material.Firstly,this article comprehensively compared the differences between cis-HTPB and conventional I-HTPB in terms of molecular weight distribution,functionality,viscosity,molecular polarity,and other physicochemical properties,which provided effective data support for its subsequent application.In addition,the reaction kinetics study showed that cis-HTPB with isocyanate curing agent has high reactivity,allowing it to be rapidly cured at low temperatures,and the cured elastomers had excellent mechanical properties,with tensile strength and elongation up to 1.89 MPa and 1100%,respectively.It was also found that cis-HTPB has extremely excellent low-temperature resistance,and the glass transition temperature(T_(g))of its cured elastomer is as low as-101℃.Based on the above studies,cis-HTPB is applied as a binder in composite solid propellants for the first time to investigate its practical performance,and the results indicated that cis-HTPB-based propellants have excellent process and mechanical properties.展开更多
A series of ferrocenyl 1,4 dihydropyridines were synthesized with high yields by a one pot cyclocondensation of formylferrocene,β ketoester and urea(or methyl 3 aminocrotonate) on the surface of SiO 2 under microwave...A series of ferrocenyl 1,4 dihydropyridines were synthesized with high yields by a one pot cyclocondensation of formylferrocene,β ketoester and urea(or methyl 3 aminocrotonate) on the surface of SiO 2 under microwave irradiation without solvent.All products were characterized by EA,IR, and 1 HNMR.展开更多
文摘Density,viscosity and ultrasonic v elocity of solutions of four Schiff bases in 1,4-dioxane and dimethylfor -mamide(DMF )were measured at 308.15K.Various acoustical properties such as specific impedance(Z),adiabatic compressibility(κ s ),Rao’s molar sound function(R m ),the van der Waals constant (b),molar compressibility(W),intermolecular free length(L f ),relaxation strength(r),solvation number(S n ),were calculated.The results are in terpret-ed in terms of molecular interactions occurring in the solutions.
文摘A method for the determination of 1,4-dioxane in washing food has been developed by using solid-phase microextraction technology coupled with gas chromatography-mass(SPME/GC-MS).The different SPME fibers were studied,in which the SPME of DVB/CAR/PDMS(50/30 μm) showed high sensitivity and selectivity for the determination of 1,4-dioxane.The calibration curve was y=3.53×105x+397 with the correlation coefficient of 0.998 8.The linear range was range of 0.05-50 mg/kg and the detection limit of 1,4-dioxane was 0.05 mg/kg with RSD of 1.01%(n=6).
基金the support from the Open Research Fund Program of Science and Technology on Aerospace Chemical Power Laboratory(Grant No.STACPL120221B03)the National Natural Science Foundation of China(Grant No.22175059).
文摘In this paper,high cis-1,4 content hydroxyl-terminated polybutadiene(cis-HTPB)with different molecular weights was prepared through the oxidative cracking process using cis-butadiene rubber as raw material.Firstly,this article comprehensively compared the differences between cis-HTPB and conventional I-HTPB in terms of molecular weight distribution,functionality,viscosity,molecular polarity,and other physicochemical properties,which provided effective data support for its subsequent application.In addition,the reaction kinetics study showed that cis-HTPB with isocyanate curing agent has high reactivity,allowing it to be rapidly cured at low temperatures,and the cured elastomers had excellent mechanical properties,with tensile strength and elongation up to 1.89 MPa and 1100%,respectively.It was also found that cis-HTPB has extremely excellent low-temperature resistance,and the glass transition temperature(T_(g))of its cured elastomer is as low as-101℃.Based on the above studies,cis-HTPB is applied as a binder in composite solid propellants for the first time to investigate its practical performance,and the results indicated that cis-HTPB-based propellants have excellent process and mechanical properties.
文摘A series of ferrocenyl 1,4 dihydropyridines were synthesized with high yields by a one pot cyclocondensation of formylferrocene,β ketoester and urea(or methyl 3 aminocrotonate) on the surface of SiO 2 under microwave irradiation without solvent.All products were characterized by EA,IR, and 1 HNMR.
