To effectively improve the performance and expand the applications of polymers, molecular dynamics(MD) simulations with the COMPASS force field have been applied to predict the miscibility, glass transition temperatur...To effectively improve the performance and expand the applications of polymers, molecular dynamics(MD) simulations with the COMPASS force field have been applied to predict the miscibility, glass transition temperature(Tg), and mechanical properties of poly(vinyl chloride)/dioctyl phthalate(PVC/DOP) blends. The solubility parameter values obtained are in good agreement with the reference data and the little difference(|Δδ|< 2.0 MPa0.5) between two components indicates that PVC/DOP is a miscible system. Tg is predicted by the slope of the free volume and density versus temperature simulation data based on density and free volume theory which is agree well with the experimental data. In addition, the analyses of mechanical properties results indicate that the values of Young’s modulus(E), bulk modulus(K), and shear modulus(G) decrease with the addition of DOP, demonstrating that the rigidity of material is weakened and the ductility is improved. The mechanical properties can also be effectively improved by increasing the temperature, which may provide a more flexible mixture, with lower E, K, G but an increased ductility.展开更多
Dioctyl sebacate(DOS)is an organic ester compound,mainly used as a low-temperature plasticizer and synthetic antirust and cold-resistant ester lubricant base oil.This study discusses the use of synthesized molybdenum ...Dioctyl sebacate(DOS)is an organic ester compound,mainly used as a low-temperature plasticizer and synthetic antirust and cold-resistant ester lubricant base oil.This study discusses the use of synthesized molybdenum disulfide/C60(MoS_(2)/C_(60))composite particles as catalysts to synthesize a new type of DOS endowed with high lubricity.This was achieved through a catalytic esterification reaction between sebacic acid and 1-octanol.After the reaction,MoS_(2)/C_(60) was dispersed in situ in this novel DOS to form a suspension(MoS_(2)/C_(60)/DOS).The tribological properties of MoS_(2)/C_(60)/DOS were examined through high-frequency reciprocating friction and wear experiments,and the friction and wear mechanisms were analyzed.The results show that MoS_(2)/C_(60)/DOS can significantly enhance the antiwear and friction reduction performance compared to commercial DOS by 91% and 95%,respectively,achieving an ultra-low friction state with an average friction coefficient of 0.006.A friction film containing elements such as Fe,O,C,Mo,and S forms on the friction surface,significantly improving the lubrication state of the friction interface and achieving low friction.展开更多
The ester base oil of dioctyl adipate (DOA) was oxidized in an oven at 200 degrees C for 30 h, and variations in the physicochemical and tribological properties were studied. To investigate the thermal-oxidation mecha...The ester base oil of dioctyl adipate (DOA) was oxidized in an oven at 200 degrees C for 30 h, and variations in the physicochemical and tribological properties were studied. To investigate the thermal-oxidation mechanism, the thermal-oxidation products were analyzed by gas chromatography-mass spectrometry (GC-MS), and the thermal-oxidation process was simulated using visual reactive force field molecular dynamics (ReaxFF MD). The results indicated that the total acid number (TAN) increased significantly because of the presence of 14% carboxylic acids and low molecular weight monoesters. The tribological properties were improved by the formation of the strongly polar carboxylic acids. Additionally, the increase in kinematic viscosity was limited due to the formation of high molecular weight polymerization products and low molecular weight degradation products. Thermal-oxidative degradation and polymerization mechanisms were proposed by combining ReaxFF MD simulations and GC-MS results.展开更多
As a kind of novel environmental-friendly surfactant,Gemini surfactant has attracted extensive research interests in its effects on gas hydrate formation.We investigated the effects of dioctyl sodium sulfosuccinate(AO...As a kind of novel environmental-friendly surfactant,Gemini surfactant has attracted extensive research interests in its effects on gas hydrate formation.We investigated the effects of dioctyl sodium sulfosuccinate(AOT)on the formation thermodynamics/kinetics of CH_(4)and CO_(2)hydrates.Experimental results indicate that while AOT does not exhibit significant thermodynamic promotion for hydrate formation,it demonstrates favorable kinetic promotion effects.Its promotion effect surpasses that of the traditional kinetic promoter SDS and can enhance the gas storage capacity of hydrates.Utilizing the Chen-Guo hydrate model and adsorption kinetic model,we established a kinetic model for AOT with a predictive deviation of 7.17%and fitted key parameters accordingly.展开更多
The preparation of peroxodisulfated zirconia titania(PSZT) solid super acid has been investigated as function of molar ratio of Ti to Zr, impregnation time, calcination time and temperature in esterification of maleic...The preparation of peroxodisulfated zirconia titania(PSZT) solid super acid has been investigated as function of molar ratio of Ti to Zr, impregnation time, calcination time and temperature in esterification of maleic anhydride with n octanol. The highest yield of dioctyl maleate was 98 2% at the optimum reaction conditions.展开更多
采用UV-Fenton技术光催化氧化高浓度邻苯二甲酸二辛酯(DOP)生产废水,确定最佳操作条件为:初始pH=3.8,H2O2浓度为9.99 g/L,H2O2/Fe2+摩尔比为20∶1,光照反应60 m in。此条件下的废水COD去除率为89.1%,出水COD值在570 mg/L左右。经正交试...采用UV-Fenton技术光催化氧化高浓度邻苯二甲酸二辛酯(DOP)生产废水,确定最佳操作条件为:初始pH=3.8,H2O2浓度为9.99 g/L,H2O2/Fe2+摩尔比为20∶1,光照反应60 m in。此条件下的废水COD去除率为89.1%,出水COD值在570 mg/L左右。经正交试验确定影响处理效果各因素的重要性顺序为:H2O2浓度>H2O2/Fe2+摩尔比>光照反应时间>pH。UV的加入与单独的Fenton体系存在正相关的协同作用。废水降解的表观过程符合一级反应动力学模式。展开更多
基金financially supported by the Fundamental Research Funds for the Central Universities
文摘To effectively improve the performance and expand the applications of polymers, molecular dynamics(MD) simulations with the COMPASS force field have been applied to predict the miscibility, glass transition temperature(Tg), and mechanical properties of poly(vinyl chloride)/dioctyl phthalate(PVC/DOP) blends. The solubility parameter values obtained are in good agreement with the reference data and the little difference(|Δδ|< 2.0 MPa0.5) between two components indicates that PVC/DOP is a miscible system. Tg is predicted by the slope of the free volume and density versus temperature simulation data based on density and free volume theory which is agree well with the experimental data. In addition, the analyses of mechanical properties results indicate that the values of Young’s modulus(E), bulk modulus(K), and shear modulus(G) decrease with the addition of DOP, demonstrating that the rigidity of material is weakened and the ductility is improved. The mechanical properties can also be effectively improved by increasing the temperature, which may provide a more flexible mixture, with lower E, K, G but an increased ductility.
基金The financial support from the National Natural Science Foundation of China(52075141,52075144)is gratefully acknowledged.
文摘Dioctyl sebacate(DOS)is an organic ester compound,mainly used as a low-temperature plasticizer and synthetic antirust and cold-resistant ester lubricant base oil.This study discusses the use of synthesized molybdenum disulfide/C60(MoS_(2)/C_(60))composite particles as catalysts to synthesize a new type of DOS endowed with high lubricity.This was achieved through a catalytic esterification reaction between sebacic acid and 1-octanol.After the reaction,MoS_(2)/C_(60) was dispersed in situ in this novel DOS to form a suspension(MoS_(2)/C_(60)/DOS).The tribological properties of MoS_(2)/C_(60)/DOS were examined through high-frequency reciprocating friction and wear experiments,and the friction and wear mechanisms were analyzed.The results show that MoS_(2)/C_(60)/DOS can significantly enhance the antiwear and friction reduction performance compared to commercial DOS by 91% and 95%,respectively,achieving an ultra-low friction state with an average friction coefficient of 0.006.A friction film containing elements such as Fe,O,C,Mo,and S forms on the friction surface,significantly improving the lubrication state of the friction interface and achieving low friction.
基金The authors are grateful for the financial support from the National Basic Research Program of China，the National Natural Science Foundation of China
文摘The ester base oil of dioctyl adipate (DOA) was oxidized in an oven at 200 degrees C for 30 h, and variations in the physicochemical and tribological properties were studied. To investigate the thermal-oxidation mechanism, the thermal-oxidation products were analyzed by gas chromatography-mass spectrometry (GC-MS), and the thermal-oxidation process was simulated using visual reactive force field molecular dynamics (ReaxFF MD). The results indicated that the total acid number (TAN) increased significantly because of the presence of 14% carboxylic acids and low molecular weight monoesters. The tribological properties were improved by the formation of the strongly polar carboxylic acids. Additionally, the increase in kinematic viscosity was limited due to the formation of high molecular weight polymerization products and low molecular weight degradation products. Thermal-oxidative degradation and polymerization mechanisms were proposed by combining ReaxFF MD simulations and GC-MS results.
基金supported by National Natural Science Foundation of China(22278424,22127812,22008257).
文摘As a kind of novel environmental-friendly surfactant,Gemini surfactant has attracted extensive research interests in its effects on gas hydrate formation.We investigated the effects of dioctyl sodium sulfosuccinate(AOT)on the formation thermodynamics/kinetics of CH_(4)and CO_(2)hydrates.Experimental results indicate that while AOT does not exhibit significant thermodynamic promotion for hydrate formation,it demonstrates favorable kinetic promotion effects.Its promotion effect surpasses that of the traditional kinetic promoter SDS and can enhance the gas storage capacity of hydrates.Utilizing the Chen-Guo hydrate model and adsorption kinetic model,we established a kinetic model for AOT with a predictive deviation of 7.17%and fitted key parameters accordingly.
文摘The preparation of peroxodisulfated zirconia titania(PSZT) solid super acid has been investigated as function of molar ratio of Ti to Zr, impregnation time, calcination time and temperature in esterification of maleic anhydride with n octanol. The highest yield of dioctyl maleate was 98 2% at the optimum reaction conditions.
文摘采用UV-Fenton技术光催化氧化高浓度邻苯二甲酸二辛酯(DOP)生产废水,确定最佳操作条件为:初始pH=3.8,H2O2浓度为9.99 g/L,H2O2/Fe2+摩尔比为20∶1,光照反应60 m in。此条件下的废水COD去除率为89.1%,出水COD值在570 mg/L左右。经正交试验确定影响处理效果各因素的重要性顺序为:H2O2浓度>H2O2/Fe2+摩尔比>光照反应时间>pH。UV的加入与单独的Fenton体系存在正相关的协同作用。废水降解的表观过程符合一级反应动力学模式。
