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6 results on '"Rao Yiwen"'

1. Study on the preparation of glycerylphosphorylcholine by transesterification under supported sodium methoxide

Author

Rao Yiwen, Zhou Lele, Fan Zejing, Li Hongya, Yan Biao, and Zhang Xiaoli

Subjects
supported catalyst, sodium methoxide, glycerylphosphorylcholine, kinetics, Chemistry, QD1-999
Abstract

Glycerylphosphorylcholine (GPC) was prepared by transesterification using supported sodium methoxide as catalyst and natural lecithin as raw material. Sodium methoxide has been proved to be an effective catalyst for the preparation of GPC, which is easy to recover and reuse. After six repeated uses, its stability is satisfactory. The effects of agitation speed, catalyst dosage, and reaction temperature on the reaction were investigated, respectively, and the optimum conditions for preparing GPC catalyzed by supported sodium methoxide were found: the concentration of phosphorylcholine was 0.1 mol·L−1, the stirring speed was 600 rpm, the amount of catalyst was 7.5 g·L−1, the reaction temperature was 45°C, and the reaction time was 4 h; then, the conversion rate of phosphatidylcholine could reach 99%. At the same time, the reaction kinetic model was established based on the mechanism of the transesterification, and the experimental data were compared with the calculated values; it was found that the experimental data fitted the model well. Finally, the reaction activation energy obtained by the Arrhenius equation is 41.6 kJ·mol−1, which indicates that the supported sodium methoxide has good catalytic performance in this reaction system.

Published
2023
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4. Application of 3D printing technology in bone tissue engineering

Author

Qinghua Wei, Cai Xianxuan, Zhang Kun, Yanen Wang, Ji Kang, Jiang Anguo, and Rao Yiwen

Subjects
Materials science, business.industry, Materials Science (miscellaneous), Biomedical Engineering, 3D printing, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Industrial and Manufacturing Engineering, Bone tissue engineering, 0104 chemical sciences, 0210 nano-technology, business, Biotechnology, Biomedical engineering
Published
2018
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5. Evaluating the Effects of Nanosilica on Mechanical and Tribological Properties of Polyvinyl Alcohol/Polyacrylamide Polymer Composites for Artificial Cartilage from an Atomic Level

Author

Zhang Kun, Rao Yiwen, Xiongbiao Chen, Tingli Lu, Qinghua Wei, Yanen Wang, and Jiang Anguo

Subjects
Materials science, Polymers and Plastics, Abrasion (mechanical), polymer composites, Composite number, Polyacrylamide, 02 engineering and technology, mechanical properties, 010402 general chemistry, 01 natural sciences, Polyvinyl alcohol, Article, lcsh:QD241-441, Shear modulus, chemistry.chemical_compound, lcsh:Organic chemistry, Nano-silica, reinforce mechanism, Composite material, chemistry.chemical_classification, Bulk modulus, tribological properties, General Chemistry, Polymer, 021001 nanoscience & nanotechnology, molecular dynamics, 0104 chemical sciences, chemistry, Particle, 0210 nano-technology
Abstract

Due to the superior performances of nanosilica particles, this research has been designed to study their effects on the mechanical and trigological properties of a PVA/PAM polymer composite by a molecular dynamics simulation method. To realize the research objectives mentioned above, the molecular models of amorphous cells and sandwiched friction models for pure polyvinyl alcohol (PVA)/polyacrylamide (PAM) (component weight ratio is 1:1) and PVA/PAM/nanosilica (component weight ratio is 5.75:5.75:1) polymer composites were constructed and simulated, respectively. The simulation results of the mechanical properties show increases about 31.6% in the bulk modulus, 53.1% in the shear modulus, and 50.1% in the Young&rsquo, s modulus by incorporating a nanosilica particle into a pure PVA/PAM polymer composite. Meanwhile, the changes in Cauchy pressure, B/G ratio, and Poisson&rsquo, s ratio values indicate that incorporating a nanosilica particle into pure PVA/PAM weakened the ductility of the composite. Incorporating a nanosilica particle into a pure PVA/PAM composite also showed a decrease about 28.2% in the abrasion rates and relative concentration distributions of polymer molecules in the final friction models. Additionally, the binding energy and the pair correlation functions between a nanosilica particle and the polymer chains in a cubic cell demonstrate that incorporating nanosilica into PVA/PAM polymer composites improves the internal binding strength between different components through the forming hydrogen bonds. As a result, the mechanical and tribological properties of PVA/PAM polymer composites can be enhanced by incorporating nanosilica particles.

Published
2018

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